1,403 results
Search Results
2. Dual-signal readout paper-based wearable biosensor with a 3D origami structure for multiplexed analyte detection in sweat
- Author
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Cheng, Yuemeng, Feng, Shaoqing, Ning, Qihong, Li, Tangan, Xu, Hao, Sun, Qingwen, Cui, Daxiang, and Wang, Kan
- Published
- 2023
- Full Text
- View/download PDF
3. Dual-signal readout paper-based wearable biosensor with a 3D origami structure for multiplexed analyte detection in sweat
- Author
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Yuemeng Cheng, Shaoqing Feng, Qihong Ning, Tangan Li, Hao Xu, Qingwen Sun, Daxiang Cui, and Kan Wang
- Subjects
Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Abstract In this research, we design and implement a small, convenient, and noninvasive paper-based microfluidic sweat sensor that can simultaneously detect multiple key biomarkers in human sweat. The origami structure of the chip includes colorimetric and electrochemical sensing regions. Different colorimetric sensing regions are modified with specific chromogenic reagents to selectively identify glucose, lactate, uric acid, and magnesium ions in sweat, as well as the pH value. The regions of electrochemical sensing detect cortisol in sweat by molecular imprinting. The entire chip is composed of hydrophilically and hydrophobically treated filter paper, and 3D microfluidic channels are constructed by using folding paper. The thread-based channels formed after the hydrophilic and hydrophobic modifications are used to control the rate of sweat flow, which in turn can be used to control the sequence of reactions in the differently developing colored regions to ensure that signals of the best color can be captured simultaneously by the colorimetric sensing regions. Finally, the results of on-body experiments verify the reliability of the proposed sweat sensor and its potential for the noninvasive identification of a variety of sweat biomarkers.
- Published
- 2023
- Full Text
- View/download PDF
4. A novel polymer-based nitrocellulose platform for implementing a multiplexed microfluidic paper-based enzyme-linked immunosorbent assay
- Author
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Lin, Dong, Li, Bowei, Fu, Longwen, Qi, Ji, Xia, Chunlei, Zhang, Yi, Chen, Jiadong, Choo, Jaebum, and Chen, Lingxin
- Published
- 2022
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- View/download PDF
5. Low-temperature processing of screen-printed piezoelectric KNbO3 with integration onto biodegradable paper substrates
- Author
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Morgan M. Monroe, L. Guillermo Villanueva, and Danick Briand
- Subjects
Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Abstract The development of fully solution-processed, biodegradable piezoelectrics is a critical step in the development of green electronics towards the worldwide reduction of harmful electronic waste. However, recent printing processes for piezoelectrics are hindered by the high sintering temperatures required for conventional perovskite fabrication techniques. Thus, a process was developed to manufacture lead-free printed piezoelectric devices at low temperatures to enable integration with eco-friendly substrates and electrodes. A printable ink was developed for screen printing potassium niobate (KNbO3) piezoelectric layers in microns of thickness at a maximum processing temperature of 120 °C with high reproducibility. Characteristic parallel plate capacitor and cantilever devices were designed and manufactured to assess the quality of this ink and evaluate its physical, dielectric, and piezoelectric characteristics; including a comparison of behaviour between conventional silicon and biodegradable paper substrates. The printed layers were 10.7–11.2 μm thick, with acceptable surface roughness values in the range of 0.4–1.1 μm. The relative permittivity of the piezoelectric layer was 29.3. The poling parameters were optimised for the piezoelectric response, with an average longitudinal piezoelectric coefficient for samples printed on paper substrates measured as d 33, eff, paper = 13.57 ± 2.84 pC/N; the largest measured value was 18.37 pC/N on paper substrates. This approach to printable biodegradable piezoelectrics opens the way forward for fully solution-processed green piezoelectric devices.
- Published
- 2023
- Full Text
- View/download PDF
6. A novel polymer-based nitrocellulose platform for implementing a multiplexed microfluidic paper-based enzyme-linked immunosorbent assay
- Author
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Dong Lin, Bowei Li, Longwen Fu, Ji Qi, Chunlei Xia, Yi Zhang, Jiadong Chen, Jaebum Choo, and Lingxin Chen
- Subjects
Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Abstract Nitrocellulose (NC) membranes, as porous paper-like substrates with high protein-binding capabilities, are very popular in the field of point-of-care immunoassays. However, generating robust hydrophobic structures in NC membranes to fabricate microfluidic paper-based analytical devices (μPADs) remains a great challenge. At present, the main method relies on an expensive wax printer. In addition, NC membranes very easy to adhere during the printing process due to electrostatic adsorption. Herein, we developed a facile, fast and low-cost strategy to fabricate μPADs in NC membranes by screen-printing polyurethane acrylate (PUA) as a barrier material for defining flow channels and reaction zones. Moreover, hydrophobic barriers based on UV-curable PUA can resist various surfactant solutions and organic solvents that are generally used in immunoassays and biochemical reactions. To validate the feasibility of this PUA-based NC membrane for immunoassays in point-of-care testing (POCT), we further designed and assembled a rotational paper-based analytical device for implementing a multiplexed enzyme-linked immunosorbent assay (ELISA) in a simple manner. Using the proposed device under the optimal conditions, alpha fetoprotein (AFP) and carcinoembryonic antigen (CEA) could be identified, with limits of detection of 136 pg/mL and 174 pg/mL, respectively, which are below the threshold values of these two cancer biomarkers for clinical diagnosis. We believe that this reliable device provides a promising platform for the diagnosis of disease based on ELISA or other related bioassays in limited settings or remote regions.
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- 2022
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7. Detection and extraction of heavy metal ions using paper-based analytical devices fabricated via atom stamp printing
- Author
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Guan, Yanfang and Sun, Baichuan
- Published
- 2020
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8. A reusable PMMA/paper hybrid plug-and-play microfluidic device for an ultrasensitive immunoassay with a wide dynamic range
- Author
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Sanjay, Sharma T., Li, Meihan, Zhou, Wan, Li, Xiaochun, and Li, XiuJun
- Published
- 2020
- Full Text
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9. Graphene oxide nanosheets coupled with paper microfluidics for enhanced on-site airborne trace metal detection
- Author
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Sun, Hao, Jia, Yuan, Dong, Hui, and Fan, Longxiang
- Published
- 2019
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10. Smart-phone, paper-based fluorescent sensor for ultra-low inorganic phosphate detection in environmental samples
- Author
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Sarwar, Mehenur, Leichner, Jared, Naja, Ghinwa M., and Li, Chen-Zhong
- Published
- 2019
- Full Text
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11. A paper-based microfluidic platform with shape-memory-polymer-actuated fluid valves for automated multi-step immunoassays
- Author
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Fu, Hao, Song, Pengfei, Wu, Qiyang, Zhao, Chen, Pan, Peng, Li, Xiao, Li-Jessen, Nicole Y. K., and Liu, Xinyu
- Published
- 2019
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12. Low sample volume origami-paper-based graphene-modified aptasensors for label-free electrochemical detection of cancer biomarker-EGFR
- Author
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Wang, Yang, Sun, Shuai, Luo, Jinping, Xiong, Ying, Ming, Tao, Liu, Juntao, Ma, Yuanyuan, Yan, Shi, Yang, Yue, Yang, Zhugen, Reboud, Julien, Yin, Huabing, Cooper, Jonathan M., and Cai, Xinxia
- Published
- 2020
- Full Text
- View/download PDF
13. A paper-based microfluidic platform with shape-memory-polymer-actuated fluid valves for automated multi-step immunoassays
- Author
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Chen Zhao, Pengfei Song, Hao Fu, Qiyang Wu, Xiao Li, Peng Pan, Xinyu Liu, and Nicole Y K Li-Jessen
- Subjects
Materials Science (miscellaneous) ,Microfluidics ,02 engineering and technology ,01 natural sciences ,lcsh:Technology ,Article ,Industrial and Manufacturing Engineering ,Engineering ,Fluidics ,Electrical and Electronic Engineering ,Smart fluid ,Heating element ,business.industry ,lcsh:T ,010401 analytical chemistry ,Paper based ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Chip ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Chemistry ,Flow control (fluid) ,Shape-memory polymer ,lcsh:TA1-2040 ,0210 nano-technology ,business ,lcsh:Engineering (General). Civil engineering (General) ,Computer hardware - Abstract
Smart fluid manipulation with automatically controlled paper valves will enable automated and multi-step immunoassays on paper-based microfluidic devices. In this work, we present an integrated paper-based microfluidic platform with shape-memory polymer (SMP)-actuated fluid valves capable of automated colorimetric enzyme-linked immunosorbent assays (ELISAs). A single-layer microfluidic paper-based analytical device (μPAD) was designed to store all the reagents on the chip, and sequentially transfer reagents to a paper test zone following a specific ELISA protocol through automatic fluidic flow control by the multiple SMP-actuated valves. The actuation of a paper valve was based on the thermally responsive, duel-state shape transformation of a SMP sheet attached to the root of a paper cantilever beam for driving a hydrophilic paper bridge to connect and disconnect two paper channels. A portable colorimetric reader was developed to control the on-chip valve operations, quantify the colorimetric signal output, display the assay result, and wirelessly transmit the data to a smart phone for the application of telemedicine. Reliable operations of the paper valve and the entire μPAD were demonstrated with success rates of 97% and 93%, respectively. A detection mechanism for valve malfunction was designed and confirmed effective to identify any mal-operation of individual valves, thus rendering our platform reliable in real assays. For device calibration, we conducted direct ELISAs of rabbit IgG in phosphate-buffered saline (PBS), and achieved a low limit of detection (LOD) of 27 pM (comparable to that of standard and paper-based ELISAs). In order to demonstrate the clinical application of our multi-step immunoassay platform, we also conducted sandwich ELISAs to quantify the protein level of an inflammatory cytokine, namely tumor necrosis factor (TNF)-α, in surgically injured laryngeal tissues of rats. The protein levels of TNF-α were shown similar between the conventional and μPAD ELISAs., Microfluidics: Paper valves open doors to new designs Researchers in Canada have improved the design of paper-based analytical devices by developing paper valves which make it possible to carry out fully-automated multi-step analyses. Previous efforts to incorporate valves have been based on electromagnets or compressed sponges, making them too cumbersome or complicated for reliable use in paper-based analytical devices. To overcome this, a team led by Xinyu Liu of the University of Toronto turned to polymers that reversibly change shape in response to temperature. They combined these with a heating element to produce thermally-activated paper valves. Test devices designed to carry out a multi-step ELISA analysis produced results comparable to a standard commercial ELISA kit. The valve design can be used to create devices for other multi-step diagnostic assays which can be used in contexts where lab equipment and skilled personnel are unavailable.
- Published
- 2019
14. Low-temperature processing of screen-printed piezoelectric KNbO3 with integration onto biodegradable paper substrates.
- Author
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Monroe, Morgan M., Villanueva, L. Guillermo, and Briand, Danick
- Subjects
PIEZOELECTRIC devices ,POTASSIUM niobate ,CANTILEVERS ,ELECTRONIC waste ,PERMITTIVITY ,PIEZOELECTRIC thin films ,BIODEGRADABLE plastics - Abstract
The development of fully solution-processed, biodegradable piezoelectrics is a critical step in the development of green electronics towards the worldwide reduction of harmful electronic waste. However, recent printing processes for piezoelectrics are hindered by the high sintering temperatures required for conventional perovskite fabrication techniques. Thus, a process was developed to manufacture lead-free printed piezoelectric devices at low temperatures to enable integration with eco-friendly substrates and electrodes. A printable ink was developed for screen printing potassium niobate (KNbO
3 ) piezoelectric layers in microns of thickness at a maximum processing temperature of 120 °C with high reproducibility. Characteristic parallel plate capacitor and cantilever devices were designed and manufactured to assess the quality of this ink and evaluate its physical, dielectric, and piezoelectric characteristics; including a comparison of behaviour between conventional silicon and biodegradable paper substrates. The printed layers were 10.7–11.2 μm thick, with acceptable surface roughness values in the range of 0.4–1.1 μm. The relative permittivity of the piezoelectric layer was 29.3. The poling parameters were optimised for the piezoelectric response, with an average longitudinal piezoelectric coefficient for samples printed on paper substrates measured as d33, eff, paper = 13.57 ± 2.84 pC/N; the largest measured value was 18.37 pC/N on paper substrates. This approach to printable biodegradable piezoelectrics opens the way forward for fully solution-processed green piezoelectric devices. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
15. Smart-phone, paper-based fluorescent sensor for ultra-low inorganic phosphate detection in environmental samples
- Author
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Jared Leichner, Mehenur Sarwar, Ghinwa Naja, and Chen-Zhong Li
- Subjects
Smart phone ,Materials Science (miscellaneous) ,02 engineering and technology ,lcsh:Technology ,01 natural sciences ,Industrial and Manufacturing Engineering ,Article ,chemistry.chemical_compound ,Inorganic phosphate ,Electrical and Electronic Engineering ,Process engineering ,lcsh:T ,business.industry ,010401 analytical chemistry ,Response time ,Paper based ,Contamination ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Phosphate ,Fluorescence ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,chemistry ,Linear range ,Optics and photonics ,lcsh:TA1-2040 ,Environmental science ,Other photonics ,lcsh:Engineering (General). Civil engineering (General) ,0210 nano-technology ,business - Abstract
A major goal of environmental agencies today is to conduct point-of-collection monitoring of excess inorganic phosphate (Pi) in environmental water samples for tracking aquatic “dead zones” caused by algae blooms. However, there are no existing commercial devices which have been miniaturized and are suitable for the point-of-need-testing (“PONT”) that is required to fully map a large region, such as the Florida Everglades. To solve this challenge, a reflection-mode fluorescence-sensing apparatus was developed, leveraging an environmentally sensitive fluorophore (MDCC) bound to a bacterial phosphate-binding protein to generate a fluorescent optical signal proportional to the concentration of (Pi) present. The combined end-to-end integrated sensor system had a response time of only 4 s, with minimal effects of common interfering agents and a linear range spanning from 1.1 to 64 ppb. To support ease-of-use during PONT, the platform incorporated disposable wax-printed paper strip sample pads and a smartphone camera detection system. Since the EPA threshold is currently 30 ppb to prevent eutrophication, this system serves as a rapid test of whether a region is compliant., A simple sensor for finding phosphates A disposable phosphate sensor that can be imaged directly with a smartphone could offer a simple and effective strategy for monitoring water contamination. The phosphates present in agricultural fertilizer can create an environmental disaster if they spill into surrounding water, producing algal ‘dead zones’. Standard methods for measuring inorganic phosphate are time-consuming and employ toxic chemicals, but researchers led by Chen-zhong Li at Florida International University (FIU) have developed a potential alternative for onsite testing. Teaming up with the Everglades Foundation, Li’s lab developed a paper-based sensor incorporating a fluorescently labeled bacterial protein, which generates a rapid visual readout upon binding to inorganic phosphate. Their sensor is capable of detecting whether phosphate levels in a water sample exceed legal limits and can be analyzed with a standard smartphone, making it a promising strategy for assessing contamination in the field.
- Published
- 2019
16. Graphene oxide nanosheets coupled with paper microfluidics for enhanced on-site airborne trace metal detection
- Author
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Hui Dong, Hao Sun, Fan Longxiang, and Yuan Jia
- Subjects
Materials Science (miscellaneous) ,Microfluidics ,Air pollution ,02 engineering and technology ,medicine.disease_cause ,01 natural sciences ,lcsh:Technology ,Industrial and Manufacturing Engineering ,law.invention ,law ,Environmental monitoring ,medicine ,Trace metal ,Electrical and Electronic Engineering ,Process engineering ,Detection limit ,Graphene ,business.industry ,lcsh:T ,010401 analytical chemistry ,Particulates ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,lcsh:TA1-2040 ,Environmental science ,Inductively coupled plasma ,0210 nano-technology ,business ,lcsh:Engineering (General). Civil engineering (General) - Abstract
Rapid on-site analysis of airborne trace metals has been heavily favored over traditional methodologies because air pollutants can be altered by environmental, behavioral, and social patterns at any given time and location. However, existing portable approaches are either not capable of performing integrated on-site analysis or not yet practically applicable. Exploiting graphene oxide (GO) in enhancing the analytical performance of paper-based colorimetric detection, for the first time, this paper reports the development of a practically useful portable system for accurate, sensitive on-site characterization of trace metals in ambient particulate matter (PM). The system consists of GO-nanosheet-coated paper devices, unmanned aerial vehicle multiaxial sampling, and cellphone-based colorimetric detection. The increased specific surface area and the homogeneity of color distribution from the coating of GO improves the accuracy and sensitivity of the assays. Additionally, by leveraging a Wi-Fi camera, a self-developed app and a sample pretreatment cartridge, metal in PM samples can be readily processed and characterized on-site within 30 min. The effects of chip geometric design, pH, reaction volume, and metal interference on detection results have been studied. The detection limits of the system were calibrated to be 16.6, 5.1, and 9.9 ng for metals Fe, Cu, and Ni, respectively, which are comparable to the detection limits of commercial inductively coupled plasma (ICP) instruments, thus making our portable system practically useful. Finally, the system was used for airborne trace-metal study at 6 locations in Fuzhou City (China), and the results obtained using our system demonstrated good agreement with those obtained by the ICP. The significance of our system in supplementing air pollution study and furthering research on rapid, accurate, on-site air toxicity assessment was demonstrated. Heavy metals in air can now be promptly and accurately quantified on site. Monitoring the amount of trace metals in air is an important component of environment control, as heavy metals such as Fe, Zn, Mn, and Ni are a health concern when present in large concentrations. While accurate equipment is available for measuring trace metal content in air, most of these are not portable, which makes measuring transient conditions difficult. Now, teams led by Hao Sun from Fuzhou University and Yuan Jia from Southeast University, China, report a portable system that makes use of the large surface area of graphene oxide nanosheets for detecting trace metals. These “paper” devices are paired with a highly portable aerial vehicle and a cell phone application developed by the authors, enabling accurate environmental monitoring at specific sites.
- Published
- 2019
17. A reusable PMMA/paper hybrid plug-and-play microfluidic device for an ultrasensitive immunoassay with a wide dynamic range
- Author
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Xiaochun Li, Meihan Li, Xiujun Li, Sharma T. Sanjay, and Wan Zhou
- Subjects
Detection limit ,Analyte ,Materials science ,Chromatography ,medicine.diagnostic_test ,lcsh:T ,Materials Science (miscellaneous) ,Microfluidics ,Substrate (chemistry) ,Condensed Matter Physics ,lcsh:Technology ,Industrial and Manufacturing Engineering ,Atomic and Molecular Physics, and Optics ,Orders of magnitude (mass) ,lcsh:TA1-2040 ,Immunoassay ,Wide dynamic range ,medicine ,Naked eye ,Electrical and Electronic Engineering ,lcsh:Engineering (General). Civil engineering (General) - Abstract
Conventional colorimetric enzyme-linked immunosorbent assay (ELISA) is a time-consuming laboratory assay that is not very sensitive and consumes a large amount of samples. Herein, the development of a reusable, cost-effective, and eco-friendly poly(methyl methacrylate) (PMMA)/paper hybrid plug-and-play (PnP) device for high-sensitivity immunoassay by analyte enrichment and efficient passing-through washing has been reported. The PMMA device has multiple slots where a pre-patterned paper substrate can be inserted. The sample flows back-and-forth through a low-cost, 3D paper substrate within the PMMA channels, thereby enhancing the amount of analyte adsorbed and dramatically increasing the sensitivity while decreasing the assay time. After the enrichment assay, the paper substrate can simply be pulled out of the device, and the results can be qualitatively viewed with the naked eye or scanned through a simple desktop scanner for quantitative analysis. The paper substrate can be replaced with a new substrate so that the device can be reused. The limits of detection (LODs) of 200 pg/mL for immunoglobulin G (IgG) and 270 pg/mL for hepatitis B surface antigen (HBsAg) were obtained. This IgG assay is at least 10 times more sensitive than commercial ELISA kits. In addition, the PnP ELISA exhibited a significant increase in the linear dynamic range from 3 orders of magnitude in a common paper-based device to a wide range of six orders of magnitude in the PnP hybrid device. This reusable PnP device has great potential for the low-cost yet high-sensitivity detection of infectious diseases, cancers, and other important biomolecules. A reusable, cost-effective, and environment-friendly PnP device has been developed for high-sensitivity immunoassays (biochemical tests that measure proteins or other substances through their properties as antigens or antibodies). Immunoassays are widely used in the diagnosis, screening, and monitoring of diseases. However, such techniques as enzyme-linked immunosorbent assay (ELISA), which are extensively applied in developed countries, are not widely available in developing nations owing to limited funding and lack of skilled manpower. They are also time consuming and lacking in sensitivity. A team headed by XiuJun Li at the University of Texas at El Paso produced a low-cost device using poly(methyl methacrylate) (PMMA or Perspex) that is 10 times more sensitive than commercial ELISA kits. The authors believe that their PMMA device offers considerable potential for application in detecting infectious diseases and cancers in resource-poor settings.
- Published
- 2020
18. Using airbrushes to pattern reagents for microarrays and paper-fluidic devices
- Author
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Cassano, Christopher L., primary, Georgiev, Teodor Z., additional, and Fan, Z Hugh, additional
- Published
- 2017
- Full Text
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19. A paper-based microfluidic biosensor integrating zinc oxide nanowires for electrochemical glucose detection
- Author
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Xiao Li, Xinyu Liu, and Chen Zhao
- Subjects
Detection limit ,Working electrode ,Materials science ,biology ,Materials Science (miscellaneous) ,Microfluidics ,Nanowire ,chemistry.chemical_element ,Nanotechnology ,Zinc ,Condensed Matter Physics ,Industrial and Manufacturing Engineering ,Atomic and Molecular Physics, and Optics ,chemistry ,Electrode ,biology.protein ,Glucose oxidase ,Electrical and Electronic Engineering ,Biosensor - Abstract
This paper reports an electrochemical microfluidic paper-based analytical device (EμPAD) for glucose detection, featuring a highly sensitive working electrode (WE) decorated with zinc oxide nanowires (ZnO NWs). In addition to the common features of μPADs, such as their low costs, high portability/disposability, and ease of operation, the reported EμPAD has three further advantages. (i) It provides higher sensitivity and a lower limit of detection (LOD) than previously reported μPADs because of the high surface-to-volume ratio and high enzyme-capturing efficiency of the ZnO NWs. (ii) It does not need any light-sensitive electron mediator (as is usually required in enzymatic glucose sensing), which leads to enhanced biosensing stability. (iii) The ZnO NWs are directly synthesized on the paper substrate via low-temperature hydrothermal growth, representing a simple, low-cost, consistent, and mass-producible process. To achieve superior analytical performance, the on-chip stored enzyme (glucose oxidase) dose and the assay incubation time are tuned. More importantly, the critical design parameters of the EμPAD, including the WE area and the ZnO-NW growth level, are adjusted to yield tunable ranges for the assay sensitivity and LOD. The highest sensitivity that we have achieved is 8.24 μA·mM−1·cm−2, with a corresponding LOD of 59.5 μM. By choosing the right combination of design parameters, we constructed EμPADs that cover the range of clinically relevant glucose concentrations (0−15 mM) and fully calibrated these devices using spiked phosphate-buffered saline and human serum. We believe that the reported approach for integrating ZnO NWs on EμPADs could be well utilized in many other designs of EμPADs and provides a facile and inexpensive paradigm for further enhancing the device performance. A paper-based microfluidic biosensor with an electrode decorated with zinc oxide nanowires is used for sensitive detection of glucose. Microfluidic paper-based analytical devices (μPADs) are attractive platforms for diagnostic biosensing, particularly in areas lacking sophisticated medical resources, because they are inexpensive and easy to operate. Now, Xiao Li, Chen Zhao and Xinyu Liu at McGill University in Canada have produced a high-sensitivity electrochemical μPAD that incorporates a working electrode decorated with zinc oxide nanowires. The μPAD has enhanced biosensing performance and stability, and can be produced by a simple, low cost process. By judicial selection of the design parameters, the researchers produced μPADs that can accurately detect glucose in a clinically relevant concentration range (0—15 millimolar) in human serum. They consider that the performance of other electrochemical μPADs could be enhanced through the integration of zinc oxide nanowires.
- Published
- 2015
20. Printed unmanned aerial vehicles using paper-based electroactive polymer actuators and organic ion gel transistors
- Author
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Grau, Gerd, primary, Frazier, Elisha J., additional, and Subramanian, Vivek, additional
- Published
- 2016
- Full Text
- View/download PDF
21. A paper-based microfluidic biosensor integrating zinc oxide nanowires for electrochemical glucose detection
- Author
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Li, Xiao, primary, Zhao, Chen, additional, and Liu, Xinyu, additional
- Published
- 2015
- Full Text
- View/download PDF
22. A novel evolutionary method for parameter-free MEMS structural design and its application in piezoresistive pressure sensors.
- Author
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Meng, Qinggang, Wang, Junbo, Chen, Deyong, Chen, Jian, Xie, Bo, and Lu, Yulan
- Subjects
PRESSURE sensors ,STRUCTURAL design ,MEMS resonators ,FINITE element method ,DEGREES of freedom ,EVOLUTIONARY algorithms ,ADHESIVE tape - Abstract
In this paper, a novel simulation-based evolutionary method is presented for designing parameter-free MEMS structures with maximum degrees of freedom. This novel design method enabled semiautomatic structure evolution by weighing the attributes of each segment of the structure and yielded an optimal design after multiple iterations. The proposed method was utilized to optimize the pressure-sensitive diaphragm of a piezoresistive pressure sensor (PPS). Finite element method (FEM) simulations revealed that, in comparison to conventional diaphragms without islands and with square islands, the optimized diaphragm increased the stress by 10% and 16% and reduced the nonlinearity by 57% and 77%, respectively. These improvements demonstrate the value of this method. Characterization of the fabricated PPS revealed a high sensitivity of 8.8 mV V
−1 MPa−1 and a low nonlinearity of 0.058% FS at 20 °C, indicating excellent sensor performance. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
23. An integrated micromachined flexible ultrasonic-inductive sensor for pipe contaminant multiparameter detection.
- Author
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Yuan, Zheng, Wu, Xiaoyu, Li, Zhikang, Yuan, Jiawei, Zhao, Yihe, Li, Zixuan, Qin, Shaohui, Ma, Qi, Shi, Xuan, Zhao, Zilong, Li, Jiazhu, Zhang, Shiwang, Jing, Weixuan, Wang, Xiaozhang, and Zhao, Libo
- Subjects
DOPPLER ultrasonography ,ACOUSTIC field ,DOPPLER effect ,MAGNETIC particles ,FINITE element method ,PIPE - Abstract
Pipe contaminant detection holds considerable importance within various industries, such as the aviation, maritime, medicine, and other pertinent fields. This capability is beneficial for forecasting equipment potential failures, ascertaining operational situations, timely maintenance, and lifespan prediction. However, the majority of existing methods operate offline, and the detectable parameters online are relatively singular. This constraint hampers real-time on-site detection and comprehensive assessments of equipment status. To address these challenges, this paper proposes a sensing method that integrates an ultrasonic unit and an electromagnetic inductive unit for the real-time detection of diverse contaminants and flow rates within a pipeline. The ultrasonic unit comprises a flexible transducer patch fabricated through micromachining technology, which can not only make installation easier but also focus the sound field. Moreover, the sensing unit incorporates three symmetrical solenoid coils. Through a comprehensive analysis of ultrasonic and induction signals, the proposed method can be used to effectively discriminate magnetic metal particles (e.g., iron), nonmagnetic metal particles (e.g., copper), nonmetallic particles (e.g., ceramics), and bubbles. This inclusive categorization encompasses nearly all types of contaminants that may be present in a pipeline. Furthermore, the fluid velocity can be determined through the ultrasonic Doppler frequency shift. The efficacy of the proposed detection principle has been validated by mathematical models and finite element simulations. Various contaminants with diverse velocities were systematically tested within a 14 mm diameter pipe. The experimental results demonstrate that the proposed sensor can effectively detect contaminants within the 0.5−3 mm range, accurately distinguish contaminant types, and measure flow velocity. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
24. Synchronization bandwidth enhancement induced by a parametrically excited oscillator.
- Author
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Song, Jiahao, Xu, Yutao, Yang, Qiqi, Huan, Ronghua, and Wei, Xueyong
- Subjects
PHASE-locked loops ,SYNCHRONIZATION ,FREQUENCY dividers ,BANDWIDTHS ,NOISE control - Abstract
The synchronization phenomenon in nature has been utilized in sensing and timekeeping fields due to its numerous advantages, including amplitude and frequency stabilization, noise reduction, and sensitivity improvement. However, the limited synchronization bandwidth hinders its broader application, and few techniques have been explored to enhance this aspect. In this paper, we conducted theoretical and experimental studies on the unidirectional synchronization characteristics of a resonator with phase lock loop oscillation. A novel enhancement method for the synchronization bandwidth using a parametrically excited MEMS oscillator is proposed, which achieves a remarkably large synchronization bandwidth of 8.85 kHz, covering more than 94% of the hysteresis interval. Importantly, the proposed method exhibits significant potential for high-order synchronization and frequency stabilization compared to the conventional directly excited oscillator. These findings present an effective approach for expanding the synchronization bandwidth, which has promising applications in nonlinear sensing, fully mechanical frequency dividers, and high-precision time references. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
25. MEMS reservoir computing system with stiffness modulation for multi-scene data processing at the edge.
- Author
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Guo, Xiaowei, Yang, Wuhao, Xiong, Xingyin, Wang, Zheng, and Zou, Xudong
- Subjects
COMPUTER systems ,MICROELECTROMECHANICAL systems ,AMPLITUDE modulation ,EDGE computing ,MEMRISTORS - Abstract
Reservoir computing (RC) is a bio-inspired neural network structure which can be implemented in hardware with ease. It has been applied across various fields such as memristors, and electrochemical reactions, among which the micro-electro-mechanical systems (MEMS) is supposed to be the closest to sensing and computing integration. While previous MEMS RCs have demonstrated their potential as reservoirs, the amplitude modulation mode was found to be inadequate for computing directly upon sensing. To achieve this objective, this paper introduces a novel MEMS reservoir computing system based on stiffness modulation, where natural signals directly influence the system stiffness as input. Under this innovative concept, information can be processed locally without the need for advanced data collection and pre-processing. We present an integrated RC system characterized by small volume and low power consumption, eliminating complicated setups in traditional MEMS RC for data discretization and transduction. Both simulation and experiment were conducted on our accelerometer. We performed nonlinearity tuning for the resonator and optimized the post-processing algorithm by introducing a digital mask operator. Consequently, our MEMS RC is capable of both classification and forecasting, surpassing the capabilities of our previous non-delay-based architecture. Our method successfully processed word classification, with a 99.8% accuracy, and chaos forecasting, with a 0.0305 normalized mean square error (NMSE), demonstrating its adaptability for multi-scene data processing. This work is essential as it presents a novel MEMS RC with stiffness modulation, offering a simplified, efficient approach to integrate sensing and computing. Our approach has initiated edge computing, enabling emergent applications in MEMS for local computations. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
26. A new strategy for the fabrication of a flexible and highly sensitive capacitive pressure sensor.
- Author
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Qin, Ruzhan, Hu, Mingjun, Li, Xin, Liang, Te, Tan, Haoyi, Liu, Jinzhang, and Shan, Guangcun
- Subjects
CAPACITIVE sensors ,PRESSURE sensors ,FABRICATION (Manufacturing) ,POVIDONE ,ELECTRODES - Abstract
The development of flexible capacitive pressure sensors has wide application prospects in the fields of electronic skin and intelligent wearable electronic devices, but it is still a great challenge to fabricate capacitive sensors with high sensitivity. Few reports have considered the use of interdigital electrode structures to improve the sensitivity of capacitive pressure sensors. In this work, a new strategy for the fabrication of a high-performance capacitive flexible pressure sensor based on MXene/polyvinylpyrrolidone (PVP) by an interdigital electrode is reported. By increasing the number of interdigital electrodes and selecting the appropriate dielectric layer, the sensitivity of the capacitive sensor can be improved. The capacitive sensor based on MXene/PVP here has a high sensitivity (~1.25 kPa
−1 ), low detection limit (~0.6 Pa), wide sensing range (up to 294 kPa), fast response and recovery times (~30/15 ms) and mechanical stability of 10000 cycles. The presented sensor here can be used for various pressure detection applications, such as finger pressing, wrist pulse measuring, breathing, swallowing and speech recognition. This work provides a new method of using interdigital electrodes to fabricate a highly sensitive capacitive sensor with very promising application prospects in flexible sensors and wearable electronics. [ABSTRACT FROM AUTHOR]- Published
- 2021
- Full Text
- View/download PDF
27. Integrated sensing and delivery of oxygen for next-generation smart wound dressings.
- Author
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Ochoa, Manuel, Rahimi, Rahim, Zhou, Jiawei, Jiang, Hongjie, Yoon, Chang Keun, Maddipatla, Dinesh, Narakathu, Binu Baby, Jain, Vaibhav, Oscai, Mark Michael, Morken, Thaddeus Joseph, Oliveira, Rebeca Hannah, Campana, Gonzalo L., Cummings, Oscar W., Zieger, Michael A., Sood, Rajiv, Atashbar, Massood Z., and Ziaie, Babak
- Abstract
Chronic wounds affect over 6.5 million Americans and are notoriously difficult to treat. Suboptimal oxygenation of the wound bed is one of the most critical and treatable wound management factors, but existing oxygenation systems do not enable concurrent measurement and delivery of oxygen in a convenient wearable platform. Thus, we developed a low-cost alternative for continuous O
2 delivery and sensing comprising of an inexpensive, paper-based, biocompatible, flexible platform for locally generating and measuring oxygen in a wound region. The platform takes advantage of recent developments in the fabrication of flexible microsystems including the incorporation of paper as a substrate and the use of a scalable manufacturing technology, inkjet printing. Here, we demonstrate the functionality of the oxygenation patch, capable of increasing oxygen concentration in a gel substrate by 13% (5 ppm) in 1 h. The platform is able to sense oxygen in a range of 5–26 ppm. In vivo studies demonstrate the biocompatibility of the patch and its ability to double or triple the oxygen level in the wound bed to clinically relevant levels. Printable patches for treating tissue trauma: Paper-based sensors that measure and adjust oxygen levels within chronic wounds could provide a low-cost solution for accelerating recovery. Such persistent injuries often result from diabetes and long-term hospitalization, and treatment is largely reliant on subjective assessment by healthcare providers. Babak Ziaie of Purdue University and colleagues have developed a proof-of-concept platform for manufacturing inkjet-printed, paper-based dressings that enable close control over oxygen levels in wound tissue—an important factor in the healing process. Their design employs arrays of integrated luminescent oxygen sensors, alongside catalytic regions that can be exposed to hydrogen peroxide to rapidly generate oxygen as needed. The authors demonstrate the potential utility of this approach with both in vitro and in vivo experiments, and they envision this platform as a foundation for future multi-sensor 'smart' wound dressings that can be affordably mass produced. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
28. A polymeric piezoelectric MEMS accelerometer with high sensitivity, low noise density, and an innovative manufacturing approach.
- Author
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Ge, Chang and Cretu, Edmond
- Subjects
3-D films ,INTEGRATED circuits ,ACCELEROMETERS ,NOISE ,THIN films ,DENSITY - Abstract
The piezoelectric coupling principle is widely used (along with capacitive coupling and piezoresistive coupling) for MEMS accelerometers. Piezoelectric MEMS accelerometers are used primarily for vibration monitoring. Polymer piezoelectric MEMS accelerometers offer the merits of heavy-metal-free structure material and simple microfabrication flow. More importantly, polymeric piezoelectric MEMS accelerometers may be the basis of novel applications, such as fully organic inertial sensing microsystems using polymer sensors and organic integrated circuits. This paper presents a novel polymer piezoelectric MEMS accelerometer design using PVDF films. A simple and rapid microfabrication flow based on laser micromachining of thin films and 3D stereolithography was developed to fabricate three samples of this design. During proof-of-concept experiments, the design achieved a sensitivity of 21.82 pC/g (equivalent open-circuit voltage sensitivity: 126.32 mV/g), a 5% flat band of 58.5 Hz, and a noise density of 6.02 µg/√Hz. Thus, this design rivals state-of-the-art PZT-based counterparts in charge sensitivity and noise density, and it surpasses the performance capabilities of several commercial MEMS accelerometers. Moreover, this design has a 10-times smaller device area and a 4-times larger flat band than previous state-of-the-art organic piezoelectric MEMS accelerometers. These experimentally validated performance metrics demonstrate the promising application potential of the polymeric piezoelectric MEMS accelerometer design presented in this article. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
29. Recent advances and research progress on microsystems and bioeffects of terahertz neuromodulation.
- Author
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Liu, Meiting, Liu, Juntao, Liang, Wei, Lu, Botao, Fan, Penghui, Song, Yilin, Wang, Mixia, Wu, Yirong, and Cai, Xinxia
- Subjects
SUBMILLIMETER waves ,PHYSIOLOGICAL effects of radiation ,NEUROMODULATION ,TERAHERTZ technology ,OPTICAL modulation ,NERVOUS system - Abstract
Terahertz waves can interact with the nervous system of organisms under certain conditions. Compared to common optical modulation methods, terahertz waves have the advantages of low photon energy and low risk; therefore, the use of terahertz waves to regulate the nervous system is a promising new method of neuromodulation. However, most of the research has focused on the use of terahertz technology for biodetection, while relatively little research has been carried out on the biological effects of terahertz radiation on the nervous system, and there are almost no review papers on this topic. In the present article, we begin by reviewing principles and objects of research regarding the biological effects of terahertz radiation and summarizing the current state of related research from a variety of aspects, including the bioeffects of terahertz radiation on neurons in vivo and in vitro, novel regulation and detection methods with terahertz radiation devices and neural microelectrode arrays, and theoretical simulations of neural information encoding and decoding. In addition, we discuss the main problems and their possible causes and give some recommendations on possible future breakthroughs. This paper will provide insight and assistance to researchers in the fields of neuroscience, terahertz technology and biomedicine. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
30. Unraveling the nature of sensing in electrostatic MEMS gas sensors.
- Author
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Shama, Yasser S., Rahmanian, Sasan, Mouharrar, Hamza, Abdelrahman, Rana, Elhady, Alaaeldin, and Abdel-Rahman, Eihab M.
- Subjects
GAS detectors ,ELECTROSTATIC fields ,GRAVITATIONAL fields ,ISOPROPYL alcohol ,PERMITTIVITY ,DETECTORS - Abstract
This paper investigates the fundamental sensing mechanism of electrostatic MEMS gas sensors. It compares among the responsivities of a set of MEMS isopropanol sensors before and after functionalization, and in the presence and absence of electrostatic fields when operated in static and dynamic detection modes. In the static mode, we found that the sensors do not exhibit a measurable change in displacement due to added mass. On the other hand, bare sensors showed a clear change in displacement in response to isopropanol vapor. In the dynamic mode, functionalized sensors showed a measurable frequency shift due to the added mass of isopropanol vapor. In the presence of strong electrostatic fields, the measured frequency shift was found to be threefold larger than that in their absence in response to the same concentration of isopropanol vapor. The enhanced responsivity of dynamic detection allows the sensors to measure the vapor mass captured by the functional material, which is not the case for static detection. The detection of isopropanol by bare sensors in static mode shows that change in the medium permittivity is the primary sensing mechanism. The enhanced responsivity of dynamic mode sensors when operated in strong electrostatic fields shows that their sensing mechanism is a combination of a weaker added mass effect and a stronger permittivity effect. These findings show that electrostatic MEMS gas sensors are independent of the direction of the gravitational field and are, thus, robust to changes in alignment. It is erroneous to refer to them as 'gravimetric' sensors. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
31. Reconfigurable transmissive metasurface with a combination of scissor and rotation actuators for independently controlling beam scanning and polarization conversion.
- Author
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Lor, Chhunheng, Phon, Ratanak, and Lim, Sungjoon
- Subjects
UNIT cell ,ACTUATORS ,CIRCULAR polarization ,ROTATIONAL motion ,ELECTROMAGNETIC waves ,BEAM steering - Abstract
Polarization conversion and beam scanning metasurfaces are commonly used to reduce polarization mismatch and direct electromagnetic waves in a specific direction to improve the strength of a wireless signal. However, identifying suitable active and mechanically reconfigurable metasurfaces for polarization conversion and beam scanning is a considerable challenge, and the reported metasurfaces have narrow scanning ranges, are expensive, and cannot be independently controlled. In this paper, we propose a reconfigurable transmissive metasurface combined with a scissor and rotation actuator for independently controlling beam scanning and polarization conversion functions. The metasurface is constructed with rotatable unit cells (UCs) that can switch the polarization state between right-handed (RHCP) and left-handed circular polarization (LHCP) by flipping the UCs to reverse their phase variation. Moreover, independent beam scanning is achieved using the scissor actuator to linearly change the distance between the UCs. Numerical and experimental results confirm that the proposed metasurface can perform beam scanning in the range of 28° for both the positive and negative regions of a radiation pattern (RHCP and LHCP beams) at an operational frequency of 10.5 GHz. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
32. A resonant high-pressure microsensor based on a composite pressure-sensitive mechanism of diaphragm bending and volume compression.
- Author
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Qian, Pan, Yu, Zongze, Yu, Jie, Lu, Yulan, Xie, Bo, Chen, Jian, Chen, Deyong, and Wang, Junbo
- Subjects
PRESSURE sensors ,MICROSENSORS ,FINITE element method ,CAVITY resonators ,DEBYE temperatures ,PRESSURE ,RESONATORS - Abstract
In this paper, a composite pressure-sensitive mechanism combining diaphragm bending and volume compression was developed for resonant pressure microsensors to achieve high-pressure measurements with excellent accuracy. The composite mechanism was explained, and the sensor structure was designed based on theoretical analysis and finite element simulation. An all-silicon resonant high-pressure microsensor with multiple miniaturized cavities and dual resonators was developed, where dual resonators positioned in two resonant cavities with suitably different widths are used to perform opposite characteristics in pressure and the same characteristics at different temperatures, which can improve pressure sensitivities and realize temperature self-compensation by differential frequency output. The microsensor was fabricated by microfabrication, and the experimental results showed that the sensor had an accuracy of ±0.015% full scale (FS) in a pressure range of 0.1~100 MPa and a temperature range of −10~50 °C. The pressure sensitivity of the differential frequency was 261.10 Hz/MPa (~2523 ppm/MPa) at a temperature of 20 °C, and the temperature sensitivities of the dual resonators were −1.54 Hz/°C (~−14.5 ppm/°C) and −1.57 Hz/°C (~−15.6 ppm/°C) at a pressure of 2 MPa. The differential output had an outstanding stability within ±0.02 Hz under constant temperature and pressure. Thus, this research provides a convenient solution for high-pressure measurements because of its advantages, namely, large range, excellent accuracy and stability. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. Design, simulation, and testing of a tunable MEMS multi-threshold inertial switch.
- Author
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Xu, Qiu, Rocha, Rodrigo T., Algoos, Yousef, Feron, Eric, and Younis, Mohammad I.
- Subjects
SENSE of direction ,IMPACT loads ,ACCELERATION measurements ,PROOF of concept ,CANTILEVERS ,MEMS resonators - Abstract
This paper presents a tunable multi-threshold micro-electromechanical inertial switch with adjustable threshold capability. The demonstrated device combines the advantages of accelerometers in providing quantitative acceleration measurements and g-threshold switches in saving power when in the inactive state upon experiencing acceleration below the thresholds. The designed proof-of-concept device with two thresholds consists of a cantilever microbeam and two stationary electrodes placed at different positions in the sensing direction. The adjustable threshold capability and the effect of the shock duration on the threshold acceleration are analytically investigated using a nonlinear beam model. Results are shown for the relationships among the applied bias voltage, the duration of shock impact, and the tunable threshold. The fabricated prototypes are tested using a shock-table system. The analytical results agree with the experimental results. The designed device concept is very promising for the classification of the shock and impact loads in transportation and healthcare applications. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
34. Flexible pressure sensors with ultrahigh stress tolerance enabled by periodic microslits.
- Author
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Wang, Song, Wang, Chenying, Zhao, Yifan, Zhang, Yujing, Zhang, Yaxin, Xu, Xiangyue, Lin, Qijing, Yao, Kai, Wang, Yuheng, Han, Feng, Sun, Yu, and Jiang, Zhuangde
- Subjects
PRESSURE sensors ,MULTIWALLED carbon nanotubes ,STRUCTURAL health monitoring ,ROBOT motion ,CARBON nanotubes - Abstract
Stress tolerance plays a vital role in ensuring the effectiveness of piezoresistive sensing films used in flexible pressure sensors. However, existing methods for enhancing stress tolerance employ dome-shaped, wrinkle-shaped, and pyramidal-shaped microstructures in intricate molding and demolding processes, which introduce significant fabrication challenges and limit the sensing performance. To address these shortcomings, this paper presents periodic microslits in a sensing film made of multiwalled carbon nanotubes and polydimethylsiloxane to realize ultrahigh stress tolerance with a theoretical maximum of 2.477 MPa and a sensitivity of 18.092 kPa
−1 . The periodic microslits permit extensive deformation under high pressure (e.g., 400 kPa) to widen the detection range. Moreover, the periodic microslits also enhance the sensitivity based on simultaneously exhibiting multiple synapses within the sensing interface and between the periodic sensing cells. The proposed solution is verified by experiments using sensors based on the microslit strategy for wind direction detection, robot movement sensing, and human health monitoring. In these experiments, vehicle load detection is achieved for ultrahigh pressure sensing under an ultrahigh pressure of over 400 kPa and a ratio of the contact area to the total area of 32.74%. The results indicate that the proposed microslit strategy can achieve ultrahigh stress tolerance while simplifying the fabrication complexity of preparing microstructure sensing films. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
35. Design of an automated robotic microinjection system for batch injection of zebrafish embryos and larvae.
- Author
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Guo, Zhongyi, Ai, Nana, Ge, Wei, and Xu, Qingsong
- Subjects
MICROINJECTIONS ,EMBRYOS ,ZEBRA danio ,BRACHYDANIO ,INJECTIONS ,ROBOTICS ,STRUCTURAL frames ,LARVAE - Abstract
This paper presents the design of a vision-based automated robotic microinjection system for batch injection of both zebrafish embryos and larvae. A novel visual recognition algorithm based on an automatic threshold and excessive dilatation is introduced to accurately identify the center of zebrafish embryos and larval yolks. A corresponding software system is developed using the producer-consumer model as the framework structure, and a friendly user interface is designed to allow operators to choose from a range of desired functions according to their different needs. In addition, a novel microstructural agarose device is designed and fabricated to simultaneously immobilize mixed batches of embryos and larvae. Moreover, a prototype microinjection system is fabricated by integrating hardware devices with visual algorithms. An experimental study is conducted to verify the performance of the robotic microinjection system. The results show that the reported system can accurately identify zebrafish embryos and larvae and efficiently complete batch microinjection tasks of the mixtures with an injection success rate of 92.05% in 13.88 s per sample. Compared with manual and existing microinjection systems, the proposed system demonstrates the merits of versatility, excellent efficiency, high success rate, high survival rate, and sufficient stability. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
36. A flexible, thin-film microchannel electrode array device for selective subdiaphragmatic vagus nerve recording.
- Author
-
Lim, Jongcheon, Zoss, Peter A., Powley, Terry L., Lee, Hyowon, and Ward, Matthew P.
- Subjects
ENTERIC nervous system ,VAGUS nerve ,GASTROINTESTINAL system ,ACTION potentials ,NERVE endings ,ELECTRODES - Abstract
The vagus nerve (VN) plays an important role in regulating physiological conditions in the gastrointestinal (GI) tract by communicating via the parasympathetic pathway to the enteric nervous system (ENS). However, the lack of knowledge in the neurophysiology of the VN and GI tract limits the development of advanced treatments for autonomic dysfunctions related to the VN. To better understand the complicated underlying mechanisms of the VN-GI tract neurophysiology, it is necessary to use an advanced device enabled by microfabrication technologies. Among several candidates including intraneural probe array and extraneural cuff electrodes, microchannel electrode array devices can be used to interface with smaller numbers of nerve fibers by securing them in the separate channel structures. Previous microchannel electrode array devices to interface teased nerve structures are relatively bulky with thickness around 200 µm. The thick design can potentially harm the delicate tissue structures, including the nerve itself. In this paper, we present a flexible thin film based microchannel electrode array device (thickness: 11.5 µm) that can interface with one of the subdiaphragmatic nerve branches of the VN in a rat. We demonstrated recording evoked compound action potentials (ECAP) from a transected nerve ending that has multiple nerve fibers. Moreover, our analysis confirmed that the signals are from C-fibers that are critical in regulating autonomic neurophysiology in the GI tract. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. Employing electrochemically derived pH gradients for Lab-on-PCB protein preconcentration devices.
- Author
-
Maxted, Grace, Estrela, Pedro, and Moschou, Despina
- Subjects
CHEMICAL reagents ,GOLD electrodes ,PRINTED circuits ,PROTEIN analysis ,ELECTROCHEMICAL electrodes - Abstract
Protein preconcentration is an essential sample preparation step for analysis in which the targeted proteins exist in low concentrations, such as bodily fluids, water, or wastewater. Nonetheless, very few practical implementations of miniaturized protein preconcentration devices have been demonstrated in practice, and even fewer have been integrated with other microanalytical steps. Existing approaches rely heavily on additional chemicals and reagents and introduce complexity to the overall assay. In this paper, we propose a novel miniaturized isoelectric focusing-based protein preconcentration screening device based on electrochemically derived pH gradients rather than existing chemical reagent approaches. In this way, we reduce the need for additional chemical reagents to zero while enabling device incorporation in a seamlessly integrated full protein analysis microsystem via Lab-on-PCB technology. We apply our previously presented Lab-on-PCB approach to quantitatively control the pH of a solution in the vicinity of planar electrodes using electrochemical acid generation through redox-active self-assembled monolayers. The presented device comprises a printed circuit board with an array of gold electrodes that were functionalized with 4-aminothiophenol; this formed a self-assembled monolayer that was electropolymerized to improve its electrochemical reversibility. Protein preconcentration was performed in two configurations. The first was open and needed the use of a holder to suspend a well of fluid above the electrodes; the second used microfluidic channels to enclose small volumes of fluid. Reported here are the resulting data for protein preconcentration in both these forms, with a quantitative concentration factor shown for the open form and qualitative proof shown for the microfluidic. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
38. A self-centering and stiffness-controlled MEMS accelerometer.
- Author
-
Jin, Yiming, Ma, Zhipeng, Ye, Ziyi, Li, Mingkang, Zheng, Xudong, and Jin, Zhonghe
- Subjects
CENTROID ,TEMPERATURE effect - Abstract
This paper presents a high-performance MEMS accelerometer with a DC/AC electrostatic stiffness tuning capability based on double-sided parallel plates (DSPPs). DC and AC electrostatic tuning enable the adjustment of the effective stiffness and the calibration of the geometric offset of the proof mass, respectively. A dynamical model of the proposed accelerometer was developed considering both DC/AC electrostatic tuning and the temperature effect. Based on the dynamical model, a self-centering closed loop is proposed for pulling the reference position of the force-to-rebalance (FTR) to the geometric center of DSPP. The self-centering accelerometer operates at the optimal reference position by eliminating the temperature drift of the readout circuit and nulling the net electrostatic tuning forces. The stiffness closed-loop is also incorporated to prevent the pull-in instability of the tuned low-stiffness accelerometer under a dramatic temperature variation. Real-time adjustments of the reference position and the DC tuning voltage are utilized to compensate for the residue temperature drift of the proposed accelerometer. As a result, a novel controlling approach composed of a self-centering closed loop, stiffness-closed loop, and temperature drift compensation is achieved for the accelerometer, realizing a temperature drift coefficient (TDC) of approximately 7 μg/°C and an Allan bias instability of less than 1 μg. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
39. A decouple-decomposition noise analysis model for closed-loop mode-localized tilt sensors.
- Author
-
Wang, Kunfeng, Xiong, XingYin, Wang, Zheng, Ma, Liangbo, Wang, BoWen, Yang, WuHao, Bie, Xiaorui, Li, ZhiTian, and Zou, XuDong
- Subjects
NOISE ,HILBERT-Huang transform ,PHASE noise ,DETECTORS ,LOCALIZATION (Mathematics) ,RESONATORS ,CLOSED loop systems - Abstract
The development of mode-localized sensors based on amplitude output metrics has attracted increasing attention in recent years due to the potential of such sensors for high sensitivity and resolution. Mode-localization phenomena leverage the interaction between multiple coupled resonant modes to achieve enhanced performance, providing a promising solution to overcome the limitations of traditional sensing technologies. Amplitude noise plays a key role in determining the resolution of mode-localized sensors, as the output metric is derived from the measured AR (amplitude ratio) within the weakly coupled resonator system. However, the amplitude noise originating from the weakly coupled resonator's closed-loop circuit has not yet been fully investigated. This paper presents a decouple-decomposition (DD) noise analysis model, which is applied to achieve high resolution in a mode-localized tilt sensor based on a weakly coupled resonator closed-loop circuit. The DD noise model separates the weakly coupled resonators using the decoupling method considering the nonlinearity of the resonators. By integrating the decoupled weakly coupled resonators, the model decomposes the weakly coupled resonator's closed-loop circuit into distinct paths for amplitude and phase noise analyses. The DD noise model reveals noise effects at various circuit nodes and models the system noise in the closed-loop circuit of the weakly coupled resonators. MATLAB/Simulink simulations verify the model's accuracy when compared to theoretical analysis. At the optimal operating point, the mode-localized tilt sensor achieves an input-referred instability of 3.91 × 10
-4° and an input-referred AR of PSD of 2.01 × 10-4° ⁄√Hz using the closed-loop noise model. This model is also applicable to other varieties of mode-localized sensors. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
40. Advances in high-performance MEMS pressure sensors: design, fabrication, and packaging.
- Author
-
Han, Xiangguang, Huang, Mimi, Wu, Zutang, Gao, Yi, Xia, Yong, Yang, Ping, Fan, Shu, Lu, Xuhao, Yang, Xiaokai, Liang, Lin, Su, Wenbi, Wang, Lu, Cui, Zeyu, Zhao, Yihe, Li, Zhikang, Zhao, Libo, and Jiang, Zhuangde
- Abstract
Pressure sensors play a vital role in aerospace, automotive, medical, and consumer electronics. Although microelectromechanical system (MEMS)-based pressure sensors have been widely used for decades, new trends in pressure sensors, including higher sensitivity, higher accuracy, better multifunctionality, smaller chip size, and smaller package size, have recently emerged. The demand for performance upgradation has led to breakthroughs in sensor materials, design, fabrication, and packaging methods, which have emerged frequently in recent decades. This paper reviews common new trends in MEMS pressure sensors, including minute differential pressure sensors (MDPSs), resonant pressure sensors (RPSs), integrated pressure sensors, miniaturized pressure chips, and leadless pressure sensors. To realize an extremely sensitive MDPS with broad application potential, including in medical ventilators and fire residual pressure monitors, the “beam-membrane-island” sensor design exhibits the best performance of 66 μV/V/kPa with a natural frequency of 11.3 kHz. In high-accuracy applications, silicon and quartz RPS are analyzed, and both materials show ±0.01%FS accuracy with respect to varying temperature coefficient of frequency (TCF) control methods. To improve MEMS sensor integration, different integrated “pressure + x” sensor designs and fabrication methods are compared. In this realm, the intercoupling effect still requires further investigation. Typical fabrication methods for microsized pressure sensor chips are also reviewed. To date, the chip thickness size can be controlled to be <0.1 mm, which is advantageous for implant sensors. Furthermore, a leadless pressure sensor was analyzed, offering an extremely small package size and harsh environmental compatibility. This review is structured as follows. The background of pressure sensors is first presented. Then, an in-depth introduction to MEMS pressure sensors based on different application scenarios is provided. Additionally, their respective characteristics and significant advancements are analyzed and summarized. Finally, development trends of MEMS pressure sensors in different fields are analyzed. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
41. MXene/PPy@PDMS sponge-based flexible pressure sensor for human posture recognition with the assistance of a convolutional neural network in deep learning.
- Author
-
Xia, Hui, Wang, Lin, Zhang, Hao, Wang, Zihu, Zhu, Liang, Cai, Haolin, Ma, Yanhua, Yang, Zhe, and Zhang, Dongzhi
- Subjects
CONVOLUTIONAL neural networks ,PRESSURE sensors ,DEEP learning ,MACHINE learning ,POSTURE ,RADIAL artery ,PHOTOPLETHYSMOGRAPHY - Abstract
The combination of flexible sensors and deep learning has attracted much attention as an efficient method for the recognition of human postures. In this paper, an in situ polymerized MXene/polypyrrole (PPy) composite is dip-coated on a polydimethylsiloxane (PDMS) sponge to fabricate an MXene/PPy@PDMS (MPP) piezoresistive sensor. The sponge sensor achieves ultrahigh sensitivity (6.8925 kPa
−1 ) at 0–15 kPa, a short response/recovery time (100/110 ms), excellent stability (5000 cycles) and wash resistance. The synergistic effect of PPy and MXene improves the performance of the composite materials and facilitates the transfer of electrons, making the MPP sponge at least five times more sensitive than sponges based on each of the individual single materials. The large-area conductive network allows the MPP sensor to maintain excellent electrical performance over a large-scale pressure range. The MPP sensor can detect a variety of human body activity signals, such as radial artery pulse and different joint movements. The detection and analysis of human motion data, which is assisted by convolutional neural network (CNN) deep learning algorithms, enable the recognition and judgment of 16 types of human postures. The MXene/PPy flexible pressure sensor based on a PDMS sponge has broad application prospects in human motion detection, intelligent sensing and wearable devices. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
42. A miniaturized transit-time ultrasonic flowmeter based on ScAlN piezoelectric micromachined ultrasonic transducers for small-diameter applications.
- Author
-
Gao, Yunfei, Chen, Minkan, Wu, Zhipeng, Yao, Lei, Tong, Zhihao, Zhang, Songsong, Gu, Yuandong Alex, and Lou, Liang
- Subjects
ACOUSTIC impedance ,PIEZOELECTRIC transducers ,ULTRASONIC transducers ,ALUMINUM nitride ,ULTRASONICS ,FLOW measurement - Abstract
Transit-time ultrasonic flowmeters (TTUFs) are among the most widely used devices for flow measurements. However, traditional TTUFs are usually based on a bulk piezoelectric transducer, which limits their application in small-diameter channels. In this paper, we developed a miniaturized TTUF based on scandium-doped aluminum nitride (ScAlN) piezoelectric micromachined ultrasonic transducers (PMUTs). The proposed TTUF contains two PMUT-based transceivers and a π-type channel. The PMUTs contain 13 × 13 square cells with dimensions of 2.8 × 2.8 mm
2 . To compensate for the acoustic impedance mismatch with liquid, a layer of polyurethane is added to the surface of the PMUTs as a matching layer. The PMUT-based transceivers show good transmitting sensitivity (with 0.94 MPa/V surface pressure) and receiving sensitivity (1.79 mV/kPa) at a frequency of 1 MHz in water. Moreover, the dimensions of the π-type channel are optimized to achieve a measurement sensitivity of 82 ns/(m/s) and a signal-to-noise ratio (SNR) better than 15 dB. Finally, we integrate the fabricated PMUTs into the TDC-GP30 platform. The experimental results show that the developed TTUF provides a wide range of flow measurements from 2 to 300 L/h in a channel of 4 mm diameter, which is smaller than most reported channels. The accuracy and repeatability of the TTUF are within 0.2% and 1%, respectively. The proposed TTUF shows great application potential in industrial applications such as medical and chemical applications. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
43. Multi-coefficient eigenmode operation—breaking through 10°/h open-loop bias instability in wideband aluminum nitride piezoelectric BAW gyroscopes.
- Author
-
Liu, Zhenming, Wen, Haoran, and Ayazi, Farrokh
- Subjects
ALUMINUM nitride ,GYROSCOPES ,SOUND waves ,RANDOM walks ,VACUUM chambers ,QUADRATURE domains - Abstract
In this paper, a modification to the eigenmode operation of resonant gyroscopes is introduced. The multi-coefficient eigenmode operation can improve cross-mode isolation due to electrode misalignments and imperfections, which is one of the causes of residual quadrature errors in conventional eigenmode operations. A 1400 µm annulus aluminum nitride (AlN) on a silicon bulk acoustic wave (BAW) resonator with gyroscopic in-plane bending modes at 2.98 MHz achieves a nearly 60 dB cross-mode isolation when operated as a gyroscope using a multi-coefficient eigenmode architecture. The as-born frequency mismatches in multiple devices are compensated by physical laser trimming. The demonstrated AlN piezoelectric BAW gyroscope shows a large open-loop bandwidth of 150 Hz and a high scale factor of 9.5 nA/°/s on a test board with a vacuum chamber. The measured angle random walk is 0.145°/√h, and the bias instability is 8.6°/h, showing significant improvement compared to the previous eigenmode AlN BAW gyroscope. The results from this paper prove that with multi-coefficient eigenmode operations, piezoelectric AlN BAW gyroscopes can achieve a noise performance comparable to that of their capacitive counterpart while having the unique advantage of a large open-loop bandwidth and not requiring large DC polarization voltages. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
44. Wearable and flexible electrochemical sensors for sweat analysis: a review.
- Author
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Gao, Fupeng, Liu, Chunxiu, Zhang, Lichao, Liu, Tiezhu, Wang, Zheng, Song, Zixuan, Cai, Haoyuan, Fang, Zhen, Chen, Jiamin, Wang, Junbo, Han, Mengdi, Wang, Jun, Lin, Kai, Wang, Ruoyong, Li, Mingxiao, Mei, Qian, Ma, Xibo, Liang, Shuli, Gou, Guangyang, and Xue, Ning
- Subjects
ELECTROCHEMICAL sensors ,WEARABLE technology ,ENERGY harvesting ,HUMAN physiology ,POWER resources ,BIOELECTROCHEMISTRY ,PERSPIRATION - Abstract
Flexible wearable sweat sensors allow continuous, real-time, noninvasive detection of sweat analytes, provide insight into human physiology at the molecular level, and have received significant attention for their promising applications in personalized health monitoring. Electrochemical sensors are the best choice for wearable sweat sensors due to their high performance, low cost, miniaturization, and wide applicability. Recent developments in soft microfluidics, multiplexed biosensing, energy harvesting devices, and materials have advanced the compatibility of wearable electrochemical sweat-sensing platforms. In this review, we summarize the potential of sweat for medical detection and methods for sweat stimulation and collection. This paper provides an overview of the components of wearable sweat sensors and recent developments in materials and power supply technologies and highlights some typical sensing platforms for different types of analytes. Finally, the paper ends with a discussion of the challenges and a view of the prospective development of this exciting field. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
45. A skin-integrated device for neck posture monitoring and correction.
- Author
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Luo, Hu, Jin, Tianhao, Zhang, Yu, Tian, Bohao, Zhang, Yuru, and Wang, Dangxiao
- Subjects
POSTURE ,COMPUTER files ,SPONDYLOSIS ,FLEXIBLE printed circuits ,ELECTRONIC circuits ,NECK muscles ,NECK - Abstract
Cervical spondylosis is a common disease that is often caused by long-term abnormal cervical curvature due to activities such as reading books and using computers or smartphones. This paper explores building an untethered and skin-integrated device in an e-skin form factor to monitor and haptically correct neck posture. The proposed design features a multilayered structure that integrates all flexible electronic circuits and components into a compact skin space while being untethered and skin conformal. An accelerometer in the e-skin attaches to the neck for posture sensing, while four vibration actuators closely touch the neck skin to provide localized vibrotactile stimuli that encode four-direction correction cues of neck flexion ± α and lateral bending ± β . To ensure the reliability of posture sensing and vibrotactile rendering during neck movement, it is necessary to prevent the e-skin device from shifting position. Thus, a hollow structure-based method is implemented for stably attaching the e-skin to the neck skin. Experiments validated the e-skin device's sensing precision, skin-conformal compliance, stickiness, stability and effectiveness during the motion of neck postures, including its discrimination of localized four-direction vibrotactile cues. A user study verified the device's performance for sensing and correcting different abnormal neck postures during activities such as using smartphones, reading books, and processing computer files. The proposed e-skin device may create opportunities for more convenient cervical spondylosis prevention and rehabilitation. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
46. Portable visual and electrochemical detection of hydrogen peroxide release from living cells based on dual-functional Pt-Ni hydrogels.
- Author
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Li, Guanglei, Chen, Yao, Liu, Fei, Bi, Wenhua, Wang, Chenxin, Lu, Danfeng, and Wen, Dan
- Subjects
HYDROGEN peroxide ,ELECTROCHEMICAL sensors ,HYDROGELS ,HELA cells ,DETECTION limit - Abstract
It is important to monitor the intra-/extracellular concentration of hydrogen peroxide (H
2 O2 ) in biological processes. However, miniaturized devices that enable portable and accurate H2 O2 measurement are still in their infancy because of the difficulty of developing facile sensing strategies and highly integrated sensing devices. In this work, portable H2 O2 sensors based on Pt-Ni hydrogels with excellent peroxidase-like and electrocatalytic activities are demonstrated. Thus, simple and sensitive H2 O2 sensing is achieved through both colorimetric and electrochemical strategies. The as-fabricated H2 O2 sensing chips exhibit favorable performance, with low detection limits (0.030 μM & 0.15 μM), wide linearity ranges (0.10 μM–10.0 mM & 0.50 μM–5.0 mM), outstanding long-term stability (up to 60 days), and excellent selectivity. With the aid of an M5stack development board, portable visual and electrochemical H2 O2 sensors are successfully constructed without complicated and expensive equipment or professional operators. When applied to the detection of H2 O2 released from HeLa cells, the results obtained by the developed sensors are in good agreement with those from an ultraviolet‒visible spectrophotometer (UV‒vis) (1.97 μM vs. 2.08 μM) and electrochemical station (1.77 μM vs. 1.84 μM). [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
47. A motion characteristics modeled angular position sensor by nonlinear transfer of differential capacitance for miniaturized scanning mirrors.
- Author
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Liu, Songtao, Zhang, Gaofei, Zhang, Lingyun, Wang, Junya, Gong, Minghao, and You, Zheng
- Abstract
In this paper, an angular position sensor (APS) designed for a resonant miniaturized scanning mirror (M-SM) is presented. The APS operates based on the principle of differential variable capacitance, significantly expanding the detectable bandwidth from a few hertz to several kilohertz. By modeling the motion characteristics, the sampling rates of the biaxial scanning angles are 1473.6 times and 539.4 times higher than those of conventional sensors. Initially, the motion characteristics model is presented as a simple harmonic motion, converting sampled capacitance into continuous capacitance. Subsequently, the nonparallel state of the M-SM and sensor is transformed into a parallel state through the space coordinate system transformation. Furthermore, a 2D nonlinear angle transfer function is developed to convert the differential capacitance into an angle, thereby mitigating the nonlinear errors resulting from large angles. Achieving an accuracy better than 0.014°, the measuring range expands from ±0.5729° (±10 mrad) to ±5.026° (± 87 mrad). Additionally, the capturing mode and tracking mode are proposed to monitor real-time angular changes of the M-SM with an accuracy of 0.017°. High-precision APSs have enhanced beam pointing accuracy and resolution and can thereby be used to advance the development of laser components, including light detection and ranging (LiDAR). [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
48. Removal of the rate table: MEMS gyrocompass with virtual maytagging.
- Author
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Miao, Tongqiao, Li, Qingsong, Chen, Liangqian, Li, Junjian, Hu, Xiaoping, Wu, Xuezhong, Wu, Wenqi, and Xiao, Dingbang
- Abstract
High-performance micro-electro-mechanical system (MEMS) gyrocompasses for north-finding systems have been very popular for decades. In this paper, a MEMS north-finding system (NFS) based on virtual maytagging (VM) is presented for the first time. In stark contrast to previous schemes of MEMS-based NFSs (e.g., carouseling, maytagging) and the abandoning rate table, we developed a honeycomb disk resonator gyroscope (HDRG) and two commercial accelerometers for azimuth detection. Instead of the physical rotation of the integrated turntable in traditional NFSs, the vibratory working modes of the HDRG are rotated periodically with electronic control to reduce the uncertainty in the azimuth. After systematically analyzing the principle of NFSs with VM, we designed tests to verify the practicability at the sensor level. A bias instability of 0.0078°/h can be obtained during one day with VM in an HDRG. We also implemented comparative north-finding experiments to further check our strategy at the system level. The accuracy in the azimuth can reach 0.204° for 5 min at 28.2° latitude with VM and 0.172° with maytagging. The results show that without any mechanical turning parts, VM technology makes it possible to develop high-precision handheld MEMS NFSs. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
49. Advanced operation of heated fluidic resonators via mechanical and thermal loss reduction in vacuum.
- Author
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Ko, Juhee, Lee, Bong Jae, and Lee, Jungchul
- Subjects
THERMAL conductivity measurement ,SPECIFIC heat capacity ,THERMAL conductivity ,RESONATORS ,DEUTERIUM oxide ,THERMOPHYSICAL properties - Abstract
For simultaneous and quantitative thermophysical measurements of ultrasmall liquid volumes, we have recently developed and reported heated fluidic resonators (HFRs). In this paper, we improve the precision of HFRs in a vacuum by significantly reducing the thermal loss around the sensing element. A vacuum chamber with optical, electrical, and microfluidic access is custom-built to decrease the convection loss by two orders of magnitude under 10
-4 mbar conditions. As a result, the measurement sensitivities for thermal conductivity and specific heat capacity are increased by 4.1 and 1.6 times, respectively. When differentiating between deionized water (H2 O) and heavy water (D2 O) with similar thermophysical properties and ~10% different mass densities, the signal-to-noise ratio (property differences over standard error) for H2 O and D2 O is increased by 9 and 5 times for thermal conductivity and specific heat capacity, respectively. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
50. Enhanced YOLOv5 network-based object detection (BALFilter Reader) promotes PERFECT filter-enabled liquid biopsy of lung cancer from bronchoalveolar lavage fluid (BALF).
- Author
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Liu, Zheng, Zhang, Jixin, Wang, Ningyu, Feng, Yun'ai, Tang, Fei, Li, Tingyu, Lv, Liping, Li, Haichao, Wang, Wei, and Liu, Yaoping
- Subjects
DEEP learning ,BRONCHOALVEOLAR lavage ,LUNG cancer ,TECHNOLOGICAL innovations ,LIQUIDS ,BIOPSY - Abstract
Liquid biopsy of cancers, detecting tumor-related information from liquid samples, has attracted wide attentions as an emerging technology. Our previously reported large-area PERFECT (Precise-Efficient-Robust-Flexible-Easy-Controllable-Thin) filter has demonstrated competitive sensitivity in recovering rare tumor cells from clinical samples. However, it is time-consuming and easily biased to manually inspect rare target cells among numerous background cells distributed in a large area (Φ ≥ 13 mm). This puts forward an urgent demand for rapid and bias-free inspection. Hereby, this paper implemented deep learning-based object detection for the inspection of rare tumor cells from large-field images of PERFECT filters with hematoxylin-eosin (HE)-stained cells recovered from bronchoalveolar lavage fluid (BALF). CenterNet, EfficientDet, and YOLOv5 were trained and validated with 240 and 60 image blocks containing tumor and/or background cells, respectively. YOLOv5 was selected as the basic network given the highest mAP@0.5 of 92.1%, compared to those of CenterNet and EfficientDet at 85.2% and 91.6%, respectively. Then, tricks including CIoU loss, image flip, mosaic, HSV augmentation and TTA were applied to enhance the performance of the YOLOv5 network, improving mAP@0.5 to 96.2%. This enhanced YOLOv5 network-based object detection, named as BALFilter Reader, was tested and cross-validated on 24 clinical cases. The overall diagnosis performance (~2 min) with sensitivity@66.7% ± 16.7%, specificity@100.0% ± 0.0% and accuracy@75.0% ± 12.5% was superior to that from two experienced pathologists (10–30 min) with sensitivity@61.1%, specificity@16.7% and accuracy@50.0%, with the histopathological result as the gold standard. The AUC of the BALFilter Reader is 0.84 ± 0.08. Moreover, a customized Web was developed for a user-friendly interface and the promotion of wide applications. The current results revealed that the developed BALFilter Reader is a rapid, bias-free and easily accessible AI-enabled tool to promote the transplantation of the BALFilter technique. This work can easily expand to other cytopathological diagnoses and improve the application value of micro/nanotechnology-based liquid biopsy in the era of intelligent pathology. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
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