426,994 results
Search Results
2. Paper-based analytical device for point-of-care nucleic acid quantification combining CRISPR/Cas12a and a personal glucose meter.
- Author
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Tanifuji, Yohei, Tong, Guodong, Hiruta, Yuki, and Citterio, Daniel
- Subjects
HUMAN papillomavirus ,NUCLEIC acids ,MAGNETIC separators ,FILTER paper ,CRISPRS - Abstract
Although CRISPR-based nucleic acid detection has great potential in point-of-care testing due to its simplicity, it has been rarely integrated into paper-based analytical devices (PADs), which are attractive platforms to simplify assays. This work introduces a CRISPR-assisted nucleic acid quantification approach integrated into a PAD with signal readout by a personal glucose meter (PGM). Retention of magnetic beads by filter paper and pre-deposition of all required reagents by freeze-drying stabilized with trehalose enabled the indirect quantification of human papilloma virus (HPV) DNA through a PGM readout without complicated user intervention and complex reagent handling. The calculated limit of detection was 57 pM, which is comparable with other amplification-free CRISPR-based assays detecting nucleic acids. The fully integrated device exhibited good storage stability for up to 4 weeks, suggesting its applicability toward practical point-of-care nucleic acid quantification. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. A non-contact porous composite fiber paper-based humidity sensor for wearable breathing and skin humidity monitoring.
- Author
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Liang, Aoxun and Chen, Xueye
- Abstract
Flexible sensors capable of continuously monitoring surface moisture and respiratory status play a crucial role in human health monitoring. However, manufacturing flexible humidity sensors at low cost remains challenging in traditional manufacturing industries. This study introduces a humidity sensor prepared by impregnating paper with LiCl solution and using carbon nanotube-carboxymethyl cellulose composite paper-based fibers to fabricate interdigital electrodes. This sensor exhibits high sensitivity to gas humidity due to its flexible and porous electrode structure and moisture-sensitive substrate. The prepared porous fiber paper-based humidity sensor (PLFC) is used for detecting small amounts of gas humidity ranging from 33% RH to 98% RH, with a response time of only 500 ms and a linearity of R
2 = 0.960. In terms of human health monitoring, it can continuously monitor respiratory rate and amplitude and non-contactly perceive the humidity status of body parts. By reflecting the tester's physiological condition based on surface humidity, it is highly beneficial for patient recovery care and health preservation. Therefore, the design and ideas proposed in this work are of significant importance for the future development and application of wearable respiratory sensors and moisture sensors. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
4. Surface modification of paper-based microfluidic devices via initiated chemical vapor deposition.
- Author
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Bacheller, Stacey and Gupta, Malancha
- Subjects
CHEMICAL vapor deposition ,MICROFLUIDIC devices ,SURFACE tension ,CELLULOSE ,SURFACE coatings - Abstract
Paper-based microfluidic devices offer an ideal platform for biological and environmental detection because they are low-cost, small, disposable, and fill by natural capillary action. In this tutorial review, we discuss the surface modification of paper-based microfluidic devices with functional polymers using the initiated chemical vapor deposition (iCVD) process. The iCVD process is solventless and therefore ideal for coating cellulose paper because there are no surface tension effects or solvent compatibility issues. The process can also be scaled up for roll-to-roll manufacturing. The chemical functionality of the iCVD coating can be tuned by varying the monomer and the structure of the coating can be tuned by varying the processing parameters. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
5. Designing a novel paper-based microfluidic disc for rapid and simultaneous determination of multiple nutrient salts in water.
- Author
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Sun, Zhentao, Zhao, Youquan, Liu, Yameng, Chen, Chen, and Chen, Hao
- Subjects
WATER quality ,SALINE waters ,POLYWATER ,WATER analysis ,WATER sampling ,NITRITES - Abstract
In the face of worsening water quality and escalating water environmental emergencies, this study developed a paper-based microfluidic disk for rapid, on-site determination of ammonia nitrogen, nitrates, nitrites, and phosphates in water. The method utilizes centrifugal microfluidics and paper-based technology, thus simplifying the operation while eliminating the need for on-site reagent preparation. Experimental results demonstrate that the disk requires only 80 microliters of a water sample and 2 minutes to complete the quantitative analysis of the four nutrients, with a coefficient of variation below 1.72% and spike recoveries ranging from 92% to 113%. The development of the disk provides an effective and rapid, on-site testing tool for water quality analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
6. Flexible trilayer cellulosic paper separators engineered with the BaTiO3 ferroelectric fillers for high energy density sodium-ion batteries.
- Author
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Sapra, Simranjot K., Das, Mononita, Raja, M. Wasim, Chang, Jeng-Kuei, and Dhaka, Rajendra S.
- Abstract
Cellulose-based paper separators are employed in sodium-ion batteries (SIBs) as a viable and economical substitute of conventional separators, owing to their sustainability, scalability, safety and cost-effectiveness. We design a full cell configuration having Na
3 V2 (PO4 )3 as the cathode and pre-sodiated hard carbon as the anode with different separators and compare the electrochemical performance of these ceramic-impregnated polymer-coated cellulose paper separators with that of commercial glass fiber separators. Notably, the paper-based multilayer separators provide desirable characteristics such as excellent electrolyte wettability, thermal stability up to 200 °C, and ionic conductivity, which are essential for the efficient operation of SIBs. The cellulose separator is coated with a layer of polyvinylidene fluoride polymer, followed by a second layer of styrene butadiene rubber (SBR) polymer in which ferroelectric filler BaTiO3 is integrated, which interacts with the polymer hosts through Lewis acid–base interactions and improves the conduction mechanism for the Na+ ions. The final lamination is performed by varying the SBR concentrations (0.5, 0.75, and 1.0 w/v%). The incorporated polymer matrices improve the flexibility, adhesion and dispersion of the nanoparticles and affinity of the electrolyte to the electrode. The morphology of the paper separators shows uniform interconnected fibers with a porous structure. Interestingly, we find that the paper separator with 0.75 w/v% content of SBR exhibits decreased interfacial resistance and improved electrochemical performance, having retention of 62% and nearly 100% coulombic efficiency up to 240 cycles, as compared to other concentrations. Moreover, we observe the energy density to be around 376 W h kg−1 (considering the cathode weight), which was found to be comparable to that of the commercially available glass fiber separator. Our results demonstrate the potential of these multilayer paper separators towards achieving sustainability and safety in energy storage systems. [ABSTRACT FROM AUTHOR]- Published
- 2025
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7. Ultrasensitive surface-enhanced Raman scattering sensing of Cr(VI) with a Au@Ag nano-sea urchin paper-tip substrate.
- Author
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Xu, Ronghui, Tan, Lu, Xu, Wei, Xiao, Li, Zheng, Yingping, Li, Ying, and Lou, Yongbing
- Subjects
SERS spectroscopy ,DRINKING water ,SUBSTRATES (Materials science) ,ENVIRONMENTAL monitoring ,OXIDATION-reduction reaction - Abstract
Bimetallic Au@Ag nano-sea urchins (Au@Ag NSUs) functionalized with methimazole were synthesized and combined with paper tips as efficient surface-enhanced Raman scattering (SERS) substrates for ultrasensitive Cr(VI) detection. The redox reaction between methimazole and Cr(VI) ensured the reliability of quantitative Cr(VI) analysis. When droplets were continuously dropped on the tip of the paper, based on the gravity effect, the nanoparticles achieved enrichment at the front end of the tip, which further improved the sensitivity of detection. The detection limit is as low as 0.956 ng L
−1 , demonstrating its excellent performance in ultrarace Cr(VI) detection. Additionally, the SERS sensor was successfully applied to the detection of Cr(VI) in real water samples, such as lake water and tap water, indicating its wide application potential in environmental monitoring. This study not only provides an efficient and reliable new method for detecting Cr(VI) but also shows the great prospect of paper-based SERS sensors in practical applications. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
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8. Humidity-enhanced microfluidic plasma separation on Chinese Xuan-papers.
- Author
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Xianchang Wu, Shuqiang Min, Tonghuan Zhan, Yange Huang, Hui Niu, and Bing Xu
- Subjects
BLOOD testing ,BLOOD sugar ,BLOOD plasma ,BLOOD volume ,MICROFLUIDIC devices - Abstract
The first step in blood testing necessitates blood separation to obtain an adequate volume of plasma. Traditional centrifugation is bulky, expensive and electricity-powered, which is not suitable for micro-scale blood plasma separation in point-of-care testing (POCT) cases. Microfluidic paper-based plasma separation devices present a promising alternative for plasma separation in such occasions. However, they are limited in terms of plasma yield, which hinders analyte detection. Herein, we proposed a humidity-enhanced paper-based microfluidic plasma separation method to address this issue. Specifically, paper was first treated by blood-typing antibodies, then samples of whole blood were introduced into the prepared paper. After waiting for 5 min for RBC agglutination and plasma wicking under high humidity, micro-scale plasma separation from whole blood was achieved. As a result, an extremely high plasma yield of up to 60.1% could be separated from whole blood through using Xuan-paper. Meanwhile, the purity of plasma could reach 99.99%. Finally, this innovative approach was effortlessly integrated into distance-based glucose concentration detection, enabling rapid determination of blood glucose levels through naked-eye observation. Considering the simplicity and inexpensiveness of this method, we believe that this technology could be integrated to more paper-based microfluidic analytical devices for rapid and accurate detection of plasma analytes in POCT. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
9. Corrective protocol to predict interference free sensor response for paper-based solution sampling coupled with heavy metal sensitive ion-selective electrodes.
- Author
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Yang, Mingpeng, Silva, Rochelle, Zhao, Ke, Ding, Ruiyu, Foo, Jit Loong Cyrus, Ge, Liya, and Lisak, Grzegorz
- Subjects
HEAVY metals ,SUBSTRATES (Materials science) ,METAL ions ,BIOCHEMICAL substrates ,MOIETIES (Chemistry) - Abstract
Paper-based microfluidics combined with potentiometric measurement has emerged as an attractive approach for detecting various chemical ionic moieties. Detection of heavy metal ions, using paper substrates as solution sampling and delivery systems remains challenging despite efforts to introduce several physico-chemical paper substrate modifications to stop adsorption of ions onto the paper substrates. This study quantitatively investigates the adsorption of heavy metal ions on the paper substrates during paper-based potentiometric measurements and explains the super-Nernstian response of potentiometric sensors through local depletion of heavy metal ions from the solution. Consequently, based on the investigated ion adsorption, a corrective potential protocol was established for the electrodes coupled with paper-based solution sampling by predicting interference free sensor response from paper-based measurement. Furthermore, the ion adsorption was also recorded for mixed metal ion solutions to understand competitive primary/interfering ions adsorption onto the paper substrates and establish corrective measures to predict interference free sensor response. In this method, no modifications of the paper substrates are necessary before actual potentiometric measurements. The proposed corrective protocol allows prediction of sensor response based on the paper-based solution sampling potentiometric measurement, providing a simple methodological approach based on correction of potential readout of the potentiometric sensor, thus completely resigning from the need of modifying paper substrate for measurements of heavy metal ions. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
10. Advancing paper-based sensors with MXenes and MOFs: exploring cutting-edge innovations.
- Author
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Larijani, Sepehr, Zarepour, Atefeh, Khosravi, Arezoo, Iravani, Siavash, Eskandari, Mahnaz, and Zarrabi, Ali
- Abstract
MXenes and metal–organic frameworks (MOFs) are emerging as promising materials for integration into paper-based sensors (PSs), offering unique properties that can enhance sensor performance in various applications. MXenes, with their high conductivity and large surface area, and MOFs, known for their tunable porosity and chemical functionalities, provide distinct advantages to PSs. By leveraging the exceptional properties of MXenes and MOFs, researchers can develop PSs with improved sensitivity, selectivity, and stability, paving the way for advanced sensing platforms with diverse capabilities in environmental monitoring, healthcare diagnostics, and beyond. However, challenges still exist for incorporating MXenes and MOFs into PSs, including sensitivity, stability, interference, and scalability. Addressing these challenges is crucial for optimizing sensor performance and reliability. Herein, recent developments pertaining to the applications of MXenes and MOFs in PSs are discussed, focusing on challenges and future perspectives. By examining the unique properties of these materials, exploring innovative sensor designs, and discussing potential solutions to current challenges, this review seeks to pave the way for the development of next-generation PSs with enhanced sensitivity, selectivity, and reliability. [ABSTRACT FROM AUTHOR]
- Published
- 2025
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11. Quantification of creatinine in whole blood by a paper-based device using an RGB sensor.
- Author
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Gautam, Neha, Verma, Ranjana, Muduli, Priya Ranjan, Kar, Shantimoy, and Sarkar, Arnab
- Published
- 2024
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12. A green approach to nanoplastic detection: SERS with untreated filter paper for polystyrene nanoplastics.
- Author
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Chaisrikhwun, Boonphop, Balani, Mary Jane Dacillo, Ekgasit, Sanong, Xie, Yunfei, Ozaki, Yukihiro, and Pienpinijtham, Prompong
- Subjects
SERS spectroscopy ,FILTER paper ,SUSTAINABILITY ,SILVER nanoparticles ,NANOPARTICLES - Abstract
Plastic pollution at the nanoscale continues to pose adverse effects on environmental sustainability and human health. However, the detection of nanoplastics (NPLs) remains challenging due to limitations in methodology and instrumentation. Herein, a "green approach" for surface-enhanced Raman spectroscopy (SERS) was exploited to detect polystyrene nanospheres (PSNSs) in water, employing untreated filter paper and a simple syringe-filtration set-up. This SERS protocol not only enabled the filtration of nano-sized PSNSs, which are smaller than the pore size of the ordinary filter paper, but also offered SERS enhancement by utilizing quasi-spherical-shaped silver nanoparticles (AgNPs) as the SERS-active substrate. The filtering of NPLs was accomplished by adding an aggregating agent to the nanoparticle mixture, which caused the aggregation of NPLs and AgNPs, resulting in a larger cluster and more hot spots for SERS detection. The optimal aggregating agent and its concentration, as well as the volume ratio between the AgNPs and NPLs, were also optimized. This SERS method successfully detected and quantified PSNSs of various sizes (i.e., 100, 300, 460, 600, and 800 nm) down to a limit of detection (LOD) of about 0.31 μg mL
−1 . The method was also validated against the presence of several interferents (i.e., salts, sugars, amino acids, and surfactants) and was proven practical, as evidenced by the detection of 800nm PSNSs in drinking and tap water (LODs of 1.47 and 1.55 μg mL−1 , respectively). [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
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13. Single-fibre coating and additive manufacturing of multifunctional papers.
- Author
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Mikolei, Joanna Judith, Helbrecht, Christiane, Pleitner, Janine Christin, Stanzel, Mathias, Pardehkhorram, Raheleh, Biesalski, Markus, Schabel, Samuel, and Andrieu-Brunsen, Annette
- Published
- 2024
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14. Screen printed 3D microfluidic paper-based and modifier-free electroanalytical device for clozapine sensing.
- Author
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Ghanbari, Mohammad Hossein, Biesalski, Markus, Friedrich, Oliver, and Etzold, Bastian J. M.
- Subjects
SCREEN process printing ,CYCLIC voltammetry ,CHARGE exchange ,DETECTION limit ,ANTIPSYCHOTIC agents - Abstract
The increasing demand in healthcare for accessible and cost-effective analytical tools is driving the development of reliable platforms to the customization of therapy according to individual patient drug serum levels, e.g. of anti-psychotics in schizophrenia. A modifier-free microfluidic paper-based electroanalytical device (μPED) holds promise as a portable, sensitive, and affordable solution. While many studies focus on the working electrode catalysts, improvements by engineering aspects e.g. of the electrode arrangement are less reported. In our study, we demonstrate the enhanced capabilities of the 3D electrode layout of μPED compared to 2D μPED arrangements. We especially show that screen printing can be employed to prepare 3D μPEDs. We conducted a comparison of different 2D and 3D electrode arrangements utilizing cyclic voltammetry in [Fe(CN)
6 ]3−/4− , along with square-wave voltammetry for clozapine (CLZ) sensing. Our findings reveal that the utilization of the 3D μPED leads to an increase in both the electrochemically active surface area and the electron transfer rate. Consequently, this enhancement contributes to improve sensitivity in the CLZ sensing. The 3D μPED clearly outperforms the 2D μPED arrangement in terms of signal strength. With the 3D μPED under the optimized conditions, a linear dose–response for a concentration range from 7.0 to 100 μM was achieved. The limit of detection and sensitivity was determined to be 1.47 μM and 1.69 μA μM−1 cm−2 , respectively. This evaluation is conducted in the context of detection and determination of CLZ in a human blood serum sample. These findings underscore the potential of the 3D μPED for future applications in pharmacokinetic analyses and clinical tests to personalize the management of schizophrenia. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
15. A composite dressing combining ultralong hydroxyapatite nanowire bio-paper and a calcium alginate hydrogel accelerates wound healing.
- Author
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Zhu, Yuankang, Hao, Liangshi, Luo, Yurui, Gao, Jing, Xu, Fengming, Li, Han, Hao, Changning, Lin, Chao-Po, Yu, Han-Ping, Zhu, Ying-Jie, and Duan, Junli
- Abstract
An acute wound is the most common type of skin injury. Developing wound dressings with excellent mechanical properties, wound protection, comfort, angiogenic capacity and therapeutic effects is significant for effective treatments, yet remains challenging. Herein, we have designed a novel HAP–Alg composite dressing comprising a complementary ultralong hydroxyapatite (HAP) nanowire bio-paper and calcium alginate hydrogel. The HAP bio-paper assembled by ultralong HAP nanowires, in contrast to typical brittle HAP bio-ceramics, exhibits a highly flexible and interwoven structure to enhance the mechanical and protective performance of an alginate hydrogel, and the alginate matrix creates a moist environment for skin regeneration. Therefore, the HAP–Alg composite dressing presents good mechanical properties and high resistance to swelling and shrinkage, along with a reliable bacterial shielding ability. In addition, its moisturizing effect can deliver bioactive calcium ions to promote angiogenesis, accelerate re-epithelialization and reduce scar formation. In vitro studies reveal that the HAP–Alg composite dressing has excellent biocompatibility, promotes cell migration and angiogenesis, and enhances calcium ion influx. In vivo wound models further prove the ability of the HAP–Alg composite dressing to accelerate wound closure, enhance collagen deposition, and induce neovascularization. This work demonstrates that the HAP–Alg composite dressing offers a promising wound dressing for acute wound treatment and protection. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
16. A paper-in-polymer-pond (PiPP) hybrid microfluidic microplate for multiplexed ultrasensitive detection of cancer biomarkers.
- Author
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Timilsina, Sanjay S. and Li, XiuJun
- Subjects
POLYMETHYLMETHACRYLATE ,RESOURCE-limited settings ,CARCINOEMBRYONIC antigen ,TUMOR markers ,COLORIMETRIC analysis - Abstract
Conventional affinity-based colorimetric enzyme-linked immunosorbent assay (ELISA) is one of the most widely used methods for the detection of biomarkers. However, rapid point-of-care (POC) detection of multiple cancer biomarkers by conventional ELISA is limited by long incubation time, large reagent volume, and costly instrumentation along with low sensitivity due to the nature of colorimetric methods. Herein, we have developed a reusable and cost-effective paper-in-polymer-pond (PiPP) hybrid microfluidic microplate for ultrasensitive and high-throughput multiplexed detection of disease biomarkers within an hour without using specialized instruments. A piece of pre-patterned chromatography paper placed in the PMMA polymer pond facilitates rapid protein immobilization to avoid intricate surface modifications of polymer and can be changed with a fresh paper layer to reuse the device. Reagents can be simply delivered from the top PMMA layer to multiple microwells in the middle PMMA layer via flow-through microwells, thereby increasing the efficiency of washing and avoiding repeated manual pipetting or costly robots. Quantitative colorimetric analysis was achieved by calculating the brightness of images scanned by an office scanner or a smartphone camera. Sandwich-type immunoassay was performed in the PiPP hybrid device after the optimization of multiple assay conditions. Limits of detection of 0.32 ng mL
−1 for carcinoembryonic antigen (CEA) and 0.20 ng mL−1 for prostate-specific antigen (PSA) were obtained, which were about 10-fold better than those of commercial ELISA kits. We envisage that this simple but versatile hybrid device can have broad applications in various bioassays in resource-limited settings. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
17. Boric acid-crosslinked poly(vinyl alcohol): biodegradable, biocompatible, robust, and high-barrier paper coating.
- Author
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Choe, Shinhyeong, You, Seulki, Park, Kitae, Kim, Youngju, Park, Jehee, Cho, Yongjun, Seo, Jongchul, Yang, Hanseul, and Myung, Jaewook
- Subjects
PLASTIC scrap ,PACKAGING waste ,SURFACE coatings ,PLASTICS in packaging ,KRAFT paper ,BIODEGRADABLE plastics - Abstract
The accumulation of plastic packaging wastes in the natural environment highlights the significance of sustainable alternatives. Paper is widely used as a biodegradable packaging material, but poor mechanical strength, barrier properties, and water resistance limit its utility. Typical paper coating materials applied to overcome such drawbacks, such as polyethylene (PE) and ethylene vinyl alcohol (EVOH), are not desirable for sustainability due to environmental persistence. Here, we report a biodegradable, biocompatible, robust, and high-barrier paper coating strategy using boric acid-crosslinked poly(vinyl alcohol) (PVA). Various crosslinked-PVA solutions were prepared using boric acid (BA) and hydrochloric acid (HCl) as a crosslinker and an acid catalyst, respectively. The solutions were coated onto the Kraft paper (KP) through facile bar coating with epichlorohydrin (ECH) as a binder (henceforth referred to as coated papers). The coated papers (KP-P, KP-PB, KP-PBH) show remarkably improved oxygen (∼0.89 cc m
−2 d−1 ) and water vapor (∼5.17 g m−2 d−1 ) barrier properties as well as tensile strength (∼53.0 MPa) that is retained in moist conditions. The coated papers were significantly mineralized into CO2 (59.2–81.6% over 111 d) in the simulated marine environment biodegradation test. Depolymerization of polymer chains and surface degradation of coated papers are evidenced via FT-IR and SEM, respectively. The microcosm test revealed that the intensive disintegration of the coated papers is synergistically driven by both biotic and abiotic factors (i.e., mechanical stress). Moreover, the in vitro biocompatibility tests employing human embryonic kidney and mouse embryonic fibroblast cells, and in vivo biocompatibility test with mice suggest that the coated papers are highly biocompatible. This work provides a promising strategy for paper packaging that enhances packaging performance without compromising environmental sustainability. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
18. Paper-based sensors: affordable, versatile, and emerging analyte detection platforms.
- Author
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Malik, Sumit, Singh, Joginder, Saini, Kajal, Chaudhary, Vivek, Umar, Ahmad, Ibrahim, Ahmed A., Akbar, Sheikh, and Baskoutas, Sotirios
- Published
- 2024
- Full Text
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19. Nanoparticle-enhanced laser-induced breakdown spectroscopy for serum element analysis using an Ag NP-coated filter paper substrate.
- Author
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Zhang, Xinxin, Li, Xiaohui, Chen, Xue, Shi, Mengshan, and Ren, Tao
- Subjects
LASER-induced breakdown spectroscopy ,BLOOD serum analysis ,FILTER paper ,RADIANT intensity ,SILVER ,ELECTRON density - Abstract
Serum contains rich elemental information, and the elemental analysis of the serum using laser-induced breakdown spectroscopy (LIBS) can help with the diagnosis and treatment of cancer. In this work, serum specimens from breast cancer patients were used as samples, and the elements Mg, Ca, and K were analyzed using LIBS. Silver nanoparticles (Ag NPs) were introduced to enhance spectral emission intensities, and this technique is known as nanoparticle-enhanced LIBS (NELIBS). An Ag NP-coated filter paper (Ag NP paper) substrate was prepared and was compared with silicon and aluminum substrates for NELIBS analysis. The Ag NP paper substrate showed lower spectral intensity variances and better elemental distribution uniformity due to the reduced coffee-ring effect compared with silicon and aluminum substrates. The enhanced effect of the Ag NP paper was optimized by adjusting serum volume and Ag NPs concentration. It was found that Mg, Ca, and K required different optimal conditions for spectral enhancement. The highest enhancement factors (EF) for Mg, Ca, and K were 1.85, 1.76, and 3.10, respectively. The electron temperature (T
e ) and electron number density (Ne ) of NELIBS plasmas were measured using the Boltzmann plot and Stark broadening methods and compared with those of the normal LIBS plasmas. The Te and Ne of the NELIBS and normal LIBS samples were generally comparable with each other. Higher Ag NP concentrations led to lower Te values for NELIBS plasmas. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
20. A length-band fluorescence-based paper analytical device for detecting dipicolinic acid via ofloxacin complexation with Cu2+.
- Author
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Nguyen Ngoc Nghia, Bui The Huy, Nguyen Huu Hieu, Nguyen Thi Kim Phuong, and Yong-Ill Lee
- Subjects
BACTERIAL spores ,FLUORESCENCE quenching ,DETECTION limit ,LABORATORY equipment & supplies ,FLUORESCENCE - Abstract
Dipicolinic acid (DPA) is a key biomarker of bacterial spores. In this study, we present a novel distancebased paper analytical device (d-PAD) for the fluorescence sensing of DPA. The detection mechanism relies on the complexation of ofloxacin (OFL) with Cu
2+ ions, where Cu2+ quenches the fluorescence of OFL via static quenching. Upon the introduction of DPA, it interacts with the OFL-Cu2+ complex, resulting in an enhanced fluorescence signal from OFL. The assay demonstrated a limit of detection (LOD) of 0.08 µM over a range of 0.6-120 µM, as measured using a spectrofluorometer. The d-PAD was designed for efficient reagent transport through capillary action on paper substrates, allowing for rapid on-site DPA analysis without requiring advanced laboratory equipment. The length of the fluorescent bands on the d-PADs was proportional to the concentration of DPA, providing a simple and effective readout method. With a sensitivity of 0.6 µM, the device shows a strong response to varying DPA concentrations. This distance-based platform offers a straightforward and quantitative approach to result interpretation, making it a promising tool for detecting bacterial spores in real samples. The development and optimization of this paper-based microfluidic assay represent a significant step forward in portable diagnostic technologies. [ABSTRACT FROM AUTHOR]- Published
- 2025
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21. Novel indoloquinoxaline-tetraphenylethylene star-like conjugated isomers: aggregation-induced emission and acidichromism for versatile fluorescent applications.
- Author
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Mao, Guanghao, Yang, Huaxin, Deng, Shuhang, Cao, Wenyu, Deng, Ping, and Yu, Yan
- Subjects
FRONTIER orbitals ,ENERGY levels (Quantum mechanics) ,LOGIC circuits ,IMPLICATION (Logic) ,FILTER paper ,STAR-branched polymers - Abstract
A pair of star-like conjugated isomers (Tetra-8-IQ and Tetra-9-IQ) with indolo[2,3-b]quinoxaline as the star arm and tetraphenylethylene as the star core have been designed and synthesized. A comparative study has been conducted on the structural characteristics, electronic energy levels, spectral absorption, aggregation-induced emission, acid-stimulus response, and fluorescent applications of the two isomers. The results show that Tetra-8-IQ has lower lowest unoccupied molecular orbital/highest occupied molecular orbital energy levels, more redshifted optical absorption, and stronger fluorescence emission than Tetra-9-IQ. The two isomers are novel organic fluorescent materials as they both possess aggregation-induced emission characteristics and reversible acidichromism features. Tetra-8-IQ and Tetra-9-IQ were successfully applied in filter paper test strips and PMMA-based blending film to achieve fluorescent switch signals. Based on these findings, the INHIBIT and IMPLICATION molecular logic gates were successfully established, where acid and base were adopted as the input stimuli. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
22. Tetracationic macrocycles form highly stable inclusion complexes with uric acid enabling solution-phase and paper-strip bicolor colorimetric detection of hyperuricemia.
- Author
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Sun, Jian-Da, Zhang, Jiangshan, Zhuang, Sheng-Yi, Wang, Hui, Zhou, Wei, Li, Zhan-Ting, and Zhang, Dan-Wei
- Abstract
The uric acid (UA) level in the human body is one of the important clinical indicators associated with gout and various metabolic diseases. Here, we appeal to side chain-appended tetracationic macrocycles that have intrinsic fluorescence emission to bind UA for its colorimetric detection. We show that the introduction of four aminoethoxy side chains to the naphthalene-derived macrocycle leads to a binding constant of 4.45 × 10
6 M−1 , which is the highest among those achieved using reported receptors. This high binding affinity enables the generation of a visual sensing system for detecting UA of hyperuricemia from that of normal by mixing with rhodamine B, which works in solution as well as paper assays. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
23. A rigid–soft hybrid paper-based flexible pressure sensor with an ultrawide working range and frequency bandwidth.
- Author
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Cong Wang, Jiamin Quan, Linpeng Liu, Peilin Cao, Kaiwen Ding, Yulong Ding, Xianshi Jia, Dejin Yan, Nai Lin, and Ji'an Duan
- Abstract
The demand for flexible pressure sensors with high performance is increasing with the growing wearable technology market. According to the developing requirement for green electronics, paper-based sensors, which are more environmentally friendly, have received more and more attention. However, the intrinsic mechanical properties of paper materials limit the sensing performance of paper-based sensors, such as restricted working range and response bandwidth. Herein, a rigid–soft hybrid design strategy is proposed to improve the sensing performance of paper-based pressure sensors, and bioinspired microstructures are introduced into the architecture of sensors for further improvement. As a result, the prepared paper-based pressure sensor has a faster response/recovery speed (<50 ms), a wide sensing range (1 MPa) and frequency response bandwidth (0.05–1000 Hz) and excellent cycling stability (5000 cycles). In addition, the paper-based pressure sensor is superhydrophobic with a water contact angle of 152.62°. Based on the excellent sensing performance and waterproofness, the paper-based pressure sensor can be used as a wearable device for detecting joint movements or gait of humans/robots in both air and underwater. In addition, it can be used to send communication signals, showing great potential for applications in future underwater rescue. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
24. Integration of paper-based analytical devices with digital microfluidics for colorimetric detection of creatinine.
- Author
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Velasco, Larissa G., Rocha, Danielly S., de Campos, Richard P. S., and Coltro, Wendell K. T.
- Subjects
TOXIC substance exposure ,DIGITAL technology ,SAMPLING (Process) ,STANDARD deviations ,MICROFLUIDICS - Abstract
Digital microfluidics (DMF) is a platform that enables the automated manipulation of individual droplets of sizes ranging from nanoliter to microliter and can be coupled with numerous techniques, including colorimetry. However, although the DMF electrode architecture is highly versatile, its integration with different analytical methods often requires either changes in sample access, top plate design, or the integration of supplementary equipment into the system. As an alternative to overcome these challenges, this study proposes a simple integration between paper-based analytical devices (PADs) and DMF for automated and eco-friendly sample processing aiming at the colorimetric detection of creatinine (CR, an important biomarker for kidney disease) in artificial urine. An optimized and selective Jaffé reaction was performed on the device, and the reaction products were delivered to the PAD, which was subsequently analyzed with a bench scanner. The optimal operational parameters on the DMF platform were a reaction time of 45 s with circular mixing and image capture after 5 min. Under optimized conditions, a linear behavior was obtained for creatinine concentrations ranging from 2 to 32 mg dL
−1 , with limits of detection and quantitation equal to 1.4 mg dL−1 and 2.0 mg dL−1 , respectively. For the concentration range tested, the relative standard deviation varied from 2.5 to 11.0%, considering four measurements per concentration. CR-spiked synthetic urine samples were subjected to analysis via DMF-PAD and the spectrophotometric reference method. The concentrations of CR determined using both analytical techniques were close to the theoretical values, with the resultant standard deviations of 2–9% and 1–4% for DMF-PADs and spectrophotometry, respectively. Furthermore, the recovery values were within the acceptable range, with DMF-PADs yielding 96–108% and spectrophotometry producing 95–102%. Finally, the greenness of the DMF-PAD and spectrophotometry methods was evaluated using the Analytical Greenness (AGREE) metric software, in which 0.71 and 0.51 scores were obtained, respectively. This indicates that the proposed method presents a higher greenness level, mainly due to its miniaturized characteristics using a smaller volume of reagent and sample and the possibility of automation, thus reducing user exposure to potentially toxic substances. Therefore, the DMF-PADs demonstrated great potential for application in the clinical analysis of creatinine, aiding in routine tests by introducing an automated, simple, and environmentally friendly process. [ABSTRACT FROM AUTHOR]- Published
- 2025
- Full Text
- View/download PDF
25. A numerical platform for predicting the performance of paper-based analytical devices.
- Author
-
Yan, Lawrence K. Q., Tam, Sze Kee, and Ng, Ka Ming
- Published
- 2024
- Full Text
- View/download PDF
26. Quantitative and equipment-free paper-based agglutination assay of bacterial cells.
- Author
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Al-Tamimi, Mohammad, Altarawneh, Shahed, Mustafa, Minas A., El-sallaq, Mariam, and Shihab, Penelope
- Published
- 2024
- Full Text
- View/download PDF
27. Catechin-induced cellulose: a new material for harvesting triboelectricity.
- Author
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Hisna, P. A. and Pradyumnan, P. P.
- Published
- 2024
- Full Text
- View/download PDF
28. A dual-mode homogeneous electrochemical-colorimetric biosensing sensor for carcinoembryonic antigen detection based on a microfluidic paper-based analysis device.
- Author
-
Zhang, Yao, Xu, Jiaqi, Shen, Jianing, Zhang, Bo, Xue, Tianhao, Lv, Xiaoqing, Zhang, Xiaofang, and Zhu, Guixian
- Published
- 2024
- Full Text
- View/download PDF
29. Simultaneous production of CO and H2O2 by paired electrolysis coupling CO2 reduction and water oxidation.
- Author
-
Wu, Jian-Hao, Guo, Rong-Jie, Wang, Jia-Wei, Niu, Fu-Jun, Guo, Lie-Jin, and Ouyang, Gangfeng
- Subjects
OXIDATION of water ,CARBON paper ,TIN oxides ,ENERGY consumption ,ELECTROLYSIS ,HYDROGEN peroxide - Abstract
Here, a novel paired electrolysis system is constructed, where fluorine-doped tin oxide glass serves as the anode for the water oxidation reaction to produce hydrogen peroxide (H
2 O2 ), and cobalt phthalocyanine (CoPc)/carbon nanotube (CNT) loaded carbon paper as the cathode for CO2 reduction to generate CO. This system demonstrates a high overall energy efficiency of 34%, where a faradaic efficiency exceeding 90% for CO2 reduction and 60% for water oxidation to H2 O2 have been achieved, demonstrating significant energy savings of nearly 40% compared to the respective half-reaction systems. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
30. Vibration mixing for enhanced paper-based recombinase polymerase amplification.
- Author
-
Shimazu, Kelli N., Bender, Andrew T., Reinhall, Per G., and Posner, Jonathan D.
- Subjects
NUCLEIC acid amplification techniques ,DIAGNOSTIC use of polymerase chain reaction ,DETECTION limit ,VIRAL DNA ,TEMPERATURE control - Abstract
Isothermal nucleic acid amplification tests (NAATs) are a vital tool for point-of-care (POC) diagnostics. These assays are well-suited for rapid, low-cost POC diagnostics for infectious diseases compared to traditional PCR tests conducted in central laboratories. There has been significant development of POC NAATs using paper-based diagnostic devices because they provide an affordable, user-friendly, and easy to store format; however, the difficulties in integrating separate liquid components, resuspending dried reagents, and achieving a low limit of detection hinder their use in commercial applications. Several studies report low assay efficiencies, poor detection output, and poorer limits of detection in porous membranes compared to traditional tube-based protocols. Recombinase polymerase amplification is a rapid, isothermal NAAT that is highly suited for POC applications, but requires viscous reaction conditions that has poor performance when amplifying in a porous paper membrane. In this work, we show that we can dramatically improve the performance of membrane-based recombinase polymerase amplification (RPA) of HIV-1 DNA and viral RNA by employing a coin cell-based vibration mixing platform. We achieve a limit of detection of 12 copies of DNA per reaction, nearly 50% reduction in time to threshold (from ∼10 minutes to ∼5 minutes), and an overall fluorescence output increase up to 16-fold when compared to unmixed experiments. This active mixing strategy enables reactions where the target and reaction cofactors are isolated from each other prior to the reaction. We also demonstrate amplification using a low-cost vibration motor for both temperature control and mixing, without the requirement of any additional heating components. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
31. A wax chalk and self-heating paper-based analytical device (SH-PAD) for the detection of bisphenol A.
- Author
-
Panicker, Shekhar, Prabhu, Anusha, Sundarrajan, Balachandar, Quadros, Buena Peninnah, and Mani, Naresh Kumar
- Published
- 2024
- Full Text
- View/download PDF
32. Ti3C2Tx-AuNP based paper substrates for label-free SERS detection of bacteria and multimodal antibacterials.
- Author
-
Shi, Boya, Jiang, Li, Ma, Ruikai, Zhao, Weidan, Zheng, Yekai, Pan, Wangwei, Liu, Mi, Jin, Shangzhong, and Zhou, Yan
- Published
- 2024
- Full Text
- View/download PDF
33. Paper-based colorimetric sensor using a single-atom nanozyme for the ultrasensitive detection of Cr(VI) in short-necked clams.
- Author
-
Wu, Shuo, Khan, Muhammad Arif, Zhang, Lifan, Zhao, Hongbin, Huang, Tianzeng, Cao, Hongmei, and Ye, Daixin
- Published
- 2024
- Full Text
- View/download PDF
34. Development and application of a CNT–Ag–Cu–Al/PS-based paper electrode for detecting diverse analytes in complex matrices.
- Author
-
Zhang, Zhiming, Zhu, Lixuan, Zhang, Yan, Zong, Yanan, Li, Yun, Zheng, Yajun, Meng, Mei, and Zhang, Zhiping
- Published
- 2024
- Full Text
- View/download PDF
35. Office paper and laser printing: a versatile and affordable approach for fabricating paper-based analytical devices with multimodal detection capabilities.
- Author
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Sousa, Lucas R., Guinati, Barbara G. S., Maciel, Lanaia I. L., Baldo, Thaisa A., Duarte, Lucas C., Takeuchi, Regina M., Faria, Ronaldo C., Vaz, Boniek G., Paixão, Thiago R. L. C., and Coltro, Wendell K. T.
- Subjects
LASER printing ,PRINTMAKING ,PROSTATE-specific antigen ,ELECTROCHEMICAL analysis ,ELECTROSPRAY ionization mass spectrometry ,IRON ,PHOTOVOLTAIC power systems - Abstract
Multiple protocols have been reported to fabricate paper-based analytical devices (PADs). However, some of these techniques must be revised because of the instrumentation required. This paper describes a versatile and globally affordable method to fabricate PADs using office paper as a substrate and a laser printing technique to define hydrophobic barriers on paper surfaces. To demonstrate the feasibility of the alternatives proposed in this study, the fabrication of devices for three types of detection commonly associated with using PADs was demonstrated: colorimetric detection, electrochemical detection, and mass spectrometry associated with a paper-spray ionization (PSI-MS) technique. Besides that, an evaluation of the type of paper used and chemical modifications required on the substrate surface are also presented in this report. Overall, the developed protocol was suitable for using office paper as a substrate, and the laser printing technique as an efficient fabrication method when using this substrate is accessible at a resource-limited point-of-need. Target analytes were used as a proof of concept for these detection techniques. Colorimetric detection was carried out for acetaminophen, iron, nitrate, and nitrite with limits of detection of 0.04 μg, 4.5 mg mL
−1 , 2.7 μmol L−1 , and 6.8 μmol L−1 , respectively. A limit of detection of 0.048 fg mL−1 was obtained for the electrochemical analysis of prostate-specific antigen. Colorimetric and electrochemical devices revealed satisfactory performance when office paper with a grammage of 90 g m−2 was employed. Methyldopa analysis was also carried out using PSI-MS, which showed a good response in the same paper weight and behavior compared to chromatographic paper. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
36. A rapid and ultrasensitive paper sensor for Bacillus cereus Haemolysin BL detection.
- Author
-
Wei, Chunhao, Xu, Xinxin, Guo, Lingling, Qu, Aihua, Wu, Aihong, Xu, Chuanlai, and Kuang, Hua
- Subjects
MICROBIAL toxins ,BACILLUS cereus ,FOOD safety ,FOOD pathogens ,ENTEROTOXINS - Abstract
Bacillus cereus is a foodborne opportunistic pathogen commonly found in humans and animals. It produces various toxins, causing frequent food safety incidents. Therefore, establishing a fast and accurate method for detecting B. cereus enterotoxin is crucial for disease diagnosis and food safety. In this study, Haemolysin BL comprising Hbl B and L2 was obtained from a prokaryotic expression system and then used to immunize mice for antibody preparation. Paired antibodies 2A10–5C7 against Hbl B and 1E2–10A4 against Hbl L2 were screened using the chessboard method and then used to construct a double-antibody sandwich detection method and a lateral flow immunochromatographic assay (LFIA) to quantify the concentrations of Hbl B and L2 in PBS and milk. The limits of detection for Hbl B and L2 in milk were 0.74 ng mL
−1 and 1 ng mL−1 with detection ranges of 1.48–645.5 ng mL−1 and 2.33–391.5 ng mL−1 . The spiked recoveries ranged from 82.2% to 105.67% and there was no cross-reactivity with common microbial toxins. The established LFIA was low in cost and rapid and was comparable with commercially available detection kits for food samples. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
37. A separation-free paper-based hydrogel device for one-step reactive oxygen species determination by a smartphone.
- Author
-
Jie Chu, Yiyi Zhang, Jingwen Li, Jun Hong, Lin Sun, and Jianshe Wei
- Abstract
Paper-based analytical devices (PADs) are very convenient for determining biomarkers in point-of-care (POC) diagnosis while requiring sample pre-treatment or impurity separation. This study reports a novel hydrogel-coupled, paper-based analytical device (PAD) for separation-free H
2 O2 colorimetric detection in both aqueous solution and cell lysis with sample-to-answer analysis by directly loading into the sample test zone. By encapsulating an inorganic mimic enzyme and chromogenic substrate into the sodium alginate (SA) hydrogel, amplification of the color signal after catalyzing the substrate could be achieved. Taking advantage of the nanoscale porous structure of the hydrogel and the lateral flow channel of the PAD, large interference fragments or bio-macromolecules are prevented from diffusing into the chromogenic reaction, whereas the small target molecules enter the sensing region to trigger the catalytic reaction. This method demonstrated a rapid and accurate analysis with a limit of detection as low as 0.06 mM and detection selectivity. Our proposed device requires no enzyme and is separation-free, portable, easy-to-fabricate, and low-cost, and may offer a platform for quantitative or qualitative analysis of other analytes in body fluids for POC applications. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
38. Basic evaluation of the CRISPR/Cas system stability for application to paper-based analytical devices.
- Author
-
Tanifuji, Yohei, Suzuki, Hikaru, Tong, Guodong, Hiruta, Yuki, and Citterio, Daniel
- Published
- 2024
- Full Text
- View/download PDF
39. Used tissue paper as a 3D substrate for non-enzyme glucose sensors.
- Author
-
Zhiyu Chen, Lei Li, Xuanyu Xiao, Yuxin Zhang, Jieyu Zhang, Qing Jiang, Xuefeng Hu, and Yunbing Wang
- Subjects
GLUCOSE analysis ,PAPER recycling ,OXIDATION of glucose ,RECYCLED paper ,DETECTORS ,DENSITY functional theory - Abstract
Non-enzymatic electrochemical blood glucose sensors often suffer from issues such as requiring an alkaline environment, limited monitoring range, and poor anti-interference properties. Carbon substrates have been demonstrated to improve the performance of non-enzymatic sensors, but complex and energy-consuming manufacturing processes restrict their use. Herein, a simple and green approach for the preparation of 3D porous Au/Au-Pt networks (PAAPNs) is proposed using tissue paper for recycling as the nanomaterial substrate to deposit Au-Pt bimetallic nanoparticles. The unique structure of the PAAPNs sensor allows for low-potential operation (-1.0 V) with a wide monitoring range (-0.25 to 36 mM) in a neutral environment. Moreover, the sensor exhibited excellent selectivity (<10% response of interference) even without the use of an anti-interference outer membrane. Further investigation using density functional theory (DFT) simulation revealed the synergistic effect between Au and Pt in promoting glucose oxidation. Overall, this work provides a simple and low-carbon footprint method for creating carbon substrates from tissue paper for recycling, offering new opportunities for fabricating novel value-added nanomaterials for medical sensing applications. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. A paper-based ratiometric fluorescence sensor based on carbon dots modified with Eu3+ for the selective detection of tetracycline in seafood aquaculture water.
- Author
-
Zhang, Jialu, Chen, Yuanyuan, Qi, Ji, Miao, Qinglan, Deng, Dongmei, He, Haibo, Yan, Xiaoxia, and Luo, Liqiang
- Subjects
FLUORESCENCE ,SEAFOOD ,TETRACYCLINE ,TETRACYCLINES ,AQUACULTURE ,DETECTORS - Abstract
Paper-based ratiometric fluorescence sensors are normally prepared using two or more types of fluorescent materials on a paper chip for simple, low-cost and fast detection. However, the choice of multi-step and one-step modifications on the paper chip affects the analytical performance. Herein, a novel paper-based dual-emission ratiometric fluorescence sensor was designed for the selective detection of tetracycline (TC). Carbon dots (CDs) modified with Eu
3+ were combined with a sealed paper-based microfluidic chip by two methods: one-step grafting of CDs-Eu3+ on paper and step-by-step grafting of CDs and Eu3+ on paper. The analytical performance was studied and optimized respectively. The red fluorescence of Eu3+ at 450 nm is enhanced and the blue fluorescence of CDs at 617 nm is quenched by energy transfer in the presence of TC. Under optimal conditions, TC is selectively determined in the linear range from 0.1 μM to 100 μM with a detection limit of 0.03 μM by the step-by-step grafting method. In addition, the sealed paper chip could effectively prevent pollution and volatilization from the reagent. This technique has been used to analyze TC in seafood aquaculture water with satisfactory results. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
41. Additive-manufactured paper–PMMA hybrid microfluidic chip for simultaneous monitoring of creatinine and pH in artificial urine.
- Author
-
Sheeraz, Asim Syed, Aiswarya, Edoth, Kumara, B. N., Sonia, J., Rodrigues, Relisha Viyona, Sheikh, Nazmin, Vidyasagar, Sachin, Kunder, Rachana. A., Elangovan, Selvakumar, Mohanty, Priti Sundar, and Prasad, K. Sudhakara
- Subjects
CREATININE ,URINE ,MICROFLUIDIC devices ,KIDNEY diseases ,ON-site evaluation ,DETECTION limit - Abstract
Nowadays, kidney dysfunction is a common health issue due to the modernized lifestyle. Even though medications are commercially available to treat kidney diseases, early diagnosis is crucial and challenging. Clinically, measuring urine creatinine and pH has gained significant interest as a way to diagnose kidney diseases early. In the present work, we attempted to develop a low-cost, robust, accurate and naked-eye colorimetric method to determine both creatinine levels and pH variations in artificial urine samples using a simple 3D-printed hybrid microfluidic device. Creatinine was detected by the incorporation of the traditional Jaffe test onto the hybrid paper–PMMA microfluidic device and pH (4–8) was measured by a simple anthocyanin test. Notably, the tests were established without employing any sophisticated or costly instrument clusters. The developed 3D-printed microfluidic probe showed a limit of detection (LOD) of 0.04 mM for creatinine over a concentration range of 1–10 mM, with a regression coefficient (R
2 ) of 0.995 in laboratory conditions. Interestingly, the experimental data obtained with artificial urine exhibited a wide linear range from 0.1 mM to 5 mM under different pH values ranging from 4 to 8 in the presence of matrices commonly found in urine samples other than proteins, indicating the potential use of this method in pre-clinical analysis. Since the wide linear range of urine creatinine in artificial urine samples falls well below the clinically relevant concentrations in humans (0.07–0.27 mM), the developed lab-on-chip device is further suitable for clinical evaluation with proper ethical clearance. This 3D-printed hybrid microfluidic colorimetry-based creatinine detection and pH indicator platform can be beneficial in the healthcare sector due to the on-site testing capability, cost-effectiveness, ease of use, robustness, and instrument-free approach. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
42. Highly selective and flexible silver nanoparticles-based paper sensor for on-site colorimetric detection of paraquat pesticide.
- Author
-
Bhandari, Sanjeev, Parihar, Vijay Singh, Kellomäki, Minna, and Mahato, Mrityunjoy
- Published
- 2024
- Full Text
- View/download PDF
43. A simple method for elemental analysis of liquids in sprayed microdroplets by laser-induced breakdown spectroscopy.
- Author
-
Feng, Jun, Yan, Yihui, Liu, Yuzhu, and Lengyel, Jozef
- Abstract
The combination of paper spray with laser-induced breakdown spectroscopy (PS-LIBS) was used to analyze trace elements in aqueous solutions. The analysis of sprayed charged microdroplets eliminates the experimental challenges of bulk liquid analysis, such as splashing and surface ripples, which often affect LIBS sensitivity. In contrast to other electrospray techniques, PS is a simple and robust method that allows for the direct loading of liquid samples onto paper. Its performance is largely dependent on the quality of the spray plume, influenced by factors like paper shape, tip angle, spray voltage, and solvent composition. The cut angle of the paper tip significantly influences the spray plume and total ion current, with sharper tips being more efficient at generating sprayed microdroplets. The detection limits for Na, K, and Cr – 11.1 mg L
−1 , 28.9 mg L−1 , and 67.9 mg L−1 , respectively, – are in line with typical values from other LIBS experiments on liquid samples. These experimental results indicate that PS-LIBS is a promising technique for the in situ analysis of trace elements in liquid samples. [ABSTRACT FROM AUTHOR]- Published
- 2025
- Full Text
- View/download PDF
44. A paper-based point-of-care device for the detection of cysteine using gold nanoparticles from whole blood.
- Author
-
Kumari, Monika, Kumar, Natish, Kumar, Sunny, Gandhi, Shivani, Zussman, Eyal, and Arun, Ravi Kumar
- Published
- 2024
- Full Text
- View/download PDF
45. Chitosan-adhered graphene/nano iron tetroxide carbon paper electrode for the detection of hexavalent chromium.
- Author
-
Liangyi Tian, Ting Huang, Yilei Xiang, Yichun Bi, Zihan Yu, Jihuan Xie, Jingping Qiu, Lemin Chen, and Linbin Jiang
- Subjects
CARBON electrodes ,CARBON paper ,HEXAVALENT chromium ,MAGNETITE ,IRON ,GRAPHENE ,CHROMIUM compounds - Abstract
This report presents an investigation into the use of carbon paper electrodes prepared from chitosan-adhered graphene magnetite nanoparticles for the analysis of Cr(VI). The preparation and storage of carbon paper electrodes is a simple process, and these electrodes are easier to replace than electrodes modified by more conventional methods. The electrochemical detection of Cr(VI) using square wave adsorption cathodic dissolution voltammetry (SWAdCSV) with high selectivity and sensitivity, as well as the optimum conditions for the preparation of the electrodes and the electrode parameters affecting the SWAdCSV signal, were the main points of focus of the investigation. Cr(VI) was detected linearly in the range of 4-40 μg L
-1 with a detection limit of 2.84 μg L-1 . The electrode output precision, calculated as %RSD, was 7.16% (n = 6), and this was the measurement used for the detection of Cr(VI) in standard and test samples with recoveries between 89% and 114%. The results were consistent with those obtained using the standard UV-Vis spectrophotometric method with a paired t-test at 95% confidence level. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
46. A dual colorimetric-electrochemical microfluidic paper-based analytical device for point-of-care testing of ischemic strokes.
- Author
-
Dortez, Silvia, Pacheco, Marta, Gasull, Teresa, Crevillen, Agustín G., and Escarpa, Alberto
- Subjects
ISCHEMIC stroke ,CHEMICAL reactors ,POINT-of-care testing ,STROKE patients ,PHYSICIAN services utilization ,TRANSFERRIN ,UREA - Abstract
A novel microfluidic paper-based analytical device with dual colorimetric and electrochemical detection (dual μPAD) was developed for the assessment of transferrin saturation (TSAT) in samples from ischemic stroke patients. TSAT was calculated from the ratio between transferrin-bound iron, which was colorimetrically measured, and the total iron-binding capacity, which was electrochemically measured. To this end, a μPAD was smartly designed, which integrated both colorimetric and electrochemical detection reservoirs, communicating via a microchannel acting as a chemical reactor, and with preloading/storing capabilities (reagent-free device). This approach allowed the dual and simultaneous determination of both parameters, providing an improvement in the reliability of the results due to an independent signal principle and processing. The μPADs were validated by analyzing a certified reference material, showing excellent accuracy (E
r ≤ 5%) and precision (RSD ≤ 2%). Then they were applied to the analysis of diagnosed serum samples from ischemic stroke patients. The results were compared to those provided by a free-interference method (urea-PAGE). Impressively, both methods exhibited a good correlation (r = 0.96, p < 0.05) and no significant differences were found between them (slope 1.0 ± 0.1 and the intercept 1 ± 4, p < 0.05), demonstrating the excellent accuracy of our approach during the analysis of complex samples from ischemic stroke patients, using just 90 μL of clinical samples and taking less than 90 min in comparison with the 18 hours required by the urea-PAGE approach. The developed fully integrated colorimetric-electrochemical μPAD is a promising ready to use reagent-free device for the point-of-care testing of TSAT, which can be used to assist physicians in the fast diagnosis and prognosis of ischemic strokes, where the decision-time is crucial for the patient's survival. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
47. A family of Cd(II) coordination polymers constructed from 6-aminopicolinate and bipyridyl co-linkers: study of their growth in paper and photoluminescence sensing of Fe3+ and Zn2+ ions.
- Author
-
Pajuelo-Corral, Oier, Ortiz-Gómez, Inmaculada, García, Jose Angel, Rodríguez-Diéguez, Antonio, Vitórica-Yrezábal, Iñigo J., Salinas-Castillo, Alfonso, Seco, Jose M., and Cepeda, Javier
- Subjects
COORDINATION polymers ,PHOTOLUMINESCENCE ,BIPYRIDINE ,COORDINATION compounds ,FLUORESCENCE ,PHOSPHORESCENCE ,METAL detectors ,IRON clusters - Abstract
In this work, we report on five novel coordination polymers (CPs) based on the linkage of the [Cd(6apic)
2 ] building block [where 6apic = 6-aminopicolinate] by different bipyridine-type organic spacers, forming different coordination compounds with the following formulae: [Cd(μ-6apic)2 ]n (1), {[Cd(6apic)2 (μ-bipy)]·H2 O}n (2), {[Cd(6apic)2 (μ-bpe)]·2H2 O}n (3), [Cd(6apic)(μ-6apic)(μ-bpa)0.5 ]n (4) and {[Cd2 (6apic)4 (μ-tmbp)]·7H2 O}n (5) [where bipy = 4,4′-bipyridine, bpe = 1,2-di(4-pyridyl)ethylene, bpa = 1,2-di(4-pyridyl)ethane (bpa) and tmbp = 1,3-di(4-pyridyl)propane]. Most of the synthesized compounds form infinite metal–organic rods through the linkage of the building block by the bipyridine-type linker, except in the case of compound 4 whose assembly forms a densely packed 3D architecture. All compounds were fully characterized and their photoluminescence properties were studied experimentally and computationally through density functional theory (DFT) calculations. All compounds display, upon UV excitation, a similar blue emission of variable intensity depending on the linker employed for the connection of the building units, among which compound 2 deserves to be highlighted for its room temperature phosphorescence (RTP) with an emission lifetime of 32 ms that extends to 79 ms at low temperature. These good photoluminescence properties, in addition to its stability in water over a wide pH range (between 2 and 10), motivated us to study compound 2 as a sensor for the detection of metal ions in water, and it showed high sensitivity to Fe3+ through a fluorescence turn-off mechanism and an unspecific turn-on response to Zn2+ . Furthermore, the compound is processed as a paper-based analytical device (PAD) in which the phosphorescence emission is preserved, improving the sensing capacity toward Fe3+ ions. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
48. Paper-based sensing of phytotoxicant gossypol in aqueous media through turn-on visible-light emitting lanthanide-luminescence.
- Author
-
Biswas, Ananya and Maitra, Uday
- Subjects
GOSSYPOL ,PETROLEUM ,LUMINESCENCE ,DETECTION limit ,COTTONSEED ,RARE earth metals - Abstract
Gossypol, a phytotoxicant in cotton-seed oil, has been found to sensitize Tb(III)-luminescence in a supramolecular hydrogel. Based on this observation, a paper-based sensor has been developed to detect gossypol with a limit of detection (LOD) of 2.9 nM. This is the first report of water-based detection with the highest sensitivity involving turn-on time-gated luminescence. This method was also able to sense gossypol in commercial crude cotton-seed oil. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
49. Engineering heterostructured Mo2C/MoS2 catalyst with hydrophilicity/aerophobicity via carbothermal shock for efficient alkaline hydrogen evolution.
- Author
-
Xiong, Hao, Zhang, Xinren, Peng, Xu, Liu, Dengke, Han, Yimeng, and Xu, Fei
- Subjects
HYDROGEN as fuel ,HYDROGEN evolution reactions ,CARBON paper ,CLEAN energy ,ELECTRONIC structure - Abstract
The exploration of high-performance hydrogen evolution reaction (HER) catalysts is conducive to the development of clean hydrogen energy, yet still remains a challenge. Herein, we rapidly synthesize the Mo
2 C/MoS2 heterostructure on carbon paper (Mo2 C/MoS2 –CP) via carbothermal shock in only two seconds. The construction of the Mo2 C/MoS2 heterostructure regulates the electronic structure of the Mo site and facilitates charge transfer during the HER process. Moreover, the catalyst exhibits enhanced hydrophilicity and aerophobicity, facilitating optimal electrolyte–catalyst interaction and efficient hydrogen bubble detachment for accelerated mass transfer. Consequently, Mo2 C/MoS2 –CP exhibits superior intrinsic alkaline HER activity, and excellent stability for 100 h. This finding provides a novel insight into the development of outstanding HER catalysts. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
50. Ultra-thin amphiphilic hydrogel electrolyte for flexible zinc-ion paper batteries.
- Author
-
Xia, Huan, Zhang, Wei, Miao, Chunyang, Chen, Hao, Yi, Chengjie, Shang, Yihan, Shui, Tao, Cao, Xin, Liu, Jiacheng, Kure-Chu, Song-Zhu, Liang, Feifei, Moloto, Nosipho, Xiong, Yipeng, Hihara, Takehiko, Lu, Weibing, and Sun, ZhengMing
- Published
- 2024
- Full Text
- View/download PDF
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