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Chronic wound biofilm infections represent a major clinical challenge which results in a substantial burden to patients and healthcare systems. Treatment with topical antibiotics is oftentimes ineffective as a result of antibiotic‐resistant microorganisms and biofilm‐specific antibiotic tolerance. Use of biocides such as hypochlorous acid (HOCl) has gained increasing attention due to the lack of known resistance mechanisms. An HOCl‐generating electrochemical bandage (e‐bandage) is designed that delivers HOCl continuously at low concentrations targeting infected wound beds in a similar manner to adhesive antimicrobial wound dressings. A battery‐operated wearable potentiostat is developed that controls the e‐bandage electrodes at potentials suitable for HOCl generation. It is demonstrated that e‐bandage treatment is tunable by changing the applied potential. HOCl generation on electrode surfaces is verified using microelectrodes. The developed e‐bandage shows time‐dependent responses against in vitro Acinetobacter baumannii and Staphylococcus aureus biofilms, reducing viable cells to nondetectable levels within 6 and 12 h of treatment, respectively. The developed e‐bandage should be further evaluated as an alternative to topical antibiotics to treat wound biofilm infections. [ABSTRACT FROM AUTHOR]

Microfluidics provides an indispensable platform for combining analytical operations such as sample preparation, mixing, separation/enrichment, and detection onto a single compact platform, defined as a lab-on-a-chip (LOC) device with applicability in biomedical and life science applications. Due to its ease of integration, 1D interdigital capacitive (IDC) sensors have been used in microfluidic platforms to detect particles of interest. This paper presents a comparative study on the use of capacitive sensors for microfluidic devices to detect bioparticles, more specifically red blood cells (RBCs). The detection sensitivities of 1D, 2D, and 3D capacitive sensors were determined by simulation using COMSOL Multiphysics® v5.5. A water-filled 25 μm × 25 μm PDMS microfluidic channel was used with different sizes (5–10 μm) of red blood cells passing across the capacitive sensor regions. The conformal mapping was used for translating the 1D IDC sensor dimensions into equivalent 2D/3D parallel plate capacitance (PPC) sensor dimensions, creating similar absolute sensor capacitance. The detection sensitivity of each capacitive sensor is determined, and a new 3D PPC sensor structure was proposed to improve the sensitivity for high-resolution RBC detection in microfluidic channels. Proposed 2D and 3D sensors provide a 3× to 20× improvement in sensitivity compared to the standard 1D IDC structures, achieving a 100 aF capacitance difference when a healthy RBC passes in the structure. [ABSTRACT FROM AUTHOR]

A photodiode (PD)-type CMOS active pixel sensor (APS) pixel is comprised of a reverse-biased p-n-junction diode (PD) for photon conversion and charge storage, and a number of MOS transistors. Junction capacitance of the PD has two major components; bottom plate (area) and side wall (periphery). Both play important roles in the electro-optical performance of PD-APS pixels. This paper reports PD peripheral junction utilization effects on the pixel's electro-optical performance, full-well capacity and spectral response for an 18 [micro]m x 18 [micro]m CMOS PD-APS pixel were improved by opening multiple circular holes in the PD diffusion layer. A prototype CMOS APS imager was designed, fabricated, and tested in 0.5-[micro]m, 5 V, 2P3M CMOS process, containing a 424 x 424 pixel array with smaller sub-arrays for multiple pixel designs. Four test pixels with 7, 11, 14, and 17 circular, 1.6-[micro]m-diameter holes were placed on one pixel array, with one control pixel for reference. Pixel characteristics, dark current, PD capacitance, quantum efficiency, sensitivity, and pixel full-well capacity were measured. It was found that increased PD junction peripheral would potentially help to improve total capacitance of the PD, with the expense of higher dark current. We also found that increased PD peripheral capacitance improves spectral response up to 12% of the PD-APS pixel, especially at short wavelengths. Index Terms--CMOS image sensors, image sensors, sensitivity.

Many algorithms have been developed for complementary metal–oxide–semiconductor (CMOS) image sensors to speed up analogue‐to‐digital (A‐to‐D) conversion of captured images. However, there is no objective blind‐image quality metric available to compare and quantify the quality and effectiveness of these speed‐up algorithms. In this work, we developed a blind‐image quality and complexity metric for this purpose. The proposed metric relies on counting the successive zeros in a code histogram. The proposed metric is called the conversion complexity metric (CCM). The CCM is designed to quantify how complex, and to predict how much time and power consuming a captured image is for A‐to‐D conversion, mainly by integrating (ramp) type A‐to‐D converter used in column‐parallel architectures of a CMOS image sensor (CIS). The proposed metric, CCM, is tested for linearity, monotonicity, and sensitivity to many types of introduced distortion. The CCM is compared with other no‐reference and full‐reference image quality and complexity metrics. It accomplished, for brightness change distortion, 99% linearity and 316% sensitivity, providing a computationally efficient blind‐image quality metric that no other metrics provide for CIS to intelligently adjust and optimise on‐chip analogue and digital signal processing. [ABSTRACT FROM AUTHOR]

A trapezoid (TZOID) pixel array complementary metal oxide semiconductor (CMOS) image sensor, and a pixel-resolution mapping (P-RM) method to extract information from the observed objects without requiring any specific patterns or man-made markings, are proposed for traffic applications. The size of each pixel in the TZOID imager was determined by pixel design equations based on the relationship between the pixel's physical size and related spatial resolution. The TZOID imager trades detection accuracy for a tolerable data loss to reduce communication bandwidth and computation power. The P-RM method determines the pixels' actual resolutions in the real world of the captured imaged by both standard rectangular single- and multiresolution TZOID pixel arrays. Both indoor and outdoor experiments were performed using single- and multiresolution imagers. The TZOID imager integrated circuit (IC) was fabricated in a 0.18-μm CMOS process. It was tested, and its performance parameters were compared with an off-the-shelf CMOS image sensor IC. Tests showed that the TZOID generates 98% less data than that of a standard image sensor, trading off only 2% detection accuracy. Results also show that the proposed method provides a general procedure for designing a multiresolution sensor for traffic applications. [ABSTRACT FROM AUTHOR]

Gain and offset represent two important measures to determine the accuracy of a comparator. Thus, analysis on these parameters is very important as they offer designers better understanding of the circuit and allow exploring trade-offs during design. In this paper, two methods were presented to derive a set of design equations that describe the gain, sensitivity, offset, and systematic mismatches observed in typical comparator circuits. A three-stage, fast complementary metal-oxide semiconductor (CMOS) comparator structure is analysed and simulated in order to validate the proposed methods. A 0.13 μm CMOS technology is used for simulations with 1.5 V supply voltage. Bisection theorem was used for gain and sensitivity analysis. Simulation results show that high gain improvement can be possible by using the design equations. The input offset voltage, due to mismatch in the width of the metal oxide semiconductor field-effect transistors (MOSFET) (W) and mismatches in the threshold voltages of the N and P type MOSFETs(VTHN, VTHP), is analysed using a proposed balanced method. The same comparator structure is used for the input offset voltage analysis. Simulations show that an offset improvement can be achieved following the design equations found through the proposed method. [ABSTRACT FROM PUBLISHER]

Fundamental characteristics of on-chip micro solar cell (MSC) structures were investigated in this study. Several MSC structures using different layers in three different CMOS processes were designed and fabricated. Effects of PN junction structure and process technology on solar cell performance were measured. Parameters for low-power and low-voltage implementation of power management strategy and boost converter based circuits utilizing fractional voltage maximum power point tracking (FVMPPT) algorithm were determined. The FVMPPT algorithm works based on the fraction between the maximum power point operation voltage and the open circuit voltage of the solar cell structure. This ratio is typically between 0.72 and 0.78 for commercially available poly crystalline silicon solar cells that produce several watts of power under typical daylight illumination. Measurements showed that the fractional voltage ratio is much higher and fairly constant between 0.82 and 0.85 for on-chip mono crystalline silicon micro solar cell structures that produce micro watts of power. Mono crystalline silicon solar cell structures were observed to result in better power fill factor (PFF) that is higher than 74% indicating a higher energy harvesting efficiency. [ABSTRACT FROM AUTHOR]

An ultra-low power CMOS image sensor with on-chip energy harvesting and power management capability is introduced in this paper. The photodiode pixel array can not only capture images but also harvest solar energy. As such, the CMOS image sensor chip is able to switch between imaging and harvesting modes towards self-power operation. Moreover, an on-chip maximum power point tracking (MPPT)-based power management system (PMS) is designed for the dual-mode image sensor to further improve the energy efficiency. A new isolated P-well energy harvesting and imaging (EHI) pixel with very high fill factor is introduced. Several ultra-low power design techniques such as reset and select boosting techniques have been utilized to maintain a wide pixel dynamic range. The chip was designed and fabricated in a 1.8 V, 1P6M 0.18 µ m CMOS process. Total power consumption of the imager is 6.53 µW for a 96 x 96 pixel array with 1 V supply and 5 fps frame rate. Up to 30 µW of power could be generated by the new EHI pixels. The PMS is capable of providing 3x the power required during imaging mode with 50% efficiency allowing energy autonomous operation with a 72.5% duty cycle. [ABSTRACT FROM AUTHOR]

A new pixel readout technique is proposed for three-transistor (3T) CMOS active pixel sensor (APS) pixels. It utilizes the supply-boosting technique (SBT) in order to reduce power consumption and allow ultra low-voltage operation. The pixel supply voltage as well as the pixel reset and select signals were boosted to achieve wider and extended linear operating ranges. A CMOS image sensor containing a 54 \times 50 array of 3T CMOS APS pixels was fabricated in a standard 2P3M 5-V 0.5- \mu\m CMOS process to confirm the effectiveness of each boosting operation. Theory, simulation, and measurement results are presented. The boosting pixel supply voltage during pixel readout provides additional 31% dynamic range improvement on top of the seven times (7\times) expansion attained by boosting the pixel reset signal. It was shown that the proposed boosted readout does not increase the number of transistors in the 3T CMOS APS pixels nor degrade the image quality. [ABSTRACT FROM AUTHOR]

A CMOS image sensor capable of imaging and energy harvesting on same focal plane is presented for retinal prosthesis. The energy harvesting and imaging (EHI) active pixel sensor (APS) imager was designed, fabricated, and tested in a standard 0.5 \mum CMOS process. It has 54\,\times\,50 array of 21\,\times\,21 \mum^2 EHI pixels, 10-bit supply boosted (SB) SAR ADC, and charge pump circuits consuming only 14.25 \muW from 1.2 V and running at 7.4 frames per second. The supply boosting technique (SBT) is used in an analog signal chain of the EHI imager. Harvested solar energy on focal plane is stored on an off-chip capacitor with the help of a charge pump circuit with better than 70% efficiency. Energy harvesting efficiency of the EHI pixel was measured at different light levels. It was 9.4% while producing 0.41 V open circuit voltage. The EHI imager delivers 3.35 \muW of power was delivered to a resistive load at maximum power point operation. The measured pixel array figure of merit (FoM) was 1.32 pW/frame/pixel while imager figure of merit (iFoM) including whole chip power consumption was 696 fJ/pixel/code for the EHI imager. [ABSTRACT FROM PUBLISHER]

A compact power-on-reset pulse generator (POR-PG) circuit with a low-power and low-voltage operation capability is presented. Proposed POR-PG was fabricated in 0.5 μm 2P3M CMOS process. It was determined from simulations and measurements that proposed POR-PG works supply voltage levels between 1.8 V and 3.3 V and supply voltage rise times between 100 ns and 1 ms. POR-PG has very small silicon footprint. Layout size of proposed POR-PG circuit was 120 μm × 5 μm in 0.5 μm CMOS process. Comparing with other POR-PG circuits in the literature, proposed design enjoys lowest power consumption (< 6 μW), smallest silicon footprint, widest supply voltage range, and additional features such as brown-out detection capability. These achieved by using a unique cascadable POR delay element that consumes very low-power. [ABSTRACT FROM AUTHOR]

Schmitt trigger (ST) circuits are widely used integrated circuit (IC) blocks with hysteretic input/output (I/O) characteristics. Like the I/O characteristics of a living neuron, STs reject noise and provide stability to systems that they are deployed in. Indeed, single-input/single-output (SISO) STs are likely candidates to be the core unit element in artificial neural networks (ANNs) due not only to their similar I/O characteristics but also to their low power consumption and small silicon footprints. This paper presents an accurate and detailed analysis and design of six widely used complementary metal-oxide-semiconductor (CMOS) SISO ST circuits. The hysteresis characteristics of these ST circuits were derived for hand calculations and compared to original design equations and simulation results. Simulations were carried out in a well-established, 0.35 μm/3.3 V, analog/mixed-signal CMOS process. Additionally, simulations were performed using a wide range of supplies and process variations, but only 3.3 V supply results are presented. Most of the new design equations provide better accuracy and insights, as broad assumptions of original derivations were avoided. [ABSTRACT FROM AUTHOR]

We have developed electrochemical bandage (e-bandage) prototypes that generate the reactive oxygen species hypochlorous acid (HOCl) or hydrogen peroxide (H 2 O 2 ) for potential use to treat biofilm-infected wounds in humans. We have shown that both e-bandage-generated HOCl and H 2 O 2 kill biofilms in vitro and in infected wounds on mice, with the former being more active in vitro. The H 2 O 2 -generating e-bandage, more so than the HOCl-generating e-bandage, was associated with improved healing of infected wounds. Here, a strategy in which H 2 O 2 and HOCl are alternately generated-for dual action-was explored. The goal was to develop a programmable multimodal wearable potentiostat [PMWP] that can generate HOCl or H 2 O 2 , as needed. An ultralow-power microcontroller unit was developed to manage operation of the PMWP. The system was operated with a 260-mAh capacity coin battery and weighed 4.6 g, making it suitable for future small animal experiments (and ultimately, potential evaluation in humans). As assessed using electrochemical parameters, the device functioned comparably to a commercial benchtop potentiostat. To confirm antimicrobial activity, PMWP-controlled e-bandages were tested in vitro against clinical isolates of methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Enterococcus faecium, and Candida auris. When programmed to deliver HOCl followed by H 2 O 2 , PMWP-controlled e-bandages exhibited activity against biofilms of all study isolates tested. Finally, we demonstrated the PMWP's usability in a murine wound infection model., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Haluk Beyenal and Robin Patel report financial support was provided by National Institutes of Health. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Chronic wound biofilm infections represent a major clinical challenge which results in a substantial burden to patients and healthcare systems. Treatment with topical antibiotics is oftentimes ineffective as a result of antibiotic-resistant microorganisms and biofilm-specific antibiotic tolerance. Use of biocides such as hypochlorous acid (HOCl) has gained increasing attention due to the lack of known resistance mechanisms. We designed an HOCl-generating electrochemical bandage (e-bandage) that delivers HOCl continuously at low concentrations targeting infected wound beds in a similar manner to adhesive antimicrobial wound dressings. We developed a battery-operated wearable potentiostat that controls the e-bandage electrodes at potentials suitable for HOCl generation. We demonstrated that e-bandage treatment was tunable by changing the applied potential. HOCl generation on electrode surfaces was verified using microelectrodes. The developed e-bandage showed time-dependent responses against in vitro Acinetobacter baumannii and Staphylococcus aureus biofilms, reducing viable cells to non-detectable levels within 6 and 12 hours of treatment, respectively. The developed e-bandage should be further evaluated as an alternative to topical antibiotics to treat wound biofilm infections., Competing Interests: Conflict of Interests Dr. Patel reports grants from ContraFect, TenNor Therapeutics Limited, and BioFire. Dr. Patel is a consultant to PhAST, Torus Biosystems, Day Zero Diagnostics, Mammoth Biosciences, and HealthTrackRx; monies are paid to Mayo Clinic. Mayo Clinic and Dr. Patel have a relationship with Pathogenomix. Dr. Patel has research supported by Adaptive Phage Therapeutics. Mayo Clinic has a royalty-bearing know-how agreement and equity in Adaptive Phage Therapeutics. Dr. Patel is also a consultant to Netflix, Abbott Laboratories, and CARB-X. In addition, Dr. Patel has a patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic, and a patent on an anti-biofilm substance issued. Dr. Patel receives honoraria from the NBME, Up-to-Date and the Infectious Diseases Board Review Course.