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Current laboratory diagnostic approaches for virus detection give reliable results, but they require a lengthy procedure, trained personnel, and expensive equipment and reagents; hence, they are not a suitable choice for home monitoring purposes. This paper addresses this challenge by developing a portable impedimetric biosensing system for the identification of COVID-19 patients. This sensing system has two main parts: a throwaway two-working electrode (2-WE) strip and a novel read-out circuit, specifically designed for simultaneous signal acquisition from both working electrodes. Highly reliable electrochemical signal tracking from multiplex immunosensors provides a potential for flexible and portable multi-biomarker detection. The electrodes' surfaces were functionalized with SARS-CoV-2 Nucleocapsid Antibody enabling the selective detection of Nucleocapsid protein (N-protein) along with self-validation in the clinical nasopharyngeal swab specimens. The proposed programmable highly sensitive impedance read-out system allows for a wide dynamic detection range, which makes the sensor capable of detecting N-protein concentrations between 0.116 and 10,000 pg/mL. This lightweight and economical read-out arrangement is an ideal prospect for being mass-produced, especially during urgent pandemic situations. Also, such an impedimetric sensing platform has the potential to be redesigned for targeting not only other infectious diseases but also other critical disorders.

Speedy and on-time detection of coronavirus disease 2019 (COVID-19) is of high importance to control the pandemic effectively and stop its disastrous consequences. A widely available, reliable, label-free, and rapid test that can recognize tiny amounts of specific biomarkers might be the solution. Nanobiosensors are one of the most attractive candidates for this purpose. Integration of graphene with biosensing devices shifts the performance of these systems to an incomparable level. Between the various arrangements using this wonder material, field-effect transistors (FETs) display a precise detection even in complex samples. The emergence of pioneering biosensors for detecting a wide range of diseases especially COVID-19 created the incentive to prepare a review of the recent graphene-FET biosensing platforms. However, the graphene fabrication and transfer to the surface of the device is an imperative factor for researchers to take into account. Therefore, we also reviewed the common methods of manufacturing graphene for biosensing applications and discuss their advantages and disadvantages. One of the most recent synthesizing techniques - laser-induced graphene (LIG) - is attracting attention owing to its extraordinary benefits which are thoroughly explained in this article. Finally, a conclusion highlighting the current challenges is presented.

The coronavirus pandemic is the most challenging incident that people have faced in recent years. Despite the time-consuming and expensive conventional methods, point-of-care diagnostics have a crucial role in deterrence, timely detection, and intensive care of the disease’s progress. Hence, this detrimental health emergency persuaded researchers to accelerate the development of highly-scalable diagnostic devices to control the propagation of the virus even in the least developed countries. The strategies exploited for detecting COVID-19 stem from the already designed systems for studying other maladies, particularly viral infections. The present report reviews not only the novel advances in portable diagnostic devices for recognizing COVID-19, but also the previously existing biosensors for detecting other viruses. It discusses their adaptability for identifying surface proteins, whole viruses, viral genomes, host antibodies, and other biomarkers in biological samples. The prominence of different types of biosensors such as electrochemical, optical, and electrical for detecting low viral loads have been underlined. Thus, it is anticipated that this review will assist scientists who have embarked on a competition to come up with more efficient and marketable in-situ test kits for identifying the infection even in its incubation time without sample pretreatment. Finally, a conclusion is provided to highlight the importance of such an approach for monitoring people to combat the spread of such contagious diseases.

DNA sequencers are being miniaturized and increasingly targeted toward mobile applications. However, the intense bioinformatic computing needs of sequencers present a challenge for remote use with limited energy supply. This article presents a step toward realizing a low-power and high-speed bioinformatic engine, a hardware-accelerated basecaller, for mobile sequencing applications. The design is targeted for nanopore-based sequencers and is architected to easily scale to the complexity of this sensor. In addition to accelerating the CPU in real time with a custom field-programmable gate array (FPGA) through a high-speed serial link, the proposed framework envisages the challenging memory requirement of high-order nanopore sensors. The framework proposes a memory management scheme, which provisions the memory requirement problem in three dimensions: the basecalling speed, the circuit’s area, and power consumption. The implementation results demonstrate a $142\times $ basecalling speed improvement over a 12-core CPU-only reference, as well as significant speedup compared with other existing solutions. Also, an energy efficiency improvement of three orders of magnitude is measured.

CMOS capacitive sensors reported for high-accuracy cellular molecular measurements typically suffer from significant parasitic capacitance changes caused by remnants and sediments during the experiment with several biological and chemical reactions. In this article, we propose a novel calibration-free capacitive sensing system that addresses this problem. The proposed CMOS capacitive sensor includes interdigitated electrodes (IDEs), a capacitance-to-current converter with a wide input dynamic range (IDR), a variable reference capacitor, and an oscillator-based analog-to-digital converter (ADC) which has been fabricated using $0.35~\mu \text{m}$ AMS CMOS process. Sweeping the value of the variable reference capacitor from 0.1 fF up to 1.27 pF with a step of 10 fF and repeating the sweep each second during the experiment allows the creation of time-resolved three-dimensional (3-D) fingerprints for the measurement of capacitance variations of the sample-electrode interface resulted from both the target material as well as non-target parasitic capacitances. We have tested the sensor using three different chemical solvents. The four different categories of curves that constitute the fingerprints of the chemicals showed a match with the post-layout simulation results. Capacitance change in the range of 0.416 fF up–1.27 pF can practically be monitored. The electrode area of 110 by $220~\mu \text{m}$ and the micrometer chamber size allows for placing tiny droplets of a few microliters. The generated fingerprint is valid for the chemicals with a conductivity of up to 5 mS/cm.

A new capacitive microelectromechanical system (MEMS) microcantilever gas flow sensor is introduced for application in industrial gas flow measurement pipelines. The chip encompasses microcantilevers with different lengths (50, 100, 250, and 400 μm) and the same thickness and wideness of 2 and 50 μm, respectively. Besides MEMS sensor development, we have designed a customized bypass channel based on the orifice principle for the placement of the MEMS sensor chip. Accordingly, a minibypass has been designed, which alleviates the harsh flow condition on the sensor that will be placed in the flowmeter housing. Simulations and the experimental study revealed that the sensor is capable of measuring airflows from 0 to 25 m/s with a sensitivity of 2 x 10⁻⁴ pF/m/s, and this can be expanded to other gas flow measurements with a certain bandwidth. This measurement allows us to apply this sensor for measuring moderate flows up to ~200 m/s in ~10-cm diameter pipes based on the current design for bypass. According to experimental results, the sensor output capacitance varied from 3.3445 to 3.350 pF for a range of airflow between 0 and 25 m/s. We have shown that capacitive microcantilever MEMS flow sensors could be used for flow measurements in heavy-load industrial applications.

This paper introduces a high-speed mixed-signal readout array in 130-nm CMOS for the amplification and digitization of picoampere-range signals. Its design is inspired by the needs of emerging DNA sequencing technologies based on biological nanopore sensors. To overcome switching and substrate noise this system adopts an in-pixel analog-to-digital converter (ADC) architecture and a novel readout technique while consuming 10x less power than similar designs described in the literature. The in-pixel ADC architecture is inherently scalable and immune to electrical interference which can be extended to 100s of channels. With a 5 pF input capacitance, the amplifiers achieve a maximum bandwidth of 100 kHz and demonstrate a noise floor as low as 4 fA/ $\sqrt {\text{Hz}}$ and a gain in the range of $\text{G}\Omega $ at 10 kHz. Circuit noise behaviour and theoretical maximum performance estimates using behavioural models are also discussed.

In this paper, we present, for the first time, the advantage of CMOS capacitive sensor for the assessment of dried DNA from an aqueous sample for DNA storage applications. The proposed capacitive sensor consists of a differential capacitance to current converter block based on a core-CBCM circuit, a 300 MHz current controlled oscillator and a 12-bit counter that creates the digital output of the chip. The chip has been fabricated using AMS 0.35µm technology. We demonstrate the functionality and applicability of the proposed sensor for dried DNA nano-mass measurement using single-strand DNA samples. The sensor shows acceptable repeatability in quantifying the DNA nano-mass with a sensitivity of 18.5 aF/ng mass of DNA based on the results described here.

This paper presents a novel method for monitoring drug cytotoxicity using a hybrid microfluidic CMOS platform. This platform consists of an array of 8 × 8 capacitive sensors integrated with a readout circuit on the same chip. In this paper, we present a layer-by-layer (LBL) polyelectrolyte deposition technique to coat the surface of microelectrodes realized in the top most metal layer in 0.35- μ m CMOS process. This process successfully enhances the biocompatibility of sensing microelectrodes and consequently increases the cell viability over a three-day period. Herein, we demonstrate and discuss the advantage of the proposed platform for drug cytotoxicity as well as cellular growth monitoring. This CMOS sensing platform possesses a wide output dynamic range and allows tracking cell growth at initial cell concentrations ranging from 10 to 200 k Cells/ml. We also use a standard Alamarblue cell-based assay and Geneticin selective antibiotic (G418) as control and cytotoxic drugs introduced to non-resistant H1299 and resistant Hek293 cell lines, respectively. Furthermore, a low complexity microfluidic packaging technique is presented to create and bond micro-wells on CMOS chip for rapid test and characterization. With the potential to perform label-free cellular analysis, the proposed platform opens an avenue to transition from traditional to smart cellular analysis techniques suitable for a variety of biological applications, in particular high throughput cell-based drug testing.

In this study the fluorinated carbon nanotubes (FCNTs) were analyzed to investigate the proficiency of this type of functionalization on removal of heavy metals from water. Electrokinetics desalination properties of (FCNTs) embedded in silicon membrane has been investigated using molecular dynamics simulation. In terms of flow rate enhancement, it was shown that with increment of voltage difference from 0 to 3 V, the water flux hit a peak of 378 H2O/ns (at 2 V) and 415 H2O/ns at (2.4 V) for FCNT and pristine carbon nanotubes (PCNT), respectively. Interestingly, FCNTs retarded the decline of flux condition which allows more water transport for higher voltages. The number of Zn2+ transport events were more than Hg2+, which shows the higher efficiency of this membranes on the removal of Zn2+ cations. Molecular dynamics simulation suggests FCNTs as a possible prospective volunteer for nanostructured carbon based material capable of removing heavy metals while gives the highest water flux compared to pristine carbon nanotubes.

This paper presents a new fully integrated CMOS capacitance sensor chip with a wider input dynamic range (IDR) compared to the state-of-the-art, suitable for a variety of life science applications. With the novel differential capacitance to current conversion topology, it achieves an IDR of about seven times higher compared to the previous charge based capacitive measurement (CBCM) circuits and about three times higher compared to the CBCM with cascode current mirrors. It also features a calibration circuitry consisting of an array of switched capacitors, interdigitated electrodes (IDEs) realized on the topmost metal layer, a current-controlled 300 MHz oscillator, and a counter-serializer to create digital output. The proposed sensor, fabricated in AMS 0.35 μm CMOS technology, enables a high-resolution measurement, equal to 416 aF, of physiochemical changes in the IDE with up to 1.27 pF input offset adjustment range (IOAR). With a measurement speed of 15 μs, this sensor is among the fast CMOS capacitive sensors in the literature. In this paper, we demonstrate its functionality and applicability and present the experimental results for monitoring 2 μL evaporating droplets of chemical solvents. By using samples of solvents with different conductivity and relative permittivity, a wide range of capacitance and resistance variations in the sample-IDE interface electric equivalent model can be created. In addition, the evaporating droplet test has inherently fast dynamic changes. Based on the results, our proposed device addresses the challenge of detecting small capacitance changes despite large parasitic elements caused by the ions in the solution or by remnants deposited on the electrode.

Purpose Nanopore-based molecular sensing and measurement, specifically Deoxyribonucleic acid (DNA) sequencing, is advancing at a fast pace. Some embodiments have matured from coarse particle counters to enabling full human genome assembly. This evolution has been powered not only by improvements in the sensors themselves, but also in the assisting microelectronic Complementary Metal Oxide Semiconductor (CMOS) readout circuitry closely interfaced to them. In this light, this paper reviews established and emerging nanopore-based sensing modalities considered for DNA sequencing and CMOS microelectronic methods currently being used. Design/methodology/approach Readout and amplifier circuits which are potentially appropriate for conditioning and conversion of nanopore signals for downstream processing are studied. Furthermore, arrayed CMOS readout implementations are focused on and the relevant status of the nanopore sensor technology is reviewed as well. Findings Ion channel nanopore devices have properties unique compared with other electrochemical cells. Currently biological nanopores are the only variants reported which can be used for actual DNA sequencing. The translocation rate of DNA through such pores, the current range at which these cells operate on and the cell capacitance effect, all impose the necessity of using low noise circuits in the process of signal detection. The requirement of using in-pixel low noise circuits in turn tends to impose challenges in the implementation of large size arrays. Originality/value The study presents an overview on the readout circuits used for signal acquisition in electrochemical cell arrays and investigates the specific requirements necessary for implementation of nanopore type electrochemical cell amplifiers and their associated readout electronics., Comment: Sensor Review (2021)

The superior mass sensitivity of microcoil technology in nuclear magnetic resonance (NMR) spectroscopy provides potential for the analysis of extremely small-mass-limited samples such as eggs, cells, and tiny organisms. For optimal performance and efficiency, the size of the microcoil should be tailored to the size of the mass-limited sample of interest, which can be costly as mass-limited samples come in many shapes and sizes. Therefore, rapid and economic microcoil production methods are needed. One method with great potential is 5-axis computer numerical control (CNC) micromilling, commonly used in the jewelry industry. Most CNC milling machines are designed to process larger objects and commonly have a precision of >25 μm (making the machining of common spiral microcoils, for example, impossible). Here, a 5-axis MiRA6 CNC milling machine, specifically designed for the jewelry industry, with a 0.3 μm precision was used to produce working planar microcoils, microstrips, and novel microsensor designs, with some tested on the NMR in less than 24 h after the start of the design process. Sample wells could be built into the microsensor and could be machined at the same time as the sensors themselves, in some cases leaving a sheet of Teflon as thin as 10 μm between the sample and the sensor. This provides the freedom to produce a wide array of designs and demonstrates 5-axis CNC micromilling as a versatile tool for the rapid prototyping of NMR microsensors. This approach allowed the experimental optimization of a prototype microstrip for the analysis of two intact adult Daphnia magna organisms. In addition, a 3D volume slotted-tube resonator was produced that allowed for 2D 1H–13C NMR of D. magna neonates and exhibited 1H sensitivity (nLODω600 = 1.49 nmol s1/2) close to that of double strip lines, which themselves offer the best compromise between concentration and mass sensitivity published to date.

This paper presents a novel method to model the deformations that occur in the retina due to macular disorders such as Age-related Macular Degeneration (AMD). In this model, the retinal pigment epithelium (RPE) covered with cones and rods is considered as a uniform layer of known pixels. The projected image on these pixels is perceived as per this model. Furthermore, this model can efficiently be used to generate the test patterns for an accurate and efficient method for monitoring macular disorder. In this proposed model, two major geometric shapes of retinal deformation are taken into account. Both colourful and grayscale images are employed to estimate the perceived images under various circumstances and inputs. Based on these results, the proposed model can be used for the assessment of the progression of macular disorders.Clinical relevance-Retinal Pigment Epithelium (RPE), Field of view (FOV), Visual Distortion (VD).

This paper presents the characterization of a smart bedsheet developed by Studio 1 Labs, which could be used to monitor the movement of an infant at night in order to detect and prevent sleep-related disorders. This smart bedsheet consists of an array of conductive fabrics to be used as pressure sensors to track the baby's movement. Electrical impedance spectroscopy (EIS) has been performed using the Metrohm Autolab potentiostat on a single and two-fabric interface. The results of this study will provide the information required to develop a sensitive and reliable smart bedsheet.

This paper introduces a new MEMS micro cantilever chip for mass flow rate and flow velocity measurement in a harsh environment where combustible gas flows are the working fluid. In such a condition, using thermal flow sensors is hazardous and may threaten a staggering amount of investment and human lives by igniting the gas flow which might lead to an explosion. To overcome these drawback mechanical sensors are more desirables for such environments. Here we have designed a MEMS chip consist of 74 polysilicon micro cantilevers that are operating based on a capacitive detection mode. There are micro cantilevers with 50, 100, 250 and 400 µm in length and same thickness and wideness, 2µm and 50µm, respectively. This sensor is capable of measuring moderate flows up to 200 m/s in a 10 cm diameter pipes based on the current design for bypass. According to experimental results, the sensor output capacitance varied from 3.3445 pF to 3.350 pF for a range of flow between 0 to 30 m/s. We have shown that MEMS flow sensor can meet large size flow measurements in the industry.

CMOS capacitive sensors have shown to be efficient label-free alternatives for optical methods in life-science applications. Their applicability to cellular monitoring for drug discovery has recently gained attraction. Solutions in the literature are typically customized for and tested by specific types of cells. This paper presents circuits and preliminary results on a versatile CMOS capacitive sensor for cellular monitoring. A new circuit and testbench is demonstrated that enjoys high linearity and achieves more than two times higher dynamic range compared to the state-of-the-art. In addition, adjustable sensitivity allows achieving higher sensitivity than reported in the literature. Results are obtained based on the implementation of the circuits in TSMC 0.18 µm technology.

This paper presents a novel non-invasive wireless device for animal breathing measurement. A flexible sensor is used to convert the berthing rate into a parodic resistive change. An interface circuit is designed to accurately measure the resistive signal, detect the breathing rate and transfer the recorded data to the computer wirelessly. Herein we demonstrate and discuss the functionality of the proposed system on a dog. Based on this result, the proposed system can reliably be used for animal behavioural studies.

This paper describes a research collaboration with Studio 1 Labs to provide the characterization for a novel smart baby monitoring device which includes conductive fabrics. The electrical characterization of the conductive fabrics is important for designing a bedsheet that can adequately be sensitive to physiological movement. Electrical impedance spectroscopy (EIS) has been performed using the Metrohm Autolab potentiostat on a two-fabric interface. For an increase in applied weight, there was an overall decrease in impedance shown both in its real and imaginary components. A simple RC circuit model could be used to describe the system. A test bedsheet was made from a 3x3 conductive fabric matrix stitched into a cotton sheet. Conversely, an increase in resistance was observed from an increase in applied weights at the intersection points of the bedsheet. The following characterization provided useful insight into the future design of the smart bedsheet.

Multiplex electrochemical biosensors have been used for eliminating the matrix effect in complex bodily fluids or enabling the detection of two or more bioanalytes, overall resulting in more sensitive assays and accurate diagnostics. Many electrochemical biosensors lack reliable and low-cost multiplexing to meet the requirements of point-of-care detection due to either limited functional biosensors for multi-electrode detection or incompatible readout systems. We developed a new dual electrochemical biosensing unit accompanied by a customized potentiostat to address the unmet need for point-of-care multi-electrode electrochemical biosensing. The two-working electrode system was developed using screen-printing of a carboxyl-rich nanomaterial containing ink, with both working electrodes offering active sites for recognition of bioanalytes. The low-cost bi-potentiostat system (∼$80) was developed and customized specifically to the bi-electrode design and used for rapid, repeatable, and accurate measurement of electrochemical impedance spectroscopy signals from the dual biosensor. This binary electrochemical data acquisition (Bi-ECDAQ) system accurately and selectively detected SARS-CoV-2 Nucleocapsid protein (N-protein) in both spiked samples and clinical nasopharyngeal swab samples of COVID-19 patients within 30 min. The two working electrodes offered the limit of detection of 116 fg/mL and 150 fg/mL, respectively, with the dynamic detection range of 1–10,000 pg/mL and the sensitivity range of 2744–2936 Ω mL/pg.mm2 for the detection of N-protein. The potentiostat performed comparable or better than commercial Autolab potentiostats while it is significantly lower cost. The open-source Bi-ECDAQ presents a customizable and flexible approach towards addressing the need for rapid and accurate point-of-care electrochemical biosensors for the rapid detection of various diseases., Graphical abstract Image 1

This paper presents a novel hybrid microfluidic electronic sensing platform, featuring an electronic sensor incorporated with a microfluidic structure for life science applications. This sensor with a large sensing area of 0.7 mm2 is implemented through a foundry process called Open-Gate Junction FET (OG-JFET). The proposed OG-JFET sensor with a back gate enables the charge by directly introducing the biological and chemical samples on the top of the device. This paper puts forward the design and implementation of a PDMS microfluidic structure integrated with an OG-JFET chip to direct the samples toward the sensing site. At the same time, the sensor’s gain is controlled with a back gate electrical voltage. Herein, we demonstrate and discuss the functionality and applicability of the proposed sensing platform using a chemical solution with different pH values. Additionally, we introduce a mathematical model to describe the charge sensitivity of the OG-JFET sensor. Based on the results, the maximum value of transconductance gain of the sensor is ~1 mA/V at Vgs = 0, which is decreased to ~0.42 mA/V at Vgs = 1, all in Vds = 5. Furthermore, the variation of the back-gate voltage from 1.0 V to 0.0 V increases the sensitivity from ~40 mV/pH to ~55 mV/pH. As per the experimental and simulation results and discussions in this paper, the proposed hybrid microfluidic OG-JFET sensor is a reliable and high-precision measurement platform for various life science and industrial applications.

This paper presents a new field-effect sensor called open-gate junction gate field-effect transistor (OG-JFET) for biosensing applications. The OG-JFET consists of a p-type channel on top of an n-type layer in which the p-type serves as the sensing conductive layer between two ohmic contacted sources and drain electrodes. The structure is novel as it is based on a junction field-effect transistor with a subtle difference in that the top gate (n-type contact) has been removed to open the space for introducing the biomaterial and solution. The channel can be controlled through a back gate, enabling the sensor’s operation without a bulky electrode inside the solution. In this research, in order to demonstrate the sensor’s functionality for chemical and biosensing, we tested OG-JFET with varying pH solutions, cell adhesion (human oral neutrophils), human exhalation, and DNA molecules. Moreover, the sensor was simulated with COMSOL Multiphysics to gain insight into the sensor operation and its ion-sensitive capability. The complete simulation procedures and the physics of pH modeling is presented here, being numerically solved in COMSOL Multiphysics software. The outcome of the current study puts forward OG-JFET as a new platform for biosensing applications.

Informational Deoxyribonucleic Acid (iDNA) has gained the attention of many researchers and pioneer companies for the development of novel storage systems for the long-term and high-density storing of information. This research focuses on the physical storage of iDNA strands to address some of the current challenges by evaluating the accuracy of the process of iDNA retrieval from the surface after the dehydration process. For this aim, a UV-Vis spectrophotometric technique was used to measure the concentration of the DNA samples. Although spectroscopy has been widely employed for the evaluation of DNA concentration and contamination in a solution, it has not been used to investigate dry-state DNA, which is one of the preferred storage formats for the long-term retention of information. These results demonstrate that the UV-Vis spectrophotometric technique can be used to accurately measure dry-state DNA before the retrieval and its residues after the DNA retrieval process. This paper further examines the storage/retrieval process by investigating the relationship between the storage time and the amount of retrieved DNA or the DNA residue left on various surfaces. Based on the experimental results demonstrated and discussed in this paper, UV-Vis spectrophotometry can be used for monitoring dry-state DNA with a high accuracy larger than 98%. Moreover, these results reveal that the hydrophilicity and hydrophobicity of the surface do not significantly affect DNA retrieval over a one-month time period.

This paper presents the design and implementation of a cantilever array device using a multi-user MEMS process for emerging point-of-care (PoC) diagnostic technologies. Each cantilever is incorporated with two capacitive sensing electrodes for the measurement of its beam deflection. A custom-made multichannel interface readout circuit was also developed using off-the-shelf elements for capacitance recording and data acquisition purposes. Herein, we demonstrate and discuss the functionality of the proposed capacitive cantilever array platform using interferometry and non-invasive rapid air-based characterization techniques. Based on simulation and experimental results, the proposed cantilever based platform can accurately measure μN-scale forces applied on each cantilever. The applicability of the proposed cantilever system was successfully investigated for PoC lung diagnostic purposes. Based on these results, the proposed system shows significant promise for use as an emerging free breathing measurement system for continuous assessment of respiratory health.

Nowadays, nanoparticles (NPs) are used in a variety of biomedical applications including brain disease diagnostics and subsequent treatments. Among the various types of NPs, magnetic nanoparticles (MNPs) have been implemented by many research groups for an array of life science applications. In this paper, we studied MNPs controlled delivery into the endothelial cells using a magnetic field. Dynamics equations of MNPs were defined in the continuous domain using control theory methods and were applied to crossing the cell membrane. This study, dedicated to clinical and biomedical research applications, offers a guideline for the generation of a magnetic field required for the delivery of MNPs.

In this paper we present a CMOS capacitive sensor array as a compact and low-cost platform for high-throughput cell growth monitoring. The proposed biosensor, consists of an array of 8 $\times$ 8 CMOS fully differential charge-based capacitive measurement sensors. A DC-input $\Sigma\Delta$ modulator is used to convert the sensors' signals to digital values for reading out the biological/chemical data and further signal processing. To compensate the mismatch variations between the current mirror transistors, a calibration circuitry is proposed which removes the output voltage offset with less than 8.2% error. We validate the chip functionality using various organic solvents with different dielectric constants. Moreover, we show the response of the chip to different concentrations of Polystyrene beads that have the same electrical properties as the living cells. The experimental results show that the chip allows the detection of a wide range of Polystyrene beads concentrations from as low as 10 beads/ml to 100 k beads/ml. In addition, we present the experimental results from H1299 (human lung carcinoma) cell line where we show that the chip successfully allows the detection of cell attachment and growth over capacitive electrodes in a 30 h measurement time and the results are in consistency with the standard cell-based assays. The capability of proposed device for label-free and real-time detection of cell growth with very high sensitivity opens up the important opportunity for utilizing the device in rapid screening of living cells.

This paper presents a novel real-time resonance-like impedance spectroscopy method using ITO electrodes. These electrodes can exhibit N-Shape Nonlinear Negative Differential Resistance (NDR) under specific conditions. In these conditions, the impedance of the electrode becomes pure capacitive, resulting in a resonance-shape spectrum. The resonance frequency is related to electrochemical changes at the interface between electrode and sample. We validated this method using microfabricated ITO electrodes exposed to two chemical solutions, including DMEM culture medium and 0.9% NaCl Solution. Based on these results, the proposed method can offer great advantages of rapid impedance spectroscopy for high throughput screening of chemical and biological materials suitable for a variety of life sciences applications.

Recent advances of computerized graphical methods have received significant attention for detection and home monitoring of various visual distortions caused by macular disorders such as macular edema, central serous chorioretinopathy, and age-related macular degeneration. After a brief review of macular disorders and their conventional diagnostic methods, this paper reviews such graphical interface methods including computerized Amsler Grid, Preferential Hyperacuity Perimeter, and Three-dimensional Computer-automated Threshold Amsler Grid. Thereafter, the challenges of these computerized methods for accurate and rapid detection of macular disorders are discussed. The early detection and progress assessment of macular disorders can significantly enhance the required clinical procedure for the diagnosis and treatment of macular disorders.

After the initiation of the current outbreak, humans’ lives have been profoundly impacted by COVID-19. During the first months, no rapid and reliable detecting tool was readily available to sufficiently respond to the requirement of massive testing. In this situation, when the development of an effective vaccine requires at least a few months, it is crucial to be prepared by developing and commercializing affordable, accurate, rapid and adaptable biosensors not only to fight Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) but also to be armed to avoid the pandemic in the earliest stages in the future. The COVID-19 diagnostic tools are categorized into two main groups of Nucleic Acid (NA)-based and protein-based tests. To date, nucleic acid-based detection has been announced as the gold-standard strategy for coronavirus detection; however, protein-based tests are promising alternatives for rapid and large-scale screening of susceptible groups. In this review, we discuss the current protein-based biosensing tools, the research advances and the potential protein-detecting strategies for COVID-19 detection. This narrative review aims to highlight the importance of the diagnostic tests, encourage the academic research groups and the companies to eliminate the shortcomings of the current techniques and step forward to mass-producing reliable point-of-care (POC) and point-of-need (PON) adaptable diagnostic tools for large-scale screening in the future outbreaks.

Field-effect transistor (FET) biosensors have been intensively researched toward label-free biomolecule sensing for different disease screening applications. High sensitivity, incredible miniaturization capability, promising extremely low minimum limit of detection (LoD) at the molecular level, integration with complementary metal oxide semiconductor (CMOS) technology and last but not least label-free operation were amongst the predominant motives for highlighting these sensors in the biosensor community. Although there are various diseases targeted by FET sensors for detection, infectious diseases are still the most demanding sector that needs higher precision in detection and integration for the realization of the diagnosis at the point of care (PoC). The COVID-19 pandemic, nevertheless, was an example of the escalated situation in terms of worldwide desperate need for fast, specific and reliable home test PoC devices for the timely screening of huge numbers of people to restrict the disease from further spread. This need spawned a wave of innovative approaches for early detection of COVID-19 antibodies in human swab or blood amongst which the FET biosensing gained much more attention due to their extraordinary LoD down to femtomolar (fM) with the comparatively faster response time. As the FET sensors are promising novel PoC devices with application in early diagnosis of various diseases and especially infectious diseases, in this research, we have reviewed the recent progress on developing FET sensors for infectious diseases diagnosis accompanied with a thorough discussion on the structure of Chem/BioFET sensors and the readout circuitry for output signal processing. This approach would help engineers and biologists to gain enough knowledge to initiate their design for accelerated innovations in response to the need for more efficient management of infectious diseases like COVID-19.

This paper examines the design and implementation of a 21 MHz CMOS differential or so-called dual-path receiver (DPR) dedicated to nuclear magnetic resonance (NMR) spectrometer. This receiver features a CMOS chip incorporated with two mini-Coils and other circuitries. Herein we discuss the design and implementation of the DPR chip as the core part of this new NMR system. The DPR consists of two differential low-noise amplifiers, voltage buffers, phase shifters and variable gain amplifiers in order to accurately cancel the effect of the background NMR signal. We put forward the design and analysis of the DPR chip and thereafter demonstrate and discuss the simulation and experimental results. Based on these results, the front-end receiver achieves a voltage gain of 80 dB at a low input referred noise of 2.7 nV/?Hz. The chip is designed in a 0.13-µm CMOS technology and occupies an area of 1 mm × 2 mm. As per experimental results, this device can be used n the future low-cost NMR technologies.

This paper presents a new approach towards the development of a spirometer-on-chip device for point-of-care diagnostics. The proposed device consists of a cantilever based airflow sensor fabricated through a multi-user MEMS process. The deflection of each cantilever beam is measured using capacitive electrodes integrated on a single semiconductor chip. These electrodes are connected to an off-chip custom-made readout interface circuit for the measurement of minute capacitive changes and for the acquisition of data into a computer. Herein, we discuss and demonstrate the characterization results of such a system using a low complexity air-based technique. Additionally, we demonstrate the applicability of these devices for spirometry on breathing tests of human subjects. Based on these results, the proposed spirometer-on-chip shows significant promise for use as a mobile portable system for continuous health assessment of respiratory health.

Emerging infectious diseases such as coronavirus disease of 2019 (COVID-19), Ebola, influenza A, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) in recent years have threatened the health and security of the global community as one of the greatest factors of mortality in the world. Accurate and immediate diagnosis of infectious agents and symptoms is a key to control the outbreak of these diseases. Rapid advances in complementary metal-oxide-semiconductor (CMOS) technology offers great advantages like high accuracy, high throughput and rapid measurements in biomedical research and disease diagnosis. These features as well as low cost, low power and scalability of CMOS technology can pave the way for the development of powerful devices such as point-of-care (PoC) systems, lab-on-chip (LoC) platforms and symptom screening devices for accurate and timely diagnosis of infectious diseases. This paper is an overview of different CMOS-based devices such as optical, electrochemical, magnetic and mechanical sensors developed by researchers to mitigate the problems associated with these diseases.