Advances in point-of-care technologies for molecular diagnostics

Visual and quantitative lateral flow immunoassay based on Au@PS SERS tags for multiplex cardiac biomarkers

Rapid and sensitive detection of multiple biomarkers by lateral flow immunoassay (LFIA) remains challenging for signal amplification for commonly used nanotags. Herein, we report a novel LFIA strip for visual and highly sensitive analysis of two cardiac biomarkers based on functionalized gold nanoparticles @ polystyrene microsphere (Au@PS）microcavity as surface-enhanced Raman scattering (SERS) tags. Antibody-modified Au@PS was designed as a SERS label. The evanescent waves propagating along the surface of the PS microcavity and the localized surface plasmons of the gold nanoparticles were coupled to enhance the light-matter interaction synergistically for Raman signal enhancement. In this strategy, the proposed Au@PS SERS tags-based LFIA was carried out to quantify the content of the heart failure and infarct biomarkers synchronously within 15 min and get the limits of detection of 1 pg/mL and 10 pg/mL for cardiac troponin I (cTnI) and N-terminal natriuretic peptide precursor (NT-proBNP), respectively. The results demonstrated 10-20 folds more sensitivity than that of the standard colloidal gold strip and fluorescent strip for the same biomarkers. This novel quantitative LFIA shows promise as a high-sensitive and visual sensing method for relevant clinical and forensic analysis.

Recent advances in smart wearable sensors for continuous human health monitoring

In recent years, the biochemical and biological research areas have shown great interest in a smart wearable sensor because of its increasing prevalence and high potential to monitor human health in a non-invasive manner by continuous screening of biomarkers dispersed throughout the biological analytes, as well as real-time diagnostic tools and time-sensitive information compared to conventional hospital-centered system. These smart wearable sensors offer an innovative option for evaluating and investigating human health by incorporating a portion of recent advances in technology and engineering that can enhance real-time point-of-care-testing capabilities. Smart wearable sensors have emerged progressively with a mixture of multiplexed biosensing, microfluidic sampling, and data acquisition systems incorporated with flexible substrate and bodily attachments for enhanced wearability, portability, and reliability. There is a good chance that smart wearable sensors will be relevant to the early detection and diagnosis of disease management and control. Therefore, pioneering smart wearable sensors into reality seems extremely promising despite possible challenges in this cutting-edge technology for a better future in the healthcare domain. This review presents critical viewpoints on recent developments in wearable sensors in the upcoming smart digital health monitoring in real-time scenarios. In addition, there have been proactive discussions in recent years on materials selection, design optimization, efficient fabrication tools, and data processing units, as well as their continuous monitoring and tracking strategy with system-level integration such as internet-of-things, cyber-physical systems, and machine learning algorithms.

Utilizing Magnetic Levitation to Detect Lung Cancer-Associated Exosomes

Extracellular vesicles, especially exosomes, have attracted attention in the last few decades as novel cancer biomarkers. Exosomal membrane proteins provide easy-to-reach targets and can be utilized as information sources of their parent cells. In this study, a MagLev-based, highly sensitive, and versatile biosensor platform for detecting minor differences in the density of suspended objects is proposed for exosome detection. The developed platform utilizes antibody-functionalized microspheres to capture exosomal membrane proteins (ExoMPs) EpCAM, CD81, and CD151 as markers for cancerous exosomes, exosomes, and non-small cell lung cancer (NSCLC)-derived exosomes, respectively. Initially, the platform was utilized for protein detection and quantification by targeting solubilized ExoMPs, and a dynamic range of 1-100 nM, with LoD values of 1.324, 0.638, and 0.722 nM for EpCAM, CD81, and CD151, were observed, respectively. Then, the sensor platform was tested using exosome isolates derived from NSCLC cell line A549 and MRC5 healthy lung fibroblast cell line. It was shown that the sensor platform is able to detect and differentiate exosomal biomarkers derived from cancerous and non-cancerous cell lines. Overall, this innovative, simple, and rapid method shows great potential for the early diagnosis of lung cancer through exosomal biomarker detection.

Bioluminescent Intercalating Dyes for Ratiometric Nucleic Acid Detection

Rapid and sensitive DNA detection methods that can be conducted at the point of need may aid in disease diagnosis and monitoring. However, translation of current assays has proven challenging, as they typically require specialized equipment or probe-specific modifications for every new target DNA. Here, we present Luminescent Multivalent Intercalating Dye (LUMID), off-the-shelf bioluminescent sensors consisting of intercalating dyes conjugated to a NanoLuc luciferase, which allow for nonspecific detection of double-stranded DNA through a blue-to-green color change. Through the incorporation of multiple, tandem-arranged dyes separated by positively charged linkers, DNA-binding affinities were improved by over 2 orders of magnitude, detecting nanomolar DNA concentrations with an 8-fold change in green/blue ratio. We show that LUMID is easily combined with loop-mediated isothermal amplification (LAMP), enabling sequence-specific detection of viral DNA with attomolar sensitivity and a smartphone-based readout. With LUMID, we have thus developed a tool for simple and sensitive DNA detection that is particularly attractive for point-of-need applications.

Integrated Point-of-Care Immune Cell Analyzer with Rapid Blood Sample Reaction and Wide Field-of-View Detection

The development of affordable, reliable, and rapid diagnostic devices is crucial for monitoring immunological responses using a drop of blood. However, conventional automated diagnostic devices typically involve expensive and impractical robotic fluid-handling approaches. Herein, we developed an integrated cell analyzer comprising a cylindrical sample cartridge connected to a direct current motor and a compact fluorescence imaging module. Sample mixing and loading are performed automatically by a programmable sequence of single motor rotation controlled by an Android application. Two distinct stained immune cell samples can be identified by using two types of fluorescence imaging modes. The effectiveness of mixing performance in antigen-antibody (Ag-Ab) reactions was assessed through a compound objective lens that collects weak fluorescence emitted by the cell membrane. Active mixing with bidirectional rotation of the cartridge in a confined space shortened the Ag-Ab reaction time by a factor of 3.3 and achieved cell counting with higher accuracy while reducing reagent consumption by 4 times compared to the conventional incubation method. High-intensity fluorescence images of cells labeled with a nucleic acid stain were acquired through a single-lens-based fluorescence imaging module with a large field of view (FOV) in an unconventional detection chamber with a curved substrate. Compared with a flat chamber, the curved detection chamber reduces the effects of field curvature and provides aberration-free wide-FOV images, even with a simple lens. Our integrated cell analyzer thus offers a practical and cost-effective solution for monitoring patient immune responses in point-of-care settings.

Ag microlabyrinth/nanoparticles coated large-area thin PDMS films as flexible and transparent SERS substrates for in situ detection

Flexible and transparent surface-enhanced Raman scattering (SERS) substrates haveattractedmuchattention as a fast, sensitive and in situ detection platform for practical applications. However, the large-area fabrication of flexible and transparent SERS substrates with high performance is still challenging. Here, a flexible and transparent SERS substrate based on large-area thin PDMS film decorated with Ag microlabyrinth/nanoparticles hierarchical structures (denoted as ALNHS@PDMS) is fabricated by using the floating-on-water method and magnetron sputtering technology. By optimizing the sputtering time, the ALNHS with multiple hot spots are uniformly distributed on the PDMS surface. Based on characterizing the rhodamine 6G (R6G) with a portable Raman spectrometer, the optimal ALNHS@PDMS film exhibits a high enhancement factor (5.2 × 106), excellent uniformity and reproducibility, as well as superior mechanical stability. In addition, thanks to the good sticky feature and bi-directional activation property of the thin ALNHS@PDMS film, the prepared flexible and transparent SERS substrate can achieve in situ detection of malachite green residues (10-6 M) on apple and tomato skins. This large-area, thin, mechanically robust, flexible and transparent ALNHS@PDMS film, integrated with a portable Raman spectrometer, shows great potential for point-of-care testing (POCT)in practical applications.

Maximising Affordability of Real-Time Colorimetric LAMP Assays

Molecular diagnostics have become indispensable in healthcare, agriculture, and environmental monitoring. This diagnostic form can offer rapid and precise identification of pathogens and biomarkers. However, traditional laboratory-based molecular testing methods can be expensive and require specialised training, limiting their accessibility in resource-limited settings and on-site applications. To overcome these challenges, this study proposes an innovative approach to reducing costs and complexity in portable colorimetric loop-mediated isothermal amplification (LAMP) devices. The research evaluates different resistive heating systems to create an energy-efficient, cost-effective, and compact device to heat a polydimethylsiloxane (PDMS) block for precise temperature control during LAMP reactions. By combining this novel heating system with an off-the-shelf red-green-blue (RGB) sensor to detect and quantify colour changes, the integrated system can accurately detect Leifsonia xyli subsp. xyli, the bacteria responsible for ratoon stunting disease (RSD) in sugarcane. The experimental validation of this system demonstrates its ability to detect the target pathogen in real time, making it an important development for low cost, portable, and easy-to-use molecular diagnostics in healthcare, agriculture, and environmental monitoring applications.

Soft microfiber-based hollow microneedle array for stretchable microfluidic biosensing patch with negative pressure-driven sampling

Wearable point-of-care testing devices are essential for personalized and decentralized healthcare. They can collect biofluid samples from the human body and use an analyzer to detect biomolecules. However, creating an integrated system is challenging due to the difficulty of achieving conformality to the human body, regulating the collection and transport of biofluids, developing a biosensor patch capable of precise biomolecule detection, and establishing a simple operation protocol that requires minimal wearer attention. In this study, we propose using a hollow microneedle (HMN) based on soft hollow microfibers and a microneedle-integrated microfluidic biosensor patch (MIMBP) capable of integrated blood sampling and electrochemical biosensing of biomolecules. The soft MIMBP includes a stretchable microfluidic device, a flexible electrochemical biosensor, and a HMN array made from flexible hollow microfibers. The HMNs are fabricated by electroplating flexible and mechanically durable hollow microfibers made from a nanocomposite matrix of polyimide, a poly (vinylidene fluoride-co-trifluoroethylene) copolymer, and single-walled carbon nanotubes. The MIMBP uses the negative pressure generated by a single button push to collect blood and deliver it to a flexible electrochemical biosensor modified with a gold nanostructure and Pt nanoparticles. We have demonstrated that glucose can be accurately measured up to the molar range in whole human blood collected through the microneedle. The MIMBP platform with HMNs has great potential as a foundation for the future development of simple, wearable, self-testing systems for minimally invasive biomolecule detection. This platform capable of sequential blood collection and high sensitivity glucose detection, which are ideal for personalized and decentralized healthcare.

Engineering Materials and Devices for the Prevention, Diagnosis, and Treatment of COVID-19 and Infectious Diseases

Following the global spread of COVID-19, scientists and engineers have adapted technologies and developed new tools to aid in the fight against COVID-19. This review discusses various approaches to engineering biomaterials, devices, and therapeutics, especially at micro and nano levels, for the prevention, diagnosis, and treatment of infectious diseases, such as COVID-19, serving as a resource for scientists to identify specific tools that can be applicable for infectious-disease-related research, technology development, and treatment. From the design and production of equipment critical to first responders and patients using three-dimensional (3D) printing technology to point-of-care devices for rapid diagnosis, these technologies and tools have been essential to address current global needs for the prevention and detection of diseases. Moreover, advancements in organ-on-a-chip platforms provide a valuable platform to not only study infections and disease development in humans but also allow for the screening of more effective therapeutics. In addition, vaccines, the repurposing of approved drugs, biomaterials, drug delivery, and cell therapy are promising approaches for the prevention and treatment of infectious diseases. Following a comprehensive review of all these topics, we discuss unsolved problems and future directions.

Artificial intelligence-driven electrochemical immunosensing biochips in multi-component detection

Electrochemical Immunosensing (EI) combines electrochemical analysis and immunology principles and is characterized by its simplicity, rapid detection, high sensitivity, and specificity. EI has become an important approach in various fields, such as clinical diagnosis, disease prevention and treatment, environmental monitoring, and food safety. However, EI multi-component detection still faces two major bottlenecks: first, the lack of cost-effective and portable detection platforms; second, the difficulty in eliminating batch differences and accurately decoupling signals from multiple analytes. With the gradual maturation of biochip technology, high-throughput analysis and portable detection utilizing the advantages of miniaturized chips, high sensitivity, and low cost have become possible. Meanwhile, Artificial Intelligence (AI) enables accurate decoupling of signals and enhances the sensitivity and specificity of multi-component detection. We believe that by evaluating and analyzing the characteristics, benefits, and linkages of EI, biochip, and AI technologies, we may considerably accelerate the development of EI multi-component detection. Therefore, we propose three specific prospects: first, AI can enhance and optimize the performance of the EI biochips, addressing the issue of multi-component detection for portable platforms. Second, the AI-enhanced EI biochips can be widely applied in home care, medical healthcare, and other areas. Third, the cross-fusion and innovation of EI, biochip, and AI technologies will effectively solve key bottlenecks in biochip detection, promoting interdisciplinary development. However, challenges may arise from AI algorithms that are difficult to explain and limited data access. Nevertheless, we believe that with technological advances and further research, there will be more methods and technologies to overcome these challenges.

Advantages and limitations of current diagnostic laboratory approaches in syphilis and congenital syphilis

INTRODUCTION

The reemergence of syphilis, especially congenital syphilis, presents a significant public health threat. Accurate diagnosis of syphilis depends on recognition of a constellation of symptoms, review of medical and sexual history, and multiple laboratory tests. While reliable, current tests for syphilis can be difficult to interpret, which can lead to delays in treatment.

AREA COVERED

This review summarizes the major advantages and limitations of available diagnostic laboratory methods for syphilis, provides an update on recent advances in laboratory tools, and highlights the urgent need for coordinated efforts to create new tools to halt the resurgence of syphilis.

EXPERT OPINION

In syphilis, the wide variety of short-lived signs and symptoms followed by periods of latency create diagnostic challenges. Currently available laboratory tests, when positive, require additional information to interpret (prior testing, treatment, and sexual history). Point-of-care tests that can rapidly and accurately detect both treponemal and non-treponemal antibodies would be a huge step toward reducing test turnaround time and time to treatment. Incorporating biological insights and technology innovations to advance the development of direct detection assays is urgently needed. A comprehensive coordinated effort is critical to stem the tide of rising syphilis in the United States and globally.

Lipidest: a lipid profile screening test under extreme point of care settings using a portable spinning disc and an office scanner

The demand for lipid profile (the cholesterol and triglyceride elements in the blood) testing outside resourced diagnostic centers is continuously increasing for personalized and community-based healthcare to ensure timely disease screening and management; however, it is inevitably challenged by several bottlenecks in the existing point of care technologies. These deficits include delicate sample pre-processing steps and device complexity, which give rise to unfavourable cost propositions to safeguard against compromised test accuracy. To circumvent these bottlenecks, herein, we introduce a new diagnostic technology, 'Lipidest', that integrates a portable spinning disc, a spin box, and an office scanner to reliably quantify the complete lipid panel from finger-prick blood. Our design facilitates the direct miniature adaptation of the established gold standard procedures as against any indirect sensing technologies that are otherwise common in point-of-care applications introduced commercially. The test procedure harmoniously connects all the elements of sample-to-answer integration in a single device, traversing the entire pipeline of the physical separation of plasma from the cellular components of the whole blood, the automated mixing with the test reagents on the same platform in situ, and office-scanner-adapted quantitative colorimetric analytics that eliminate any undesirable artefacts on account of variabilities in the background illumination and camera specifications. The exclusive value of eliminating sample preparation steps, including the rotationally actuated segregation of the specific blood constituents without any cross-interference between them, their automated homogeneous mixing with the respective test reagents, and the simultaneous, yet independent, quantitative readout without specialized instrumentation, render the test user-friendly and deployable in resource-constrained settings with a reasonably wide detection window. The extreme simplicity and modular nature of the device further make it amenable to mass manufacturing without incurring unfavourable costs. Extensive validation with laboratory-benchmark gold standards provide acceptable accuracy and indicates the value of the first-of-its-kind ultra-low-cost extreme-point-of-care test with a scientific foundation akin to highly accurate laboratory-centric technologies for cardiovascular health monitoring and beyond.

Advances in point-of-care genetic testing for personalized medicine applications

Breakthroughs within the fields of genomics and bioinformatics have enabled the identification of numerous genetic biomarkers that reflect an individual's disease susceptibility, disease progression, and therapy responsiveness. The personalized medicine paradigm capitalizes on these breakthroughs by utilizing an individual's genetic profile to guide treatment selection, dosing, and preventative care. However, integration of personalized medicine into routine clinical practice has been limited-in part-by a dearth of widely deployable, timely, and cost-effective genetic analysis tools. Fortunately, the last several decades have been characterized by tremendous progress with respect to the development of molecular point-of-care tests (POCTs). Advances in microfluidic technologies, accompanied by improvements and innovations in amplification methods, have opened new doors to health monitoring at the point-of-care. While many of these technologies were developed with rapid infectious disease diagnostics in mind, they are well-suited for deployment as genetic testing platforms for personalized medicine applications. In the coming years, we expect that these innovations in molecular POCT technology will play a critical role in enabling widespread adoption of personalized medicine methods. In this work, we review the current and emerging generations of point-of-care molecular testing platforms and assess their applicability toward accelerating the personalized medicine paradigm.

COVID-19 detection using AIE-active iridium complexes

The highly contagious COVID-19, caused by the outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is commonly diagnosed using reverse transcription polymerase chain reaction (RT-PCR). However, despite being highly sensitive, RT-PCR is also time consuming and quite complex, which limits its use for point-of-care (POC) testing. We have developed a simple single-step fluorescence assay for SARS-CoV-2 RNA detection based on the principle of aggregation-induced emission (AIE) using iridium complexes. Our smartly designed iridium probes fluorescently "turn-on" in the presence of SARS-CoV-2 RNA and give specific results at room temperature within 10 min. The lower limit of detection (LOD) is 1.84 genome copies per reaction, and the sensitivity and specificity of the assay in 20 clinical samples are found to be 90% and 80%, respectively.

Collection, nucleic acid release, amplification, and visualization platform for rapid field detection of rice false smut

Rice false smut (RFS) has brought serious food safety problems to the world. Reliable diagnostic tools are needed for the field detection of RFS. Traditional polymerase chain reaction (PCR) is inefficient due to sample transport and preparation, which cannot adapt to the needs of field detection. Herein, we successfully developed a simple, portable microfluidic test platform to rapidly detect RFS. To simplify the operation, we integrated spore purification, nucleic acid release, and amplification into one chip. A micro air pump was used to separate the spores from the impurities and complete the collection of the spores through the airflow. We rapidly lysed spores and released nucleic acids by the benzyl chloride method. The loop-mediated isothermal amplification (LAMP) products could be combined with SYBR Green I to observe the results visually. On-chip sample tests showed that the spore collection efficiency was approximately 78%. By providing on-chip detection results, the chip had 100% specificity and a detection limit of 100 copies/reaction. At the same time, the stability (CV < 5%) and quantitative ability (R² = 0.989) of the chip were also guaranteed. Through the visual detection of large samples, the on-chip detection results were highly concordant with the classical RT-PCR detection results, and the detection timeliness was greatly enhanced. Compared with RT-PCR, the single-sample detection time was shortened by about twenty minutes. The proposed micro-diagnostic tool did not require any large end-point detection instruments and avoided the complicated operation of nucleic acid extraction. As a result, in the future, our microfluidic chip could be used for rapid and real-time monitoring and early warning of rice false smut spores in rice paddies.

Optimizing mycobacteria molecular diagnostics: No decontamination! Human DNA depletion? Greener storage at 4 °C!

Introduction

Tuberculosis (TB) is an infectious disease caused by the group of bacterial pathogens Mycobacterium tuberculosis complex (MTBC) and is one of the leading causes of death worldwide. Timely diagnosis and treatment of drug-resistant TB is a key pillar of WHO's strategy to combat global TB. The time required to carry out drug susceptibility testing (DST) for MTBC via the classic culture method is in the range of weeks and such delays have a detrimental effect on treatment outcomes. Given that molecular testing is in the range of hours to 1 or 2 days its value in treating drug resistant TB cannot be overstated. When developing such tests, one wants to optimize each step so that tests are successful even when confronted with samples that have a low MTBC load or contain large amounts of host DNA. This could improve the performance of the popular rapid molecular tests, especially for samples with mycobacterial loads close to the limits of detection. Where optimizations could have a more significant impact is for tests based on targeted next generation sequencing (tNGS) which typically require higher quantities of DNA. This would be significant as tNGS can provide more comprehensive drug resistance profiles than the relatively limited resistance information provided by rapid tests. In this work we endeavor to optimize pre-treatment and extraction steps for molecular testing.

Methods

We begin by choosing the best DNA extraction device by comparing the amount of DNA extracted by five commonly used devices from identical samples. Following this, the effect that decontamination and human DNA depletion have on extraction efficiency is explored.

Results

The best results were achieved (i.e., the lowest C_t values) when neither decontamination nor human DNA depletion were used. As expected, in all tested scenarios the addition of decontamination to our workflow substantially reduced the yield of DNA extracted. This illustrates that the standard TB laboratory practice of applying decontamination, although being vital for culture-based testing, can negatively impact the performance of molecular testing. As a complement to the above experiments, we also considered the best Mycobacterium tuberculosis DNA storage method to optimize molecular testing carried out in the near- to medium-term. Comparing C_t values following three-month storage at 4 °C and at -20 °C and showed little difference between the two.

Discussion

In summary, for molecular diagnostics aimed at mycobacteria this work highlights the importance of choosing the right DNA extraction device, indicates that decontamination causes significant loss of mycobacterial DNA, and shows that samples preserved for further molecular testing can be stored at 4 °C, just as well at -20 °C. Under our experimental settings, human DNA depletion gave no significant improvement in C_t values for the detection of MTBC.

After Theranos: Using point-of-care testing to advance measures of health biomarkers in human biology research

OBJECTIVES

The rise and fall of the health technology startup Theranos is emblematic of the promise and peril of point-of-care testing (POCT). Instruments that deliver immediate results from minimally invasive samples at the location of collection can provide powerful tools to deliver health data in clinical and public health contexts. Yet, POCT availability is driven largely by market interests, which limits the development of inexpensive tests for diverse health conditions that can be used in resource-limited settings. These constraints, combined with complex regulatory hurdles and substantial ethical challenges, have contributed to the underutilization of POCT in human biology research.

METHODS

We evaluate current POCT capabilities and limitations, discuss promising applications for POCT devices in resource-limited settings, and discuss the future of POCT.

RESULTS

As evidenced by publication trends, POCT platforms have rapidly advanced in recent years, gaining traction among clinicians and health researchers. We highlight POCT devices of potential interest to population-based researchers and present specific examples of POCT applications in human biology research.

CONCLUSIONS

Several barriers can limit POCT applications, including cost, lack of regulatory approval for non-clinical use, requirements for expensive equipment, and the dearth of validation in remote field conditions. Despite these issues, we see immense potential for emerging POCT technology capable of analyzing new sample types and used in conjunction with increasingly common technology (e.g., smart phones). We argue that the fallout from Theranos may ultimately provide an opportunity to advance POCT, leading to more ethical data collection and novel opportunities in human biology research.

Photoacoustic detection of SARS-CoV-2 spike N501Y single-nucleotide polymorphism based on branched rolling circle amplification

Rapid and accurate diagnosis of SARS-CoV-2 single-nucleotide variations is an urgent need for the initial detection of local circulation and monitoring the alternation of dominant variant. In this proof-of-concept study, a homogeneous and isothermal photoacoustic biosensor is demonstrated for rapid molecular amplification and detection of a synthetic DNA corresponding to SARS-CoV-2 spike N501Y. Branched rolling circle amplification produces single-stranded amplicons that can aggregate detection probe-modified AuNPs, which induces a strong photoacoustic signal at 640 nm due to both the surface plasmon resonance shift and the size-dependent effect of laser-induced nanobubbles, achieving a sub-femtomolar detection limit within a total assay time of 80 min. The limit of detection can be kept when measuring 5% serum samples. Moreover, the proposed biosensor is highly specific for single-nucleotide polymorphism discrimination and robust against background DNA.

Recent Advancements in Nanobiosensors: Current Trends, Challenges, Applications, and Future Scope

In recent years, there has been immense advancement in the development of nanobiosensors as these are a fundamental need of the hour that act as a potential candidate integrated with point-of-care-testing for several applications, such as healthcare, the environment, energy harvesting, electronics, and the food industry. Nanomaterials have an important part in efficiently sensing bioreceptors such as cells, enzymes, and antibodies to develop biosensors with high selectivity, peculiarity, and sensibility. It is virtually impossible in science and technology to perform any application without nanomaterials. Nanomaterials are distinguished from fine particles used for numerous applications as a result of being unique in properties such as electrical, thermal, chemical, optical, mechanical, and physical. The combination of nanostructured materials and biosensors is generally known as nanobiosensor technology. These miniaturized nanobiosensors are revolutionizing the healthcare domain for sensing, monitoring, and diagnosing pathogens, viruses, and bacteria. However, the conventional approach is time-consuming, expensive, laborious, and requires sophisticated instruments with skilled operators. Further, automating and integrating is quite a challenging process. Thus, there is a considerable demand for the development of nanobiosensors that can be used along with the POCT module for testing real samples. Additionally, with the advent of nano/biotechnology and the impact on designing portable ultrasensitive devices, it can be stated that it is probably one of the most capable ways of overcoming the aforementioned problems concerning the cumulative requirement for the development of a rapid, economical, and highly sensible device for analyzing applications within biomedical diagnostics, energy harvesting, the environment, food and water, agriculture, and the pharmaceutical industry.

Surface Wrinkling for Flexible and Stretchable Sensors

Recent advances in nanolithography, miniaturization, and material science, along with developments in wearable electronics, are pushing the frontiers of sensor technology into the large-scale fabrication of highly sensitive, flexible, stretchable, and multimodal detection systems. Various strategies, including surface engineering, have been developed to control the electrical and mechanical characteristics of sensors. In particular, surface wrinkling provides an effective alternative for improving both the sensing performance and mechanical deformability of flexible and stretchable sensors by releasing interfacial stress, preventing electrical failure, and enlarging surface areas. In this study, recent developments in the fabrication strategies of wrinkling structures for sensor applications are discussed. The fundamental mechanics, geometry control strategies, and various fabricating methods for wrinkling patterns are summarized. Furthermore, the current state of wrinkling approaches and their impacts on the development of various types of sensors, including strain, pressure, temperature, chemical, photodetectors, and multimodal sensors, are reviewed. Finally, existing wrinkling approaches, designs, and sensing strategies are extrapolated into future applications.

Optomagnetic biosensors: Volumetric sensing based on magnetic actuation-induced optical modulations

In comparison to alternative nanomaterials, magnetic micron/nano-sized particles show unique advantages, e.g., easy manipulation, stable signal, and high contrast. By applying magnetic actuation, magnetic particles exert forces on target objects for highly selective operation even in non-purified samples. We herein describe a subgroup of magnetic biosensors, namely optomagnetic biosensors, which employ alternating magnetic fields to generate periodic movements of magnetic labels. The optical modulation induced by the dynamics of magnetic labels is then analyzed by photodetectors, providing information of, e.g., hydrodynamic size changes of the magnetic labels. Optomagnetic sensing mechanisms can suppress the noise (by performing lock-in detection), accelerate the reaction (by magnetic force-enhanced molecular collision), and facilitate homogeneous/volumetric detection. Moreover, optomagnetic sensing can be performed using a low magnetic field (<10 mT) without sophisticated light sources or pickup coils, further enhancing its applicability for point-of-care tests. This review concentrates on optomagnetic biosensing techniques of different concepts classified by the magnetic actuation strategy, i.e., magnetic field-enhanced agglutination, rotating magnetic field-based particle rotation, and oscillating magnetic field-induced Brownian relaxation. Optomagnetic sensing principles applied with different actuation strategies are introduced as well. For each representative optomagnetic biosensor, a simple immunoassay strategy-based application is introduced (if possible) for methodological comparison. Thereafter, challenges and perspectives are discussed, including minimization of nonspecific binding, on-chip integration, and multiplex detection, all of which are key requirements in point-of-care diagnostics.

Unidirectional self-actuation transport of a liquid metal nanodroplet in a two-plate confinement microchannel

Controllable directional transport of a liquid metal nanodroplet in a microchannel has been a challenge in the field of nanosensors, nanofluidics, and nanofabrication. In this paper, we report a novel design that the self-actuation of a gallium nanodroplet in a two-plate confinement microchannel could be achieved via a continuous wetting gradient. More importantly, suitable channel parameters could be used to manipulate the dynamic behavior of the gallium nanodroplet. The self-actuation transport in the two-plate confinement microchannel is the result of the competition between the driving force from the difference of the Laplace pressure and energy dissipation from the viscous resistance. Furthermore, we have identified the conditions to assess whether the droplet will pass through the contractive cross-section or not. This work can provide guidance for manipulating liquid metal nanodroplets in microchannels.

Diagnosis of disease relevant nucleic acid biomarkers with off-the-shelf devices

Changes in the level of nucleic acids in blood may be correlated with some clinical disorders like cancer, stroke, trauma and autoimmune diseases, and thus, nucleic acids can serve as potential biomarkers for pathological processes. The requirement of technical equipment and operator expertise in effective information readout of modern molecular diagnostic technologies significantly restricted application outside clinical laboratories. The ability to detect nucleic acid biomarkers with off-the-shelf devices, which have the advantages of portability, simplicity, low cost and short response time, is critical to provide a prompt clinical result in circumstances where the laboratory instruments are not available. This review throws light on the current strategies and challenges for nucleic acid diagnosis with commercial portable devices, indicating the future prospect of portable diagnostic devices and making a great difference in improving the healthcare and disease surveillance in resource-limited areas.

Noble Metal Nanoparticle Biosensors: From Fundamental Studies toward Point-of-Care Diagnostics

Noble metal nanoparticles (NMNPs) have become firmly established as effective agents to detect various biomolecules with extremely high sensitivity. This ability stems from the collective oscillation of free electrons and extremely large electric field enhancement under exposure to light, leading to various light-matter interactions such as localized surface plasmon resonance (LSPR) and surface-enhanced Raman scattering. A remarkable feature of NMNPs is their customizability by mechanisms such as particle etching, growth, and aggregation/dispersion, yielding distinct color changes and excellent opportunities for colorimetric biosensing in user-friendly assays and devices. They are readily functionalized with a large variety of capping agents and biomolecules, with resultant bioconjugates often possessing excellent biocompatibility, which can be used to quantitatively detect analytes from physiological fluids. Furthermore, they can possess excellent catalytic properties that can achieve significant signal amplification through mechanisms such as the catalytic transformation of colorless substrates to colored reporters. The various excellent attributes of NMNP biosensors have put them in the spotlight for developing high-performance in vitro diagnostic (IVD) devices that are particularly well-suited to mitigate the societal threat that infectious diseases pose. This threat continues to dominate the global health care landscape, claiming millions of lives annually. NMNP IVDs possess the potential to sensitively detect infections even at very early stages with affordable and field-deployable devices, which will be key to strengthening infectious disease management. This has been the major focal point of current research, with a view to new avenues for early multiplexed detection of infectious diseases with portable devices such as smartphones, especially in resource-limited settings.In this Account, we provide an overview of our original inspiration and efforts in NMNP-based assay development, together with some more sophisticated IVD assays by ourselves and many others. Our work in the area has led to our recent efforts in developing IVDs for high-profile infectious diseases, including Ebola and HIV. We emphasize that integration with digital platforms represents an opportunity to establish and efficiently manage widespread testing, tracking, epidemiological intelligence, and data sharing backed by community participation. We highlight how digital technologies can address the limitations of conventional diagnostic technologies at the point of care (POC) and how they may be used to abate and contain the spread of infectious diseases. Finally, we focus on more recent integrations of noble metal nanoparticles with Raman spectroscopy for accurate, noninvasive POC diagnostics with improved sensitivity and specificity.

Thin flexible lab-on-a-film for impedimetric sensing in biomedical applications

Microfluidic cytometers based on coulter principle have recently shown a great potential for point of care biosensors for medical diagnostics. Here, we explore the design of an impedimetric microfluidic cytometer on flexible substrate. Two coplanar microfluidic geometries are compared to highlight the sensitivity of the device to the microelectrode positions relative to the detection volume. We show that the microelectrodes surface area and the geometry of the sensing volume for the cells strongly influence the output response of the sensor. Reducing the sensing volume decreases the pulse width but increases the overall pulse amplitude with an enhanced signal-to-noise ratio (~ max. SNR = 38.78 dB). For the proposed design, the SNR was adequate to enable good detection and differentiation of 10 µm diameter polystyrene beads and leukemia cells (~ 6–21 µm). Also, a systematic approach for irreversible & strong bond strength between the thin flexible surfaces that make up the biochip is explored in this work. We observed the changes in surface wettability due to various methods of surface treatment can be a valuable metric for determining bond strength. We observed permanent bonding between microelectrode defined polypropylene surface and microchannel carved PDMS due to polar/silanol groups formed by plasma treatment and consequent covalent crosslinking by amine groups. These experimental insights provide valuable design guidelines for enhancing the sensitivity of coulter based flexible lab-on-a-chip devices which have a wide range of applications in point of care diagnostics.

Immunoassay based on Au-Ag bimetallic nanoclusters for colorimetric/fluorescent double biosensing of dicofol

The high toxicity of dicofol (DICO) to nontarget organisms has resulted in the contamination of food materials and caused a threat to human health. Developing a rapid and sensitive detection method of DICO in food samples is essential and still pursued. Fluorescent nanomaterials have been widely applied in biosensors to improve the sensitivity of detection. Herein, glutathione-capped Au-Ag bimetallic nanoclusters (Au-Ag NCs) exhibited the outstanding fluorescence characteristic with the average fluorescence lifetime of 1971.08 ns and photoluminescence quantum yield of 9.84% when the molar ratio of Au to Ag was 5:1. Polyethyleneimine modified gold nanoparticles (PEI-Au NPs) with the positive charge were prepared to generate a strong colorimetric signal. A dual-model colorimetric/fluorescent immune probe based on the Au-Ag NCs and PEI-Au NPs was successfully constructed by electrostatic force, and could be applied in both ic-ELISA and LFIA methods for rapid and ultrasensitive detection of DICO. In the ic-ELISA method, the introduction of fluorescence signal significantly increased the sensitivity of detection with the limit of detection (LOD) of 0.62 ng/mL and exhibited an excellent linear relationship within the range of 1.36 ng/mL-19.92 ng/mL. In the LFIA method, the fluorescence signal of Au-Ag NCs was accumulated on the test line and control line for the fluorescence model detection with a quantitative LOD at the level of 1.59 ng/mL. Such a dual-model colorimetric/fluorescent immunoassay serves as a promising candidate to develop new approaches in field detection.

Portable point-of-care diagnostic devices: an updated review

The global pandemic caused by the SARS-CoV-2 (COVID) virus indiscriminately impacted people worldwide with unquantifiable and severe impacts on all aspects of our lives, regardless of socioeconomic status. The pandemic brought to light the very real possibility of pathogens changing and shaping the way we live, and our lack of preparedness to deal with viral/bacterial outbreaks. Importantly, the quick detection of pathogens can help prevent and control the spread of disease, making the importance of diagnostic techniques undeniable. Point-of-care diagnostics started as a supplement to standard lab-based diagnostics, and are gradually becoming mainstream. Because of this, and their importance in detecting pathogens (especially in the developing world), their development has accelerated at an unprecedented rate. In this review, we highlight some important and recent examples of point-of-care diagnostics for detecting nucleic acids, proteins, bacteria, and other biomarkers, with the intent of making apparent their positive impact on society and human health.

Cloud-Based Software Architecture for Fully Automated Point-of-Care Molecular Diagnostic Device

This paper proposes a cloud-based software architecture for fully automated point-of-care molecular diagnostic devices. The target system operates a cartridge consisting of an extraction body for DNA extraction and a PCR chip for amplification and fluorescence detection. To facilitate control and monitoring via the cloud, a socket server was employed for fundamental molecular diagnostic functions such as DNA extraction, amplification, and fluorescence detection. The user interface for experimental control and monitoring was constructed with the RESTful application programming interface, allowing access from the terminal device, edge, and cloud. Furthermore, it can also be accessed through any web-based user interface on smart computing devices such as smart phones or tablets. An emulator with the proposed software architecture was fabricated to validate successful operation.

Cost-Effective Multiplex Fluorescence Detection System for PCR Chip

The lack of portability and high cost of multiplex real-time PCR systems limits the device to be used in POC. To overcome this issue, this paper proposes a compact and cost-effective fluorescence detection system that can be integrated to a multiplex real-time PCR equipment. An open platform camera with embedded lens was used instead of photodiodes or an industrial camera. A compact filter wheel using a sliding tape is integrated, and the excitation LEDs are fixed at a 45° angle near the PCR chip, eliminating the need of additional filter wheels. The results show precise positioning of the filter wheel with an error less than 20 μm. Fluorescence detection results using a reference dye and standard DNA amplification showed comparable performance to that of the photodiode system.

Hepatitis C Diagnosis: Simplified Solutions, Predictive Barriers, and Future Promises

The simplification of current hepatitis C diagnostic algorithms and the emergence of digital diagnostic devices will be very crucial to achieving the WHO's set goals of hepatitis C diagnosis (i.e., 90%) by 2030. From the last decade, hepatitis C diagnosis has been revolutionized by the advent and approval of state-of-the-art HCV diagnostic platforms which have been efficiently implemented in high-risk HCV populations in developed nations as well as in some low-to-middle income countries (LMICs) to identify millions of undiagnosed hepatitis C-infected individuals. Point-of-care (POC) rapid diagnostic tests (RDTs; POC-RDTs), RNA reflex testing, hepatitis C self-test assays, and dried blood spot (DBS) sample analysis have been proven their diagnostic worth in real-world clinical experiences both at centralized and decentralized diagnostic settings, in mass hepatitis C screening campaigns, and hard-to-reach aboriginal hepatitis C populations in remote areas. The present review article overviews the significance of current and emerging hepatitis C diagnostic packages to subvert the public health care burden of this 'silent epidemic' worldwide. We also highlight the challenges that remain to be met about the affordability, accessibility, and health system-related barriers to overcome while modulating the hepatitis C care cascade to adopt a 'test and treat' strategy for every hepatitis C-affected individual. We also elaborate some key measures and strategies in terms of policy and progress to be part of hepatitis C care plans to effectively link diagnosis to care cascade for rapid treatment uptake and, consequently, hepatitis C cure.

3D printed imaging platform for portable cell counting

Despite having widespread application in the biomedical sciences, flow cytometers have several limitations that prevent their application to point-of-care (POC) diagnostics in resource-limited environments. 3D printing provides a cost-effective approach to improve the accessibility of POC devices in resource-limited environments. Towards this goal, we introduce a 3D-printed imaging platform (3DPIP) capable of accurately counting particles and perform fluorescence microscopy. In our 3DPIP, captured microscopic images of particle flow are processed on a custom developed particle counter code to provide a particle count. This prototype uses a machine vision-based algorithm to identify particles from captured flow images and is flexible enough to allow for labeled and label-free particle counting. Additionally, the particle counter code returns particle coordinates with respect to time which can further be used to perform particle image velocimetry. These results can help estimate forces acting on particles, and identify and sort different types of cells/particles. We evaluated the performance of this prototype by counting 10 μm polystyrene particles diluted in deionized water at different concentrations and comparing the results with a commercial Beckman-Coulter Z2 particle counter. The 3DPIP can count particle concentrations down to ∼100 particles per mL with a standard deviation of ±20 particles, which is comparable to the results obtained on a commercial particle counter. Our platform produces accurate results at flow rates up to 9 mL h-1 for concentrations below 1000 particle per mL, while 5 mL h-1 produces accurate results above this concentration limit. Aside from performing flow-through experiments, our instrument is capable of performing static experiments that are comparable to a plate reader. In this configuration, our instrument is able to count between 10 and 250 cells per image, depending on the prepared concentration of bacteria samples (Citrobacter freundii; ATCC 8090). Overall, this platform represents a first step towards the development of an affordable fully 3D printable imaging flow cytometry instrument for use in resource-limited clinical environments.

Length-Dependent, Single-Molecule Analysis of Short Double-Stranded DNA Fragments through Hydrogel-Filled Nanopores: A Potential Tool for Size Profiling Cell-Free DNA

Fast sampling followed by sequence-independent sensing and length-dependent detection of short double-stranded DNA fragments, the size of those found in blood and other bodily fluids, is achieved using engineered molecular sensors, dubbed hydrogel-filled nanopores (HFNs). Fragments as short as 100 base pairs were blindly sampled and concentrated at the tip of an HFN before reversing the applied potential to detect and distinguish individual molecules based on fragment length as they translocate out of the nanopore. A remarkable 16-fold increase in the signal-to-noise ratio was observed in the eject configuration compared to the load configuration, enabling the resolution of fragments with a size difference of 50 nucleotides in length. This fast and versatile technology offers great tunability for both sampling and detection. While increasing sampling time leads to an increase in the local DNA concentration at the tip prior to detection, a linear correlation between the peak current and DNA fragment size enables good resolution of fragments up to 250 bp long.

A low-cost and high-throughput benchtop cell sorter for isolating white blood cells from whole blood

The ability to isolate and purify white blood cells (WBCs) from mixed ensembles such as blood would benefit autologous cell-based therapeutics as well as diagnosis of WBC disorders. Current WBCs isolation methods have the limitations of low purity or requiring complex and expensive equipment. In addition, due to the overlap in size distribution between lymphocytes (i.e., a sub-population of WBCs) and red blood cells (RBCs), it is challenging to achieve isolation of entire WBCs populations. In this work, we developed an inertial microfluidics-based cell sorter, which enables size-based, high-throughput isolation, and enrichment of WBCs from RBC-lysed whole blood. Using the developed inertial microfluidic chip, the sorting resolution is sharpened within 2 μm, which achieved separation between 3 and 5 μm diameter particles. Thus, with the present cell sorter, a full population of WBCs can be isolated from RBC-lysed blood samples with recovery ratio of 92%, and merely 5% difference in the composition percentage of the three subpopulations of granulocytes, monocytes, and lymphocytes compared to the original sample. Furthermore, our cell sorter is designed to enable broad application of size-based inertial cell sorting by supplying a series of microchips with different sorting cutoff size. This strategy allows us to further enrich the lymphocytes population by twofold using another microchip with a cutoff size between 10 and 15 μm. With simplicity and efficiency, our cell sorter provides a powerful platform for isolating and sorting of WBCs and also envisions broad potential sorting applications for other cell types.

Advances in Plant Disease Detection and Monitoring: From Traditional Assays to In-Field Diagnostics

Human activities significantly contribute to worldwide spread of phytopathological adversities. Pathogen-related food losses are today responsible for a reduction in quantity and quality of yield and decrease value and financial returns. As a result, “early detection” in combination with “fast, accurate, and cheap” diagnostics have also become the new mantra in plant pathology, especially for emerging diseases or challenging pathogens that spread thanks to asymptomatic individuals with subtle initial symptoms but are then difficult to face. Furthermore, in a globalized market sensitive to epidemics, innovative tools suitable for field-use represent the new frontier with respect to diagnostic laboratories, ensuring that the instruments and techniques used are suitable for the operational contexts. In this framework, portable systems and interconnection with Internet of Things (IoT) play a pivotal role. Here we review innovative diagnostic methods based on nanotechnologies and new perspectives concerning information and communication technology (ICT) in agriculture, resulting in an improvement in agricultural and rural development and in the ability to revolutionize the concept of “preventive actions”, making the difference in fighting against phytopathogens, all over the world.

CRISPR-based tools: Alternative methods for the diagnosis of COVID-19

The recently emerged severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spread all over the world rapidly and caused a global pandemic. To prevent the virus from spreading to more individuals, it is of great importance to identify and isolate infected individuals through testing. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) is the gold standard method for the diagnosis of coronavirus disease (COVID-19) worldwide. However, performing RT-qPCR is limited to centralized laboratories because of the need for sophisticated laboratory equipment and skilled personnel. Further, it can sometimes give false negative or uncertain results. Recently, new methods have been developed for nucleic acid detection and pathogen diagnosis using CRISPR-Cas systems. These methods present rapid and cost-effective diagnostic platforms that provide high sensitivity and specificity without the need for complex instrumentation. Using the CRISPR-based SARS-CoV-2 detection methods, it is possible to increase the number of daily tests in existing laboratories, reduce false negative or uncertain result rates obtained with RT-qPCR, and perform testing in resource-limited settings or at points of need where performing RT-qPCR is not feasible. Here, we briefly describe the RT-qPCR method, and discuss its limitations in meeting the current diagnostic needs. We explain how the unique properties of various CRISPR-associated enzymes are utilized for nucleic acid detection and pathogen diagnosis. Then, we highlight the important features of CRISPR-based diagnostic methods developed for SARS-CoV-2 detection. Finally, we examine the advantages and limitations of these methods, and discuss how they can contribute to improving the efficiency of the current testing systems for combating SARS-CoV-2.

Developing an integrated microfluidic and miniaturized electrochemical biosensor for point of care determination of glucose in human plasma samples

A cost-effective, point of care (POC) device based on highly oriented CNT arrays was developed as an electrochemical assay for real-time and sensitive detection of glucose in complex samples. A low-cost, microcontroller-based potentiostat consisting of Arduino Due and LMP9100-EVM was developed to perform electrochemical measurements such as cyclic voltammetry (CV) and amperometry. A syringe pump based on open-source electronics was designed to direct the flow through a microfluidic chip. Vertically aligned carbon nanotube (VACNT) sensor arrays, in combination with the miniature potentiostat and the syringe pumps, were utilized as a POC device for the rapid and accurate detection of glucose. The structure and morphology of samples were characterized by field emission scanning electron microscopy (FESEM) and attenuated total reflectance Fourier transform infrared spectrometry (ATR-FTIR). CV as well as electrochemical impedance spectroscopy (EIS) was performed to investigate the electrochemical behavior of the electrode with respect to different diffusion regimes. The mediator-less biosensor had a limit of detection of 23 μM and sensitivity of 1462 μA mM^-1 cm^-2 and 1050 μA mM^-1 cm^-2 at the linear range of 1.2-7.8 mM and 7.8-11.2 mM, respectively. The presence of other biological compounds such as uric acid (UA) and ascorbic acid (AA) did not interfere with the detection of glucose. Finally, the designed POC device was successfully applied for the determination of glucose in human blood plasma samples.

Protein array-based companion diagnostics in precision medicine

INTRODUCTION

The development of companion diagnostics (CDx) will increase efficacy and cost-benefit markedly, compared to the currently prevailing trial-and-error approach for treatment. Recent improvements in high-throughput protein technology have resulted in large amounts of predictive biomarkers that are potentially useful components of future CDx assays. Current high multiplex protein arrays are suitable for discovery-based approaches, while low-density and more simple arrays are suitable for use in point-of-care facilities.

AREA COVERED

This review discusses the technical platforms available for protein array focused CDx, explains the technical details of the platforms and provide examples of clinical use, ranging from multiplex arrays to low-density clinically applicable arrays. We thereafter highlight recent predictive biomarkers within different disease areas, such as oncology and autoimmune diseases. Lastly, we discuss some of the challenges connected to the implementation of CDx assays as point-of-care tests.

EXPERT OPINION

Recent advances in the field of protein arrays have enabled high-density arrays permitting large biomarker discovery studies, which are beneficial for future CDx assays. The density of protein arrays range from a single protein to proteome-wide arrays, allowing the discovery of protein signatures that may correlate with drug response. Protein arrays will undoubtedly play a key role in future CDx assays.

Label-Free Optical Resonator-Based Biosensors

The demand for biosensor technology has grown drastically over the last few decades, mainly in disease diagnosis, drug development, and environmental health and safety. Optical resonator-based biosensors have been widely exploited to achieve highly sensitive, rapid, and label-free detection of biological analytes. The advancements in microfluidic and micro/nanofabrication technologies allow them to be miniaturized and simultaneously detect various analytes in a small sample volume. By virtue of these advantages and advancements, the optical resonator-based biosensor is considered a promising platform not only for general medical diagnostics but also for point-of-care applications. This review aims to provide an overview of recent progresses in label-free optical resonator-based biosensors published mostly over the last 5 years. We categorized them into Fabry-Perot interferometer-based and whispering gallery mode-based biosensors. The principles behind each biosensor are concisely introduced, and recent progresses in configurations, materials, test setup, and light confinement methods are described. Finally, the current challenges and future research topics of the optical resonator-based biosensor are discussed.

CytoPAN-Portable cellular analyses for rapid point-of-care cancer diagnosis

Rapid, automated, point-of-care cellular diagnosis of cancer remains difficult in remote settings due to lack of specialists and medical infrastructure. To address the need for same-day diagnosis, we developed an automated image cytometry system (CytoPAN) that allows rapid breast cancer diagnosis of scant cellular specimens obtained by fine needle aspiration (FNA) of palpable mass lesions. The system is devoid of moving parts for stable operations, harnesses optimized antibody kits for multiplexed analysis, and offers a user-friendly interface with automated analysis for rapid diagnoses. Through extensive optimization and validation using cell lines and mouse models, we established breast cancer diagnosis and receptor subtyping in 1 hour using as few as 50 harvested cells. In a prospective patient cohort study (n = 68), we showed that the diagnostic accuracy was 100% for cancer detection and the receptor subtyping accuracy was 96% for human epidermal growth factor receptor 2 and 93% for hormonal receptors (ER/PR), two key biomarkers associated with breast cancer. A combination of FNA and CytoPAN offers faster, less invasive cancer diagnoses than the current standard (core biopsy and histopathology). This approach should enable the ability to more rapidly diagnose breast cancer in global and remote settings.

Elevating Chemistry Research with a Modern Electronics Toolkit

With the rapid development of high technology, chemical science is not as it used to be a century ago. Many chemists acquire and utilize skills that are well beyond the traditional definition of chemistry. The digital age has transformed chemistry laboratories. One aspect of this transformation is the progressing implementation of electronics and computer science in chemistry research. In the past decade, numerous chemistry-oriented studies have benefited from the implementation of electronic modules, including microcontroller boards (MCBs), single-board computers (SBCs), professional grade control and data acquisition systems, as well as field-programmable gate arrays (FPGAs). In particular, MCBs and SBCs provide good value for money. The application areas for electronic modules in chemistry research include construction of simple detection systems based on spectrophotometry and spectrofluorometry principles, customizing laboratory devices for automation of common laboratory practices, control of reaction systems (batch- and flow-based), extraction systems, chromatographic and electrophoretic systems, microfluidic systems (classical and nonclassical), custom-built polymerase chain reaction devices, gas-phase analyte detection systems, chemical robots and drones, construction of FPGA-based imaging systems, and the Internet-of-Chemical-Things. The technology is easy to handle, and many chemists have managed to train themselves in its implementation. The only major obstacle in its implementation is probably one's imagination.

Weaving Off-The-Shelf Yarns into Textile Micro Total Analysis Systems (μTAS)

Textile based biosensors have garnered much interest in recent years. Devices woven out of yarns have the ability to be incorporated into clothing and bandages. Most woven devices reported in the literature require yarns that are not available on an industrial scale or that require modifications which are not possible in large scale manufacturing. In this work, commercially produced yarns are taken without any modification or cleaning, and developed woven textile diagnostic devices out of them. The yarn properties that are important to their function within the device have been characterised and discussed. The wicking ability and analyte retention of Coolmax yarns, developed to wick sweat in mass produced sportswear, are determined. The electrochemistry and functionalizability of Au coated multifilament yarns are investigated with no cleaning or treatment and are found to have as good a thiolate self-assembled monolayer (SAM) coverage as cleaned Au disk electrodes. The feasibility of using these yarns is established off the shelf, with no cleaning, to make woven capillary force driven microfluidic devices and three electrode sensing devices. A proof of principle three electrode system capable of detecting clinically relevant concentrations of glucose in human sweat is reported.

Point-of-Care Devices to Detect Zika and Other Emerging Viruses

Rapid diagnostic tests (point-of-care devices) are critical components of informed patient care and public health monitoring (surveillance applications). We propose that among the many rapid diagnostics platforms that have been tested or are in development, lateral flow immunoassays and synthetic biology–based diagnostics (including CRISPR-based diagnostics) represent the best overall options given their ease of use, scalability for manufacturing, sensitivity, and specificity. This review describes the identification of lateral flow immunoassay monoclonal antibody pairs that detect and distinguish between closely related pathogens and that are used in combination with functionalized multicolored nanoparticles and computational methods to deconvolute data. We also highlight the promise of synthetic biology–based diagnostic tests, which use synthetic genetic circuits that activate upon recognition of a pathogen-associated nucleic acid sequence, and discuss how the combined or parallel use of lateral flow immunoassays and synthetic biology tools may represent the future of scalable rapid diagnostics.

Development of Point-of-Care Biosensors for COVID-19

Coronavirus disease 2019 (COVID-19) outbreak has become a global pandemic. The deleterious effects of coronavirus have prompted the development of diagnostic tools to manage the spread of disease. While conventional technologies such as quantitative real time polymerase chain reaction (qRT-PCR) have been broadly used to detect COVID-19, they are time-consuming, labor-intensive and are unavailable in remote settings. Point-of-care (POC) biosensors, including chip-based and paper-based biosensors are typically low-cost and user-friendly, which offer tremendous potential for rapid medical diagnosis. This mini review article discusses the recent advances in POC biosensors for COVID-19. First, the development of POC biosensors which are made of polydimethylsiloxane (PDMS), papers, and other flexible materials such as textile, film, and carbon nanosheets are reviewed. The advantages of each biosensors along with the commercially available COVID-19 biosensors are highlighted. Lastly, the existing challenges and future perspectives of developing robust POC biosensors to rapidly identify and manage the spread of COVID-19 are briefly discussed.

Biosensors in Occupational Safety and Health Management: A Narrative Review

A sensor is a device used to gather information registered by some biological, physical or chemical change, and then convert the information into a measurable signal. The first biosensor prototype was conceived more than a century ago, in 1906, but a properly defined biosensor was only developed later in 1956. Some of them have reached the commercial stage and are routinely used in environmental and agricultural applications, and especially, in clinical laboratory and industrial analysis, mostly because it is an economical, simple and efficient instrument for the in situ detection of the bioavailability of a broad range of environmental pollutants. We propose a narrative review, that found 32 papers and aims to discuss the possible uses of biosensors, focusing on their use in the area of occupational safety and health (OSH).

Electrochemical immunoassay for the detection of stress biomarkers

A rapid electrochemical immunoassay method was developed to detect and measure stress biomarkers (cortisol and cortisone) in two biological samples (Zebrafish whole-body and artificial saliva). This methodology utilizes an immunoassay approach taking advantage of the lock and key mechanism that is related to the antibody-antigen interaction depending on the reliable immobilization of the antibody labelled with ferrocene tags (Ab-Fc) on a modified tin-doped indium oxide (ITO) electrode using electrochemical instrumentation to build a POC platform. The limit of detection (LOD) obtained for this biosensor was 1.03 pg ml⁻¹ for cortisol and 0.68 pg ml⁻¹ for cortisone, respectively. The correlation coefficient was 0.9852 and 0.9841 for cortisol and cortisone, respectively with a linear concentration from (0-50 ng ml⁻¹) which covers the standard levels of stress hormones in both selected biological samples. The incubation time was investigated and 30 min was found to be the optimum incubation time. This time would be acceptable for the POC system as total process time can be determined within 35 min.

A smartphone-based biomedical sensory system

Disease diagnostics, food safety monitoring and environmental quality monitoring are the key means to safeguard human health. However, conventional detection devices for health care are costly, bulky and complex, restricting their applications in resource-limited areas of the world. With the rapid development of biosensors and the popularization of smartphones, smartphone-based sensing systems have emerged as novel detection devices that combine the sensitivity of biosensors and diverse functions of smartphones to provide a rapid, low-cost and convenient detection method. In these systems, a smartphone is used as a microscope to observe and count cells, as a camera to record fluorescence images, as an analytical platform to analyze experimental data, and as an effective tool to connect detection devices and online doctors. These systems are widely used for cell analysis, biochemical analysis, immunoassays, and molecular diagnosis, which are applied in the fields of disease diagnostics, food safety monitoring and environmental quality monitoring. Therefore, we discuss four types of smartphone-based sensing systems in this review paper, specifically in terms of the structure, performance and efficiency of these systems. Finally, we give some suggestions for improvement and future prospective trends.