Smartphone-Based Fluorescent Diagnostic System for Highly Pathogenic H5N1 Viruses

Smartphone based lateral flow immunoassay quantifications

Lateral Flow Immunoassay (LFI) is a disposable tool designed to detect target substances using minimal resources. For qualitative analysis, LFI does not require a device (i.e., reader) to interpret test results. However, various studies have been conducted to implement quantitative analysis using LFI systems, incorporating LFI along with electrical/electronic readers, to overcome the limitations associated with qualitative LFI analysis. The reader used for the quantitative analysis of LFI should ensure mobility for easy on-site diagnostics and inspections, be user-friendly in operation, and have a fast processing speed until the results are obtained. Due to these requirements, smartphones are increasingly utilized as readers in quantitative analysis of LFI. Among the various components constituting a smartphone, high-performance cameras can serve as sensors converting visual signals into electrical signals. With powerful processing units, large storage capacity, and network capabilities for transmitting analysis results, smartphones are also utilized as interfaces for quantitative analysis. Absolutely, the widespread global use of smartphones is a key advantage, leading to their utilization as diagnostic devices for acquiring, analyzing, storing, and transmitting assay test results. This paper summarizes research cases where smartphones are utilized as readers for quantitative LFI systems used in confirming contamination in food or the environment, detecting drugs, and diagnosing diseases in humans or animals. The systems are classified based on the types of label particles used in the assay, and efforts to improve the quantitative analysis performance for each are examined. Cases where smartphones were used as LFI readers for the diagnosis of the 2019 Coronavirus Disease (COVID-19), which has recently caused significant global damage, have also been investigated.

Advancing Point-of-Care Diagnosis: Digitalizing Combinatorial Biomarker Signals for Lupus Nephritis

To improve the efficiency and patient coverage of the current healthcare system, user-friendly novel homecare devices are urgently needed. In this work, we developed a smartphone-based analyzing and reporting system (SBARS) for biomarker detection in lupus nephritis (LN). This system offers a cost-effective alternative to traditional, expensive large equipment in signal detection and quantification. This innovative approach involves using a portable and affordable microscopic reader to capture biomarker signals. Through smartphone-based image processing techniques, the intensity of each biomarker signal is analyzed. This system exhibited comparable performance to a commercial Genepix scanner in the detection of two potential novel biomarkers of LN, VISG4 and TNFRSF1b. Importantly, this smartphone-based analyzing and reporting system allows for discriminating LN patients with active renal disease from healthy controls with the area-under-the-curve (AUC) value = 0.9 for TNFRSF1b and 1.0 for VSIG4, respectively, indicating high predictive accuracy.

Detection of Frog Virus 3 by Integrating RPA-CRISPR/Cas12a-SPM with Deep Learning

A fast, easy-to-implement, highly sensitive, and point-of-care (POC) detection system for frog virus 3 (FV3) is proposed. Combining recombinase polymerase amplification (RPA) and CRISPR/Cas12a, a limit of detection (LoD) of 100 aM (60.2 copies/μL) is achieved by optimizing RPA primers and CRISPR RNAs (crRNAs). For POC detection, smartphone microscopy is implemented, and an LoD of 10 aM is achieved in 40 min. The proposed system detects four positive animal-derived samples with a quantitation cycle (Cq) value of quantitative PCR (qPCR) in the range of 13 to 32. In addition, deep learning models are deployed for binary classification (positive or negative samples) and multiclass classification (different concentrations of FV3 and negative samples), achieving 100 and 98.75% accuracy, respectively. Without temperature regulation and expensive equipment, the proposed RPA-CRISPR/Cas12a combined with smartphone readouts and artificial-intelligence-assisted classification showcases the great potential for FV3 detection, specifically POC detection of DNA virus.

Solid-Phase Optical Sensing Techniques for Sensitive Virus Detection

Viral infections can pose a major threat to public health by causing serious illness, leading to pandemics, and burdening healthcare systems. The global spread of such infections causes disruptions to every aspect of life including business, education, and social life. Fast and accurate diagnosis of viral infections has significant implications for saving lives, preventing the spread of the diseases, and minimizing social and economic damages. Polymerase chain reaction (PCR)-based techniques are commonly used to detect viruses in the clinic. However, PCR has several drawbacks, as highlighted during the recent COVID-19 pandemic, such as long processing times and the requirement for sophisticated laboratory instruments. Therefore, there is an urgent need for fast and accurate techniques for virus detection. For this purpose, a variety of biosensor systems are being developed to provide rapid, sensitive, and high-throughput viral diagnostic platforms, enabling quick diagnosis and efficient control of the virus's spread. Optical devices, in particular, are of great interest due to their advantages such as high sensitivity and direct readout. The current review discusses solid-phase optical sensing techniques for virus detection, including fluorescence-based sensors, surface plasmon resonance (SPR), surface-enhanced Raman scattering (SERS), optical resonators, and interferometry-based platforms. Then, we focus on an interferometric biosensor developed by our group, the single-particle interferometric reflectance imaging sensor (SP-IRIS), which has the capability to visualize single nanoparticles, to demonstrate its application for digital virus detection.

Smartphone-based diagnostics for biosensing infectious human pathogens

The widespread usage of smartphones has made accessing vast troves of data easier for everyone. Smartphones are powerful, handy, and easy to operate, making them a valuable tool for improving public health through diagnostics. When combined with other devices and sensors, smartphones have shown potential for detecting, visualizing, collecting, and transferring data, enabling rapid disease diagnosis. In resource-limited settings, the user-friendly operating system of smartphones allows them to function as a point-of-care platform for healthcare and disease diagnosis. Herein, we critically reviewed the smartphone-based biosensors for the diagnosis and detection of diseases caused by infectious human pathogens, such as deadly viruses, bacteria, and fungi. These biosensors use several analytical sensing methods, including microscopic imaging, instrumental interface, colorimetric, fluorescence, and electrochemical biosensors. We have discussed the diverse diagnosis strategies and analytical performances of smartphone-based detection systems in identifying infectious human pathogens, along with future perspectives.

Fluorophore-encapsulated nanobeads for on-site, rapid, and sensitive lateral flow assay

Since December 2019, the rapid and sensitive detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a priority for public health. Although the lateral flow assay (LFA) sensor has emerged as a rapid and on-site SARS-CoV-2 detection technique, the conventional approach of using gold nanoparticles for the signaling probe had limitations in increasing the sensitivity of the sensor. Herein, our newly suggested methodology to improve the performance of the LFA system could amplify the sensor signal with a facile fabrication method by concentrating fluorescent organic molecules. A large Stokes shift fluorophore (single benzene) was encapsulated into polystyrene nanobeads to enhance the fluorescence intensity of the probe for LFA sensor, which was detected on the test line with a longpass filter under ultraviolet light irradiation. This approach provides comparatively high sensitivity with the limit of detection of 1 ng mL^-1 for the SARS-CoV-2 spike protein and a fast detection process, which takes less than 20 min. Furthermore, our sensor showed higher performance than gold nanoparticle-based commercial rapid diagnostics test kits in clinical tests, proving that this approach is more suitable and reliable for the sensitive and rapid detection of viruses, bacteria, and other hazardous materials.

Moving toward smart biomedical sensing

The development of novel biomedical sensors as highly promising devices/tools in early diagnosis and therapy monitoring of many diseases and disorders has recently witnessed unprecedented growth; more and faster than ever. Nonetheless, on the eve of Industry 5.0 and by learning from defects of current sensors in smart diagnostics of pandemics, there is still a long way to go to achieve the ideal biomedical sensors capable of meeting the growing needs and expectations for smart biomedical/diagnostic sensing through eHealth systems. Herein, an overview is provided to highlight the importance and necessity of an inevitable transition in the era of digital health/Healthcare 4.0 towards smart biomedical/diagnostic sensing and how to approach it via new digital technologies including Internet of Things (IoT), artificial intelligence, IoT gateways (smartphones, readers), etc. This review will bring together the different types of smartphone/reader-based biomedical sensors, which have been employing for a wide variety of optical/electrical/electrochemical biosensing applications and paving the way for future eHealth diagnostic devices by moving towards smart biomedical sensing. Here, alongside highlighting the characteristics/criteria that should be met by the developed sensors towards smart biomedical sensing, the challenging issues ahead are delineated along with a comprehensive outlook on this extremely necessary field.

Flash Characterization of Smartphones Used in Point-of-Care Diagnostics

Rapidly growing interest in smartphone cameras as the basis of point-of-need diagnostic and bioanalytical technologies increases the importance of quantitative characterization of phone optical performance under real-world operating conditions. In the context of our development of lateral-flow immunoassays based on phosphorescent nanoparticles, we have developed a suite of tools for characterizing the temporal and spectral profiles of smartphone torch and flash emissions, and their dependence on phone power state. In this work, these tools are described and documented to make them easily available to others, and demonstrated by application to characterization of Apple iPhone 5s, iPhone 6s, iPhone 8, iPhone XR, and Samsung Note8 flash performance as a function of time and wavelength, at a variety of power settings. Flash and torch intensity and duration vary with phone state and among phone models. Flash has high variability when the battery charge is below 10%, thus, smartphone-based Point-of-Care (POC) tests should only be performed at a battery level of at least 15%. Some output variations could substantially affect the results of assays that rely on the smartphone flash.

Cysteamine-Gold Coated Carboxylated Fluorescent Nanoparticle Mediated Point-of-Care Dual-Modality Detection of the H5N1 Pathogenic Virus

Globally, point-of-care testing (POCT) is the most preferable on-site technique for disease detection and includes a rapid diagnostic test (RDT) and fluorescent immunochromatographic strip test (FICT). The testing kits are generally insufficient in terms of signal enhancement, which is a major drawback of this approach. Sensitive and timely on-site POCT methods with high signal enhancement are therefore essential for the accurate diagnosis of infectious diseases. Herein, we prepare cysteamine-gold coated carboxylated europium chelated nanoparticle (Cys Au-EuNPs)-mediated POCT for the detection of the H5N1 avian influenza virus (AIV). Commercial nanoparticles were used for comparison. The spectral characteristics, surface morphologies, functional groups, surface charge and stability of the Cys AuNPs, EuNPs, and Cys Au-EuNPs were confirmed by UV-visible spectrophotometry, fluorescence spectrometry, transmission electron microscope with Selected area electron diffraction (TEM-SAED), Fourier-transform infrared spectroscopy (FTIR) and zeta potential analysis. The particle size distribution revealed an average size of ~130 ± 0.66 nm for the Cys Au-EuNPs. The Cys Au-EuNP-mediated RDT (colorimetric analysis) and FICT kit revealed a limit of detection (LOD) of 10 HAU/mL and 2.5 HAU/mL, respectively, for H5N1 under different titer conditions. The obtained LOD is eight-fold that of commercial nanoparticle conjugates. The photo luminance (PL) stability of ~3% the Cys Au-EuNPs conjugates that was obtained under UV light irradiation differs considerably from that of the commercial nanoparticle conjugates. Overall, the developed Cys Au-EuNPs-mediated dual-mode POCT kit can be used as an effective nanocomposite for the development of on-site monitoring systems for infectious disease surveillance.

Virus Detection: From State-of-the-Art Laboratories to Smartphone-Based Point-of-Care Testing

Infectious virus outbreaks pose a significant challenge to public healthcare systems. Early and accurate virus diagnosis is critical to prevent the spread of the virus, especially when no specific vaccine or effective medicine is available. In clinics, the most commonly used viral detection methods are molecular techniques that involve the measurement of nucleic acids or proteins biomarkers. However, most clinic-based methods require complex infrastructure and expensive equipment, which are not suitable for low-resource settings. Over the past years, smartphone-based point-of-care testing (POCT) has rapidly emerged as a potential alternative to laboratory-based clinical diagnosis. This review summarizes the latest development of virus detection. First, laboratory-based and POCT-based viral diagnostic techniques are compared, both of which rely on immunosensing and nucleic acid detection. Then, various smartphone-based POCT diagnostic techniques, including optical biosensors, electrochemical biosensors, and other types of biosensors are discussed. Moreover, this review covers the development of smartphone-based POCT diagnostics for various viruses including COVID-19, Ebola, influenza, Zika, HIV, et al. Finally, the prospects and challenges of smartphone-based POCT diagnostics are discussed. It is believed that this review will aid researchers better understand the current challenges and prospects for achieving the ultimate goal of containing disease-causing viruses worldwide.

A generalizable one health framework for the control of zoonotic diseases

Effectively preventing and controlling zoonotic diseases requires a One Health approach that involves collaboration across sectors responsible for human health, animal health (both domestic and wildlife), and the environment, as well as other partners. Here we describe the Generalizable One Health Framework (GOHF), a five-step framework that provides structure for using a One Health approach in zoonotic disease programs being implemented at the local, sub-national, national, regional, or international level. Part of the framework is a toolkit that compiles existing resources and presents them following a stepwise schematic, allowing users to identify relevant resources as they are required. Coupled with recommendations for implementing a One Health approach for zoonotic disease prevention and control in technical domains including laboratory, surveillance, preparedness and response, this framework can mobilize One Health and thereby enhance and guide capacity building to combat zoonotic disease threats at the human-animal-environment interface.

Photoluminescent Molecules and Materials as Diagnostic Reporters in Lateral Flow Assays

The lateral flow assay (LFA) is a point-of-care diagnostic test commonly available in an over-the-counter format because of its simplicity, speed, low cost, and portability. The reporter particles in these assays are among their most significant components because they perform the diagnostic readout and dictate the test's sensitivity. Today, gold nanoparticles are frequently used as reporters, but recent work focusing on photoluminescent-based reporter technologies has pushed LFAs to better performance. These efforts have focused specifically on reporters made of organic fluorophores, quantum dots, lanthanide chelates, persistent luminescent phosphors, and upconversion phosphors. In most cases, photoluminescent reporters show enhanced sensitivity compared to conventional gold nanoparticle-based assays. Here, we examine the advantages and disadvantages of these different reporters and highlight their potential benefits in LFAs. Our assessment shows that photoluminescent-based LFAs can not only reach lower detection limits than LFAs with traditional reporters, but they also can be capable of quantitative and multiplex analyte detection. As a result, the photoluminescent reporters make LFAs well-suited for medical diagnostics, the food and agricultural industry, and environmental testing.

A survey of 3D printing technology applied to paper microfluidics

Paper microfluidics is a rapidly growing subfield of microfluidics in which paper-like porous materials are used to create analytical devices that are well-suited for use in field applications. 3D printing technology has the potential to positively affect paper microfluidic device development by enabling tools and methods for the creation of devices with well-defined and tunable fluidic networks of porous matrices for high performance signal generation. This critical review focuses on the progress that has been made in using 3D printing technologies to advance the development of paper microfluidic devices. We describe printing work in three general categories: (i) solid support structures for paper microfluidic device components; (ii) channel barrier definition in existing porous materials; and (iii) porous channels for capillary flow, and discuss their value in advancing paper microfluidic device development. Finally, we discuss major areas of focus for highest impact on the next generation of paper microfluidics devices.

A Cross-Disciplinary View of Testing and Bioinformatic Analysis of SARS-CoV-2 and Other Human Respiratory Viruses in Pandemic Settings

The SARS-Coronavirus-2 (SARS-CoV-2) infectious disease, COVID-19, has spread rapidly, resulting in a global pandemic with significant mortality. The combination of early diagnosis via rapid screening, contact tracing, social distancing and quarantine has helped to control the pandemic. The absence of real time response and diagnosis is a crucial technology shortfall and is a key reason why current contact tracing methods are inadequate to control spread. In contrast, current information technology combined with a new generation of near-real time tests offers consumer-engaged smartphone-based "lab-in-a-phone" internet-of-things (IoT) connected devices that provide increased pandemic monitoring. This review brings together key aspects required to create an entire global diagnostic ecosystem. Cross-disciplinary understanding and integration of both mechanisms and technologies for effective detection, incidence mapping and disease containment in near real-time is summarized. Available measures to monitor and/or sterilize surfaces, next-generation laboratory and smartphone-based diagnostic approaches can be brought together and networked for instant global monitoring that informs Public Health policy. Cloud-based analysis enabling real-time mapping will enable future pandemic control, drive the suppression and elimination of disease spread, saving millions of lives globally. A new paradigm is introduced - scaled and multiple diagnostics for mapping and spreading of a pandemic rather than traditional accumulation of individual measurements. This can do away with the need for ultra-precise and ultra-accurate analysis by taking mass measurements that can relax tolerances and build resilience through networked analytics and informatics, the basis for novel swarm diagnostics. These include addressing ethical standards, local, national and international collaborative engagement, multidisciplinary and analytical measurements and standards, and data handling and storage protocols.

Application of dendrimer-based nanosensors in immunodiagnosis

Conventional immunoassays such as ELISA and FLISA have been used for clinical diagnosis for a long time. These assays are complex, time-consuming, and uneconomical. They have been overwhelmed with newer and more efficient methods such as electrochemical and electrochemiluminescent immunosensors that are cost-effective and require less time. Immunosensor is a biosensor that consists of a signal transducer and a biologically interactive system such as antigen and antibody interaction. Recent advances in nanotechnology have seen numerous efforts towards the usage of nanoparticles such as dendrimers in immunoassays. Dendrimers are highly branched structures with a high density of active peripheral groups, expanding their wide range of applications in immunoassays. A vast number of peripheral groups enrich the sensitivity of the immunosensor by governing the orientation of the antibody on the sensor surface. The current review highlights recent progress and developments in applying dendrimers for different immunoassays and their applicability in analyzing various biomarkers in clinical disease diagnosis.

Development of a Rapid Fluorescent Diagnostic System to Detect Subtype H9 Influenza A Virus in Chicken Feces

The circulation of the H9N2 virus results in significant economic losses in the poultry industry, and its zoonotic transmission highlights the need for a highly sensitive and rapid diagnostic and detection system for this virus. In this study, the performance of lateral flow test strips for a fluorescent immunochromatographic test (FICT) was optimized for the diagnosis of H9N2 virus-infected animal samples. The novel monoclonal antibodies (McAbs) against influenza A H9 viruses were developed, and two categories of McAbs with linear and conformational epitopes were compared for the performance of rapid diagnostic performance in the presence of feces sample at different time points (2, 4, and 6 days) post-infection (dpi). The limit of detection (LOD) of FICT and Kd values were comparable between linear and conformational epitope McAbs. However, superior performance of linear epitope McAbs pairs were confirmed by two animal studies, showing the better diagnostic performance showing 100% relative sensitivity in fecal samples at 6 dpi although it showed less than 80% sensitivity in early infection. Our results imply that the comparable performance of the linear epitope McAbs can potentially improve the diagnostic performance of FICT for H9N2 detection in feces samples. This highly sensitive rapid diagnostic method can be utilized in field studies of broiler poultry and wild birds.

Avian Influenza in Wild Birds and Poultry: Dissemination Pathways, Monitoring Methods, and Virus Ecology

Avian influenza is one of the largest known threats to domestic poultry. Influenza outbreaks on poultry farms typically lead to the complete slaughter of the entire domestic bird population, causing severe economic losses worldwide. Moreover, there are highly pathogenic avian influenza (HPAI) strains that are able to infect the swine or human population in addition to their primary avian host and, as such, have the potential of being a global zoonotic and pandemic threat. Migratory birds, especially waterfowl, are a natural reservoir of the avian influenza virus; they carry and exchange different virus strains along their migration routes, leading to antigenic drift and antigenic shift, which results in the emergence of novel HPAI viruses. This requires monitoring over time and in different locations to allow for the upkeep of relevant knowledge on avian influenza virus evolution and the prevention of novel epizootic and epidemic outbreaks. In this review, we assess the role of migratory birds in the spread and introduction of influenza strains on a global level, based on recent data. Our analysis sheds light on the details of viral dissemination linked to avian migration, the viral exchange between migratory waterfowl and domestic poultry, virus ecology in general, and viral evolution as a process tightly linked to bird migration. We also provide insight into methods used to detect and quantify avian influenza in the wild. This review may be beneficial for the influenza research community and may pave the way to novel strategies of avian influenza and HPAI zoonosis outbreak monitoring and prevention.

Optical Biosensors for Virus Detection: Prospects for SARS-CoV-2/COVID-19

The recent pandemic of the novel coronavirus disease 2019 (COVID-19) has caused huge worldwide disruption due to the lack of available testing locations and equipment. The use of optical techniques for viral detection has flourished in the past 15 years, providing more reliable, inexpensive, and accurate detection methods. In the current minireview, optical phenomena including fluorescence, surface plasmons, surface-enhanced Raman scattering (SERS), and colorimetry are discussed in the context of detecting virus pathogens. The sensitivity of a viral detection method can be dramatically improved by using materials that exhibit surface plasmons or SERS, but often this requires advanced instrumentation for detection. Although fluorescence and colorimetry lack high sensitivity, they show promise as point-of-care diagnostics because of their relatively less complicated instrumentation, ease of use, lower costs, and the fact that they do not require nucleic acid amplification. The advantages and disadvantages of each optical detection method are presented, and prospects for applying optical biosensors in COVID-19 detection are discussed.

Biological characteristics and biomarkers of novel SARS-CoV-2 facilitated rapid development and implementation of diagnostic tools and surveillance measures

Existing coronavirus named as a severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has speeded its spread across the globe immediately after emergence in China, Wuhan region, at the end of the year 2019. Different techniques, including genome sequencing, structural feature classification by electron microscopy, and chest imaging using computed tomography, are primarily used to diagnose and screen SARS-CoV-2 suspected individuals. Determination of the viral structure, surface proteins, and genome sequence has provided a design blueprint for the diagnostic investigations of novel SARS-CoV-2 virus and rapidly emerging diagnostic technologies, vaccine trials, and cell-entry-inhibiting drugs. Here, we describe recent understandings on the spike glycoprotein (S protein), receptor-binding domain (RBD), and angiotensin-converting enzyme 2 (ACE2) and their receptor complex. This report also aims to review recently established diagnostic technologies and developments in surveillance measures for SARS-CoV-2 as well as the characteristics and performance of emerging techniques. Smartphone apps for contact tracing can help nations to conduct surveillance measures before a vaccine and effective medicines become available. We also describe promising point-of-care (POC) diagnostic technologies that are under consideration by researchers for advancement beyond the proof-of-concept stage. Developing novel diagnostic techniques needs to be facilitated to establish automatic systems, without any personal involvement or arrangement to curb an existing SARS-CoV-2 epidemic crisis, and could also be appropriate for avoiding the emergence of a future epidemic crisis.

Point-of-care diagnostics for infectious diseases: From methods to devices

The current widespread of COVID-19 all over the world, which is caused by SARS-CoV-2 virus, has again emphasized the importance of development of point-of-care (POC) diagnostics for timely prevention and control of the pandemic. Compared with labor- and time-consuming traditional diagnostic methods, POC diagnostics exhibit several advantages such as faster diagnostic speed, better sensitivity and specificity, lower cost, higher efficiency and ability of on-site detection. To achieve POC diagnostics, developing POC detection methods and correlated POC devices is the key and should be given top priority. The fast development of microfluidics, micro electro-mechanical systems (MEMS) technology, nanotechnology and materials science, have benefited the production of a series of portable, miniaturized, low cost and highly integrated POC devices for POC diagnostics of various infectious diseases. In this review, various POC detection methods for the diagnosis of infectious diseases, including electrochemical biosensors, fluorescence biosensors, surface-enhanced Raman scattering (SERS)-based biosensors, colorimetric biosensors, chemiluminiscence biosensors, surface plasmon resonance (SPR)-based biosensors, and magnetic biosensors, were first summarized. Then, recent progresses in the development of POC devices including lab-on-a-chip (LOC) devices, lab-on-a-disc (LOAD) devices, microfluidic paper-based analytical devices (μPADs), lateral flow devices, miniaturized PCR devices, and isothermal nucleic acid amplification (INAA) devices, were systematically discussed. Finally, the challenges and future perspectives for the design and development of POC detection methods and correlated devices were presented. The ultimate goal of this review is to provide new insights and directions for the future development of POC diagnostics for the management of infectious diseases and contribute to the prevention and control of infectious pandemics like COVID-19.

Recent trends in smartphone-based detection for biomedical applications: a review

Smartphone-based imaging devices (SIDs) have shown to be versatile and have a wide range of biomedical applications. With the increasing demand for high-quality medical services, technological interventions such as portable devices that can be used in remote and resource-less conditions and have an impact on quantity and quality of care. Additionally, smartphone-based devices have shown their application in the field of teleimaging, food technology, education, etc. Depending on the application and imaging capability required, the optical arrangement of the SID varies which enables them to be used in multiple setups like bright-field, fluorescence, dark-field, and multiple arrays with certain changes in their optics and illumination. This comprehensive review discusses the numerous applications and development of SIDs towards histopathological examination, detection of bacteria and viruses, food technology, and routine diagnosis. Smartphone-based devices are complemented with deep learning methods to further increase the efficiency of the devices. Graphical Abstract.

Lateral flow immunoassay for furazolidone point-of-care testing: Cater to the call of saving time, labor, and cost by coomassie brilliant blue labeling

Furazolidone (FZD) and its metabolite called 3-amino-2-oxazolidinone (AOZ) would induce carcinogenic and mutagenic effects to human. In this work, to develop a novel, stable, and simple point of care testing (POCT) with a potential to social applied for FZD detection, we utilized the aspect of protein staining of coomassie brilliant blue (CBB) to exploit a new CBB-LFIA strategy free of NPs. Only one mixing step is needed during the probe manufacturing process, which requires just 2 h and is a great time saving strategy compared with other methods (requiring 4-33 h for probe preparation). Besides, the cost of CBB-LFIA is 300 times lesser than other LFIA with respect to obtaining the label. The developed CBB-LFIA was successfully applied to detect AOZ with a detection limit of 2 ng mL^-1, without any influence from other potential interfering compounds. The proposed CBB-LFIA exhibited prominent practical application, and possesses considerable utilization potential in the related field.

Integrated, Automated, Fast PCR System for Point-Of-Care Molecular Diagnosis of Bacterial Infection

We developed an integrated PCR system that performs automated sample preparation and fast polymerase chain reaction (PCR) for application in point-of care (POC) testing. This system is assembled from inexpensive 3D-printing parts, off-the-shelf electronics and motors. Molecular detection requires a series of procedures including sample preparation, amplification, and fluorescence intensity analysis. The system can perform automated DNA sample preparation (extraction, separation and purification) in ≤5 min. The variance of the automated sample preparation was clearly lower than that achieved using manual DNA extraction. Fast thermal ramp cycles were generated by a customized thermocycler designed to automatically transport samples between heating and cooling blocks. Despite the large sample volume (50 μL), rapid two-step PCR amplification completed 40 cycles in ≤13.8 min. Variations in fluorescence intensity were measured by analyzing fluorescence images. As proof of concept of this system, we demonstrated the rapid DNA detection of pathogenic bacteria. We also compared the sensitivity of this system with that of a commercial device during the automated extraction and fast PCR of Salmonella bacteria.

Application of smartphone-based spectroscopy to biosample analysis: A review

The emergence of the smartphones has brought extensive changes to our lifestyles, from communicating with one another, to shopping and enjoyment of entertainment, and from studying to functioning at the workplace (and in the field). At the same time, this portable device has also provided new possibilities in scientific research and applications. Based on the growing awareness of good health management, researchers have coupled health monitoring to smartphone sensing technologies. Along the way, there have been developed a variety of smartphone-based optical detection platforms for analyzing biological samples, including standalone smartphone units and integrated smartphone sensing systems. In this review, we outline the applications of smartphone-based optical sensors for biosamples. These applications focus mainly on three aspects: Microscopic imaging sensing, colorimetric sensing and luminescence sensing. We also discuss briefly some limitations of the current state of smartphone-based spectroscopy and present prospects of the future applicability of smartphone sensors.

A smartphone-based particle diffusometry platform for sub-attomolar detection of Vibrio cholerae in environmental water

Each year, 3.4 million people die from waterborne diseases worldwide. Development of a rapid and portable platform for detecting and monitoring waterborne pathogens would significantly aid in reducing the incidence and spread of infectious diseases. By combining optical methods and smartphone technology with molecular assays, the sensitivity required to detect exceedingly low concentrations of waterborne pathogens can readily be achieved. Here, we implement smartphone-based particle diffusometry (PD) detection of loop-mediated isothermal amplification (LAMP) targeting the waterborne pathogen Vibrio cholerae (V. cholerae). By measuring the diffusion of 400 nm streptavidin-coated fluorescent nanoparticles imaged at 68X magnification on a smartphone, we can detect as few as 6 V. cholerae cells per reaction (0.66 aM) in just 35 minutes. In a double-blinded study with 132 pond water samples, we establish a 91.8% sensitivity, 95.2% specificity, and 94.3% accuracy of the smartphone-based PD platform for detection of V. cholerae. Together, these results demonstrate the utility of this smartphone-based PD platform for rapid and sensitive detection of V. cholerae at the point of use.

CdSe quantum dots evaluation in primary cellular models or tissues derived from patients

In recent years quantum dots (QDs) have risen as useful luminescent nanoparticles with multiple applications ranging from laser, image displays and biomedical applications. Here we review and discuss the studies of these nanoparticles in patient derived cellular samples or tissues, including cellular models from iPSCs from patients, biopsied and post-mortem tissue. QD-based multiplexed imaging has been proved to overcome most of the major drawbacks of conventional techniques, exhibiting higher sensitivity, reliability, accuracy and simultaneous labeling of key biomarkers. In this sense, QDs are very promising tools to be further used in clinical applications including diagnosis and therapy approaches. Analyzing the possibilities of these materials in these biological samples gives an overview of the future applications of the nanoparticles in models closer to patients and their specific disease.

Frugal Innovation for Point-of-Care Diagnostics Controlling Outbreaks and Epidemics

Today epidemics of infectious diseases occur more often and spread both faster and further due to globalization and changes in our lifestyle. One way to meet these biological threats are so-called "Frugal Innovations", which focus on the development of affordable, rapid, and easy-to-use diagnostics with widespread use. In this context, point-of-care-tests (POCTs), performed at the patient's bedside, reduce extensive waiting times and unnecessary treatments and enable effective containment measures. This Perspective covers advances in POCT diagnostics on the basis of frugal innovation characteristics that will enable a faster, less expensive, and more convenient reaction to upcoming epidemics. Established POCT systems on the health care market, as well as currently evolving technological advancements in that sector are discussed. Progress in POCT technology and insights on how to most effectively use them allows the handling of more patients in a shorter time frame and consequently improves clinical outcomes at lower cost.

Biotinylated Phosphorus Dendrimers as Control Line in Nucleic Acid Lateral Flow Tests

Lateral flow assays (LFA) are an affordable, easy-to-use, qualitative rapid test for clinical diagnosis in nonlaboratory environments and low-resource facilities. The control line of these tests is very important to provide a valid result, confirming that the platform operates correctly. A clear, nondiffused line is desirable. The number of colored nanoparticles that reach the control line in a positive test can be very small, and they should all be trapped efficiently by the molecules adsorbed there. In this work, we proposed the use of robust biotinylated dendrimers of two different generations as signal amplifiers in control lines of LFA, able to react with streptavidin-modified gold nanoparticles. Besides the synthesis and characterization, the analytical performance as control lines will be studied, and their response will be compared with other commercially available biotinylated molecules. Finally, the utility of the dendrimer implemented in a NALF (Nucleic Acid Lateral Flow) strip was also demonstrated for detection of the amplicons obtained by double-tagging PCR (polymerase chain reaction) for the detection of E. coli as a model of foodborne pathogen.

Biotechnological innovations in farm and pet animal disease diagnosis

The application of innovative diagnostic technologies for the detection of animal pathogens at an early stage is essential in restricting the economic loss incurred due to emerging infectious animal diseases. The desirable characteristics of such diagnostic methods are easy to use, cost-effective, highly sensitive, and specific, coupled with the high-throughput detection capabilities. The enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) are still the most common assays used for the detection of animal pathogens across the globe. However, utilizing the principles of ELISA and PCR, several serological and molecular technologies have been developed to achieve higher sensitivity, rapid, and point-of-care (POC) detection such as lateral flow assays, biosensors, loop-mediated isothermal amplification, recombinase polymerase amplification, and molecular platforms for field-level detection of animal pathogens. Furthermore, animal disease diagnostics need to be updated regularly to capture new, emerging and divergent infectious pathogens, and biotechnological innovations are helpful in fulfilling the rising demand for such diagnostics for the welfare of the society. Therefore, this chapter primarily describes and discusses in detail the serological, molecular, novel high-throughput, and POC assays to detect pathogens affecting farm and companion animals.

Lateral flow biosensors based on the use of micro- and nanomaterials: a review on recent developments

This review (with 187 refs.) summarizes the progress that has been made in the design of lateral flow biosensors (LFBs) based on the use of micro- and nano-materials. Following a short introduction into the field, a first section covers features related to the design of LFBs, with subsections on strip-based, cotton thread-based and vertical flow- and syringe-based LFBs. The next chapter summarizes methods for sample pretreatment, from simple method to membrane-based methods, pretreatment by magnetic methods to device-integrated sample preparation. Advances in flow control are treated next, with subsections on cross-flow strategies, delayed and controlled release and various other strategies. Detection conditionst and mathematical modelling are briefly introduced in the following chapter. A further chapter covers methods for reliability improvement, for example by adding other validation lines or adopting different detection methods. Signal readouts are summarized next, with subsections on color-based, luminescent, smartphone-based and SERS-based methods. A concluding section summarizes the current status and addresses challenges in future perspectives. Graphical abstractRecent development and breakthrough points of lateral flow biosensors.

The Current and Future Use of Telemedicine in Infectious Diseases Practice

PURPOSE OF REVIEW

Novel technologies, such as high-definition cameras, encryption software, electronic stethoscopes, microfluidic diagnostic systems, and widely available broadband Internet have expanded the potential for telemedicine. This narrative review presents current and future uses of telemedicine in the prevention, diagnosis, treatment, stewardship, and management of infectious disease.

RECENT FINDINGS

Beginning in the 1990s, early approaches to telemedicine in infectious disease focused largely on treatment of HIV/AIDS, hepatitis C, and tuberculosis. However, recent innovations allow for targeting of additional diseases and in increasingly remote settings. Telemedicine allows virtual visits between patients in the home and remote providers, permitting outpatient management of complex conditions, such as post-surgical site monitoring, and non-urgent infectious maladies, such as uncomplicated urinary tract infection. Remote provider education by videoconference and integrated clinical decision support tools create avenues to improve inpatient care, including antimicrobial stewardship. Technological strides from miniaturization of diagnostic tests to robotic telepresence physical exams improve access to infectious disease care in isolated and infrastructure-poor environments, from cargo ships to other resource-limited settings. Telemedicine in the field of infectious disease is rapidly expanding in clinical, technological, geographical, and human capacity. Recent innovations narrow gaps in access to care for populations traditionally underserved, stigmatized, isolated by remote geography, or lacking technological infrastructure. Current and future approaches will transform inpatient, outpatient, and remote care.

Mobile imaging platform for digital influenza virus counting

Droplet-based digital bioassays enable highly sensitive and quantitative analysis of biomolecules, and are thought to be suitable for point-of-care diagnosis. However, digital bioassays generally require fluorescence microscopy for detection, which is too large for point-of-care testing. Here, we developed a simple smartphone-based mobile imaging platform for digital bioassays. The size of the mobile imaging platform was 23 × 10 × 7 cm (length × width × height). With this platform, a digital enzyme assay of bovine alkaline phosphatase was successfully completed. Digital influenza virus counting-based on a fluorogenic assay for neuraminidase activity of the virus-was also demonstrated. Distinct fluorescence spots derived from single virus particles were observed with the mobile imaging platform. The number of detected fluorescence spots showed good linearity against the virus titer, suggesting that high sensitivity and quantification were achieved, although the imaging with the mobile platform detected 60% of influenza virus particles that were identified with conventional fluorescence microscopy. The lower detection efficiency is due to its relatively lower signal-to-noise ratio than that found with conventional microscopes, and unavoidable intrinsic heterogeneity of neuraminidase activity among virus particles. Digital influenza virus counting with the mobile imaging platform still showed 100 times greater sensitivity than that with a commercial rapid influenza test kit. Virus detection of clinical samples was also successfully demonstrated, suggesting the potential to realize a highly sensitive point-of-care system for influenza virus detection with smartphones.

Early Detection and Treatment of Patients with Alzheimer's Disease: Future Perspectives

Alzheimer's disease affects approximately 6% of people over the age of 65 years. It is characterized as chronic degeneration of cortical neurons, with loss of memory, cognition and executive functions. As the disease progresses, it is accompanied by accumulation of amyloid plaques and neurofibrillary tangles in key areas of the brain, leading to a loss of neurogenesis and synaptic plasticity in the hippocampus, along with changes in the levels of essential neurotransmitters such as acetylcholine and glutamate. Individuals with concomitant diseases such as depression, diabetes and cardiovascular disorders have a higher risk of developing Alzheimer's disease, and those who have a healthier diet and partake in regular exercise and intellectual stimulation have a lower risk of developing the disorder. This chapter describes the advances made in early diagnosis of Alzheimer's disease as this could help to improve outcomes for the patients by facilitating earlier treatment.

Highly sensitive immunodiagnostics at the point of care employing alternative recognition elements and smartphones: hype, trend, or revolution?

Immunodiagnostic tests performed at the point of care (POC) today usually employ antibodies for biorecognition and are read out either visually or with specialized equipment. Availability of alternative biorecognition elements with promising features as well as smartphone-based approaches for signal readout, however, challenge the described established configuration in terms of analytical performance and practicability. Assessing these developments' clinical relevance and their impact on POC immunodiagnostics is demanding. The first part of this review will therefore give an overview on suitable diagnostic biosensors based on alternative recognition elements (such as nucleic acid-based aptamers or engineered binding proteins) and exemplify advantages and drawbacks of these biomolecules on the base of selected assays. The second part of the review then focuses on smartphone-connected diagnostics and discusses the indispensable considerations required for successful future clinical POCT implementation. Together, the joint depiction of two of the most innovative and exciting developments in the field will enable the reader to cast a glance into the distant future of POC immunodiagnostics.

Detection platforms for point-of-care testing based on colorimetric, luminescent and magnetic assays: A review

Along with the considerable potential and increasing demand of the point-of-care testing (POCT), corresponding detection platforms have attracted great interest in both academic and practical fields. The first few generations of conventional detection devices tend to be costly, complicated to operate and hard to move on account of early limitations in the level of technological development and relatively high requirement of performance. Owing to the requirements for rapidity, simplicity, accuracy and cost controlling in the POCT, reader systems are urgently needed to be developed, upgraded and modified constantly, realizing on-site testing and healthcare management without a specific place or cumbersome operation. Accordingly, numerous rapid detection platforms with diverse size and performance have emerged such as bench-top apparatuses, handheld devices and intelligent detection devices. This review discusses various devices developed mainly for the detection of lateral flow test strips (LFTSs) or microfluidic strips in the POCT and summarizes these devices by size and portability. Furthermore, on the basis of various detection methods and diverse probes usually containing specific nanoparticles composites, three most common aspects of detection rationale in the POCT are selected to elaborate each kind of detection platforms in this paper: colorimetric assay, luminescent detection and magnetic signal detection. Herein, we focus on their structures, detection mechanisms and assay results, accompany with discussions and comments on the performances, costs and potential application, as well as advantages and limitations of each technique. In addition, perspectives on the future advances of detection platforms and some conclusions are proposed.

A signal amplification system on a lateral flow immunoassay detecting for hepatitis e-antigen in human blood samples

Hepatitis B e-antigen (HBeAg) is the secretory form of the nucleocapsid of the hepatitis B virus (HBV), which is a marker of viral replication. In this study, a novel signal amplification system (SAS) based on the lateral flow immunoassay (LFIA) was used for rapid detection of HBeAg in blood samples from patients or blood donors. In this assay, the detection antibody was conjugated with gold nanoparticles (GNPs), and the capture antibody was labeled with biotin. The presence of targeting antigen HBeAg in blood sample would act as a bridge with biotinylated captured antibody and GNP-conjugated detection antibody to form the dendritic nanoparticle complex. The dendritic complexes in the sample solution were migrated and immobilized on the testing line of strip coated with antibiotin antibodies. Signal intensity was massively amplified by the SAS, which was positively correlated with the concentration of targeting antigen in the blood sample and was assessed by eyes or strip scanner. The SAS worked only when targeting antigens were present in the sample. By using this SAS-LFIA, we were able to detect a very low concentration of HBeAg (9 ng/mL), which was 27-fold sensitive than that by conventional LFIA (cLFIA). A number of 420 blood samples were detested by this novel SAS-LFIA, the results were in accordance with those of enzyme-linked immunosorbent assay (ELISA) completely, while the cLFIA missed an HBeAg-positive sample. In conclusion, the novel SAS has high specificity and sensitivity, which can be used to replace the conventional rapid test and ELISA in clinical diagnosis.

Benchmarking Smartphone Fluorescence-Based Microscopy with DNA Origami Nanobeads: Reducing the Gap toward Single-Molecule Sensitivity

Smartphone-based fluorescence microscopy has been rapidly developing over the last few years, enabling point-of-need detection of cells, bacteria, viruses, and biomarkers. These mobile microscopy devices are cost-effective, field-portable, and easy to use, and benefit from economies of scale. Recent developments in smartphone camera technology have improved their performance, getting closer to that of lab microscopes. Here, we report the use of DNA origami nanobeads with predefined numbers of fluorophores to quantify the sensitivity of a smartphone-based fluorescence microscope in terms of the minimum number of detectable molecules per diffraction-limited spot. With the brightness of a single dye molecule as a reference, we compare the performance of color and monochrome sensors embedded in state-of-the-art smartphones. Our results show that the monochrome sensor of a smartphone can achieve better sensitivity, with a detection limit of ∼10 fluorophores per spot. The use of DNA origami nanobeads to quantify the minimum number of detectable molecules of a sensor is broadly applicable to evaluate the sensitivity of various optical instruments.

Proteomic Studies of Psychiatric Disorders

Many diseases result from programming effects in utero. This chapter describes recent advances in proteomic studies which have improved our understanding of the underlying pathophysiological pathways in the major psychiatric disorders, resulting in the development of potential novel biomarker tests. Such tests should be based on measurement of blood-based proteins given the ease of accessibility of this medium and the known connections between the periphery and the central nervous system. Most importantly, emerging biomarker tests should be developed on lab-on-a-chip and other handheld devices to enable point-of-care use. This should help to identify individuals with psychiatric disorders much sooner than ever before, which will allow more rapid treatment options for the best possible patient outcomes.

Smartphone-based clinical diagnostics: towards democratization of evidence-based health care

Recent advancements in bioanalytical techniques have led to the development of novel and robust diagnostic approaches that hold promise for providing optimal patient treatment, guiding prevention programs and widening the scope of personalized medicine. However, these advanced diagnostic techniques are still complex, expensive and limited to centralized healthcare facilities or research laboratories. This significantly hinders the use of evidence-based diagnostics for resource-limited settings and the primary care, thus creating a gap between healthcare providers and patients, leaving these populations without access to precision and quality medicine. Smartphone-based imaging and sensing platforms are emerging as promising alternatives for bridging this gap and decentralizing diagnostic tests offering practical features such as portability, cost-effectiveness and connectivity. Moreover, towards simplifying and automating bioanalytical techniques, biosensors and lab-on-a-chip technologies have become essential to interface and integrate these assays, bringing together the high precision and sensitivity of diagnostic techniques with the connectivity and computational power of smartphones. Here, we provide an overview of the emerging field of clinical smartphone diagnostics and its contributing technologies, as well as their wide range of areas of application, which span from haematology to digital pathology and rapid infectious disease diagnostics.

Recent Advances in AIV Biosensors Composed of Nanobio Hybrid Material

Since the beginning of the 2000s, globalization has accelerated because of the development of transportation systems that allow for human and material exchanges throughout the world. However, this globalization has brought with it the rise of various pathogenic viral agents, such as Middle East respiratory syndrome coronavirus (MERS-CoV), severe acute respiratory syndrome coronavirus (SARS-CoV), Zika virus, and Dengue virus. In particular, avian influenza virus (AIV) is highly infectious and causes economic, health, ethnical, and social problems to human beings, which has necessitated the development of an ultrasensitive and selective rapid-detection system of AIV. To prevent the damage associated with the spread of AIV, early detection and adequate treatment of AIV is key. There are traditional techniques that have been used to detect AIV in chickens, ducks, humans, and other living organisms. However, the development of a technique that allows for the more rapid diagnosis of AIV is still necessary. To achieve this goal, the present article reviews the use of an AIV biosensor employing nanobio hybrid materials to enhance the sensitivity and selectivity of the technique while also reducing the detection time and high-throughput process time. This review mainly focused on four techniques: the electrochemical detection system, electrical detection method, optical detection methods based on localized surface plasmon resonance, and fluorescence.

Development of a smartphone-based rapid dual fluorescent diagnostic system for the simultaneous detection of influenza A and H5 subtype in avian influenza A-infected patients

Accurate and rapid diagnosis of highly pathogenic avian influenza A H5N1 is of critical importance for the effective clinical management of patients. Here, we developed a rapid and simultaneous detection toolkit for influenza A H5 subtype viruses in human samples based on a bioconjugate of quantum dots (QDs) assembly and a smartphone-based rapid dual fluorescent diagnostic system (SRDFDS). Methods: Two types of QDs were assembled on a latex bead to enhance the detection sensitivity and specificity of influenza A infection (QD580) and H5 subtype (QD650). The dual signals of influenza A and H5 subtype of H5N1-infected patients were detected simultaneously and quantified separately by SRDFDS equipped with two emission filters. Results: Our results showed a high sensitivity of 92.86% (13/14) and 78.57% (11/14), and a specificity of 100% (38/38, P < 0.0001) and 97.37% (37/38) for influenza A and H5 subtype detection, respectively. Conclusion: Therefore, our multiplex QD bioconjugates and SRDFDS-based influenza virus detection toolkit potentially provide accurate and meaningful diagnosis information with improved detection accuracies and sensitivities for H5N1 patients.