Developments in Point-of-Care Diagnostic Technology for Cancer Detection

Cancer Methylation Biomarker Detection in an Automated, Portable, Multichannel Magnetofluidic Platform

Early detection of cancer is critical to improving clinical outcomes, especially in territories with limited healthcare resources. DNA methylation biomarkers have shown promise in early cancer detection, but typical workflows require highly trained personnel and specialized equipment for manual and lengthy processing, limiting use in resource-constrained areas. As a potential solution, we introduce the Automated Cartridge-based Cancer Early Screening System (ACCESS), a compact, portable, multiplexed, automated platform that performs droplet magnetofluidic- and methylation-specific qPCR-based assays for the detection of DNA methylation cancer biomarkers. Development of ACCESS focuses on esophageal cancer, which is among the most prevalent cancers in low- and middle-income countries with extremely low survival rates. Upon implementing detection assays for two esophageal cancer methylation biomarkers within ACCESS, we demonstrated successful detection of both biomarkers from esophageal tumor tissue samples from eight esophageal cancer patients while showing specificity in paired normal esophageal tissue samples. These results illustrate ACCESS's potential as an amenable epigenetic diagnostic tool for resource-constrained areas toward early detection of esophageal cancer and potentially other malignancies.

An Innovative Approach for Tailoring Molecularly Imprinted Polymers for Biosensors-Application to Cancer Antigen 15-3

This work presents a novel approach for tailoring molecularly imprinted polymers (MIPs) with a preliminary stage of atom transfer radical polymerization (ATRP), for a more precise definition of the imprinted cavity. A well-defined copolymer of acrylamide and N,N'-methylenebisacrylamide (PAAm-co-PMBAm) was synthesized by ATRP and applied to gold electrodes with the template, followed by a crosslinking reaction. The template was removed from the polymer matrix by enzymatic/chemical action. The surface modifications were monitored via electrochemical impedance spectroscopy (EIS), having the MIP polymer as a non-conducting film designed with affinity sites for CA15-3. The resulting biosensor exhibited a linear response to CA15-3 log concentrations from 0.001 to 100 U/mL in PBS or in diluted fetal bovine serum (1000×) in PBS. Compared to the polyacrylamide (PAAm) MIP from conventional free-radical polymerization, the ATRP-based MIP extended the biosensor's dynamic linear range 10-fold, improving low concentration detection, and enhanced the signal reproducibility across units. The biosensor demonstrated good sensitivity and selectivity. Overall, the work described confirmed that the process of radical polymerization to build an MIP material influences the detection capacity for the target substance and the reproducibility among different biosensor units. Extending this approach to other cancer biomarkers, the methodology presented could open doors to a new generation of MIP-based biosensors for point-of-care disease diagnosis.

Polydiacetylene-based aptasensors for rapid and specific colorimetric detection of malignant exosomes

Exosomes (50-150 nm) play significant biological functions in intercellular communication and transportation of diverse biomolecules, including proteins and nucleic acids. In particular, malignant exosomes have received a great deal of attention as possible indicators for cancer detection and treatment. To swiftly and precisely identify malignant exosomes from normal exosomes in diverse bodily fluids, we developed polydiacetylene (PDA)-based aptasensors with distinct optical features exhibiting color shift in response to biological recognition. To identify epithelial cell adhesion molecules (EpCAM) overexpressed on the surface of malignant exosomes, anti-EpCAM aptamer-conjugated diacetylene monomer (TCDA-Apt) was synthesized and used to create anti-EpCAM aptamer-conjugated PDA (anti-EpCAM Apt-PDA) vesicles. In just 15 min following the reaction with malignant exosomes, the anti-EpCAM Apt-PDA vesicles underwent a visible color change from blue to purple. They showed high specificity to EpCAM-positive malignant exosomes over non-malignant exosomes, bovine serum albumin (BSA), and fibrinogen. Moreover, its effectiveness in the point-of-care (POC) detection of malignant exosomes was evaluated using human sera. Therefore, our PDA-based aptasensors have tremendous potential for on-site cancer diagnosis.

MicroRNA biosensors for the detection of liver cancer

Liver cancer is one of the deadliest types worldwide and early diagnosis is highly important for successful treatment. Therefore, it is necessary to develop rapid, sensitive, simple, and inexpensive analytical tools for its detection. MicroRNAs (miRNA) represent unique biomarkers whose expression in biofluids is strongly associated with cancer in general and miR-21, -31, -122, -145, -146a, -200c, -221, -222, and -223 in liver cancer, specifically. Various biosensors for miRNA detection have been developed. These include electrochemical biosensors based on amperometric, potentiometric, conductometric and impedimetric technology. Furthermore, the use of advanced nanomaterials with enhanced chemical stability, conductivity and electrocatalytic activity have greatly increased the sensitivity and specificity of these devices. The present review focuses on recent advances in electrochemical biosensors for miRNA detection in liver cancer.

Inhalable point-of-care urinary diagnostic platform

Although low-dose computed tomography screening improves lung cancer survival in at-risk groups, inequality remains in lung cancer diagnosis due to limited access to and high costs of medical imaging infrastructure. We designed a needleless and imaging-free platform, termed PATROL (point-of-care aerosolizable nanosensors with tumor-responsive oligonucleotide barcodes), to reduce resource disparities for early detection of lung cancer. PATROL formulates a set of DNA-barcoded, activity-based nanosensors (ABNs) into an inhalable format. Lung cancer-associated proteases selectively cleave the ABNs, releasing synthetic DNA reporters that are eventually excreted via the urine. The urinary signatures of barcoded nanosensors are quantified within 20 min at room temperature using a multiplexable paper-based lateral flow assay. PATROL detects early-stage tumors in an autochthonous lung adenocarcinoma mouse model with high sensitivity and specificity. Tailoring the library of ABNs may enable not only the modular PATROL platform to lower the resource threshold for lung cancer early detection tools but also the rapid detection of chronic pulmonary disorders and infections.

Recent advances in nanobiosensors for sustainable healthcare applications: A systematic literature review

The need for novel healthcare treatments and drugs has increased due to the expanding human population, detection of newer diseases, and looming pandemics. The development of nanotechnology offers a platform for cutting-edge in vivo non-invasive monitoring and point-of-care-testing (POCT) for rehabilitative disease detection and management. The advancement and uses of nanobiosensors are currently becoming more common in a variety of scientific fields, such as environmental monitoring, food safety, biomedical, clinical, and sustainable healthcare sciences, since the advent of nanotechnology. The identification and detection of biological patterns connected to any type of disease (communicable or not) have been made possible in recent years by several sensing techniques utilizing nanotechnology concerning biosensors and nanobiosensors. In this work, 2218 articles are drawn and screened from six digital databases out of which 17 were shortlisted for this review by using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) technique. As a result, this study uses a systematic methodology to review some recently developed extremely sensitive nanobiosensors, along with their biomedical, point-of-care diagnostics (POCD), or healthcare applications and their capabilities, particularly for the prediction of some fatal diseases based on a few of the most recent publications. The potential of nanobiosensors for medicinal, therapeutic, or other sustainable healthcare applications, notably for ailments diagnostics, is also recognized as a way forward in the manifestation of future trends.

Lateral flow assay: a promising rapid point-of-care testing tool for infections and non-communicable diseases

The point-of-care testing (POCT) approach has established itself as having remarkable importance in diagnosing various infectious and non-communicable diseases (NCDs). The POCT approach has succeeded in meeting the current demand for having diagnostic strategies that can provide fast, sensitive, and highly accurate test results without involving complicated procedures. This has been accomplished by introducing rapid bioanalytical tools or biosensors such as lateral flow assays (LFAs). The production cost of these tools is very low, allowing developing countries with limited resources to utilize them or produce them on their own. Thus, their use has grown in various fields in recent years. More importantly, LFAs have created the possibility for a new era of incorporating nanotechnology in disease diagnosis and have already attained significant commercial success worldwide, making POCT an essential approach not just for now but also for the future. In this review, we have provided an overview of POCT and its evolution into the most promising rapid diagnostic approach. We also elaborate on LFAs with a special focus on nucleic acid LFAs.

Simultaneous and rapid colorimetric detection of distinct miRNAs using Split-LAMP

Introduction: Aberrant microRNA (miRNA) expressions are often discovered in many life threatening diseases such as cancer. In particular, recent studies show combinations of miRNA levels have greater diagnostic accuracy as opposed to single miRNA levels. For point-of-care applications, rapid and sensitive isothermal amplification with loop-mediated isothermal amplification (LAMP) has gained significant interest. Method: We developed a cost-effective point-of-care testing (POCT) device for multiple miRNAs that can integrate miRNA signals into a single output. Results and Discussion: We demonstrate that the loop primers for LAMP can be broken and be used for miRNA detection. This split-LAMP approach provides a logic AND-gate output for two distinct miRNA inputs. We then show that this is potentially useable in point-of-care testing using pH-sensitive dye to give a rapid, colorimetric endpoint readout within 30 min. This novel logic gate approach can potentially be extended to multiple miRNAs such that there can be a powerful diagnostic concept for multiple short RNAs in a point-of-care rapid test.

Point-of-Care Prostate Specific Antigen Testing: Examining Translational Progress toward Clinical Implementation

Prostate cancer (PCa) is the second most common male cancer and is attributable to over 375,000 deaths annually. Prostate specific antigen (PSA) is a key biomarker for PCa and therefore measuring patient PSA levels is an important aspect of the diagnostic pathway. Automated immunoassays are currently utilized for PSA analysis, but they require a laboratory setting with specialized equipment and trained personnel. This results in high diagnostic costs, extended therapeutic turnaround times, and restrictions on testing capabilities in resource-limited settings. Consequently, there is a strong drive to develop point-of-care (PoC) PSA tests that can offer accurate, low-cost, and rapid results at the time and place of the patient. However, many emerging PoC tests experience a trade-off between accuracy, affordability, and accessibility which distinctly limits their translational potential. This review comprehensively assesses the translational advantages and limitations of emerging laboratory-level and commercial PoC tests for PSA determination. Electrochemical and optical PSA sensors from 2013 to 2023 are systematically examined. Furthermore, we suggest how the translational potential of emerging tests can be optimized to achieve clinical implementation and thus improve PCa diagnosis globally.

Emerging trends in nanomaterial design for the development of point-of-care platforms and practical applications

Nanomaterials and nanotechnology offer promising opportunities in point-of-care (POC) diagnostics and therapeutics due to their unique physical and chemical properties. POC platforms aim to provide rapid and portable diagnostic and therapeutic capabilities at the site of patient care, offering cost-effective solutions. Incorporating nanomaterials with distinct optical, electrical, and magnetic properties can revolutionize the POC industry, significantly enhancing the effectiveness and efficiency of diagnostic and theragnostic devices. By leveraging nanoparticles and nanofibers in POC devices, nanomaterials have the potential to improve the accuracy and speed of diagnostic tests, making them more practical for POC settings. Technological advancements, such as smartphone integration, imagery instruments, and attachments, complement and expand the application scope of POCs, reducing invasiveness by enabling analysis of various matrices like saliva and breath. These integrated testing platforms facilitate procedures without compromising diagnosis quality. This review provides a summary of recent trends in POC technologies utilizing nanomaterials and nanotechnologies for analyzing disease biomarkers. It highlights advances in device development, nanomaterial design, and their applications in POC. Additionally, complementary tools used in POC and nanomaterials are discussed, followed by critical analysis of challenges and future directions for these technologies.

Biosensors Based on Inorganic Composite Fluorescent Hydrogels

Fluorescent hydrogels are promising candidate materials for portable biosensors to be used in point-of-care diagnosis because (1) they have a greater capacity for binding organic molecules than immunochromatographic test systems, determined by the immobilization of affinity labels within the three-dimensional hydrogel structure; (2) fluorescent detection is more sensitive than the colorimetric detection of gold nanoparticles or stained latex microparticles; (3) the properties of the gel matrix can be finely tuned for better compatibility and detection of different analytes; and (4) hydrogel biosensors can be made to be reusable and suitable for studying dynamic processes in real time. Water-soluble fluorescent nanocrystals are widely used for in vitro and in vivo biological imaging due to their unique optical properties, and hydrogels based on these allow the preservation of these properties in bulk composite macrostructures. Here we review the techniques for obtaining analyte-sensitive fluorescent hydrogels based on nanocrystals, the main methods used for detecting the fluorescent signal changes, and the approaches to the formation of inorganic fluorescent hydrogels via sol-gel phase transition using surface ligands of the nanocrystals.

Bioinspired Materials for Wearable Devices and Point-of-Care Testing of Cancer

Wearable, point-of-care diagnostics, and biosensors are on the verge of bringing transformative changes in detection, management, and treatment of cancer. Bioinspired materials with new forms and functions have frequently been used, in both translational and commercial spaces, to fabricate such diagnostic platforms. Engineered from organic or inorganic molecules, bioinspired systems are naturally equipped with biorecognition and stimuli-sensitive properties. Mechanisms of action of bioinspired materials are deeply connected with thermodynamically or kinetically controlled self-assembly at the molecular and supramolecular levels. Thus, integration of bioinspired materials into wearable devices, either as triggers or sensors, brings about unique device properties usable for detection, capture, or rapid readout for an analyte of interest. In this review, we present the basic principles and mechanisms of action of diagnostic devices engineered from bioinspired materials, describe current advances, and discuss future trends of the field, particularly in the context of cancer.

Lab-in-a-fiber-based integrated particle separation and counting

An all-fiber integrated device capable of separating and counting particles is presented. A sequence of silica fiber capillaries with various diameters and longitudinal cavities are used to fabricate the component for size-based elasto-inertial passive separation of particles followed by detection in an uninterrupted continuous flow. Experimentally, fluorescent particles of 1 μm and 10 μm sizes are mixed in a visco-elastic fluid and fed into the all-fiber separation component. The particles are sheathed by an elasticity enhancer (PEO - polyethylene oxide) to the side walls. Larger 10 μm particles migrate to the center of the silica capillary due to the combined inertial lift force and elastic force, while the smaller 1 μm particles are unaffected, and exit from a side capillary. A separation efficiency of 100% for the 10 μm and 97% for the 1 μm particles is achieved at a total flow rate of 50 μL min^-1. To the best of our knowledge, this is the first time effective inertial-based separation has been demonstrated in circular cross-section microchannels. In the following step, the separated 10 μm particles are routed through another all-fiber component for counting and a counting throughput of ∼1400 particles per min is demonstrated. We anticipate the ability to combine high throughput separation and precise 3D control of particle position for ease of counting will aid in the development of advanced microflow cytometers capable of particle separation and quantification for various biomedical applications.

Integrating Microfluidics and Electronics in Point-of-Care Diagnostics: Current and Future Challenges

Point-of-Care (POC) diagnostics have gained increasing attention in recent years due to its numerous advantages over conventional diagnostic approaches. As proven during the recent COVID-19 pandemic, the rapidity and portability of POC testing improves the efficiency of healthcare services and reduces the burden on healthcare providers. There are hundreds of thousands of different applications for POC diagnostics, however, the ultimate requirement for the test is the same: sample-in and result-out. Many technologies have been implemented, such as microfluidics, semiconductors, and nanostructure, to achieve this end. The development of even more powerful POC systems was also enabled by merging multiple technologies into the same system. One successful example is the integration of microfluidics and electronics in POC diagnostics, which has simplified the sample handling process, reduced sample usage, and reduced the cost of the test. This review will analyze the current development of the POC diagnostic systems with the integration of microfluidics and electronics and discuss the future challenges and perspectives that researchers might have.

Lateral Flow Immunoassays for Detecting Viral Infectious Antigens and Antibodies

Abundant immunological assays currently exist for detecting pathogens and identifying infected individuals, making detection of diseases at early stages integral to preventing their spread, together with the consequent emergence of global health crises. Lateral flow immunoassay (LFIA) is a test characterized by simplicity, low cost, and quick results. Furthermore, LFIA testing does not need well-trained individuals or laboratory settings. Therefore, it has been serving as an attractive tool that has been extensively used during the ongoing COVID-19 pandemic. Here, the LFIA strip's available formats, reporter systems, components, and preparation are discussed. Moreover, this review provides an overview of the current LFIAs in detecting infectious viral antigens and humoral responses to viral infections.

Factor VIII companion diagnostic for haemophilia

Haemophilia is predominantly an inherited disorder that impairs the body’s ability to make blood clots, a process needed to stop bleeding. The condition of this disease is complex to manage, but many patients do so through home therapy and often only see their core multidisciplinary healthcare team annually. There is an increasing need for patients to be able to monitor their condition efficiently at home while staying connected with their healthcare team. As a consequence, a low-cost handheld self-monitoring solution for clotting factor is required. Here we have demonstrated a suitable one-step Factor VIII companion diagnostic sensing approach based on a chromogenic assay for haemophilia A. The results show comparable performance to the gold standard method. Our approach is able to deliver accurate cost-effective results in under 5 min from undiluted human plasma. It has the potential to be able to reduce the human and monetary costs of over- or under-medication for haemophiliacs.

Bioluminescent RAPPID Sensors for the Single-Step Detection of Soluble Axl and Multiplex Analysis of Cell Surface Cancer Biomarkers

Early diagnosis of cancer is essential for the efficacy of treatment. Our group recently developed RAPPID, a bioluminescent immunoassay platform capable of measuring a wide panel of biomarkers directly in solution. Here, we developed and systematically screened different RAPPID sensors for sensitive detection of the soluble fraction of Axl (sAxl), a cell surface receptor that is overexpressed in several types of cancer. The best-performing RAPPID sensor, with a limit of detection of 8 pM and a >9-fold maximal change in emission ratio, was applied to measure Axl in three different contexts: clinically relevant sAxl levels (∼0.5 and ∼1 nM) in diluted blood plasma, proteolytically cleaved Axl in the cell culture medium of A431 and HeLa cancer cells, and Axl on the membrane of A431 cells. We further extended the sensor toolbox by developing dual-color RAPPID for simultaneous detection of Axl and EGFR on A431 and HeLa cells, as well as an AND-gate RAPPID that measures the concurrent presence of these two cell surface receptors on the same cell. These new RAPPID sensors provide attractive alternatives for more laborious protein detection and quantification methods such as FACS and immunostainings, due to their simple practical implantation and low intrinsic background signal.

Liquid Biopsy as a Prognostic and Theranostic Tool for the Management of Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinomas (PDAC) represent one of the deadliest cancers worldwide. Survival is still low due to diagnosis at an advanced stage and resistance to treatment. Herein, we review the main types of liquid biopsy able to help in both prognosis and adaptation of treatments.

Recent advances in biosensing approaches for point-of-care breast cancer diagnostics: challenges and future prospects

Timely and accurate diagnosis of breast cancer is essential for efficient treatment and the best possible survival rates. Biosensors have emerged as a smart diagnostic platform for the detection of biomarkers specific to the onset, recurrence, and therapeutic drug monitoring of breast cancer. There have been exciting recent developments, including significant improvements in the validation, sensitivity, specificity, and integration of sample processing steps to develop point-of-care (POC) integrated micro-total analysis systems for clinical settings. The present review highlights various biosensing modalities (electrical, optical, piezoelectric, mass, and acoustic sensing). It provides deep insights into their design principles, signal amplification strategies, and comparative performance analysis. Finally, this review emphasizes the status of existing integrated micro-total analysis systems (μ-TAS) for personalized breast cancer therapeutics and associated challenges and outlines the approach required to realize their successful translation into clinical settings.

Early detection of kidney cancer using urinary proteins: a truly non-invasive strategy

OBJECTIVES

To review urinary protein biomarkers as potential non-invasive, easily obtainable, early diagnostic tools in renal cell carcinoma (RCC).

METHODS

A PubMed database search was performed up to the year 2020 to identify primary studies reporting potential urinary protein biomarkers for RCC. Separate searches were conducted to identify studies describing appropriate methods of developing cancer screening programmes and detection of cancer biomarkers.

RESULTS

Several urinary protein biomarkers are under validation for RCC diagnostics, e.g. aquaporin-1, perilipin-2, carbonic anhydrase-9, Raf-kinase inhibitory protein, nuclear matrix protein-22, 14-3-3 Protein β/α and neutrophil gelatinase-associated lipocalin. However, none has yet been validated or approved for clinical use due to low sensitivity or specificity, inconsistencies in appropriate study design, or lack of external validation.

CONCLUSIONS

Evaluation of biomarkers' feasibility, sample preparation and storage, biomarker validation, and the application of novel technologies may provide a solution that maximises the potential for a truly non-invasive biomarker in early RCC diagnostics.

Biomarkers and Lung Cancer Early Detection: State of the Art

Simple Summary

Lung cancer is the leading cause of cancer death worldwide. Detecting lung malignancies promptly is essential for any anticancer treatment to reduce mortality and morbidity, especially in high-risk individuals. The use of liquid biopsy to detect circulating biomarkers such as RNA, microRNA, DNA, proteins, autoantibodies in the blood, as well as circulating tumor cells (CTCs), can substantially change the way we manage lung cancer patients by improving disease stratification using intrinsic molecular characteristics, identification of therapeutic targets and monitoring molecular residual disease. Here, we made an update on recent developments in liquid biopsy-based biomarkers for lung cancer early diagnosis, and we propose guidelines for an accurate study design, execution, and data interpretation for biomarker development.

Abstract

Lung cancer burden is increasing, with 2 million deaths/year worldwide. Current limitations in early detection impede lung cancer diagnosis when the disease is still localized and thus more curable by surgery or multimodality treatment. Liquid biopsy is emerging as an important tool for lung cancer early detection and for monitoring therapy response. Here, we reviewed recent advances in liquid biopsy for early diagnosis of lung cancer. We summarized DNA- or RNA-based biomarkers, proteins, autoantibodies circulating in the blood, as well as circulating tumor cells (CTCs), and compared the most promising studies in terms of biomarkers prediction performance. While we observed an overall good performance for the proposed biomarkers, we noticed some critical aspects which may complicate the successful translation of these biomarkers into the clinical setting. We, therefore, proposed a roadmap for successful development of lung cancer biomarkers during the discovery, prioritization, and clinical validation phase. The integration of innovative minimally invasive biomarkers in screening programs is highly demanded to augment lung cancer early detection.

Nanozymes-Hitting the Biosensing "Target"

Nanozymes are a class of artificial enzymes that have dimensions in the nanometer range and can be composed of simple metal and metal oxide nanoparticles, metal nanoclusters, dots (both quantum and carbon), nanotubes, nanowires, or multiple metal-organic frameworks (MOFs). They exhibit excellent catalytic activities with low cost, high operational robustness, and a stable shelf-life. More importantly, they are amenable to modifications that can change their surface structures and increase the range of their applications. There are three main classes of nanozymes including the peroxidase-like, the oxidase-like, and the antioxidant nanozymes. Each of these classes catalyzes a specific group of reactions. With the development of nanoscience and nanotechnology, the variety of applications for nanozymes in diverse fields has expanded dramatically, with the most popular applications in biosensing. Nanozyme-based novel biosensors have been designed to detect ions, small molecules, nucleic acids, proteins, and cancer cells. The current review focuses on the catalytic mechanism of nanozymes, their application in biosensing, and the identification of future directions for the field.

The role of antibody-based troponin detection in cardiovascular disease: A critical assessment

Cardiovascular disease has remained the world's biggest killer for 30 years. To aid in the diagnosis and prognosis of patients suffering cardiovascular-related disease accurate detection methods are essential. For over 20 years, the cardiac-specific troponins, I (cTnI) and T (cTnT), have acted as sensitive and specific biomarkers to assist in the diagnosis of various types of heart diseases. Various cardiovascular complications were commonly detected in patients with COVID-19, where cTn elevation is detectable, which suggested potential great prognostic value of cTn in COVID-19-infected patients. Detection of these biomarkers circulating in the bloodstream is generally facilitated by immunoassays employing cTnI- and/or cTnT-specific antibodies. While several anti-troponin assays are commercially available, there are still obstacles to overcome to achieve optimal troponin detection. Such obstacles include the proteolytic degradation of N and C terminals on cTnI, epitope occlusion of troponin binding-sites by the cTnI/cTnT complex, cross reactivity of antibodies with skeletal troponins or assay interference caused by human anti-species antibodies. Therefore, further research into multi-antibody based platforms, multi-epitope targeting and rigorous validation of immunoassays is required to ensure accurate measurements. Moreover, with combination and modification of various latest technical (e.g. microfluidics), antibody-based troponin detection systems can be more specific, sensitive and rapid which could be incorporated into portable biosensor systems to be used at point-of care.

Recent advances in point-of-care diagnostics for oral cancer

Early-stage diagnosis is a crucial step in reducing the mortality rate in oral cancer cases. Point-of-care (POC) devices for oral cancer diagnosis hold great future potential in improving the survival rates as well as the quality of life of oral cancer patients. The conventional oral examination followed by needle biopsy and histopathological analysis have limited diagnostic accuracy. Besides, it involves patient discomfort and is not feasible in resource-limited settings. POC detection of biomarkers and diagnostic adjuncts has emerged as non- or minimally invasive tools for the diagnosis of oral cancer at an early stage. Various biosensors have been developed for the rapid detection of oral cancer biomarkers at the point-of-care. Several optical imaging methods have also been employed as adjuncts to detect alterations in oral tissue indicative of malignancy. This review summarizes the different POC platforms developed for the detection of oral cancer biomarkers, along with various POC imaging and cytological adjuncts that aid in oral cancer diagnosis, especially in low resource settings. Various immunosensors and nucleic acid biosensors developed to detect oral cancer biomarkers are summarized with examples. The different imaging methods used to detect oral tissue malignancy are also discussed herein. Additionally, the currently available commercial devices used as adjuncts in the POC detection of oral cancer are emphasized along with their characteristics. Finally, we discuss the limitations and challenges that persist in translating the developed POC techniques in the clinical settings for oral cancer diagnosis, along with future perspectives.

Rapid lateral flow tests for the detection of SARS-CoV-2 neutralizing antibodies

Background: Rapid Lateral Flow Test (LFT) has been broadly utilized in detection or diagnosis of numerous disease-related antigens and antibodies. It is the most popular format of point-of-care test (POCT) and quickest and easiest way to detect a targeted molecule. In the combat against COVID-19 pandemic, hundreds of POCTs have been developed and are commercially available now. They are designed to detect either a SARS-CoV-2 viral antigen or IgG and IgM antibodies binding to it. Among the binding antibodies, a special type of functional antibodies that block the interaction between SARS-CoV-2 virus and its human receptor, neutralizing antibodies (NAbs), are of particular interest to public as well as in vaccination management. However as of today, POCTs for the detection of SARS-CoV-2 NAbs remain under late stage of development.Scope and method:In this review, we first summarize the importance of awareness and monitoring of SARS-CoV-2 NAbs in the combat against COVID-19 pandemic. Secondly, we compare the available methods for the detection of SARS-CoV-2 NAbs. Next, we describe challenges in the development of a rapid lateral flow test for the detection of SARS-CoV-2 NAbs. Finally, we outline its product formats and applications in research and in disease management. Conclusion:Vaccine effectiveness is unknown for an individual unless measured. NAb level is the most viable measurement for vaccine effectiveness or immunity. A broadly accessible NAb POCT is urgently needed.

A monolithic single-chip point-of-care platform for metabolomic prostate cancer detection

There is a global unmet need for rapid and cost-effective prognostic and diagnostic tools that can be used at the bedside or in the doctor's office to reduce the impact of serious disease. Many cancers are diagnosed late, leading to costly treatment and reduced life expectancy. With prostate cancer, the absence of a reliable test has inhibited the adoption of screening programs. We report a microelectronic point-of-care metabolite biomarker measurement platform and use it for prostate cancer detection. The platform, using an array of photodetectors configured to operate with targeted, multiplexed, colorimetric assays confined in monolithically integrated passive microfluidic channels, completes a combined assay of 4 metabolites in a drop of human plasma in under 2 min. A preliminary clinical study using l-amino acids, glutamate, choline, and sarcosine was used to train a cross-validated random forest algorithm. The system demonstrated sensitivity to prostate cancer of 94% with a specificity of 70% and an area under the curve of 0.78. The technology can implement many similar assay panels and hence has the potential to revolutionize low-cost, rapid, point-of-care testing.

Gold nanostructured laser-scribed graphene: A new electrochemical biosensing platform for potential point-of-care testing of disease biomarkers

Improvements in the laser-scribed graphene (LSG)-based electrodes are critical to overcoming limitations of bare LSG electrodes in terms of sensitivity, direct immobilization of detection probes for biosensor fabrication, and ease of integration with point-of-care (POC) devices. Herein, we introduce a new class of nanostructured gold modified LSG (LSG-AuNS) electrochemical sensing system comprising LSG-AuNS working electrode, LSG reference, and LSG counter electrode. LSG-AuNS electrodes are realized by electrodeposition of gold chloride (HAuCl₄) solution, which gave~2-fold enhancement in sensitivity and electrocatalytic activity compared to bare LSG electrode and commercially available screen-printed gold electrode (SPAuE). We demonstrate LSG-AuNS electrochemical aptasensor for detecting human epidermal growth factor receptor 2 (Her-2) with a limit of detection (LOD) of 0.008 ng/mL and a linear range of 0.1-200 ng/mL. LSG-AuNS-aptasensor can easily detect different concentrations of Her-2 spiked in undiluted human serum. Finally, to show the LSG-AuNS sensor system's potential to develop POC biosensor devices, we integrated LSG-AuNS electrodes with a handheld electrochemical system operated using a custom-developed mobile application.

Monitoring hepatitis B by using point-of-care testing: biomarkers, current technologies, and perspectives

Introduction: Liver diseases caused by hepatitis B virus (HBV) are pandemic infectious diseases that seriously endanger human health, conventional diagnosis methods can not meet the requirements in resource-limited areas. The point of acre detection methods can easily resolve those problems. Herein, we review the most recent advances in POC-based hepatitis B detection methods and present some recommendations for future development. It aims to provide ideas for future research.Areas covered: Epidemiological data on Hepatitis B, conventional diagnostic methods for hepatitis B detection, some latest point of care detection methods for hepatitis B detection and list out the recommendations for future development.Expert opinion: This manuscript summarized traditional biomarkers of different hepatitis B stages and recent-developed POCT platforms (including microfluidic platforms and lateral-flow strips) and discuss the challenges associated with their use. Some emerging biomarkers that can be used in hepatitis B diagnosis are also listed. This manuscript has certain guiding significance to the development of hepatitis B detection.

Integrated dielectrophoretic and impedimetric biosensor provides a template for universal biomarker sensing in clinical samples

The detection and quantification of nucleic acid and proteomic biomarkers in bodily fluids is a critical part of many medical screening and diagnoses. However, majority of the current detection platforms are not ideal for routine, rapid, and low-cost testing in point-of-care settings. To address this issue, we developed a concept for a disposable universal point-of-care biosensor that can detect and quantify nucleic acid and proteomic biomarkers in diluted serum samples. The central tenet of sensing is the use of dielectrophoresis, electrothermal effects, and thermophoresis to selectively and rapidly isolate the biomarkers of interest in electrodes and then quantify using electrical impedance. When the sensor was applied to quantify microRNA and antigen biomarker molecules directly in diluted serum samples, it produced a LOD values in the fM range and sensitivity values from 10¹² to 10¹⁵ Ω/M with a 30 min assay time and assay cost of less than $50 per assay.

Demonstration of a Label-Free and Low-Cost Optical Cavity-Based Biosensor Using Streptavidin and C-Reactive Protein

An optical cavity-based biosensor (OCB) has been developed for point-of-care (POC) applications. This label-free biosensor employs low-cost components and simple fabrication processes to lower the overall cost while achieving high sensitivity using a differential detection method. To experimentally demonstrate its limit of detection (LOD), we conducted biosensing experiments with streptavidin and C-reactive protein (CRP). The optical cavity structure was optimized further for better sensitivity and easier fluid control. We utilized the polymer swelling property to fine-tune the optical cavity width, which significantly improved the success rate to produce measurable samples. Four different concentrations of streptavidin were tested in triplicate, and the LOD of the OCB was determined to be 1.35 nM. The OCB also successfully detected three different concentrations of human CRP using biotinylated CRP antibody. The LOD for CRP detection was 377 pM. All measurements were done using a small sample volume of 15 µL within 30 min. By reducing the sensing area, improving the functionalization and passivation processes, and increasing the sample volume, the LOD of the OCB are estimated to be reduced further to the femto-molar range. Overall, the demonstrated capability of the OCB in the present work shows great potential to be used as a promising POC biosensor.

Point-of-care cancer diagnostic devices: From academic research to clinical translation

Early and timely diagnosis of cancer plays a decisive role in appropriate treatment and improves clinical outcomes, improving public health. Significant advances in biosensor technologies are leading to the development of point-of-care (POC) diagnostics, making the testing process faster, easier, cost-effective, and suitable for on-site measurements. Moreover, the incorporation of various nanomaterials into the sensing platforms has yielded POC testing (POCT) platforms with enhanced sensitivity, cost-effectiveness and simplified detection schemes. POC cancer diagnostic devices provide promising platforms for cancer biomarker detection as compared to conventional in vitro diagnostics, which are time-consuming and require sophisticated instrumentation, centralized laboratories, and experienced operators. Current innovative approaches in POC technologies, including biosensors, smartphone interfaces, and lab-on-a-chip (LOC) devices are expected to quickly transform the healthcare landscape. However, only a few cancer POC devices (e.g. lateral flow platforms) have been translated from research laboratories to clinical care, likely due to challenges include sampling procedures, low levels of sensitivity and specificity in clinical samples, system integration and signal readout requirements. In this review, we emphasize recent advances in POC diagnostic devices for cancer biomarker detection and discuss the critical challenges which must be surmounted to facilitate their translation into clinical settings.

Genetic predisposition and prediction protocol for epithelial neoplasms in disease-free individuals: A systematic review

Background

Epithelial neoplasm is an important global health-care problem, with high morbidity and mortality rates. Early diagnosis and appropriate treatment are essential for increased life survival. Prediction of occurrence of malignancy in a disease-free individual by any means will be a great breakthrough for healthy living.

Aims and Objectives

The aims and objectives were to predict the genetic predisposition and propose a prediction protocol for epithelial malignancy of various systems in our body, in a disease-free individual.

Methods

We have searched databases both manually and electronically, published in English language in Cochrane group, Google search, MEDLINE and PubMed from 2000 to 2019. We have included all the published, peer-reviewed, narrative reviews; randomized controlled trials; case-control studies; and cohort studies and excluded the abstract-only articles and duplicates. Specific words such as "etiological factors," "pathology and mutations," "signs and symptoms," "genetics and IHC marker," and "treatment outcome" were used for the search. A total of 1032 citations were taken, and only 141 citations met the inclusion criteria and were analyzed.

Results

After analyzing various articles, the etiological factors, clinical signs and symptoms, genes and the pathology involved and the commonly used blood and tissue markers were analyzed. A basic investigation strategy using immunohistochemistry markers was established.

Conclusion

The set of proposed biomarkers should be studied in future to predict genetic predisposition in disease-free individuals.

Recent advances in aptamer-based sensors for breast cancer diagnosis: special cases for nanomaterial-based VEGF, HER2, and MUC1 aptasensors

Cancer is one of the most common and important diseases with a high mortality rate. Breast cancer is among the three most common types of cancer in women, and the mortality rate has reached 0.024% in some countries. For early-stage preclinical diagnosis of breast cancer, sensitive and reliable tools are needed. Today, there are many types of biomarkers that have been identified for cancer diagnosis. A wide variety of detection strategies have also been developed for the detection of these biomarkers from serum or other body fluids at physiological concentrations. Aptamers are single-stranded DNA or RNA oligonucleotides and promising in the production of more sensitive and reliable biosensor platforms in combination with a wide range of nanomaterials. Conformational changes triggered by the target analyte have been successfully applied in fluorometric, colorimetric, plasmonic, and electrochemical-based detection strategies. This review article presents aptasensor approaches used in the detection of vascular endothelial growth factor (VEGF), human epidermal growth factor receptor 2 (HER2), and mucin-1 glycoprotein (MUC1) biomarkers, which are frequently studied in the diagnosis of breast cancer. The focus of this review article is on developments of the last decade for detecting these biomarkers using various sensitivity enhancement techniques and nanomaterials.

Glycovariant-based lateral flow immunoassay to detect ovarian cancer-associated serum CA125

Cancer antigen 125 (CA125) is a widely used biomarker in monitoring of epithelial ovarian cancer (EOC). Due to insufficient cancer specificity of CA125, its diagnostic use is severely compromised. Abnormal glycosylation of CA125 is a unique feature of ovarian cancer cells and could improve differential diagnosis of the disease. Here we describe the development of a quantitative lateral flow immunoassay (LFIA) of aberrantly glycosylated CA125 which is widely superior to the conventional CA125 immunoassay (CA125IA). With a 30 min read-out time, the LFIA showed 72% sensitivity, at 98% specificity using diagnostically challenging samples with marginally elevated CA125 (35–200 U/mL), in comparison to 16% sensitivity with the CA125IA. We envision the clinical use of the developed LFIA to be based on the substantially enhanced disease specificity against the many benign conditions confounding the diagnostic evaluation and against other cancers.

Sherif Bayoumy et al. report a lateral flow immunoassay (LFIA) to quantify aberrantly glycosylated CA125 to diagnose epithelial ovarian cancer. Their method has a 30-minute read-out time, high sensitivity and specificity, and can distinguish ovarian cancer from benign endometriosis and other cancers.

Current and emerging trends in point-of-care urinalysis tests

Introduction: The development of point-of-care testing (POCT) has made clinical diagnostics available, affordable, rapid, and easy to use since the 1990s.The significance of this platform rests on its potential to empower patients to monitor their own health status more frequently, in the convenience of their home, so that diseases can be diagnosed at the earliest possible time-point. Recent advances have expanded traditional formats such as qualitative or semi-quantitative dipsticks and lateral flow immunoassays to newer platforms such as microfluidics and paper-based assays where signals can be measured quantitatively using handheld devices.Areas covered: This review discusses: (1) working principles and operating mechanisms of both existing and emerging POCT platforms, (2) urine analytes measured using POCT in comparison to the laboratory or clinical 'gold standard,' and (3) limitations of existing POCT and expectations of emerging POCT in urinalysis.Expert opinion: Currently, a variety of biological samples such as urine, saliva, serum, plasma, and other fluids can be applied to POCT for quick diagnosis, especially in resource-limited settings. Emerging platforms will increasingly empower individuals to monitor their health status through frequent urine analysis even from their homes. The impact of these emerging technologies on healthcare is likely to be transformative.

Novel Epigenetic Biomarkers in Pregnancy-Related Disorders and Cancers

As the majority of cancers and gestational diseases are prognostically stage- and grade-dependent, the ultimate goal of ongoing studies in precision medicine is to provide early and timely diagnosis of such disorders. These studies have enabled the development of various new diagnostic biomarkers, such as free circulating nucleic acids, and detection of their epigenetic changes. Recently, extracellular vesicles including exosomes, microvesicles, oncosomes, and apoptotic bodies have been recognized as powerful diagnostic tools. Extracellular vesicles carry specific proteins, lipids, DNAs, mRNAs, and miRNAs of the cells that produced them, thus reflecting the function of these cells. It is believed that exosomes, in particular, may be the optimal biomarkers of pathological pregnancies and cancers, especially those that are frequently diagnosed at an advanced stage, such as ovarian cancer. In the present review, we survey and critically appraise novel epigenetic biomarkers related to free circulating nucleic acids and extracellular vesicles, focusing especially on their status in trophoblasts (pregnancy) and neoplastic cells (cancers).

Current Trends of Nanobiosensors for Point-of-Care Diagnostics

In order to provide better-quality health care, it is very important that high standards of health care management are achieved by making timely decisions based on rapid diagnostics, smart data analysis, and informatics analysis. Point-of-care testing ensures fast detection of analytes near to the patients facilitating a better disease diagnosis, monitoring, and management. It also enables quick medical decisions since the diseases can be diagnosed at an early stage which leads to improved health outcomes for the patients enabling them to start early treatment. In the recent past, various potential point-of-care devices have been developed and they are paving the way to next-generation point-of-care testing. Biosensors are very critical components of point-of-care devices since they are directly responsible for the bioanalytical performance of an essay. As such, they have been explored for their prospective point-of-care applications necessary for personalized health care management since they usually estimate the levels of biological markers or any chemical reaction by producing signals mainly associated with the concentration of an analyte and hence can detect disease causing markers such as body fluids. Their high selectivity and sensitivity have allowed for early diagnosis and management of targeted diseases; hence, facilitating timely therapy decisions and combination with nanotechnology can improve assessment of the disease onset and its progression and help to plan for treatment of many diseases. In this review, we explore how nanotechnology has been utilized in the development of nanosensors and the current trends of these nanosensors for point-of-care diagnosis of various diseases.

2D Materials in Development of Electrochemical Point-of-Care Cancer Screening Devices

Effective cancer treatment requires early detection and monitoring the development progress in a simple and affordable manner. Point-of care (POC) screening can provide a portable and inexpensive tool for the end-users to conveniently operate test and screen their health conditions without the necessity of special skills. Electrochemical methods hold great potential for clinical analysis of variety of chemicals and substances as well as cancer biomarkers due to their low cost, high sensitivity, multiplex detection ability, and miniaturization aptitude. Advances in two-dimensional (2D) material-based electrochemical biosensors/sensors are accelerating the performance of conventional devices toward more practical approaches. Here, recent trends in the development of 2D material-based electrochemical biosensors/sensors, as the next generation of POC cancer screening tools, are summarized. Three cancer biomarker categories, including proteins, nucleic acids, and some small molecules, will be considered. Various 2D materials will be introduced and their biomedical applications and electrochemical properties will be given. The role of 2D materials in improving the performance of electrochemical sensing mechanisms as well as the pros and cons of current sensors as the prospective devices for POC screening will be emphasized. Finally, the future scopes of implementing 2D materials in electrochemical POC cancer diagnostics for the clinical translation will be discussed.

Demonstration of a Low-Cost and Portable Optical Cavity-Based Sensor through Refractive Index Measurements

An optical cavity-based sensor using a differential detection method has been proposed for point-of-care diagnostics. We developed a low-cost and portable optical cavity-based sensor system using a 3D printer and off-the-shelf optical components. In this paper, we demonstrate the sensing capability of the portable system through refractive index measurements. Fabricated optical cavity samples were tested using the portable system and compared to simulation results. A referencing technique and digital low pass filtering were applied to reduce the noise of the portable system. The measurement results match the simulation results well and show the improved linearity and sensitivity by employing the differential detection method. The limit of detection achieved was 1.73 × 10⁻⁵ Refractive Index Unit (RIU), which is comparable to other methods for refractive index sensing.