Microfluidic-integrated biosensors: Prospects for point-of-care diagnostics

There is a growing demand to integrate biosensors with microfluidics to provide miniaturized platforms with many favorable properties, such as reduced sample volume, decreased processing time, low cost analysis and low reagent consumption. These microfluidics-integrated biosensors would also have numerous advantages such as laminar flow, minimal handling of hazardous materials, multiple sample detection in parallel, portability and versatility in design. Microfluidics involves the science and technology of manipulation of fluids at the micro- to nano-liter level. It is predicted that combining biosensors with microfluidic chips will yield enhanced analytical capability, and widen the possibilities for applications in clinical diagnostics. The recent developments in microfluidics have helped researchers working in industries and educational institutes to adopt some of these platforms for point-of-care (POC) diagnostics. This review focuses on the latest advancements in the fields of microfluidic biosensing technologies, and on the challenges and possible solutions for translation of this technology for POC diagnostic applications. We also discuss the fabrication techniques required for developing microfluidic-integrated biosensors, recently reported biomarkers, and the prospects of POC diagnostics in the medical industry.     

Ultrasensitive nucleic acid biosensors for early cancer diagnostics

We have developed ultrasensitive nucleic acid detection systems involving an amplification step where the analytical signal correlates directly to the amount of nucleic acid in the solution So far, we have performed nucleic acid quantification on several breast cancer susceptibility genes and were able to detect nucleic acid amounts that ranged from 0.1–1.0 fg of nucleic acid, which is at least 1000 times more sensitive than conventional fluorescent detection methods. The biosensors are so sensitive that they can be used for direct detection of breast cancer susceptibility genes in mRNA without involving a PCR step.     

CRISPR-based point-of-care plant disease diagnostics

The coupling of clustered regularly interspaced short palindromic repeats (CRISPR)-Cas RNA-programmable nucleases with nucleic acid detection platforms has brought radical changes to the field of disease diagnosis. Recently, Sánchez et al. developed a simple, rapid, highly sensitive, precise, and in-field deployable point-of-care (POC) and point-of-need (PON) molecular disease detection tool that can be used in diverse agricultural applications.     

Diagnosing point-of-care diagnostics for neglected tropical diseases

Inadequate and nonintegrated diagnostics are the Achilles’ heel of global efforts to monitor, control, and eradicate neglected tropical diseases (NTDs). While treatment is often available, NTDs are endemic among marginalized populations, due to the unavailability or inadequacy of diagnostic tests that cause empirical misdiagnoses. The need of the hour is early diagnosis at the point-of-care (PoC) of NTD patients. Here, we review the status quo of PoC diagnostic tests and practices for all of the 24 NTDs identified in the World Health Organization’s (WHO) 2021–2030 roadmap, based on their different diagnostic requirements. We discuss the capabilities and shortcomings of current diagnostic tests, identify diagnostic needs, and formulate prerequisites of relevant PoC tests. Next to technical requirements, we stress the importance of availability and awareness programs for establishing PoC tests that fit endemic resource-limited settings. Better understanding of NTD diagnostics will pave the path for setting realistic goals for healthcare in areas with minimal resources, thereby alleviating the global healthcare burden.     

Electrochemical biosensors: recommended definitions and classification

Two Divisions of the International Union of Pure and Applied Chemistry (IUPAC), namely Physical Chemistry (Commission 1.7 on Biophysical Chemistry formerly Steering Committee on Biophysical Chemistry) and Analytical Chemistry (Commission V.5 on Electroanalytical Chemistry) have prepared recommendations on the definition, classification and nomenclature related to electrochemical biosensors: these recommendations could, in the future, be extended to other types of biosensors. An electrochemical biosensor is a self-contained integrated device, which is capable of providing specific quantitative or semi-quantitative analytical information using a biological recognition element (biochemical receptor) which is retained in direct spatial contact with an electrochemical transduction element. Because of their ability to be repeatedly calibrated, we recommend that a biosensor should be clearly distinguished from a bioanalytical system, which requires additional processing steps, such as reagent addition. A device that is both disposable after one measurement, i.e. single use, and unable to monitor the analyte concentration continuously or after rapid and reproducible regeneration, should be designated a single use biosensor. Biosensors may be classified according to the biological specificity-conferring mechanism or, alternatively, to the mode of physico-chemical signal transduction. The biological recognition element may be based on a chemical reaction catalysed by, or on an equilibrium reaction with macromolecules that have been isolated, engineered or present in their original biological environment. In the latter cases. equilibrium is generally reached and there is no further, if any, net consumption of analyte(s) by the immobilized biocomplexing agent incorporated into the sensor. Biosensors may be further classified according to the analytes or reactions that they monitor: direct monitoring of analyte concentration or of reactions producing or consuming such analytes; alternatively, an indirect monitoring of inhibitor or activator of the biological recognition element (biochemical receptor) may be achieved. A rapid proliferation of biosensors and their diversity has led to a lack of rigour in defining their performance criteria. Although each biosensor can only truly be evaluated for a particular application, it is still useful to examine how standard protocols for performance criteria may be defined in accordance with standard IUPAC protocols or definitions. These criteria are recommended for authors. referees and educators and include calibration characteristics (sensitivity, operational and linear concentration range, detection and quantitative determination limits), selectivity, steady-state and transient response times, sample throughput, reproducibility, stability and lifetime.     

Advances in microfluidic PCR for point-of-care infectious disease diagnostics

Global burdens from existing or emerging infectious diseases emphasize the need for point-of-care (POC) diagnostics to enhance timely recognition and intervention. Molecular approaches based on PCR methods have made significant inroads by improving detection time and accuracy but are still largely hampered by resource-intensive processing in centralized laboratories, thereby precluding their routine bedside- or field-use. Microfluidic technologies have enabled miniaturization of PCR processes onto a chip device with potential benefits including speed, cost, portability, throughput, and automation. In this review, we provide an overview of recent advances in microfluidic PCR technologies and discuss practical issues and perspectives related to implementing them into infectious disease diagnostics.     

Exploiting recombinant antibodies in point-of-care (POC) diagnostics: the combinatorial advantage

Antibodies are ubiquitously deployed on in vitro diagnostic (IVD) platforms for detecting a panoply of analytes indicative of environmental and food contamination, residue adulteration and both veterinary and medical diagnostics. In the clinical realm, rapid and accurate determination of disease status is paramount. The significance of immunodiagnostic performance cannot be overemphasized and in many cases reliable diagnosis informs medical intervention which can mean the difference between patient recovery and demise. Cardiovascular disease (CVD) is the single biggest cause of adult mortality in the western world and principal burden on the healthcare services. Although the troponin (Tn) family, in particular troponin I (TnI), are regarded as the gold standard for diagnosis of myocardial damage, over the last decade much research has focused on the identification of alternative cardiac biomarker molecules that can either supplant or complement TnI metrics to add value to cardiac risk stratification criteria. In particular, markers that appear earlier than TnI in the pathophyisiology of cardiac disease are highly sought after. The subject?of this addendum represents part of a broader challenge to deliver novel rapid point-of-care (POC) diagnostics to provide a chip-based multi-plexed platform for more comprehensive profiling of cardiac status with additive diagnostic and prognostic value.?Specifically, it outlines proof-of-concept direct myeloperoxidase (MPO) detection, demonstrates the benefits of using recombinant antibodies in POC diagnostics and describes optimized strategies for generation of superior candidate antibody panels.     

A multidisciplinary approach for molecular diagnostics based on biosensors and microarrays

The present review describes the multidisciplinary approach followed by the Chemistry and Nanobiotechnology group of INL since ten years, to develop a complete technological platform dedicated to molecular diagnosis using biochips and biosensors. This work, replaced in an international context, illustrates the importance to identify the various pitfalls inherent to molecular analysis throughout an elaboration and analysis line: choice of solid support, surface physicochemistry, immobilisation of biomolecules, biomolecular recognition, microfluidics and detection.     

Urinary proteomics: towards biomarker discovery, diagnostics and prognostics

During recent years, the proteomics field has moved onward to clinical applications, particularly for biomarker discovery, diagnostics and prognostics of human diseases. The urine is one of the ideal clinical samples for such applications because it is readily available in almost all patients, and its collection is very simple and non-invasive. Urinary proteomics thus becomes one of the most interesting subdisciplines in the clinical proteomics area. This article highlights and updates recent progress in the urinary proteomics field for clinical applications.     

Integration of biomolecules and nanomaterials: towards highly selective and sensitive biosensors

Significant efforts have been made toward the development of high-performance biosensors for various applications. Advances in nanotechnology have resulted in the development of highly sensitive electrochemical sensing devices. It is believed that highly sensitive and selective biosensors can be realized through the integration of biomolecules and nanomaterial-based sensor platforms. Numerous articles have described combining biomolecules as recognition elements with nanotechnology for the development of biosensors with enhanced selectivity and sensitivity. Recent advances in the development of biosensors through the integration of biomolecules with nanotechnology are reviewed in this article.     

Switch-based biosensors: a new approach towards real-time, in vivo molecular detection

Although the ability to monitor specific molecules in vivo in real-time could revolutionize many aspects of healthcare, the technological challenges that stand in the way of reaching this goal are considerable and are poorly met by most existing analytical approaches. Nature, however, has already solved the problem of real-time molecular detection in complex media by employing biomolecular "switches". That is, protein and nucleic acids that sense chemical cues and, by undergoing specific, binding-induced conformational changes, transduce this recognition into high-gain signal outputs. Here, we argue that devices that employ such switches represent a promising route towards versatile, real-time molecular monitoring in vivo.     

Toward the development of smart and low cost point-of-care biosensors based on screen printed electrodes

Screen printing technology provides a cheap and easy means to fabricate disposable electrochemical devices in bulk quantities which are used for rapid, low-cost, on-site, real-time and recurrent industrial, pharmaceutical or environmental analyses. Recent developments in micro-fabrication and nano-characterization made it possible to screen print reproducible feature on materials including plastics, ceramics and metals. The processed features forms screen-printed disposable biochip (SPDB) upon the application of suitable bio-chemical recognition receptors following appropriate methods. Adequacy of biological and non-biological materials is the key to successful biochip development. We can further improve recognition ability of SPDBs by adopting new screen printed electrode (SPE) configurations. This review covers screen-printing theory with special emphasis on the technical impacts of SPE architectures, surface treatments, operational stability and signal sensitivity. The application of SPE in different areas has also been summarized. The article aims to highlight the state-of-the-art of SPDB at the laboratory scale to enable us in envisaging the deployment of emerging SPDB technology on the commercial scale.     

Personalized diagnostics and biosensors: a review of the biology and technology needed for personalized medicine

Abstract

Exploiting the burgeoning fields of genomics, proteomics and metabolomics improves understanding of human physiology and, critically, the mutations that signal disease susceptibility. Through these emerging fields, rational design approaches to diagnosis, drug development and ultimately personalized medicine are possible. Personalized medicine and point-of-care testing techniques must fulfill a host of constraints for real-world applicability. Point-of-care devices (POCDs) must ultimately provide a cost-effective alternative to expensive and time-consuming laboratory tests in order to assist health care personnel with disease diagnosis and treatment decisions. Sensor technologies are also expanding beyond the more traditional classes of biomarkers – nucleic acids and proteins – to metabolites and direct detection of pathogens, ultimately increasing the palette of available techniques for the use of personalized medicine. The technologies needed to perform such diagnostics have also been rapidly evolving, with each generation being increasingly sensitive and selective while being more resource conscious. Ultimately, the final hurdle for all such technologies is to be able to drive consumer adoption and achieve a meaningful medical outcome for the patient.