Point-of-care biochemical assays using electrochemical technologies: approaches, applications, and opportunities

Abstract

Against the backdrop of hidden symptoms of diseases and limited medical resources of their investigation, in vitro diagnosis has become a popular mode of real-time healthcare monitoring. Electrochemical biosensors have considerable potential for use in wearable products since they can consistently monitor the physiological information of the patient. This review classifies and briefly compares commonly available electrochemical biosensors and the techniques of detection used. Following this, the authors focus on recent studies and applications of various types of sensors based on a variety of methods to detect common compounds and cancer biomarkers in humans. The primary gaps in research are discussed and strategies for improvement are proposed along the dimensions of hardware and software. The work here provides new guidelines for advanced research on and a wider scope of applications of electrochemical biosensors to in vitro diagnosis. Graphical abstract

Electrochemical Affinity Biosensors: Pervasive Devices with Exciting Alliances and Horizons Ahead

“…Advances and developments in smartphone-assisted (Figure ), “all-in-one” and PON electrochemical affinity biosensing platforms are also relentless. ,− …”

Introducing Nanoscale Electrochemistry in Small-Molecule Detection for Tackling Existing Limitations of Affinity-Based Label-Free Biosensing Applications

“…Detection of small molecules such as metabolites, neurotransmitters, and hormones can provide useful biological information for the diagnosis of specific diseases, prediction of treatment responses, and monitoring of health conditions. , Among various sensing techniques, electrochemical detection has great advantages for point-of-care (PoC) applications due to its merits, such as easy miniaturization, low cost, and fast response. , While electroactive small target molecules are easily detected by direct charge transfer from their own redox reactions on electrode surfaces, electrochemically inactive small molecules can also be detected by monitoring the electroactive products generated from highly selective enzymatic reactions with target molecules. , However, electrochemically inactive small molecules, not involving proper enzymatic reactions generating electroactive products, can be detected with affinity-based electrochemical (bio)­sensors, in which small target molecules are selectively bound with bioreceptors (e.g., antibodies and aptamers) or biomimetic receptors (e.g., molecularly imprinted polymers). − Traditional affinity-based electrochemical (bio)­sensors require either electroactive labels such as labeled secondary antibodies for voltammetric detections or external solutions containing redox probes for electrochemical impedance spectroscopic detections, which are not suitable for PoC applications. , Moreover, the affinity-based (bio)­sensors exhibit extremely high binding affinity, which renders highly selective detection of target molecules but creates difficulty in the regeneration of receptors, impeding repetitive and continuous measurements. Therefore, a significant effort has been made on developing “label-free” and “bind-and-read” electrochemical sensing techniques by coimmobilizing (bio)­receptors and redox probes on electrode surfaces toward the decentralized on-site monitoring of clinically important molecules. − …”

“…1,2 Among various sensing techniques, electrochemical detection has great advantages for point-of-care (PoC) applications due to its merits, such as easy miniaturization, low cost, and fast response. 3,4 While electroactive small target molecules are easily detected by direct charge transfer from their own redox reactions on electrode surfaces, electrochemically inactive small molecules can also be detected by monitoring the electroactive products generated from highly selective enzymatic reactions with target molecules. 5,6 However, electrochemically inactive small molecules, not involving proper enzymatic reactions generating electroactive products, can be detected with affinity-based electrochemical (bio)sensors, in which small target molecules are selectively bound with bioreceptors (e.g., antibodies and aptamers) or biomimetic receptors (e.g., molecularly imprinted polymers).…”

Urine protein quantification in human urine on boron-doped diamond electrodes based on the electrochemical reaction of Coomassie brilliant blue

“…In recent years, sensing methods based on electrochemical principles have been developed as simple detection methods for bio-relevant substances, and have been aimed at home use. [8][9][10][11] Electrochemical methods are more compact and energy-saving than spectroscopic and gravimetric (including QCM) techniques. 12,13 Many highly sensitive and highly selective sensors have been developed for research on biopolymers, such as nucleic acids, proteins, sugar chains, and peptides.…”