Electrochemical vs. Optical Biosensors for Point-of-Care Applications: A Critical Review

Abstract

Analytical chemistry applied to medical and diagnostic analysis has recently focused on the development of cost-effective biosensors able to monitor the health status or to assess the level of specific biomarkers that can be indicative of several diseases. The improvement of technologies relating to the possibility of the non-invasive sampling of biological fluids, as well as sensors for the detection of analytical signals and the computational capabilities of the systems routinely employed in everyday life (e.g., smartphones, computers, etc.), makes the complete integration of self-standing analytical devices more accessible. This review aims to discuss the biosensors that have been proposed in the last five years focusing on two principal detecting approaches, optical and electrochemical, which have been employed for quantifying different kinds of target analytes reaching detection limits below the clinical sample levels required. These detection principles applied to point-of-care (POC) devices have been extensively reported in literature, and even the limited examples found on the market are based on these strategies. This work will show the latest innovations considering the integration of optical and electrochemical detection with the most commonly reported analytical platforms for POC applications such as paper-based or wearable and implantable devices.

Optical Sensors for Bacterial Detection

“…According to Markets and Markets, the biosensor market was valued at USD 25.5 billion in 2021 and is forecast to reach USD 36.7 billion by 2026 [171,172]. Recently, there has been a growing trend towards the use of smartphone-based optical bacterial analysis systems (smartphone-based photo-and spectrometers and smartphone-based fluorimeters [66,173]. The use of optical biosensors may strongly increase the possibility of early pathogen detection and, as a result, may facilitate disease screening.…”

“…It is triggered by an electrochemical stimulus on a specific molecule and ensures high control of the emitted light, a low background signal, and high sensitivity. These aspects make electrochemiluminescence particularly suitable for the development of portable biosensor devices [66]. Compared with fluorescence, electrochemiluminescence does not require an excitation light source, thereby avoiding autofluorescence or a diffuse light background.…”

Functional Interface for Glycoprotein Sensing: Focusing on Biosensors

“…Similarly, for optical biosensors, the biological recognition of glycoproteins by receptors is transformed into various optical signals for readout and various optical detection approaches include chemiluminescence, fluorescence, colorimetry, surfaceenhanced Raman spectroscopy, etc. 64 ECL, as a popular biosensing technique, combines the advantages of electrochemical and optical detection, which has found numerous applications in glycoprotein sensing. For instance, an electrochemiluminescence resonance energy transfer and electrochemical dual-mode immunosensor was reported to enable highly sensitive analysis of rabies virus glycoprotein.…”