Portable Electrochemical Biosensors Based on Microcontrollers for Detection of Viruses: A Review

Abstract

With the rise of zoonotic diseases in recent years, there is an urgent need for improved and more accessible screening and diagnostic methods to mitigate future outbreaks. The recent COVID-19 pandemic revealed an over-reliance on RT-PCR, a slow, costly and lab-based method for diagnostics. To better manage the pandemic, a high-throughput, rapid point-of-care device is needed for early detection and isolation of patients. Electrochemical biosensors offer a promising solution, as they can be used to perform on-site tests without the need for centralized labs, producing high-throughput and accurate measurements compared to rapid test kits. In this work, we detail important considerations for the use of electrochemical biosensors for the detection of respiratory viruses. Methods of enhancing signal outputs via amplification of the analyte, biorecognition of elements and modification of the transducer are also explained. The use of portable potentiostats and microfluidics chambers that create a miniature lab are also discussed in detail as an alternative to centralized laboratory settings. The state-of-the-art usage of portable potentiostats for detection of viruses is also elaborated and categorized according to detection technique: amperometry, voltammetry and electrochemical impedance spectroscopy. In terms of integration with microfluidics, RT-LAMP is identified as the preferred method for DNA amplification virus detection. RT-LAMP methods have shorter turnaround times compared to RT-PCR and do not require thermal cycling. Current applications of RT-LAMP for virus detection are also elaborated upon.

Keywords: RT-LAMP; amperometry; electrochemical biosensors; electrochemical impedance spectroscopy; potentiostat; virus detection; voltammetry.

Figure 1

Important elements in a biosensing system. Clockwise from top right: analyte [32], electrochemical impedance spectroscopy readout data, potentiostat [33], biorecognition elements (spike protein [34] and antibodies [35]) and transducers and their surface structures (screen-printed gold electrode [36], polymer electrode [37], nanowire structure [38] and nanopore structure [39]).

Figure 2

From left to right: virus form factors, types of biorecognition elements, methods to enhance the sensitivity of transducers, various measurement techniques using electrochemical testing and the multi-usability of electrochemical biosensors [26].

Figure 3

Cyclic voltammetry graph of a commercialized screen-printed carbon electrode (SPCE) and a screen-printed gold electrode (SPGE) in 10 mM ferrocyanide.

Figure 4

Electropolymerization technique using molecular imprinted polymer (MIP) to enhance the surface area and sensitivity of electrodes. (a) Imprinted MIP is electrodeposited on a screen-printed carbon electrode to create enhanced anodic/cathodic currents during cyclic voltammetry measurements. (b) Electrode surface before polymerization. (c) Electrode surface after polymerization, indicating polymer modification and a change in topography [59].

Figure 5

Cyclic voltammograms of bare gold, a nanoporous gold thin film (NPGF) electrode, NPGF/6-MHA/Hb and NPGF/DNA/Hb in PBS [60].

Figure 6

(a) SIC4341 circuit board diagram of a portable NFC potentiostat [87]. (b) PalmSens4 potentiostat used for SARS-CoV-2 detection [88]. (c) Portable potentiostat developed by Kaci et al. (2022) [23]. (d) Proposed potentiostat flow developed by Bianchi et al., n.d. [24].

Figure 7

(a) Expanded view of the SenSARS portable device [86]. (b) PalmSens Sensit module used by Torres et al. (2021) [89]. (c) 3D rendering of the Bisense system [90].

Figure 8

Microfluidic system in a portable electrochemical sensor for virus detection.