Antifouling Strategies for Electrochemical Biosensing: Mechanisms and Performance toward Point of Care Based Diagnostic Applications

Abstract

Although there exist numerous established laboratory-based technologies for sample diagnostics and analyte detection, many medical and forensic science applications require point of care based platforms for rapid on-the-spot sample analysis. Electrochemical biosensors provide a promising avenue for such applications due to the portability and functional simplicity of the technology. However, the ability to develop such platforms with the high sensitivity and selectivity required for analysis of low analyte concentrations in complex biological samples remains a paramount issue in the field of biosensing. Nonspecific adsorption, or fouling, at the electrode interface via the innumerable biomolecules present in these sample types (i.e., serum, urine, blood/plasma, and saliva) can drastically obstruct electrochemical performance, increasing background "noise" and diminishing both the electrochemical signal magnitude and specificity of the biosensor. Consequently, this review aims to discuss strategies and concepts used throughout the literature to prevent electrode surface fouling in biosensors and to communicate the nature of the antifouling mechanisms by which they operate. Evaluation of each antifouling strategy is focused primarily on the fabrication method, experimental technique, sample composition, and electrochemical performance of each technology highlighting the overall feasibility of the platform for point of care based diagnostic/detection applications.

Advances in Nanomaterials-Based Electrochemical Biosensors for Foodborne Pathogen Detection

“…Surface chemistry is used to immobilize recognition elements onto the working electrode and to prevent a background signal [11]. To eliminate the matrix effect, common strategies involve electrode functionalization using specific surface chemistry and additional electrode covering with poly(ethylene glycol) (PEG) or oligo(ethylene glycol) (OEG) layers that effectively passivate the electrode [12]. Usually, immobilization of biomolecules is performed via amine-, carboxyl-, aldehyde-and thiolconjugation, depending on the chemical reactivity of the electrode material and its modifications.…”

Zwitterionic Polymer Electroplating Facilitates the Preparation of Electrode Surfaces for Biosensing

“…An alternative workaround is to surface‐treat electrodes with nonfouling polymers. [ 9 ] A list of organic polymers are available to minimize nonspecific molecular adsorption, including poly(ethylene glycol) and its derivatives, [ 10 ] polyamides, polyurethanes, and naturally occurring polysaccharides such as dextran or chitosan. [ 11 ] For biosensing applications, however, polymers need to meet other requirements: they should not impede electrochemical measurements, and the deposition process should be controllable for reproducibility.…”

A Micro Electrochemical Sensor for Multi-Analyte Detection Based on Oxygenated Graphene Modified Screen-Printed Electrode

“…In addition, voltammetry demonstrates high selectivity and thus could be used for multi-analyte measurements. Many chemical and physical strategies have been reported to alleviate the biofouling issues, including nanoengineered surfaces (i.e., nanoporous metals and nanocarbons), antifouling layers (PEG, zwitterionic polymers, and biopolymers), nanoporous membranes, and hydrogels [4]. For example, a nanoporous gold (NPG) electrode derived from the dealloying of a silver-gold alloy was recently employed as an antibiofouling electrode for the simultaneous determination of AA and UA [5].…”