Electrochemical Biosensor with Enhanced Antifouling Capability for COVID-19 Nucleic Acid Detection in Complex Biological Media

Abstract

Biofouling caused by the accumulation of biomolecules on sensing surfaces is one of the major problems and challenges to realize the practical application of electrochemical biosensors, and an effective way to counter this problem is the construction of antifouling biosensors. Herein, an antifouling electrochemical biosensor was constructed based on electropolymerized polyaniline (PANI) nanowires and newly designed peptides for the detection of the COVID-19 N-gene. The inverted Y-shaped peptides were designed with excellent antifouling properties and two anchoring branches, and their antifouling performances against proteins and complex biological media were investigated using different approaches. Based on the biotin–streptavidin affinity system, biotin-labeled probes specific to the N-gene (nucleocapsid phosphoprotein) of COVID-19 were immobilized onto the peptide-coated PANI nanowires, forming a highly sensitive and antifouling electrochemical sensing interface for the detection of COVID-19 nucleic acid. The antifouling genosensor demonstrated a wide linear range (10 –14 to 10 –9 M) and an exceptional low detection limit (3.5 fM). The remarkable performance of the genosensor derives from the high peak current of PANI, which is chosen as the sensing signal, and the extraordinary antifouling properties of designed peptides, which guarantee accurate detection in complex systems. These crucial features represent essential elements for future rapid and decentralized clinical testing.

Enzyme Immobilization on Gold Nanoparticles for Electrochemical Glucose Biosensors

“…The multianalyte detection of glucose, lactose, fructose, cortisol, dopamine, vitamin C or paracetamol, and more, will be expanded [ 76 ]. We believe that the development of protective biofouling materials [ 77 ], as well as the minimization of sensors and wearable technology [ 78 ], will receive great attention. The huge number of articles as well as projects concerning sensors, among others glucose biosensors, lead us to the conclusion that they will become an integral part of human life.…”

Electrochemical sensors for the detection of SARS-CoV-2 virus

“…This method was very effective to detect pharmacological inhibitors against SARS-CoV-2ACE2 binding. Alternatively, Song et al, [39] fabricated electrochemically polymerized polyaniline (PANI) nanowires onto glassy carbon electrode (GCE) to immobilize the newly designed peptides for the detection of SARS-CoV-2 N-gene, where the inverted Y-peptides have antifouling properties and two anchoring branches. The antifouling performance against the complex biological media and protein was examined via different approaches.…”

“…The key challenges in sensor development are specificity or selectivity of the sensor. Therefore, to enhance selectivity of the sensor, different types of nanomaterials have been used to fabricate novel sensors such as gold-based thin-film, gold nanoparticles, graphene oxide, reduced graphene oxide, cobalt-functionalized TiO 2 nanotubes, palladium nano-thin film, poly-aniline, activated graphene oxide, and Au nanostars [19] , [24] , [37] , [38] , [39] , [40] , [41] .…”

“…For instance, some protective layer or barrier on the electrode substrate can be used to prevent electrode fouling, but they are inappropriate for the system where the target analytes themselves behave as a fouling agent. In such situations, other approaches such as surface modification and electrochemical activation can be more effective [39] , [46] , [47] , [48] , [49] .…”

The Role of Peptides in the Design of Electrochemical Biosensors for Clinical Diagnostics

“…An inverted Y-shaped peptide was recently used for COVID-19 nucleic acid electrochemical detection in complex biological media [51]. The peptide consists of one antifouling main chain (KEPPPPKEKEKEKEK-biotin) in the upper part, in which the four proline residues (PPPP) assist in the formation of a stable secondary structure, and two anchorantifouling side chains (CKEKEKEKE) in the lower part.…”