A sensitive electrochemical immunosensor for label-free detection of Zika-virus protein

Abstract

This work, as a proof of principle, presents a sensitive and selective electrochemical immunosensor for Zika-virus (ZIKV)-protein detection using a functionalized interdigitated micro-electrode of gold (IDE-Au) array. A miniaturized IDE-Au immunosensing chip was prepared via immobilization of ZIKV specific envelop protein antibody (Zev-Abs) onto dithiobis(succinimidyl propionate) i.e., (DTSP) functionalized IDE-Au (electrode gap/width of 10 µm). Electrochemical impedance spectroscopy (EIS) was performed to measure the electrical response of developed sensing chip as a function of ZIKV-protein concentrations. The results of EIS studies confirmed that sensing chip detected ZIKV-protein selectively and exhibited a detection range from 10 pM to 1 nM and a detection limit of 10 pM along with a high sensitivity of 12 kΩM^-1. Such developed ZIKV immune-sensing chip can be integrated with a miniaturized potentiostat (MP)-interfaced with a smartphone for rapid ZIKV-infection detection required for early stage diagnostics at point-of-care application.

Figure 1

(A) Necessity of a smart sensitive ZIKV biosensor in order to manage ZIKV diseases, (B) Illustration of IDE-Au based electrochemical ZIKV immunosensor.

Figure 2

(A) EIS response of IDE-Au electrode and its electronic circuit simulation, (B) EIS studies of (a) DTSP modified IDEs-Au, (b) ZVev-Abs immobilized DTSP/IDEs-Au electrode, (c) BSA immobilized ZVev-Abs/IDEs-Au immuno-electrode, and (d) change is electrochemical response of immuno-electrode on adding 50 pM ZIKV using 5 µL of 5 mM PBS containing 5 mM Fe(II)/Fe(III) as redox moieties (pH = 7.4) at 100 kHz.

Figure 3

(A) Electrochemical response studies of developed immuno-sensor as a function of known ZIKV concentrations (10 pM to 1 nM). (B) Selectivity evaluation of developed ZIKV immunosensor with reference to interferents (10 µL of 50 pM) such as dengue, chikungunya, and west nile virus proteins.

Figure 4

(A) Summary of IDE-Au based electrochemical ZIKV immunosensor characteristics in caparison of literature. (B) Roadmap of future plan in order to develop an electrochemical ZIKV immunosensor at POC application.