Performance enhancement of ZnO/Zn nanostructure biosensor via cold atmosphere plasma

Non-enzymatic glucose has been detected using highly sensitive ZnO/Zn nanostructures produced with the cold atmosphere plasma (CAP) technique. Electrochemical nanobiosensors use an electrode as a transducer and a biological element as a diagnostic component. This work presents an interesting and novel method for the surface modification of Zn foil using dielectric barrier discharge (Ar/O) plasma at different exposure times, which leads to the formation of a thin layer of ZnO. Many tests were performed to characterise and ensure the efficiency of the samples as biological sensors. The photoluminescence (PL) test for ZnO/Zn nanostructures showed a shift at the vertex, confirming the reaction in all PL spectra with a strong UV emission peak. High-resolution XPS spectra contained Zn 2p_1/2, Zn 2p_3/2 and O s₁ peaks. The Raman spectra contained two strong peaks, E₁ high at 77.5 nm and E₂ low at 522 nm, and one weak peak, A₁ Low at 1524.8 nm. Distributed nanosheets were observed using FE-SEM at an exposure time of 30 s with thickness ranging from 16.3 to 80.7 nm and nanoparticles of different sizes ranging from 31 to 259.3 nm at an exposure time of 60 s. The shape of the nanoparticles changed from nanoparticles to a form resembling brain fibrosis with diameters between 75.7 and 189.8 nm at 90 s. The sensing current of the ZnO/Zn nanostructure biosensors increased with plasma exposure times of 30, 60, and 90 s to 1.99, 2.3, and 2.9 mA respectively. The response time changed with plasma exposure time (0.82, 0.32, and 0.48 s), as did the correlation coefficient (\({R}^{2}\) = 0.8922, 0.9432, and 0.9476).

Graphical abstract