Novel plasmonic Z‐scheme-based photocatalysts and electrochemical aptasensor for the degradation and determination of epirubicin

Abstract

A novel type of aptasensor and Z-scheme-based photocatalyst was fabricated and used for photodegradation as well as estimation of epirubicin (EP) using the nanocomposite of carbon nano-onion (CNO), flower-like MoS2, and dendritic Ag. We have developed a new type of sensor design having the ability to detect and differentiate between various molecules with greater sensitivity and accuracy than the existing sensors. The biosensor based on aptamer immobilization on a screen-printed carbon electrode was modified with CNO/MoS2/Ag dendrites nanocomposite synthesized by hydrothermal and co-precipitation methods. Materials were fully characterized by FE-SEM, TEM, XRD, DRS, and XPS. Cyclic voltammetry (CV) and electrochemical impedance spectroscopic (EIS) studies were performed in 1 mM K3[Fe(CN)6]/K4[Fe(CN)6] for a quantitative assessment of EP in terms of charge transfer resistance (Rct) changes. The difference in Rct increased linearly with increasing EP concentration from 0.1− 500 nM with a detection limit of 0.03 nM. For achieving better response, aptamer concentration, incubation time, and modifier content were optimized, and the measurement of EP in real samples was also performed. The photocatalytic degradation of EP was investigated using CNO/MoS2/Ag dendrites with a band gap of 1.7 eV to show that superoxide anion and hydroxide radicals significantly affected the degradation of EP during 50 min, and 99.50 % of EP was degraded.