Improvement of a selective modified electrochemical aptasensor using Amino-rGO/ Ionic Liquid/Mesoporous Silica Nanoparticle for the ultrasensitive detection of lysozyme protein

An aptamer-based method is described for electrochemical determination of lysozyme. A screen-printed electrode was modified with a nanocomposite composed of Amino-reduced graphene oxide (Amino-rGO), Ionic Liquid (IL) and Mesoporous Silica Nanoparticle (MSN). The composition of the nanocomposite (Amino-rGO/IL/MSN) warrants a high surface-to-volume ratio, high conductivity, high stability, and great electrocatalytic activity. This nanocomposite provides a suitable site for better immobilization of aptamers due to the existence of many amino groups. In addition, this nanocomposite allows considerable enhancement of the electrochemical signal and contributes to improving sensitivity. The amino-linked lysozyme aptamers were immobilized on the nanocomposite through covalent coupling between the amino groups of the aptamer and the amino groups of the nanocomposite using glutaraldehyde (GLA) linker. Using the obtained data from differential pulse voltammetry (DPV) and EIS techniques, two calibration curves were drawn. The anti-lysozyme aptasensor proposed has two very low LODs. These measures are 2.8 and 1.1 fmol L-1 within the wide detection ranges of 15 fmol L-1 to 10 nmol L-1, and 10 fmol L-1 to 100 nmol L-1 for DPV and (electrochemical impedance spectroscopy) EIS calibration curves, respectively