Multienzymatic Cholesterol Nanobiosensor Using Core–Shell Nanoparticles Incorporated Silica Nanocomposite

The silica sol–gel matrix was prepared with tetraethyl orthosilicate as a precursor by sol–gel method besides functionalized with bovine serum albumin to minimize cracking and to stabilize enzymes for biosensing. Core–shell Fe3O4@C@Ag NPs are prepared using a facile method and applied to enhance electron transfer between enzymes and electrode surface. The Fe3O4 NPs prepared by modifying co-precipitation method; subsequently depositing carbon and silver on Fe3O4 NPs core by the facile green approach. Fe3O4@C@Ag NPs and silica/Fe3O4@C@Ag nanocomposite have been characterized by Fourier Transform Infra-Red spectroscopy, UV–visible spectroscopy, and X-ray diffraction technique. The surface topographies of the nanomaterials were investigated by Scanning electron microscopy and Transmission electron microscopy. Cyclic voltammetry employed to study the electrochemical behavior of nanobiosensor. The sensitivity of modified electrode is 0.0346 µAmM−1cm−1 with detection limit 0.5 mM. The high sensitivity of the biosensor is attributed to the large surface area of Fe3O4@C@Ag NPs for effective loading of HRP besides its high electron communication capability with the aid of enhanced selectivity and anti-interference ability due to the silica sol–gel matrix immobilized with ChOx.