Synthesis of one-dimensional gold nanostructures and the electrochemical application of the nanohybrid containing functionalized graphene oxide for cholesterol biosensing

• Published in: Bioelectrochemistry (Amsterdam, Netherlands) Netherlands), 2016-08, Vol.110, p.79-90
• Main Authors: Nandini, Seetharamaiah, Nalini, Seetharamaiah, Reddy, M.B. Madhusudana, Suresh, Gurukar Shivappa, Melo, Jose Savio, Niranjana, Pathappa, Sanetuntikul, Jakkid, Shanmugam, Sangaraju
• Format: Article
• Language: English
• Subjects: Biosensing Techniques - methods; Chemistry Techniques, Synthetic; Cholesterol; Cholesterol - analysis; Cholesterol Oxidase - chemistry; Cholesterol Oxidase - metabolism; Electrochemical biosensor; Electrochemistry; Electrodes; Ferricyanides - chemistry; Functionalized graphene oxide; Gold - chemistry; Gold nanostrucutres; Graphite - chemistry; Hydrogen-Ion Concentration; Metal Nanoparticles - chemistry; Nanotechnology; Oxides - chemistry; Peptide nanotubes; Temperature; β-diphenylalanine
• ISSN: 1567-5394; 1878-562X
• DOI: 10.1016/j.bioelechem.2016.03.006

This manuscript reports a new approach for the synthesis of one dimensional gold nanostructure (AuNs) and its application in the development of cholesterol biosensor. Au nanostructures have been synthesized by exploiting β-diphenylalanine (β-FF) as an sacrificial template, whereas the Au nanoparticles (AuNPs) were synthesized by ultrasound irradiation. X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy dispersive analysis of X-rays (EDAX) have been employed to characterize the morphology and composition of the prepared samples. With the aim to develop a highly sensitive cholesterol biosensor, cholesterol oxidase (ChOx) was immobilized on AuNs which were appended on the graphite (Gr) electrode via chemisorption onto thiol-functionalized graphene oxide (GO-SH). This Gr/GO-SH/AuNs/ChOx biosensor has been characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy and chronoamperometry. CV results indicated a direct electron transfer between the enzyme and the electrode surface. A new potentiostat intermitant titration technique (PITT) has been studied to determine the diffusion coefficient and maxima potential value. The proposed biosensor showed rapid response, high sensitivity, wide linear range and low detection limit. Furthermore, our AuNs modified electrode showed excellent selectivity, repeatability, reproducibility and long term stability. The proposed electrode has also been used successfully to determine cholesterol in serum samples. [Display omitted] •The present work has employed a new template (β-FFNTs) for the synthesis of AuNs.•AuNs was chemisorbed on GO-SH for the fabrication of cholesterol biosensor.•The nanohybrid composite offers enhanced enzyme loading and high sensitivity.•The biosensor shows rapid response time, high sensitivity and low detection limit.•The proposed biosensor has excellent repeatability, reproducibility and stability.