Enhanced Response of a Proteinase K-Based Conductometric Biosensor Using Nanoparticles

Abstract

Proteinases are involved in a multitude of important physiological processes, such as protein metabolism. For this reason, a conductometric enzyme biosensor based on proteinase K was developed using two types of nanoparticles (gold and magnetic). The enzyme was directly adsorbed on negatively charged nanoparticles and then deposited and cross-linked on a planar interdigitated electrode (IDE). The biosensor was characterized with bovine serum albumin (BSA) as a standard protein. Higher sensitivity was obtained using gold nanoparticles. The linear range for BSA determination was then from 0.5 to 10 mg/L with a maximum response of 154 μs. These results are greater than that found without any nanoparticles (maximum response of 10 μs). The limit of detection (LOD) was 0.3 mg/L. An inter-sensor reproducibility of 3.5% was obtained.

Thermolysin entrapped in a gold nanoparticles/polymer composite for direct and sensitive conductometric biosensing of ochratoxin A in olive oil

“…S3, full squares), confirming the positive effect of the conductive nano-objects on the conductometric signal, in agreement with previous results obtained in our group [69]. However, the substitution of (PVA/PEI) blend by BSA induced a significant loss of sensitivity (4.286 S/M instead of 597 S/M).…”