Synthesis and Surface Modification of Nanostructured F-Doped ZnO: Toward a Transducer for Label-Free Optical Biosensing

Giovanna Chianese,Rosalba Moretta,Ilaria Rea,Chiara Schiattarella,Luca De Stefano,Monica Terracciano,Antonio Aronne,Giuseppe Vitiello,Paolo Cappiello

doi:10.3390/app9163380

Abstract

In this work, the surface of nanostructured fluorine-doped ZnO (nZnO·F) is functionalized with protein A (PrA), and used as a model biomolecule. The chemical procedure is characterized by several analytical techniques such as Fourier Transform Infrared Spectroscopy, water contact angle analysis, and fluorescence microscopy. The surface modification of nZnO·F by binding increasing concentrations of PrA is also investigated by two label-free optical techniques, i.e., the spectroscopic reflectometry and the steady-state photoluminescence. The results are compared with those obtained using undoped nZnO substrates in order to highlight the better performances of nZnO·F due to the fluorine doping. The results of this study pave the way for the design and realization of a ZnO-based nanostructured platform for label-free optical sensing.

Highlights

A biosensor is an analytical device constituted by a biological recognition element, generally defined as a probe immobilized on a transduction system, which converts a molecular interaction into a useful signal
NZnO·F was synthesized on a silicon substrate by a hydrothermal process performed
NZnO·F was synthesized on a silicon substrate by a hydrothermal process in presence of ammonium hydrogen fluoride

Summary

Introduction

A biosensor is an analytical device constituted by a biological recognition element, generally defined as a probe immobilized on a transduction system, which converts a molecular interaction into a useful signal. There are several types of biosensors based on different sensing recognition mechanisms such as amperometric, electrochemical, optical, and thermometric. The interaction between the biomolecular probe, bound on its surface, and the target analyte is transduced in a change of an optical signal (e.g., phase, intensity, color, and fluorescence) [1,2,3]. On the other hand, nanostructured metal oxides showed great potential for the detection of biomolecules, owing to several characteristics such as the controllable size/shape, large specific surface area, biocompatibility, catalytic and optical properties, and chemical stability [9]. Among them, nanostructured zinc oxide (nZnO) is considered an interesting transducer material due to its multifunctional characteristics

Methods

Discussion

Conclusion