Ultrathin and nanostructured ZnO-based films for fluorescence biosensing applications

Abstract

a b s t r a c tThe fluorescence-based sensing capability of ultrathin ZnO-SiO 2 nanoplatforms, deposited by an integrated approach of colloidal lithography and metal organic chemical vapor deposition, has been investigated upon adsorption of fluorescein-labeled albumin, used as model analyte biomolecule. The protein immobilization process after spontaneous adsorption/desorption significantly enhances the green emission of the different ZnO-based films, as evidenced by scanning confocal microscopy, corresponding to a comparable protein coverage detected by X-ray photoelectron spectroscopy. Moreover, experiments of fluorescence recovery after photobleaching evidence that the protein lateral diffusion at the biointerface is affected by the chemical and/or topographical patterning of hybrid ZnO-SiO 2 surfaces. The used approach is very promising for biomolecular detection applications of these ZnO-SiO 2 nanoplatforms, by simple sizing of the 2D vs. 3D patterning design, which in turn is accomplished by the fine tuning of the integrated colloidal lithography-chemical vapor deposition processes.

The structure, morphology, and the metal-enhanced fluorescence of nano-Ag/ZnO core–shell structure

“…This result indicates that the ZnO shell was used to maintain a certain distance between the fluorescent molecule and the metal core, which caused the interaction between the surface plasmon and excitation light field to produce a FL emission enhancement. Furthermore, the ZnO shell layer also could enhance the FL emission of dye, which was caused by the change in photonic mode density and/or reduction in self-quenching of fluorophores for ZnO nanostructure (Satriano 2012). But the FL intensity of R6G mixed with Ag nanoparticle was only 13 % larger than that of the same amount of R6G solution, which might be due to the non-radiation energy transfer between dye molecular and the metal (Yang et al 2011).…”

ZnO for performance enhancement of surface plasmon resonance biosensor: a review

“…The physical and chemical properties of ZnO nanostructures changed as their size, shape and surface chemistry changed. An increased surface area of the ZnO at sensing region can enhance the sensitivity of the SPR sensor and provides a good platform for biomolecules immobilization due to its biocompatibility and biodegradability [51,109,110]. ZnO at nanoscale confers specific property that allows for signal enhancement [111].…”

Vibrational spectroscopy for probing molecular-level interactions in organic films mimicking biointerfaces

“…These include techniques to probe surface properties such as wetting and adhesion, methods to determine structure, e.g. X-ray [31][32][33] and neutron reflectivity [34][35][36][37], several types of microscopy and various spectroscopic methods [38][39][40][41][42][43]. For the purposes of this review paper, we shall concentrate on the vibrational spectroscopy methods, whose use will be exemplified for two types of systems associated with biointerfaces.…”