Application of Room Temperature Photoluminescence From ZnO Nanorods for Salmonella Detection

Abstract

Abstract-ZnO nano-rods grown by gaseous-disperse synthesis (GDS) are confirmed by XRD analysis to have the wurtzite crystal structure. The obtained crystallites, as found from SEM studies, are 57±9 nm in diameter and 470±30 nm long on the average. Two emission bands of photoluminescence from ZnO nano-rods observed at room temperature are centered at 376 nm and 520 nm. A bio-sensitive layer is prepared by immobilization of Anti-Salmonella antibodies (Ab) from liquid solutions on the ZnO surface. Immobilization of the bio-sensitive layer onto ZnO nano-rods is found to increase the intensity of PL. After further reaction with Salmonella antigens (Ag) the PL intensity is found to decrease proportional to antigen concentrations in the range of 1000 -1000000 cell/ml. The possible mechanism of biosensor response is suggested and discussed.

Optical biosensors based on ZnO nanostructures: advantages and perspectives. A review

“…It is known, that ZnO has high value of isoelectric point (pH~9.1) [34,35,43,62,[66][67][68][69][74][75][76][77] which makes ZnO nanostructures attractive for immobilization of biomolecules on its surface. It is important to note that the morphology and the structure properties of ZnO play important role in the process of immobilization.…”

“…The intensity of PL signal from ZnO nanorods (57 ± 9 nm in diameter and 470 ± 30 nm long) was used to detect sallmonella spp antigens by Viter et al [62]. Two emission bands of PL from ZnO nanorods observed at room temperature are centered at 376 and 520 nm.…”

“…Considering PL based biosensors, it is worth noting that the quenching of PL signal after target adsorption is being observed [62,68,[74][75][76][77]. The mechanism of PL quenching may be due to several reasons.…”

“…It is known, that ZnO nanostructures can be formed using different techniques [62,67,89,90]. Among these methods, Atomic layer deposition and hydrothermal growth allow depositing ZnO nanostructues at low temperatures [66,89,92] simplifying the actual problem of miniaturization and integration with testing systems.…”

“…There were proposed several possible mechanisms of interaction: charge transfer [34], resonance energy transfer [53], hydrophobic and electrostatic interaction [32,39,60,62].…”