Novel Dipstick model for Portable Bio-sensing Application

Abstract

In this work, we propose a novel bio-chip functionalized with hybrid nanomaterials which can provide a platform with a potential of dipstick biosensor. A ZnO-Au nanocomposite layer has been fabricated and utilized to perform FRET-based detection of E. coli DH5a. In solution form, FRET is always compromised due to the presence of a water-based solution and associated quenching effects. But when the FRET is carried out over films of nanoporous silica with embedded nanomaterials as synthesized in this work, there is an overall signal enhancement leading to an increase in sensitivity of the detection process. The signal enhancement is primarily due to the change in band gap energy of ZnO owing to doping through a gold layer which in turn leads to tune gap of the composite to the emission range of dye pairs. The sensitivity enhancement eventually is found to happen due to the electron cascading on gold film due to a changed band gap of the Zinc Oxide and a parallel ongoing surface-enhanced Raman scattering effect on thin gold coating causing an increased emission intensity by a few nanometres. This results in an overall enhanced signal and can lead to the detection of trace sample concentrations of microorganisms. In this way, the proposed technology can be used as an easy to use dipstick bio-sensor for microorganisms