SERS Biosensor Using Metallic Nano‐Sculptured Thin Films for the Detection of Endocrine Disrupting Compound Biomarker Vitellogenin

Abstract

A biosensor chip is developed for the detection of a protein biomarker of endocrine disrupting compounds, vitellogenin (Vg) in aquatic environment. The sensor chip is fabricated by immobilizing anti-Vg antibody on 4-Aminothiophenol (4-ATP) coated nanosculptured thin films (nSTFs) of silver on Si substrates. The biosensor is based on the SERS of 4-ATP, enhanced by the Ag nSTFs. Before the fabrication of the sensor, the performance of the enhancement is optimized with respect to the porosity of nSTFs. Further, the biosensor is developed on the nSTF with optimized enhancement. The SERS signals are recorded from the sensor chip for varying concentrations of Vg. A control experiment is performed on another similar protein Fetuin to confirm the specificity of the sensor. The repeatability and reusability of the sensor, along with its shelf life are also checked. The limit of detection of the sensor is found to be 5 pg mL −1 of Vg in PBS within our experimental window. Apart from high sensitivity, specificity and reusability, the present sensor provides additional advantages of miniaturization, requirement of very small volumes of the analyte solution (15 μL) and fast response as compared to conventional techniques e.g., ELISA, as its response time is less than 3 minutes.

Plasmonic Sensing Using Metallic Nano‐Sculptured Thin Films

“…Above the percolation threshold the plamons excited become localized causing the electromagnetic field enhancement. Recently we have found that actually 30% porosity is also about the optimum for SERS enahncement and the results will be published shortly …”

“…Recently we have found that actually 30% porosity is also about the optimum for SERS enahncement and the results will be published shortly. [ 60 ] Another interesting morphological effect is when zigzag type nSTF morphology is used. Zhou et al [ 61 ] have shown that investigated by Song et al [ 59 ] as shown in Figure 14 showing that only above certain deposition angle (∼85 o ) the enhancement starts.…”

Controlled positioning of analytes and cells on a plasmonic platform for glycan sensing using surface enhanced Raman spectroscopy

“…27,28 Antibody functionalization of SERS substrates to detect biomarkers of endocrine disrupting compounds was also described. 29 Furthermore, simultaneous detection and quantification of bacterial pathogens and enzymatic processes such as histone demethylase activity have been probed using SERS-based assays. 30,31 However, using such platforms, significant challenges are still encountered in the study of biological processes, such as intracellular sensing, 32 chemical exchanges between cells or responses of cells to endogenous or exogenous stimuli.…”

A Rapid and Label‐free SERS Detection Method for Biomarkers in Clinical Biofluids

“…A potential solution is to couple a SERS reporter anchored onto a planar substrate with the biomolecule capture receptor so that the analyte recognition event is revealed by spectral changes in the reporter SERS signal. Such a change can arise from re‐orientation of the label with respect to the plasmonic surface (i.e., surface selection rules) or deformation of its molecular structure (rearrangement of the electronic cloud) . The use of a planar substrate also overcomes the problem of nanoparticle aggregation with samples of high ionic strength.…”

“…Such a change can arise from re-orientation of the label with respect to the plasmonic surface (i.e., surface selection rules) or deformation of its molecular structure (rearrangement of the electronic cloud). [23][24][25][26][27] The use of a planar substrate also overcomes the problem of nanoparticle aggregation with samples of high ionic strength. A suitable planar substrate for this purpose is bimetallic fi lm over nanosphere (BMFON), [ 28 ] a stable, highly cost-effective and easy to fabricate, SERSactive substrate that we have recently developed.…”