Font Size: a A A

Fabrication Of3D Biomimetic SERS Substrate For Label-free Animal Viruses Detection

Posted on:2015-01-02Degree:MasterType:Thesis
Country:ChinaCandidate:F ShaoFull Text:PDF
GTID:2251330428465727Subject:Applied Chemistry
Abstract/Summary:PDF Full Text Request
Surface-enhanced Raman scattering (SERS) spectroscopy is one of the most powerful analytical techniques and has been widely used in biomedicine, molecular recognition, trace analysis and materials research, owing to its numerous unique merits including sharp bandwidth, high sensitivity, anti-photobleaching as well as the ability of in-situ and noninvasive analysis. Fabrication of low-cost and high-performance SERS substrates is the one of keys to promoting the further developments of SERS techniques, as well as applying them in the analysis of practical samples. This thesis is devoted to developing new avenues for simply and large-scale fabricating three-dimensional (3D) biomimetic SERS substrates with high sensitivity, high reproducibility and good stability, and applying it in label-free animal viruses detection. Main researches and the results as follows:(1) A novel3D SERS biomimetic substrates was fabricated by intermittent ion sputtering in different dimensions of naturally occurring chitin nanopillar arrays (CNAs) to form multiple sub-10nm nanogaps based on cicada wings. We elaborately created and regulated hierarchical nanostructures on the CNAs with four types nano-gaps to produce high density of hot spot, also analyzed the reasons and causes of its formation. Experimental results suggested that we developed a straightforward, cost-effective method to large-scale prepare high-performance3D biomimetic SERS substrates. By the proposed approach, the3D biomimetic SERS substrates combined high sensitivity (R6G,10-13M), good point-to-point reproducibility (comparable to Klarite chip) and sub stare-to-substrate reproducibility (RSD=5.4%), as well as excellent stability.(2) By controlling ion sputtering, we also conveniently fabricated two-dimensional (2D) Au-capped and2D Ag-capped CNAs for acting as SERS-active substrates and mading comparation with3D biomimetic SERS substrates. Results indicated that enhancement effect of substrates was related to both characters of modified metal and nanostructures on the substrates. The electric field distributions calculated by finite different time domain (FDTD) shown that high density hotspots reside in3D biomimetic SERS substrates. We also calculated the contribution of electromagnetic enhancement and the average enhancement factor. Significantly, when the785nm laser was employed, the largest average EF=5.8×1O7from3D biomimetic SERS substrates was observed, which is a factor of approximately12,16and34times higher, respectively, than that from2D Ag-capped CNAs,2D Au-capped CNAs and Klarite substrate. Accordingly,3D Ag-decorated CNAs (3D biomimetic substrate) could serve as one feasible platform for biosensing.(3) The novel SERS substrates were applied in the label-free detection and differentiation of animal viruses including porcine circovirus type2(PCV2), porcine pseudorabies virus (PRV) and avian influenza virus (AVI) subtype H5N1. A high degree of reproducibility have observed in the spectra of individual virus obtained on the3D biomimetic substrate, that indicated the high sensitivity and reproducibility of these substrates. Results indicated that several typical characteristic bands of PCV2SERS spectra as low as1×103PFU/mL were readily detectable on the3D biomimetic substrate, a detection limit about two orders of magnitude lower than that obtained from Klarite substrate. And also the results manifest that the3D biomimetic substrates have the huge potential to make a promising candidate for creating low-cost, rapid and accurate pathogen monitoring platform.
Keywords/Search Tags:surface-enhanced Raman scattering, 3D SERS substrate, cicada wings, biomimetic, hot spot, enhancement factor, label-free detection, animalviruses
PDF Full Text Request
Related items