半导体纳米粒子SERS基底对大肠杆菌的无损检测研究

很多致命的疾病都与细菌感染密切相关,快速、准确地检测和鉴定细菌及微生物,一直是微生物学家及有关科研工作者追求的目标,拉曼光谱可以提供丰富的谱图信息,而表面增强拉曼光谱(SERS)有很高的检测灵敏度,然而一些贵金属SERS基底却容易使蛋白质变性,影响检测结果。以大肠杆菌(E.Coli)作为目标检测细菌,首先检测到大肠杆菌的拉曼光谱,之后采用两种不同的SERS基底(ZnO,Ag溶胶)进行检测。结果表明Ag溶胶基底有很强且较丰富的SERS信号,但是相对于E.Coli的本体拉曼谱峰有较大位移,说明与银溶胶相互作用的细菌存在一定的蛋白质变性过程;而ZnO纳米粒子与细菌作用的SERS信号虽然较弱,但是与E.Coli的本体拉曼信号较为相似,说明ZnO纳米粒子对E.Coli本体基本无损,这将有利于SERS在生物体系的无损检测。该结果可以为利用生物相容性好的半导体SERS基底进行细菌的检测提供有益的参考。

Non-Destructive Detection of Escherichia Coli Based on the SERSSubstrate of Semiconductor Nanoparticles

Most of diseases are closely related to bactrerial infection while the fast and accurate detection of bacteria is always a focus subject which has attracted great attention by microbiologists and other relevant researchers.Raman spectroscopy can provide rich spectrum information,and surface-enhanced Raman Spectroscopy (SERS) has a high detection sensitivity,however,some of the noble metal SERS substrate will cause protein denaturation,which obtained the incorrect results.In this work,it is shown that Escherichia coli (E.Coli) can be detected by the SERS technique by using semiconductor nanoparticles as the substrate.The SERS spectrum of the E.Coli on the ZnO nanoparticle substrate with that on the Ag sol substrate was compared.The results indicated that stronger and richer SERS signals were observed on the Ag sol substrate compared with that on the ZnO substrate.However,an obvious difference was obtained between SERS spectrum of E.Coli on the Ag sol substrate and the Raman spectrum of bulk E.Coli,which could be due to the protein denaturation process.On the other hand,although the SERS signal of the E.Coli on the ZnO nanoparticles substrate is relatively weak,the signal is similar with that of the Raman spectrum of the bukl E.Coli,indicating that ZnO nanoparticles is an efficient and biocompatible SERS substrate for the detection of E.Coli.This study provides the important information for the non-destructive detection of bacteria by SERS technique based on the semiconductor nanoparticles substrate.