Preparation Of Highly Sensitive 3d Sers Substrate And Its Application For Biological Detection

The contamination of medical devices and human injury tissue caused by various bacteria has caused a series of medical problems.Quorum sensing(QS)occurs when bacteria infect tissues and medical devices and the final result of the bacterial contamination on the surface is the formation of biofilms,which in turn allow for the survival of the bacteria for an extended period by resisting both antibiotics and host immune response.It makes treatment very difficult and increases the lethality of bacterial infections.The bacteria need to secrete biological signal molecules to regulate QS.It is very important to detect biological signal molecules quickly and accurately.The surface enhanced Raman scattering(SERS)is a highly sensitive non-invasive detection method,which is very important for the detection of biological signal molecules with extremely low concentration.Therefore,it is of special significance to build the SERS substrate with high sensitivity.In this study,oligomeric ethylene glycol methyl acrylate(OEGMA)was used as monomer.The poly(oligo(ethylene glycol)methacrylate)POEGMA brushes was grafted from the substrate surface through atom transfer radical polymerization(ATRP).The Ag nanoparticles(AgNPs)were synthesized by seed growth method.Then,the silver nanoparticles were assembled on the polymer brush by immersion method to form the composite SERS substrate.Fourier transform infrared spectroscopy(FT-IR),ultraviolet-visible spectrophotometer(UV vis),field emission scanning electron microscope(FE-SEM),transmission electron microscope(TEM),Raman spectroscopy methods were used to characterize the size distribution of AgNPs,the condition of POEGMA brush on the surface and Raman enhancement effect of the substrate.Finally,pyocyanin(PCN),N-ethanoyl-homoserine lactone(C2-HSL),N-dodeanoyl-homoserine lactone(C12-HSL)signal molecules and pseudomonas aeruginosa were detected by highly sensitive SERS substrate.The results showed that we can produce highly sensitive SERS substrate and the SERS substrate can detect and identify PCN,C2-HSL,C12-HSL and the detection limit is 10-10M,10-8M and 10-8M respectively.Pseudomonas aeruginosa can be detected,the detection limit is 40 cfu/mL.