Fabrication of Ag@TiO2 electrospinning nanofibrous felts as SERS substrate for direct and sensitive bacterial detection

• Published in: Sensors and actuators. B, Chemical Chemical, 2018-11, Vol.273, p.600-609
• Main Authors: Yang, Yan, Zhang, Zhijie, He, Yali, Wang, Zhihua, Zhao, Yanbao, Sun, Lei
• Format: Article
• Language: English
• Subjects: Ag nanoparticles; Electrospinning; Microbiological detection; SERS substrates; TiO2 nanofibers
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2018.05.129

[Display omitted] •Ag@TiO2 nanofibrous felts were fabricated by electrospinning and in suit deposition.•As SERS substrate, it can detect microorganism directly without aptamer conjugation.•It also exhibit excellent antibacterial activities with a bacteriostasis rate of 99%. In order to develop a novel method for bacteria detection, Ag@TiO2 electrospinning Nanofibrous felts have been fabricated by in situ decoration of size tunable Ag nanoparticles on anatase TiO2 nanofibers. The morphologies and structures of the as-prepared Ag@TiO2 electrospinning nanofibrous felts were characterized by techniques of scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and X-ray diffraction. The result show that Ag NPs were uniformly deposited on the surfaces of TiO2 nanofibers, especially when the deposition time in Tollens’ reagent was 10 min. The free-standing composite nanofibrous felts processes superb performance of surface enhanced Raman scattering, which was demonstrated by small probe mecules of 4-mercaptobenzoic acid and 4-mercaptophenol, and the lowest detection limit was near to10−9 mol/L. More importantly, the as-fabricated Ag@TiO2 nanofibrous felts as SERS substrate can detect biomacromolecules such as bacteria of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) directly without previous bacteria-aptamer conjugation as the traditonal process. In addition, the composite nanofibrous felts also show outstanding antimicrobial activities against both Gram-negative of E. coli and Gram-positive of S. aureus, evaluated by method of absorption and microscopic observation. The results show that the bacteriostasis rate is reached to 99%, especially significant for E. coli. The free-standing, high porous, and flexible substrate of Ag@TiO2 electrospun nanofibrous membranes have potential application in versatile fields such as microorganism sensors and water purifier.