Fabrication of Ag modified SiO2 electrospun nanofibrous membranes as ultrasensitive and high stable SERS substrates for multiple analytes detection

Surface-enhanced Raman spectroscopy (SERS) is a powerful analytical tool, but how to obtain effective and versatile SERS substrates is still a challenge. Herein, a simple and efficient strategy to prepare SERS substrates with ultra-sensitivity, high stability and wide applicability is presented. SiO 2 nanofibrous membranes were prepared by electrospinning and calcination , and modified with Ag nanoparticles . The results show that Ag nanoparticles decorated on SiO 2 nanofibers evenly and tightly through chemical bonding. The as-prepared membranes exhibit high flexibility and thermostability. The electrospun nanofibrous membranes show an ultra-high sensitivity of 10 −11  mol/L (an enhancement factor of 10 7 ) for small molecules, and the lowest detection limit near to 10 −8  mol/L for pesticides thiram . It is also demonstrated that the substrates remain excellent SERS signal stability even after standing for 60 days (intensity decrease only for 21.7%). More importantly, the as-prepared substrates can be performed for quantitative detection of bacteria.