Gold, Gold-silver Alloy Nanoparticle-functionalized PMMA Nanofibers for Ultrasensitive SERS-based Detection of Nile Blue and Malachite Green

Abstract Flexile SERS substrates accompany distinct advantages for real-time detection, not only because of their high porosity, but also their ability to adapt to irregular surfaces and withstand bending or movement, making them ideal for practical, on-the-go sensing applications. The present work includes the fabrication of flexible substrates by combining electro-spun PMMA polymer nanofibers with femtosecond pulse laser ablated pure Gold (Au) and bimetallic (Au-Ag) NPs. Hydrophobic PMMA fibers were functionalised by drop casting plasmonic-active Au and Au-Ag NPs for surface-enhanced Raman scattering/spectroscopy (SERS) studies. A micro-Raman spectrometer (M/s Horiba) was used for the SERS data acquisition for two dye molecules, Nile blue (NB) and malachite green (MG). Au-loaded PMMA fibers detected up to 50 nM concentration of Nile blue and 200 nM concentration of MG, and also demonstrated a good reproducibility with R² values of 9.59% and 10.77% for NB (5 µM) and MG (5 µM), respectively. Similarly, PMMA-Au-Ag substrates detected NB with 10 nM concentration and Mg with 100 nM concentration as the lowest detection and showed reproducibility of 12.63% and 14.63% for NB (5 µM) and MG (5 µM), respectively.