Synthesis of mesoporous-silica coated multi-branched gold nanoparticles for surface enhanced Raman scattering evaluation of 4-bromomethcathinone

Abstract

Mesoporous silica-coated multi-branched gold nanoparticles (bAu@mesoSiO2) aiming for enhanced Raman sensing for 4-bromomethcathinone (4-BMC) detection is reported. In this work, we present an effective strategy to probe the Raman signal of 4-MBC. Morphologies and optical properties of the synthesized materials with different [Au3+]/[Au0] ratios are characterized utilizing transmission electron microscopy (TEM), UV–vis and mid-infrared spectroscopy. Both experimental and theoretical (simulation) studies were investigated. Taking advantages of gold core branches that provide highly localized and strongly enhanced electromagnetic fields due to plasmon resonance, surface-enhanced Raman scattering (SERS) is observed. The experimental results show that the SERS intensity exhibits a 100-fold increase with the increased average length and quantity of gold branches (nano tips). The analytical performance yielded a detection limit of 0.1 mg/ml for the 4-MBC target within 5 mins. The sensing method will likely find further improvement and broad use in the forensic science. Besides rapid detection and portability, the combination of the Raman effect and enhanced materials imparts other notable advantages, such as its non-contact and free of reagents. Keywords: Multi-branched gold nanoparticles, SERS, Spectroscopy, 4-Bromomethcathinone, Rapid detection