Functionalized Plasmonic Nanoparticles: Synthesis, Surface Engineering and Emerging Biomedical Applications

Résumé

Functionalized plasmonic nanoparticles have attracted significant attention in biomedical research due to their unique optical properties, high surface reactivity, and versatile surface chemistry. In this study, gold nanoparticles (AuNPs) were synthesized via the Turkevich citrate reduction method and subsequently functionalized using (3-glycidyloxypropyl) trimethoxysilane (GPTMS) to enhance their stability and surface reactivity. The synthesized and functionalized nanoparticles were comprehensively characterized using multiple analytical techniques. Morphological features and particle size distribution were investigated by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), while elemental composition was confirmed by energy-dispersive X-ray spectroscopy (EDS). The crystalline structure was analysed using X-ray diffraction (XRD), and the average crystallite size was estimated using the Scherrer equation. Fourier-transform infrared spectroscopy (FTIR) was employed to identify surface functional groups and confirm successful GPTMS functionalization. Additionally, UV–Vis spectrophotometry was used to evaluate the optical properties of the nanoparticles and to assess their localized surface plasmon resonance (LSPR) behavior. The results demonstrate that the functionalized AuNPs exhibit stable colloidal properties, controlled morphology, and modified optical responses due to surface engineering. The presence of additional absorption features in the UV region highlights the influence of GPTMS on the interfacial environment of the nanoparticles. The obtained results underscore the potential of GPTMSfunctionalized gold nanoparticles for applications in nanomedicine, including biosensing, drug delivery, and optical bioimaging.