Controlling the Association of Metallic Nanoparticles with Polysaccharides for Use in Biomedical Theranostics

Metallic nanoparticles (NPs) exhibit a localized surface plasmon resonance (LSPR) that make them suitable for a variety of important applications, including their use as theranostic probes in biomedicine, and for dramatic signal enhancements in Raman and infrared spectroscopy. Improvements in the stability of NPs can be achieved through association with polysaccharides [1]. We have generated “bare” gold NPs using a two-step laser ablation process in Milli-Q water using a green pulsed laser, resulting in monodisperse NPs that are between 5 and 10 nm in diameter. We have chemically modified the NPs to strongly associate with the abundance of hydroxyl groups present on polysaccharides. For dispersions containing modified NPs and polysaccharides, we compared the NP LSPR measured using UV-Vis spectroscopy and the stability of the dispersions to that for dispersions containing bare NPs and the same polysaccharides. By controlling the association of NPs with polysaccharides to achieve improved dispersion stability, a key impediment to their use in biomedical theranostics can be removed.
[1] H. Huang and X. Yang, Carbohydr. Res. 339, 2627 (2004).