Quantum dot/glycol chitosan fluorescent nanoconjugates

In this study, novel carbohydrate-based nanoconjugates combining chemically modified chitosan with semiconductor quantum dots (QDs) were designed and synthesised via single-step aqueous route at room temperature. Glycol chitosan (G-CHI) was used as the capping ligand aiming to improve the water solubility of the nanoconjugates to produce stable and biocompatible colloidal systems. UV-visible (UV-vis) spectroscopy, photoluminescence (PL) spectroscopy, and Fourier transform infrared (FTIR) spectroscopy were used to characterise the synthesis and the relative stability of biopolymer-capped semiconductor nanocrystals. The results clearly demonstrated that the glycol chitosan derivative was remarkably effective at nucleating and stabilising semiconductor CdS quantum dots in aqueous suspensions under acidic, neutral, and alkaline media with an average size of approximately 2.5 nm and a fluorescent activity in the visible range of the spectra.