Studies of the interaction of CS@ZnS:Mn with bovine serum albumin under illumination

Abstract In this study, chitosan coated Mn-doped ZnS quantum dots (CS@ZnS:Mn D-dots) were obtained in aqueous media under ambient pressure. The interaction and illumination damages of CS@ZnS:Mn D-dots with bovine serum albumin (BSA) were studied by means of ultraviolet–visible (UV–vis) and fluorescence (FL) spectra. It was found that the FL of BSA was quenched by CS@ZnS:Mn D-dots. The dominating quenching mechanism of CS@ZnS:Mn D-dots with BSA belongs to dynamic quenching. Hydrophobic interaction plays a major role in the CS@ZnS:Mn–BSA interaction; binding processes are spontaneous. Influencing factors such as illumination time and CS@ZnS:Mn D-dots concentrations were considered. The FL quenching effect of BSA by CS@ZnS:Mn D-dots is enhanced with the increase of illumination time and CS@ZnS:Mn D-dots concentration. The FL enhancement of CS@ZnS:Mn D-dots by BSA under UV illumination was also observed. It was proved that, the interaction of CS@ZnS:Mn D-dots with BSA under UV illumination is mainly a result of a photo-induced free radical procedure. CS@ZnS:Mn D-dots may be used as photosensitizers in photodynamic therapy.