Studies on interaction and illumination damage of CS-Fe3O4-ZnS:Mn to bovine serum albumin

In this study, the interaction of chitosan (CS) coated CS-Fe3O4-ZnS:Mn magnetic-fluorescent nanoparticles (MFNPs) with bovine serum albumin (BSA) was studied by means of ultraviolet–visible and fluorescence spectra; evidences for the damage of BSA molecule in the presence of CS-Fe3O4-ZnS:Mn MFNPs under UV illumination were also obtained. The results show that the dominating fluorescence quenching mechanism of CS-Fe3O4-ZnS:Mn MFNPs with BSA belongs to static quenching. Fluorescence resonance energy transfer (FRET) occurred from BSA to CS-Fe3O4-ZnS:Mn MFNPs. The thermodynamic parameters indicated that electrostatic interaction play major roles in CS-Fe3O4-ZnS:Mn-BSA, while binding processes exist spontaneously. In addition, the damage of CS-Fe3O4-ZnS:Mn MFNPs to BSA molecule under UV illumination was studied under various experimental parameters. It was proved that: the damage of BSA is prone to happen in the presence of CS-Fe3O4-ZnS:Mn MFNPs under UV illumination, there is synergic effect of oxygen and UV illumination on the damage of BSA, and the fluorescence quenching of BSA by CS-Fe3O4-ZnS:Mn MFNPs under UV illumination is mainly a result of a photo-induced free radical procedure.