Nano-bio interface between As4S4 nanoparticles and albumin influenced by wet stirred media milling

Arsenic sulfide (As4S4) nanoparticles have been intensively researched as a promising drug in a cancer treatment. For the first time, the interaction between As4S4 and bovine serum albumin has been studied in this paper. Initially, the sorption kinetics of albumin on the surface of nanoparticles was investigated. Subsequently, its structural changes influenced by interaction with the As4S4 nanoparticles during wet stirred media milling were studied in deep. Both the dynamic and static quenching were detected after analyzing the fluorescence quenching spectra. From the synchronous fluorescence spectra it was investigated, that the fluorescence intensity for tyrosine residues decreased by about 55%, and for tryptophan it was about 80%. It indicates the fluorescence from tryptophan is more intense and gets more efficiently quenched than those from tyrosine residues in presence of As4S4, implying that the tryptophan can be closer to the binding site. From the circular dichroisms and FTIR spectra it was observed that conformation of the protein remains almost unchanged. The content of appropriate secondary structures was determined by deconvolution of the absorption peak attributed to the amide I band in FTIR spectra. The preliminary anti-tumor cytotoxic effect of prepared albumin-As4S4 system was also tested on multiple myeloma cell lines.