Investigation on Sonocatalytic Damage to Bovine Serum Albumin (BSA) Under Ultrasonic Irradiation in the Presence of Fe(III)–Citrate Complexes

The interaction of bovine serum albumin (BSA) with Fe(III)–citrate complexes ([FeIII(cit)(H2O)3]− and [FeIII(cit)2]5−) and the sonocatalytic damage of BSA under ultrasonic irradiation were studied. Additionally, the various factors influencing the sonocatalytic damage of BSA were also studied by means of UV–Vis and fluorescence spectra. The experimental results indicate that the probable fluorescence quenching mechanisms of BSA by Fe(III)–citrate complexes ([FeIII(cit)(H2O)3]− and [FeIII(cit)2]5−) are both static quenching. Under certain conditions, the degree of damage to BSA is aggravated with increases of ultrasonic irradiation time, Fe(III)–citrate complex concentration, pH value and ionic strength. Moreover, all of the results demonstrate that [FeIII(cit)2]5− displays higher sonocatalytic activity than [FeIII(cit)(H2O)3]− under the same experimental conditions during the damage process of BSA. Finally, the generation of ·O2 − and ·OH during sonocatalytic processes was estimated using scavengers. Perhaps, the results will be significant for promoting sonodynamic treatment to treat tumors at the molecular level.