Probing the in vitro binding mechanism between human serum albumin and La2O2CO3 nanoparticles

The interaction of La2O2CO3 nanoparticles (La NPs) with human serum albumin (HSA) has been studied. Analysis of the fluorescence quenching data of HSA using Stern-Volmer method showed that La NPs quenched HSA fluorescence in static quenching mode. Thermodynamic analysis indicated that hydrogen bonds and Van der Waals interactions play a major role for HSA-La NPs associations. Fluorescent displacement measurements confirmed that the primary binding site of La NPs was mainly located within site I (subdomain IIA) of HSA. The binding distance was calculated by using Forster resonance energy transfer theory. Also, the results of Fourier-transform infrared spectroscopy, circular dichroism, three-dimensional fluorescence and UV-visible measurements indicated that the binding of above La NPs to HSA may induce conformational and micro-environmental changes of protein. This study suggested that the conformational change of HSA was at secondary structure of it and the biological activity of this protein was changed in the present of La NPs.