Optical Studies of the Interactions CdS and CdTe Nanoparticles with a Human Serum Albumin

The interaction between CdS , CdTe nanoparticles and human serum albumin (HSA) was studied by absorption and photoluminescence spectroscopy. The performed transmission electron microscopy (TEM) analysis suggests of spherical shape of nanostructures with small size distribution. In the absorption spectra of the colloidal nanoparticles exciton band was found to be shifted to higher photon energy as compared with that for bulk crystals due to the quantum confinement effect. It was shown that addition of HSA to colloidal nanocrystals leds to a gradual decrease of absorption and broadening of exciton structure, resulting in forming nanoparticles–HSA complexes. The photoluminescence quenching results indicated that the quenching effect of nanoparticles CdTe on HSA fluorescence depend on the temperature and the nature of quenching is static. When the concentration of CdS nanoparticles in solution with HSA over 1.5 10<sup>-6</sup> mol L<sup>-1</sup>, in addition to static quenching mechanism of photoluminescence increases of dynamic quenching mechanism.Keywords: CdTe, CdS, nanoparticles, nanocrystal, optical absorption, photoluminescence, fluorescence quenching, human serum albumin.