Human serum albumin (HSA) adsorbed onto silica nanoparticles modified by 3-aminopropyltriethoxysilane (APTES) and polyethyleneimine
(PEI) was investigated by differential scanning calorimetry, IR spectroscopy, and photon correlation spectroscopy. The structural
alterations of the protein molecules induced from adsorption process were estimated on the basis of temperatures of denaturation
transition (Td) of the protein in free (native) and adsorbed form. It was found that adsorption of the protein onto the APTES-modified silica
nanoparticles results in an increase in the temperature of denaturation transition from 42 to 47.4 °C. HSA adsorbed onto the
PEI-modified silica nanoparticles unfolds extensively.