Structure and interaction among globular protein bovine serum albumin (BSA) and silica nanoparticle mixtures in solutions have been studied using small angle neutron scattering technique by varying the solution temperature. Our study shows that in absence of nanoparticles and up to 70 degrees C, an intermediate range repulsive and one long range attractive interaction potential between the proteins exist. Above that temperature, fractal structure forms. In presence of nanoparticles, fractal structures form even at room temperature by both the protein and nanoparticles. Fractal dimension increases with the increase of BSA concentration and solution temperature, and this temperature induced structural transition is irreversible. (C) 2015 Elsevier B.V. All rights reserved.