Collagen can absorb and associate with nanoparticles, which can have significant impact on the biological behavior of collagen and nanoparticles in a biological fluid. Iron oxide nanoparticles encapsulated with polystyrene-block-poly(acrylic acid) has been synthesized and characterized. Viscosity, circular dichroism, and Fourier transform infrared spectroscopy techniques have been used to study the Fe 2 O 3 -PS-b-PAA-collagen interaction. Encapsulated nanoparticles do not alter the collagen conformational stability and changes in functional groups are due to the aggregation of protein onto the surface of nanoparticle. The ability of PS-b-PAA encapsulated nanoparticles to maintain the collagen properties will have impact in the biomedical applications of the same.