Adsorption and conformation variation of BSA protein with the size variation of the metallic nanoparticles in LB film

• BSA adsorption is possible on both bare and Au nanoparticle covered quartz surfaces.
• BSA adsorption increases with the increase of the Au nanoparticle size.
• Secondary structural conformation of BSA modifies on the nanoparticle covered surfaces.
• Some specific secondary conformation enhances as the particle size increases.
• Variation of the pyramid-like interparticle gap area and gap volume modifies the BSA adsorption and conformation.

Adsorption and conformation variation of globular protein bovine serum albumin (BSA) on the surfaces of different sized gold nanoparticle Langmuir–Blodgett (LB) films have been studied by using atomic force microscopy, UV–vis and FTIR spectroscopy. Films of Au nanoparticles of different sizes were prepared on the quartz substrates by the LB method. Our study reveals that the protein adsorption increases on the nanoparticle covered quartz surfaces with the increase of the nanoparticle size. Moreover, modifications in the secondary conformations of the adsorbed protein occur on the surfaces of the nanoparticles in comparison with the bare quartz surface. Interparticle gap area and gap volume dependent protein adsorption and conformation variation have been proposed.

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