Sorption of Proteins onto Porous Single-Component Poly(vinyl amine) Multilayer Thin Films

Abstract

Porous multilayer thin films consisting solely of cross-linked poly(vinyl amine) ((PVAm)(n)) were generated by a selective cross-linking of the PVAm layers in the [PVAm/poly(acrylic acid) (PAA)](n) thin films, followed by the removal of PAA. A regular increase in the (PVAm/PAA)(n) multilayer onto silica particles was observed by potentiometric titration when PVAm with a low molar mass (M(w) = 15 000 g mol(-1)) was used in the construction of LbL thin films. The amount of human serum albumin (HSA) loaded on the single-component (PVAm)(5) thin film was approximately 32 mg HSA/g of hybrid when PVAm with a molar mass of 15 000 g mol(-1) was used compared with the single-component film prepared with PVAm with a molar mass of 340 000 g mol(-1) when the amount of HSA loaded was 15.5 mg HSA/g of hybrid. The sorption modalities of HSA and bovine serum albumin (BSA) onto the single-component thin films deposited on silicon wafers as a function of the number of PVAm layers was investigated by atomic force microscopy and contact angle measurements. The decrease in the film roughness and the increase in the film wettability after the loading of both proteins showed the protein was mainly absorbed into the porous (PVAm)(n) thin film.