Abstract text (incl. figure legends and references)
Introduction: Proteins adsorb onto biomaterial surface within seconds of the first material-tissue contact and play a pivotal function as mediators between the biomaterial and tussie. Ruling the adsorption of proteins onto biomaterials allows controlling subsequent cell adhesion and growth, and therefore is critical for the successful implantation and proper functioning of implants. In this work, polyelectrolyte multilayer (PEM) coatings were explored as a strategy for biofunctionalization of biomaterials by controlling the extent of protein adsorption.
Materials & methods: Three types of ultratin PEM coatings, composed of pairs of natural and synthetic polyelectrolytes, were build and characterized by ellipsometry, water contact angle, atomic force microscopy and streaming potential. Adsorption of human serum albumin (HSA) on the coatings was quantified by protein-dye binding (Bradford assay). Human umbilical vein endothelial cells (HUVEC) and mouse embryonic fibroblast 3T3 cells were used for cell adhesion and proliferation studies.
Results: The extent of HSA adsorption was found to be related to the surface properties of PEM coatings. The major role was played by the surface charge, and for all three PEM types, a greater amount of protein was adsorbed on coatings with a positively charged surface. The number of adhered cells, their proliferation and viability increased in parallel with the amount of the adsorbed HSA. All investigated coating were found to be non-cytotoxic.
Conclusion: We demonstrated that application of ultratin PEM coatings is one avenue to regulate the extent of protein adsorption and thereby cell adhesion and growth. The amount of adsorbed proteins correlated to the adhesion and proliferation of cells on the model surfaces. The results of this study may help to improve the biocompatibility of biomaterials.
Acknowledgements: The authors gratefully acknowledge the funding by the German Research Foundation (DFG) for the subproject 2 within the Research Unit FOR5250 "Permanent and bioresorbable implants with tailored functionality" (No. 449916462).