Effective Adsorption of Functional Biological Macromolecules on Stainless Steel Surface with Micro/Nanoporous Texture

Abstract

Stainless steel (AISI 316L) is commonly used as a material in medical devices. Modification of the metal surface with bioactive molecules and/or nanoparticles to develop next-generation smart biomaterial, e.g., cardiovascular stents, has recently attracted great attention. The present work investigated adsorption of antibodies and enzymes on micro/nanoporous 316L stainless steel compared with that on smooth and gold-coated stainless steel surfaces. The experimental results showed that the micro/nanoporous stainless steel surface produced by electrochemical erosion can adsorb a large amount of proteins (antibodies or horse radish peroxidase (HRP)), with comparable or better results than the sputtered-gold surface. Washes with surfactants (e.g., 10% bull serum albumin (BSA) or 0.2% Tween 20 solution) did not remove the enzymes/antibodies. In contrast, pretreatment of the metal plates with 5% Tween 20 halved antibody adsorption but did not affect adsorption of HRP. The wettability of the porous metal surface coated with proteins depended on the protein species and amount of protein adsorbed. The 1595 Acta Phys. ⁃Chim. Sin. 2013 Vol.29 protein-coated porous surface was hydrophilic (water contact angle<50°), which should make it biocompatible. The proteins on the micro/nanoporous stainless steel surface retained their high biological activity; in particular, micro/nanoporous stainless steel stents modified with an anti-CD34 antibody using the present method can effectively and selectively capture KG-1 cells. Our work provides a basis for developing novel polymer-free, smart, economic biomaterials with stainless steel for biomedical applications.