Chemical nanocavitation of surfaces to enhance the utility of stainless steel as a medical material

Colloids Surf B Biointerfaces. 2018 Jan 1:161:677-687. doi: 10.1016/j.colsurfb.2017.11.051. Epub 2017 Nov 22.


While stainless steel is a broadly used alloy with interesting mechanical properties, its applications in medicine suffers from inherent biocompatibility limitations. An attractive opportunity to improve its performance is to alter its surface, but this has proven challenging. We now show how high range anodization conditions using H2SO4/H2O2 as an atypical electrolyte can efficiently nanocavitate the surface of both stainless steel SS304 and SS316 and create a topography with advantageous biomedical characteristics. We describe the structural and chemical features of the resulting surfaces, and propose a nanocorrosion/transpassivation/repassivation mechanism for its creation. Our approach creates a thin mesoporous layer of crystalline oxide that selectively promotes mammalian cell activity and limits bacterial adhesion. The modified surfaces favor the formation and maturation of focal adhesion plaques and environment-sensing filopodia with abundant extra small lateral membrane protrusions, suggesting an increase in membrane fluidity. These protrusions represent a yet undescribed cellular response. Such surfaces promise to facilitate the integration of implantable SS devices, in general. In addition, our strategy simultaneously provides a simple, commercially attractive way to control the adhesion of microorganisms, making nanostructured stainless steel broadly useful in hospital environments, in manufacturing medical devices, as well as offering possibilities for non-medical applications.

Keywords: Antibacterial properties; Cell adhesion; Electrochemical anodization; Nanotopography; Stainless steel.

MeSH terms

  • Animals
  • Bacterial Adhesion / drug effects
  • Cell Adhesion / drug effects
  • Cell Line
  • Coated Materials, Biocompatible / chemistry*
  • Coated Materials, Biocompatible / pharmacology
  • Electrochemical Techniques / methods
  • Electrolytes / chemistry*
  • Hydrogen Peroxide / chemistry
  • Mice
  • Microscopy, Atomic Force
  • NIH 3T3 Cells
  • Nanostructures / chemistry*
  • Nanostructures / ultrastructure
  • Porosity
  • Stainless Steel / chemistry*
  • Sulfuric Acids / chemistry
  • Surface Properties


  • Coated Materials, Biocompatible
  • Electrolytes
  • Sulfuric Acids
  • Stainless Steel
  • Hydrogen Peroxide