Tribological properties of micro/nano-textured surfaces under physiological conditions

In the last decade, surface texturing in micro/nano scale has been extensively used in biomedical engineering to modulate mammalian cell adhesion and proliferation, implant integration with human body and infection prevention. However, the tribological implications of texturing under wet physiological conditions have not been well quantified.
Research in Xi’s dissertation is carried out to understand the effects of material interaction with different (micro/nano) textures, under physiologically relevant conditions for the applications in tissue engineering. Textures with ordered pattern (e.g., micro- and nanopores, and microlines) have been made on various materials, including hard silicon (Si), soft polydimethylsiloxane (PDMS) and hydrogels (i.e., poly(2-hydroxyethyl methacrylate(pHEMA) hydrogel).
The result shows that texturing increases friction under physiological sliding conditions in general, and that the texture’s edge effect plays a major role in increasing friction when the difference in stiffness is large between the textured and untextured surfaces while sliding. Xi’s study indicates that one should be careful in using micro/nano-textured surfaces to modulate mammalian and bacterial cell behaviors as, even with the assistance of lubricious proteins, textures can cause an increase in the friction between the biomaterial and any surrounding tissue or other biomaterial, which can further give rise to inflammation and tissue wear.