UCSF

Varying geometry and layout of microposts on a cell culture substrate provides an effective technique for applying mechanical stimuli to living cells. In the current study, the optimal geometry and arrangement of microposts on the polydimethylsiloxane (PDMS) surfaces to enhance cell growth behavior were investigated. Human bone marrow derived connective tissue progenitor cells were cultured on PDMS substrates comprising unpatterned smooth surfaces and cylindrical post microtextures that were 10 μm in diameter, 4 heights (5, 10, 20 and 40 μm) and 3 pitches (10, 20, and 40 μm). With the same 10 μm diameter, post heights ranging from 5 to 40 μm resulted in a more than 535 fold range of rigidity from 0.011 nNμm⁻¹ (40 μm height) up to 5.888 nNμm⁻¹(5 μm height). Even though shorter microposts result in higher effective stiffness, decreasing post heights below the optimal value, 5 μm height micropost in this study decreased cell growth behavior. The maximum number of cells was observed on the post microtextures with 20 μm height and 10 μm inter-space, which exhibited a 675 % increase relative to the smooth surfaces. The cells on all heights of post microtextures with 10 μm and 20 μm inter-spaces exhibited highly contoured morphology. Elucidating the cellular response to various external geometry cues enables us to better predict and control cellular behavior. In addition, knowledge of cell response to surface stimuli could lead to the incorporation of specific size post microtextures into surfaces of implants to achieve surface-textured scaffold materials for tissue engineering applications.