Connective tissue progenitor cell growth characteristics on textured substrates

Alvaro Mata^1,2, Cynthia Boehm^2,3, Aaron J Fleischman^2,4, George F Muschler^2,3,5, Shuvo Roy^2,4

¹Department of Chemical and Biomedical Engineering, Cleveland State University; ²Department of Biomedical Engineering, The Cleveland Clinic Foundation; ³Bone Biology Laboratory, The Cleveland Clinic Foundation; ⁴BioMEMS Laboratory, The Cleveland Clinic Foundation; ⁵Department of Orthopaedic Surgery, The Cleveland Clinic Foundation

Abstract: Growth characteristics of human connective tissue progenitor (CTP) cells were investigated on smooth and textured substrates, which were produced using MEMS (microelectromechanical systems) fabrication technology. Human bone marrow derived cells were cultured for 9 days under conditions promoting osteoblastic differentiation on polydimethylsiloxane (PDMS) substrates comprising smooth (non-patterned) surfaces (SMOOTH), 4 different cylindrical post micro-textures (POSTS) that were 7–10 μm high and 5, 10, 20, and 40 μm diameter, respectively, and channel micro-textures (CHANNELS) with curved cross-sections that were 11 μm high, 45 μm wide, and separated by 5 μm wide ridges. Standard glass-tissue culture surfaces were used as controls. Micro-textures resulted in the modification of CTP morphology, attachment, migration, and proliferation characteristics. Specifically, cells on POSTS exhibited more contoured morphology with closely packed cytoskeletal actin microfilaments compared to the more random orientation in cells grown on SMOOTH. CTP colonies on 10 μm-diameter POSTS exhibited higher cell number than any other POSTS, and a significant increase in cell number (442%) compared to colonies on SMOOTH (71%). On CHANNELS, colonies tended to be denser (229%) than on POSTS (up to 140% on 10 μm POSTS), and significantly more so compared to those on SMOOTH (104%).

Keywords: PDMS, polydimethylsiloxane, MEMS, microelectromechanical systems, tissue engineering, bone grafts, connective tissue progenitor cells, osteoprogenitors, stem cells