Three-dimensional chemical structures by protein functionalized micron-sized beads bound to polylysine-coated silicone surfaces.

A novel method is described here that allows three-dimensional (3D) control of both chemistry and morphology by a series of wet chemical steps: the attachment of protein functionalized micron-sized beads onto a flat silicone surface that has been functionalized with a distinct chemical modification. Bovine serum albumin (BSA), laminin, or polylysine is covalently bound to 6.5-microm-diameter spherical beads. A chemical method is then used to bind these beads to a flat silicone surface that is subsequently functionalized with polylysine. This process leads to a nonspecific cell adhesive background on the flat surface (polylysine) with the option of differing chemistry on the third-dimension due to the protein BSA or laminin on the bead protruding from the surface. The beads do not detach during cyclic stretching in vitro. Neo-natal rat cardiac fibroblasts are cultured on the beaded surfaces and compared with fibroblasts cultured on nonbeaded, flat polylysine surfaces. Fibroblast plating density, integrin, and physical responses are examined as a function of varying the ligands on the beads.