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Osteoblast (bone-forming cell) and chondrocyte (cartilage-synthesizing cell) adhesion on novel nanostructured polylactic/glycolic acid (PLGA) and titania composites were investigated in the present in vitro study. Nanostructured polymers were created by chemically treating micron-structured PLGA with select concentrations of NaOH for various periods of time. Dimensions of ceramics were controlled by utilizing either micron or nanometer grain size titania. Compared with surfaces with conventional or micron surface roughness dimensions, results provided the first evidence of increased osteoblast and chondrocyte adhesion on 100 wt% PLGA films with nanometer polymer surface roughness dimensions. Results also confirmed other literature reports of enhanced osteoblast adhesion on 100 wt% nanometer compared with conventional grain size titania compacts; however, the present study provided the first evidence that decreasing titania grain size into the nanometer range did not influence chondrocyte adhesion. Finally, osteoblast and chondrocyte adhesion increased on 70/30 wt% PLGA/titania composites formulated to possess nanosurface rather than conventional surface feature dimensions. The present study, thus, provided evidence that these nanostructured PLGA/titania composites may possess the ability to simulate surface and/or chemical properties of bone and cartilage, respectively, to allow for exciting alternatives in the design of prostheses with greater efficacy.

Previous studies investigating the design of synthetic bladder wall substitutes have involved polymers with micro dimensional structures. Since the body is made up of nano-structured components (e.g., extracellular matrix proteins), the focus of the present in vitro study was to design nano-structured polymers for use as synthetic bladder constructs that mimic the topography of natural bladder tissue. In order to complete this task, novel nano-structured biodegradable polymeric films of poly-lactic-co-glycolic-acid (PLGA), poly-ether-urethane (PU), and poly-caprolactone (PCL) were fabricated and separately treated with various concentrations of NaOH (for PLGA and PCL) and HNO(3) (for PU) for select time periods. These treatments reduced the polymer surface feature dimensions from conventional micron dimensions to biologically inspired nanometer dimensions. Select cytocompatibility properties of these biomaterials were tested in vitro. Results provide the first evidence that adhesion of bladder smooth muscle cells is enhanced as polymer surface feature dimensions are reduced into the nanometer range. In addition, surface analysis results reveal that the polymer nanometer surface roughness is the primary design parameter that increases bladder smooth muscle cell adhesion. For this reason, the "next generation" of tissue-engineered bladder constructs with increased efficacy should contain surfaces with nanometer (as opposed to micron) surface features.