No abstract

Biodegradable polymers are of interest for developing controlled protein drug delivery platforms. In this study, two poly (alpha-hydroxy) esters were formulated with Aerosol-OT, a surfactant stabilizer, to encapsulate the protein keratinocyte growth factor (KGF) for controlled release KGF is involved in a number of crucial biologic processes, most notably epithelial growth and repair. The concentration of KGF that caused a biological response in vitro was determined (optimally 10 ng/mL) and compared with the release of KGF from the two biodegradable polymer membrane formulations. Each polymer formulation released biologically relevant levels, 10 ng/mL of active KGF, although with different times release kinetics. The membrane composed of PLGA/AOT/KGF exhibited a faster release rate of KGF into solution after 120 h of degradation time than the release rate of the PLLA/AOT/KGF matrices. Cell seeding assays showed that both polymer matrices, when formulated with AOT, sustained cell growth. Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) was used to characterize the distribution of AOT and KGF through the polymer membrane. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010.

Cartilage modulates TGF-alpha and TGF-beta expression in REC, and may contribute to regulation of REC proliferation and differentiation.

Facilitating tissue regeneration or replacement requires development of synthetic surfaces that promote cell adhesion, migration, and proliferation. Two successful approaches have been to incorporate minimal cell adhesion recognition sequences at the biomaterial surface and to integrate the entire adhesion molecule into a compatible synthetic matrix. While adhesion assays using immortalized cell lines are important in evaluating synthetic materials, cell type and source play a significant role in the ability of such models to mimic real tissues. Models that utilize multiple cell types or primary cells are more representative of native tissues than models that use single cell types or primary cells. In this study we investigated primary respiratory epithelial cell (REC) adhesion to modified fluoropolymers incorporating simple functional groups and minimal peptide recognition sequences, and we evaluated the potential of hybrid biopolymer materials to support adhesion and proliferation. X-ray photoelectron spectroscopy (XPS) was used to verify substrate surface composition. Significant differences were found in the adhesion characteristics of primary REC and in the A549 lung carcinoma cell line. Model systems composed of multiple cell types and/or primary cells necessarily represent increased levels of complexity for an investigation of cellular responses to synthetic surfaces. When evaluating biomaterials, adhesion studies using immortalized cell lines cannot necessarily be extrapolated to normal cell behavior.

Cartilage production and activity of MMP after injury to the large conducting airway may be a factor in the failure of luminal reepithelialization, resulting in aberrant repair.