The growth and morphological behavior of salivary epithelial cells on matrix protein-coated biodegradable substrata

The purpose of this study was to examine the growth and morphology of a sal ivary epithelial cell line (HSG) in vitro on several biodegradable substrat a as an important step toward developing an artificial salivary gland. The substrates examined were poly-(L)-lactic acid (PLLA), polyglycolic acid (PG A), and two co-polymers, 85% and 50% PLGA, respectively. The substrates wer e formed into 20- to 25-mm disks, and the cells were seeded directly onto t he polymers or onto polymers coated with specific extracellular matrix prot eins. The two copolymer substrates became friable over time in aqueous medi a and proved not useful for these experiments. The purified matrix proteins examined included fibronectin (FN), laminin (LN), collagen I, collagen IV, and gelatin. In the absence of preadsorbed proteins, HSG cells did not att ach to the polymer disks. The cells, in general, behaved similarly on both PLLA and PGA, although optimal results were obtained consistently in PLLA. On FN-coated PLLA disks, HSG cells were able to form a uniform monolayer, w hich was dependent on time and FN concentration. Coating of disks with LN, collagen I, and gelatin also promoted monolayer growth. This study defines the conditions necessary for establishing a monolayer organization of saliv ary epithelial cells with rapid proliferation on a biodegradable substrate useful for tissue engineering.