Determining early adhesion of cells on polysaccharides/PCL surfaces by a quartz crystal microbalance

The early adhesions of cells to various biopolymers are important to their growths and proliferations. Here, the adhesion of cells (e.g., fibroblasts) on the electrode of a quartz crystal microbalance (QCM) that was coated by PCL or PEG/PCL and further adsorbed by chitosan (CS) or CS/hyaluronic acid (HA) layers, was examined by cell-counting technique, QCM method and MTS assay under a serum-free condition for 3 h. The surfaces on electrodes of the QCM were confirmed to have been modified by measuring their contact angles, FT-IR spectra and the weights of biopolymers affected the frequency shifts of the QCM. Among tested surfaces on electrodes, the adhesion of fibroblasts on a HA/CS/PCL surface was the most (e.g., 3.08 x 10(5) cells/cm(2)) while that on a PEG/PCL surface was the least (e.g., 0.7 x 10(5) cells/cm(2)), as determined by cell-counting technique. The frequency shift and the mass of adhering fibroblasts on HA/CS/PCL electrodes were -3,537 +/- A 770 Hz and 3.78 +/- A 0.22 mu g (n = 3), respectively, that were significantly exceeded those on other electrodes (-393 +/- A 58 Hz and 0.32 +/- A 0.06 mu g, n = 3, respectively, for PEG/PCL electrodes). These results were consistent with cell-counting technique. Although MTS assay yielded similar results, it was less sensitive than the two aforementioned methods. In conclusion, modified electrodes of a QCM provide a convenient and sensitive method for examining the early adhesion of cells (e.g., 3 h) to biopolymer surfaces.