The extracellular matrix (ECM) environment plays a critical role in organism development and disease. Consequently, developing complementary analytical techniques to study bioactive scaffolds can assist in understanding cell-ECM processes. We have previously established the formation and utility of a model ECM comprised of type I collagen fibril thin films. In this report, we analyze the well-characterized ECM model of hydrated collagen fibril films and dehydrated films to assess the utility of time-of- flight secondary ion mass spectrometry (TOF-SIMS) as an analytical technique for determining the chemical environment specific to the cell-ECM interface. We tested the effect a high vacuum (HV) environment has on hydrated fibril films to determine if the HV of TOF-SIMS analysis affected the structure and functionality of the collagen matrix. Our results indicate that cell behavior on fibril films exposed to HV was similar to that of unexposed films. Furthermore, the elastic modulus of the HV-exposed films was comparable in mechanical compliance to fully hydrated films, and several times more compliant than the stiffened dehydrated films. No observable differences in the TOF-SIMS positive-ion spectra were found between the hydrated and dehydrated fibril films. Principal component analysis (PCA) of the TOF-SIMS data was able to reproducibility discriminate the two types of fibril films, but this discrimination was based on the relative intensity of small fragments compared to larger molecular fragments, as opposed to the appearance or disappearance of fragments due to biochemical changes at the surface of the fibrils during the dehydration process. These results futher suggest that measureable differences in cellular responses on the hydrated and dehydrated films are primarily a function of the mechanical environment.
Pub Type: Journals
Atomic Force Microscopy, Collagen Type I, Mechanical properties, SIMS, PCA