A detailed
understanding
of the cell adhesion on polymeric surfaces
is required to improve the performance of biomaterials. Quartz crystal
microbalance with dissipation (QCM-D) as a surface-sensitive technique
has the advantage of label-free and real-time monitoring of the cell–polymer
interface, providing distinct signal patterns for cell–polymer
interactions. In this study, QCM-D was used to monitor human fetal
osteoblastic (hFOB) cell adhesion onto polycaprolactone (PCL) and
chitosan (CH) homopolymer films as well as their blend films (75:25
and 25:75). Complementary cell culture assays were performed to verify
the findings of QCM-D. The thin polymer films were successfully prepared
by spin-coating, and relevant properties,i.e., surface
morphology, ζ-potential, wettability, film swelling, and fibrinogen
adsorption, were characterized. The adsorbed amount of fibrinogen
decreased with an increasing percentage of chitosan in the films,
which predominantly showed an inverse correlation with surface hydrophilicity.
Similarly, the initial cell sedimentation after 1 h resulted in lesser
cell deposition as the chitosan ratio increased in the film. Furthermore,
the QCM-D signal patterns, which were measured on the homopolymer
and blend films during the first 18 h of cell adhesion, also showed
an influence of the different interfacial properties. Cells fully
spread on pure PCL films and had elongated morphologies as monitored
by fluorescence microscopy and scanning electron microscopy (SEM).
Corresponding QCM-D signals showed the highest frequency drop and
the highest dissipation. Blend films supported cell adhesion but with
lower dissipation values than for the PCL film. This could be the
result of a higher rigidity of the cell–blend interface because
the cells do not pass to the next stages of spreading after secretion
of their extracellular matrix (ECM) proteins. Variations in the QCM-D
data, which were obtained at the blend films, could be attributed
to differences in the morphology of the films. Pure chitosan films
showed limited cell adhesion accompanied by low frequency drop and
low dissipation.