Carbon Nanotube Substrates for Tissue Engineering Applications

Abstract

The present study investigates the applicability of multiwalled carbon nanotubes in creating novel nanostructured matrices exhibiting biomimetic designed features. The thus produced CNT-based constructs were employed to gain a deeper insight into the cellular response to nanoscale structures, especially to effects resulting from the local topography.<br /> The first part of the work comprises the mechanical characterization of the CNTs matrices by means of nanoindentation and nanoscratch experiments, revealing a good mechanical stability of the MWNT-based polymer matrices.<br /> The biocompatibility of the MWNTs constructs and cell-matrix surface interaction was assessed using human osteoblast-like cells. In general, osteoblasts were found to adhere and proliferate on all nanostructured matrices. The observed increase of osteoblastic metabolic activity after incubation on CNTs matrices proved their capability to support long-term survival of osteoblast cells and excluded the toxic impact of carbon nanotubes on cell viability. Furthermore, results from immunofluorescence staining revealed the improved cell adhesion capacity to nanostructured matrices and clearly showed the sensitivity of the cell to physical features at the nanoscale.<br /> The atomic force microscopy was applied to investigate the cytomechanical properties of osteoblast cells cultured on diverse CNT matrix topographies. Experimental data showed that cell adhesion and therefore the elastic modulus of the cells are affected by the regularity of the topography, i.e., regular topography contributed to increased Young’s modulus, whereas irregular one led to decreased cell stiffness.<br /> Concluding, it could be shown that carbon nanotubes can be effectively used to fabricate various nanoscale topographies, which in turn have a powerful influence on osteoblasts behavior. The results furthermore indicate that carbon nanotubes can mimic nanofeatures of the native extracellular matrix and may therefore find an application in the design of new biomaterials for tissue engineering.