3D bioprinting is a rapidly growing field of tissue engineering. Currently, one of the main obstacles is the scarcity of biomaterials tailored for particular use cases. This study is focused on exploring thermoplastic material – polycaprolactone, reinforced with multiwalled (MWCNT) and bamboo (BCNT) type of carbon nanotubes, for use in tissue engineering. Toxicity of various nanomaterials, including carbon nanotubes is still a subject of ongoing debate. The added complexity of hybrid biomaterials necessitates further studies, extending beyond properties of a single constituent, taking into account various interactions between given materials. In the study, mechanical, structural, optical and biological evaluations of the materials were performed, including: nanoindentation, rheology studies, differential scanning calorimetry, scanning electron microscopy, confocal microscopy, proliferation, and cytotoxicity assays. Human normal chondrocytes were utilized for biological studies. Carbon nanotubes were added in concentrations ranging from 0.005% to 0.2% w/w. Cellink BioX printer with thermoplastic printhead was utilized. Preliminary results indicate that both the concentration and type of carbon nanotubes used significantly affect the mechanical properties and biocompatibility of the scaffold 3D bioprinted with PCL/CNT composite. The study aims to find a link between material`s crystallinity, surface topography, mechanical properties, and biocompatibility, necessary for furthering our understanding of thermoplastic biomaterials in tissue engineering, and 3D bioprinting. This work tries to navigate through the issues inherent for composite bionanomaterials, proposing analytical techniques helpful in evaluation of the materials` properties, crucial from the standpoint of 3D bioprinting and tissue engineering.