Surface Modification of Carbon Nanofibers to Improve Their Biocompatibility in Contact with Osteoblast and Chondrocytes Cell Lines

Abstract

The goal of this study is to investigate the influence of different types of modifiers, such as sodium hyaluronate (NaH), graphene oxide (GO), silica oxycarbide (SiOC) and oxidation process (ox) on physicochemical, morphological, and biological properties of electrospun carbon nanofibers (eCNFs). Scanning electron microscopy, X-ray photoelectron spectroscopy and infrared spectroscopy (FTIR) were used to evaluate the microstructure and chemistry of as-prepared and modified CNFs. The electrical properties of CNFs scaffolds were examined using a four-point probe method to evaluate the influence of modifiers on the volume conductivity and surface resistivity of the obtained samples. The wettability of the surfaces of modified and unmodified CNFs scaffolds was also tested by contact angle measurement. During the in vitro study all samples were put into direct contact with human chondrocyte CHON-001 cells and human osteosarcoma MG-63 cells. Their viability was analysed after 72 h in culture. Moreover, the cell morphology and cell area in contact with CNFs was observed by means of fluorescence microscopy. The obtained results show great potential for the modification of CNFs with polymer, ceramic and carbon modifiers, which do not change the fiber form of the substrate but significantly affect their surface and volume properties. Preliminary biological studies have shown that the type of modification of CNFs affects either the rate of increase in the number of cells or the degree of spreading in relation to the unmodified sample. More hydrophilic and low electrically conductive samples such as CNF_ox and CNF_NaH significantly increase cell proliferation, while other GO and SiOC modified samples have an effect on cell adhesion and thus cell spreading. From the point of view of further research and the possibility of combining the electrical properties of modified CNF scaffolds with electrical stimulation, where these scaffolds would be able to transport electrical signals to cells and thus affect cell adhesion, spreading, and consequently tissue regeneration, samples CNF_GO and CNF_SiOC would be the most desirable.

Influence of Heat Treatment of Electrospun Carbon Nanofibers on Biological Response

“…In general, all carbon materials, including eCNF, have a hydrophobic surface due to their structure, where carbon exists almost exclusively in the form of aromatic, non-polar sheets, so their interaction with polar molecules such as water is very low [ 42 ]. Graphite, as a model material, is assumed to have contact angle values in the range from 75° to 95° [ 43 , 44 , 45 ].…”

Evaluation of the polycaprolactone hydrolytic degradation in acid solvent and its influence on the electrospinning process

“…These variations in band intensity and the narrowing of the band shown in Figure 2b demonstrate the hydrolysis by chain cleavage processes of PCL, leading to by‐products related to the acid degradation of the polyester, influencing CH 2 vibrations 46 . Furthermore, there are variations on the band at about 1699 cm −1 , as seen in Figure 2c, which was assigned to the CO stretching vibrations of carboxylic/lactone groups 47 . These results may indicate chemical changes in PCL both when it is solubilized in AA and after its hydrolysis.…”

“…46 Furthermore, there are variations on the band at about 1699 cm À1 , as seen in Figure 2c, which was assigned to the C O stretching vibrations of carboxylic/lactone groups. 47 These results may indicate chemical changes in PCL both when it is solubilized in AA and after its hydrolysis. Supported by the decrease in these bands observed in the spectrum obtained for PCL in pellets and their absence after contact with the acidic solvent used in this study.…”

Evaluation of the polycaprolactone (PCL) hydrolytic degradation in acid solvent and its influence on the electrospinning process

“…the polyester, influencing CH2 vibrations [51]. On the other hand, variations on the peak at about 1699 cm -1 , which was assigned to the C=O stretching vibrations of carboxylic/lactone groups [52]. These results may indicate chemical changes in PCL both when it is solubilized in acetic acid and after its hydrolysis.…”