Cell Response Driven by Surface Charge as a Result of rGO and MXene Incorporation in Electrospun Polymer Scaffolds

Recent advances in tissue engineering focus on bioactive materials that replicate extracellular matrix (ECM) properties and activate cells via specific pathways. Electrospinning is a widely used method to develop hybrid systems by incorporating nanoparticles or nanosheets, extending beyond medical applications. However, many extensively applied fillers, even those showing positive effects on cells, are missing the critical research needed to understand which stimulation pathway initiates the cascade of cellular responses. In this study, we incorporated reduced graphene oxide (rGO) and Ti₃C₂T_X (MXenes, a MAX phase material) as fillers, which have been shown in the literature to enhance osteogenic responses, into PLLA fibers and compared their effects on scaffold surface properties and cellular behavior.
One of the key effects of incorporating fillers into polymer scaffolds is the significant change in surface potential, particularly when using highly conductive materials like reduced graphene oxide and MXenes. These materials create charged fiber surfaces that not only modify the scaffold's geometry but also influence cell behavior (Polak et al., 2023). The combination of altered surface charge and fiber geometry plays a crucial role in determining cellular responses, as the charged fibers interact with cells, leading to different integration of cells with the scaffold (Polak et al., 2024).
The surface potential of the fibers was assessed using Kelvin probe force microscopy (KPFM), while X-ray photoelectron spectroscopy (XPS) was employed to verify the surface chemistry. In addition, we thoroughly examined the fibers to characterize their chemical composition, mechanical properties, morphology, and other standard material properties. Osteoblast cell cultures were used for further biocompatibility studies, including cell adhesion, proliferation, and morphology examination. Additionally, confocal laser scanning microscopy (CLSM) with the AiryScan enabled detailed analysis of the cells' focal adhesion points to our fibers (Berniak et al., 2024). These results provided insights into how the incorporation of rGO and MXenes influenced cells development, contributing to the enhancement of tissue regeneration processes.

Acknowledgments
This research was supported by the ERC-2020-STG project (BioCom4SavEn), under ERC grant agreement no. 948840, funded by the European Research Council within the EU’s Horizon 2020 Framework Programme and supported partly by the program ''Excellence Initiative – Research University'' for the AGH University of Krakow in Poland. The cell culture study was conducted with funding from the OPUS 17 project granted by the National Science Centre in Poland, No 2019/33/B/ST5/01311 and PIECRISCI project founded by the European Union’s Horizon 2020 research and innovation programme under grant agreement No 958174 and within M-ERA.NET 3 funded by National Science Centre, Poland No 2021/03/Y/ST5/00231


References
Berniak, K., Ura, D. P., Piórkowski, A. & Stachewicz, U. (2024). ACS Appl Mater Interfaces https://doi.org/10.1021/acsami.3c19035.
Polak, M., Berniak, K., Szewczyk, P. K., Karbowniczek, J. E., Marzec, M. M. & Stachewicz, U. (2023). Appl Surf Sci 621, https://doi.org/10.1016/j.apsusc.2023.156835.
Polak, M., Ura, D. P., Berniak, K., Szewczyk, P. K., Marzec, M. M. & Stachewicz, U. (2024). Colloids Surf B Biointerfaces 237, 113864.