Modulating cell adhesion and infiltration in advanced scaffold designs based on PLLA fibers with rGO and MXene...

The development of electrospun scaffolds that support cell adhesion and infiltration remains a critical challenge in tissue engineering. In this study, we investigate the influence of two-dimensional (2D) fillers-reduced graphene oxide (rGO) and MXene (Ti₃C₂T )-incorporated into poly(L-lactic acid) (PLLA) electrospun fibers on their properties and osteoblast responses. The presence of fillers modified fiber arrangement and created varying inter-fiber spacing due to surface charge repulsion and agglomeration. Importantly, surface potential measurements via Kelvin probe force microscopy (KPFM) of PLLA fibers show a significant shift caused by the incorporation of Ti₃C₂T to ∼400 mV compared to ∼50 mV for rGO. In vitro tests indicate that rGO-modified scaffolds support osteoblast infiltration up to ∼100 μm, unlike PLLA fibers, which limit cell infiltration to a maximum of ∼70 μm. However, Ti₃C₂T promotes even deeper (∼120 μm) and more uniform cell's infiltration due to changes in scaffold architecture. High-resolution confocal imaging confirmed that PLLA-Ti₃C₂T fosters larger, elongated adhesion site clusters of cells, whereas rGO increases cell's adhesion site density in relation to PLLA scaffolds without any filler. Our findings highlight the distinct roles of rGO and Ti₃C₂T in modulating scaffold geometry, mechanical behavior, and cellular interactions. Tailoring the composition and distribution of conductive fillers in fibers offers a promising strategy for optimizing scaffold performance in tissue engineering applications.