(K-409) Biocompatibility and Distribution of 2D MΧene Flakes with Neural Cells In Vitro

The ability to functionally interface with neural tissues for recording or stimulation has provided valuable insights into the brain and potential treatments for neurological disorders [1]. Recently MXenes, a novel class of 2D nanomaterials with favorable electrical and chemical properties, have gained attention for their potential in neural interfaces [2]. However, despite evidence of MXenes’ high biocompatibility with neuronal cells [3, 4], there currently exists no study evaluating the biocompatibility of 2D MXenes with astrocytes, the most abundant cell type in the brain that is primarily responsible for supporting neuronal health and function. Therefore, this study aims to assess the dose- and time-dependent health of astrocytes interfaced with 2D MXene flakes (average lateral size 1.17 ± 0.06 μm).

Primary cerebral cortical astrocytes were obtained from P0 rat pups following an approved animal protocol. Cells were cultured in T-75 flasks with DMEM/F12 supplemented with 10% FBS to allow for cell proliferation. Next, 12-well plates were coated with Poly-L-lysine (PLL) and laminin, and the cells were re-seeded in Neurobasal medium supplemented with G5, B27, and Glutamax. After 48 hours of incubation (37°C, 5% CO₂), the cells were interfaced with 2D MXene flakes to evaluate potential dose- and time-dependent cytotoxicity. The cells were treated with 4μg/mL of Ti₃C₂T_x MXene (compared to 0μg/mL in vehicle), and cell viability was assessed at 48h with a live/dead assay (Calcein AM/EthD-1) and confocal microscopy. A blinded researcher quantified the number of live and dead cells (per unit area), and the viability (%) was calculated as: %(number of live cells)/(total number of cells). Phase contrast imaging was also performed to assess structural/morphological changes between control and MXene-treated groups.

Treating primary cerebral cortical astrocytes with 4μg/mL of Ti₃C₂T_x MXene resulted in 96.3 ± 3.1 percent cell viability, compared to 99.8 ± 0.2 in the control group (Figure 1). We found high biocompatibility of 4 μg/mL of Ti₃C₂T_x MXene flakes interfaced with cortical astrocytes after 48h, without significant cytotoxicity at 2 days in vitro (p=0.23). Future work will involve varying concentrations of multiple MXene subtypes (e.g., Ti₃C₂T_x, Ta₄C₃, and Nb₂C), assessing viability at later time points, as well as ascertaining the ability of MXene stimulation to modulate glial functionality. Also, comparisons of astrocyte viability with that of cortical neurons and neuronal/astrocyte co-cultures may provide insights into the biocompatibility of 2D MXene flakes within the cellular microenvironment of neural tissues, informing the development of novel neural interfaces. Overall, this study contributes to the growing body of knowledge on the biocompatibility of 2D MXenes with neural cells, evaluating the dosage and structural properties of non-cytotoxic MXene-based neural interfaces. Safe and effective integration of 2D nanomaterials, such as MXene flakes, may ultimately enhance the development of novel approaches for the recording and modulation of neural activity.