Boron nitride nanotubes chemically functionalized with glycol chitosan for gene transfection in eukaryotic cell lines

Nanostructured materials have been widely studied concerning their potential biomedical applications, primarily to selectively carry specific drugs or molecules within a tissue or organ. In this context, boron nitride nanotubes (BNNTs) have generated considerable interest in the scientific community because of their unique properties, presenting good chemical inertness and high thermal stability. Among the many applications proposed for BNNTs in the biomedical field in recent years, the most important include their use as biosensors, nanovectors for the delivery of proteins, drugs, and genes. In the present study, BNNTs were synthesized, purified, and functionalized with glycol chitosan through a chemical process, yielding the BNNT-GC. The size of BNNT-GC was reduced using an ultrasound probe. Two samples with different sizes were selected for in vitro assays. The nanostructures were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), thermal analysis (TGA), and dynamic light scattering (DLS). The in vitro assays MTT and neutral red (NR) were performed with NIH-3T3 and A549 cell lines and demonstrated that this material is not cytotoxic. Furthermore, the BNNT-GC was applied in gene transfection of plasmid pIRES containing a gene region that express a green fluorescent protein (GFP) in NIH-3T3 and A549 cell lines. The gene transfection was characterized by fluorescent protein produced in the cells and pictured by fluorescent microscopy. Our results suggest that BNNT-GC has moderate stability and presents great potential as a gene carrier agent in nonviral-based therapy, with low cytotoxicity and good transfection efficiency.