Anti-bacterial efficacy of Boron Nanosheet against clinical isolates and its in vivo toxicity assessment using Artemiasalina.

Microbes have been increasing their potential against newly developed drugs and antibiotics daily. The increased microbial drug resistance is still a challenging societal inconvenience. 2D nanomaterials, such as graphene, fascinate researchers with their unique physical and chemical properties and have a major role in current science and technology. Nowadays, researchers have been replacing graphene with its analogous 2D material, borophene, which is a single layer of boron with a honeycomb plane. Boron nanosheets which are theoretically investigated, have been synthesized by various top-down and bottom-up approaches. Our study focuses on synthesizing boron-based material from the precursor MgB which possesses a honeycomb boron structure with sandwiched Mg atoms. The Mg atoms have been selectively removed using the chelating agents at alkaline pH. The synthesized boron nanosheets have been characterized by FT-IR, Raman, XRD, FESEM, EDS, and TGA. The formation of B-H-B, B-B and B-O bond is confirmed by FT-IR and Raman spectra. It is also evident from XPS spectra which possess B1s spectra at 193 eV. The efficient chelation and exfoliation is confirmed by EDS and FESEM analysis which shows the presence of boron and trace amount of Mg with bark like projections. Though there are several studies on antibacterial activity of compounds, generally the studies are with laboratory cultures of bacterial strains. Clinical studies offer more valid results and are very sparse in literature. The use of clinical strains in the present study is one of the novelty. It has also been analyzed for its anti-bacterial activity against clinical strains of B. subtilis, S. aureus, E. coli, and K. pneumonia. Boron nanosheets possess an enhanced zone of inhibition (8 mm, 11 mm) against clinical strains of B. subtilis where the micro dilution studies show MIC and MBC values as 125 μg and 62.5 μg. The in vivo toxicity studies carried out using Brine Shrimp Lethality Assay reveal higher LC50 values of boron nanosheets (>1 mg/ml), which in turn portrays its non-toxic nature. Thus, the synthesized boron nanosheets are toxic to multidrug-resistant B. subtilis where it is non-toxic to mammalian cells. Thus, the study could advance the applications of borophene in biomedical applications.