Poster N17 - Differential Internalization of Biocompatible Chiral Borophene Nanoplatelets

Introduction: Chirality is one structural metric connecting biological and abiological forms of matter. Our knowledge of the chemistry and physics of chiral inorganic nanoparticles has advanced as a result of the last ten years of intensive research on two-dimensional (2D) materials and their relationships to intricate biological networks. Much research needs to be done before we can fully understand the effects of chiral (2D) borophene nanoplatelets on complex biological networks. Being polymorphic in nature borophene constitutes of different bonding patterns among boron atoms. Borophene stands apart from other 2D materials and allows for further customization of its material properties. This study introduces a synthetic method that can be utilized to produce chiral two-dimensional borophene nanoplatelets with various structural variations using chiral amino acids. Our method allows us to demonstrate that chiral borophene is biocompatible by internalization of them inside breast cancer cells. The borophene as we have observed in our study is biocompatible. Its internalization pathways have been studied in detail and has led into an understanding of how amino acids conjugated with borophene internalize through various mechanistic pathways. It is imperative for a new material’s comprehensive understanding to be able to show low toxicity, and chiral borophene has aced with being a potential candidate for biomedical applications.

Materials and

Methods: Borophene has been synthesized with continuous and intermittent sonication. Each giving a different phase of borophene. We have then used cysteine to conjugate with the bororphene. Finally these derivatives have been used to study cell internalization methods focusing in 5 mechanistic pathways. To understand how these agents are taken up by cells, we conducted mechanistic studies. To achieve this, we treated the cells with various inhibitors blocking a specific pathway involved in endocytic internalization of nanoplatelets. The outcome of this study would be a decrease cellular uptake of the nanoplatelets and feasibly increase the cellular viability. Sodium azide (NaN3) and 2-deoxyglucose (DOG) mixture was used to investigate the energy-dependent pathways by inhibiting glycogenosis and cellular respiration, respectively. Chlorpromazine (CPM) reduces the formation of clathrin-coated pits and was used to probe into the clathrin-dependent endocytosis. Dynasore inhibits dynamin (GTPase) dependence in the endocytosis process of cells and was consequently used. Nystatin was used to study clathrin-independent inhibition of endocytosis.

Results, Conclusions, and Discussions: Results and Discussions

The data obatined from the internalization pathways provided vital information. The pristine borophene was primarily internalized by dynamin mediated endocytosis (6.42%) and then minimally by clathrin-dependent endocytosis (1.58%). Bph-L-Cys internalized the cells mainly by energy-dependent pathways (7.47%) and minimally by dynamin mediated endocytosis (0.88%). On the other hand, Bph-D-Cys entered the cells primarily by clathrin-dependent endocytosis (17.44%) and clathrin-independent endocytosis (21.1%), whereas Bph-DL-Cys internalized the MDA-MB-231 cells by energy-dependent (1.66%) and clathrin-dependent endocytotic pathways (2.77%). This study confirmed that borophene derivatives have differential cellular internalization pathways depending on their chirality.

Conclusions

It was concluded with evidence that there is differential cellular internalization pathways followed by the chiral borophene derivative. The chiral borophene conjugates uptake has been confirmed from cellular toxicity data while incubating the MDA-MB-231 cells with different pathway inhibitors. Hyperspectral microscopic analyses also help consolidate differential cellular internalization. Through this study we gained insight into the synthetic organic-inorganic hybrid chiral nanostructures of borophene that may lead to significant progress in biological applications.

Acknowledgements (Optional): We would like to acknowledge Material Characterization Laboratory, Pennsylvania State University for their facilities. We would also like to acknowledge Dr. Christy George spectroscopist Chemistry department, Pennsylvania State University for the NMR analysis.