Hexagonal Boron Nitride Functionalized with Au Nanoparticles—Properties and Potential Biological Applications

Abstract

Hexagonal boron nitride is often referred to as white graphene. This is a 2D layered material, with a structure similar to graphene. It has gained many applications in cosmetics, dental cements, ceramics etc. Hexagonal boron nitride is also used in medicine, as a drug carrier similar as graphene or graphene oxide. Here we report that this material can be exfoliated in two steps: chemical treatment (via modified Hummers method) followed by the sonication treatment. Afterwards, the surface of the obtained material can be efficiently functionalized with gold nanoparticles. The mitochondrial activity was not affected in L929 and MCF-7 cell line cultures during 24-h incubation, whereas longer incubation (for 48, and 72 h) with this nanocomposite affected the cellular metabolism. Lysosome functionality, analyzed using the NR uptake assay, was also reduced in both cell lines. Interestingly, the rate of MCF-7 cell proliferation was reduced when exposed to h-BN loaded with gold nanoparticles. It is believed that h-BN nanocomposite with gold nanoparticles is an attractive material for cancer drug delivery and photodynamic therapy in cancer killing.

Few-Layered Hexagonal Boron Nitride: Functionalization, Nanocomposites, and Physicochemical and Biological Properties

“…The optimization to use two-step exfoliation technique combining chemical and mechanical exfoliation was also reported [29]. Chemical exfoliation of h-BN was carried out by a modified Hummer's method.…”

“…In research [29] simple and repeatable Au-fBN nanocomposite synthesis method was demonstrated. Briefly, exfoliated h-BN was sonicated in distilled water.…”

“…The biocompatibility of h-BN-based nanocomposites synthesized in studies [29,41] was determined in three main steps. The first step of the in vitro study was based on morphological cell analysis.…”

“…In the third step of the study, a comparison of biocompatibility results of the fBN-OH and Au-fBN nanocomposites at 3.125, 6.25, 10.0, 12.5, 25.0, 50.0, 100.0, and 200.0 μg mL −1 concentrations was determined using Cell Counting Kit-8 (CCK-8), neutral red uptake (NRU), and lactate dehydrogenase leaking (LDH) assays (Figure 10) [29]. The highest reduction of the cell viability was recorded at the concentrations of 100.0-200.0 μg mL −1 for fBN-OH and 200.0 μg mL −1 for Au-fBN in L929 cell cultures incubated for 48 hours (Figure 10).…”

“…Thus, the h-BN preparation (e.g., exfoliation, functionalization) should be optimized to obtain a nanomaterial that exhibits suitable properties in required applications (e.g., higher hydrophobicity that allows stable dispersion in aqueous solutions) [41]. The functionalization of the h-BN by hydroxyl groups improve h-BN hydrophobicity and allows to obtain stable dispersion in phosphate buffer solution [41] or in phosphate buffer solution supplemented with dispersant Pluronic F-127 [29]. This is crucial for cytotoxicity experimentations and biological/medical applications.…”