Boron Nitride Nanotubes for Curcumin Delivery as an Anticancer Drug: A DFT Investigation

The electrical properties and characteristics of the armchair boron nitride nanotube (BNNT) that interacts with the curcumin molecule as an anticancer drug were studied using ab initio calculations based on density functional theory (DFT). In this study, a (5,5) armchair BNNT was employed, and two different interactions were investigated, including the interaction of the curcumin molecule with the outer and inner surfaces of the BNNT. The adsorption of curcumin molecules on the investigated BNNT inside the surface is a more favorable process than adsorption on the outside surface, and the more persistent and stronger connection correlates with curcumin molecule adsorption in this case. Furthermore, analysis of the HOMO–LUMO gap after the adsorption process showed that the HOMO value increased marginally while the LUMO value decreased dramatically in the curcumin-BNNT complexes. As a result, the energy gaps between HOMO and LUMO (Eg) are narrowed, emphasizing the stronger intermolecular bonds. As a result, BNNTs can be employed as a drug carrier in biological systems to transport curcumin, an anticancer medication, and thereby improve its bioavailability.

Enhanced Catalytic Activity of Boron Nitride Nanotubes by Encapsulation of Nickel Wire Toward O2 Activation and CO Oxidation: A Theoretical Study

Perfect boron nitride (BN) nanotubes are chemically inert, and hardly considered as catalysts. Nevertheless, metal wire encapsulated BN nanotubes show extraordinarily high chemical activity. We report nickel (Ni) nanowire encapsulated BN(8.0) and BN(9.0) nanotubes toward O2 activation and CO oxidization on the basis of first-principles calculations. Our results suggest that Ni wire encapsulated BN(8.0) and BN(9.0) nanotubes can easily adsorb and activate O2 molecules to form peroxo or superoxo species exothermically. Meanwhile, superoxo species are ready to react with CO molecules forming OCOO intermediate state and finally yielding CO2 molecules. Meanwhile, the rate-limiting step barrier is only 0.637 eV, implying excellent performance for CO oxidation on Ni nanowire encapsulated BN nanotubes. Furthermore, encapsulation of nickel wire improves the catalytic activity of BN nanotubes by facilitating electron transfer from Ni wire to BN nanotubes, which facilitates the adsorption of highly electronegative O2 molecules and subsequent CO oxidation. This study provides a practical and efficient strategy for activating O2 on a metal encapsulated BN nanotube toward CO oxidation.

A Novel Biomimetic Nanocomposite Exhibiting Petal Wetting Phenomenon: Fabrication and Experimental Investigations

A functional composite material that simultaneously exhibits hydrophobicity and water droplet adhesion has monumental potential in controlling fluid flow, studying phase separation, and biological research. This article reports the fabrication of a petal wetting biomimetic Boron Nitride Nanotubes (BNNTs) -Polydimethylsiloxane (PDMS) nanocomposite achieved by drop casting. The petal effect was investigated by non-destructive techniques. The nanotubes were synthesized by chemical vapor deposition at 1150 °C and were characterized by X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. The mean diameter of the nanotubes was found to be 70 nm. The nanocomposites had BNNT fillers ranging from 0.5 wt. % to 2 wt. %. Water contact angles for pure PDMS polymer was 94.7° and for the 2 wt. % BNNT-PDMS nanocomposite was 132.4°. The petal wetting nanocomposite displayed a characteristic trait of high contact angle hysteresis. The surface roughness parameters of the nanocomposites were determined by atomic force microscopy. Laser scanning confocal microscopy aided in analyzing the droplet penetration and in observing the trapped air between the water droplet and the nanocomposite surface. Based on surface observations, roughness parameters, and the extent of droplet penetration by the surface, we shed light on the Cassie impregnating wetting regime followed by the biomimetic nanocomposite. Such a surface would be beneficial in the study of the embryogenesis of cells and aid in moisture collection.

Phonon Localization in Boron Nitride Nanotubes: Mixing Effect of 10B Isotopes and Vacancies

We explored the mixing effect of 10B isotopes and boron (B) or nitrogen (N) vacancies on the atomic vibrational properties of (10, 0) single-wall boron nitride nanotubes (BNNT). The forced oscillation technique was employed to evaluate the phonon modes for the entire range (0-100%) of 10B isotopes and atomic vacancy densities ranging from 0 to 30%. With increasing isotope densities, we noticed a blue-shift of the Raman active A1 phonon peak, whereas an increased density of mixed or independent B and N vacancies resulted in the emergence of a new low-frequency peak and the annihilation of the A1 peak in the phonon density-of-states. High-energy optical phonons were localized as a result of both 10B isotopes and the presence of mixing defects. We generated typical mode patterns for different defects to show the phonon localization processes due to the defects. We found an asymmetrical nature of the localization length with increasing 10B isotope content, which corresponds well with the isotope inherited localization length of carbon nanotubes and mono-layer graphene. The localization length falls abruptly with the increase in concentration of both atomic vacancies (B or N) and mixing defects (10B isotope and vacancies). These findings are critical for understanding heat conduction and nanoscopic vibrational investigations like tip-enhanced Raman spectra in BNNT, which can map local phonon energies.