Riboflavin Adsorption on h-BN for Drug Delivery Applications

The paper was published in International Journal of Molecular Sciences.

The presented study employed density functional theory (DFT) simulations to comprehensively investigate the adsorption behavior of riboflavin (Rf) on both defect-free and vacancy-containing hexagonal boron nitride systems. The findings reveal that the Rf molecule undergoes physical adsorption on the surface of the carrier, exhibiting minimal alteration in its chemical structure.

The most stable configuration observed involves the parallel alignment of the riboflavin molecule with the h-BN surface, forming π-π stacking interactions. This is corroborated by the adsorption energies obtained at various positions of the drug molecule. The molecular orbitals of riboflavin's isosurfaces provides a comprehensive understanding of the binding nature between riboflavin and h-BN based on the HOMO and LUMO location on the isoalloxazine site.

Remarkably, the presence of nitrogen vacancies significantly impacts the binding characteristics, as the carriers interact with the vacant riboflavin orbitals. Consequently, riboflavin transforms into an electron acceptor in the BN(Nv)@Rf system, attracting electron density by approximately 0.5 e-. This behavior starkly contrasts with the interactions observed in defect-free h-BN and h-BN with boron vacancies (BN(Bv)), see the Figure.

Distribution of spatial charge density difference in (a) BN@Rf, (b) BN(Bv)@Rf and (c) BN(Nv)@Rf structures and corresponding freestanding parts, side and top view. The loss and gain of charge are denoted by blue and yellow clouds, respectively. The boron, nitrogen, carbon, oxygen, and hydrogen atoms are marked by green, blue, black, red and cyan colors, respectively

These results validate the potential of h-BN as a promising carrier for riboflavin molecules, as the π-π bond formed between the drug and the carrier exhibits substantial strength, providing a solid foundation for drug delivery systems. However, it is crucial to exercise control over the structural perfection of h-BN, as the presence of vacancies can induce charging on riboflavin.

In summary, our study provides valuable insights into the stability and interactions of vitamin B2 with hexagonal boron nitride. The comprehensive understanding gained regarding their binding characteristics and the influence of defects enhances our ability to design and optimize drug delivery systems based on h-BN.

Funding application supported

The project of our team "Modelling of low-dimensional magnetic heterostructures for next-generation spintronic devices" was supported by the Russian Science Foundation!»

The challenge of finding new ways of storing and processing information is extremely relevant nowadays, as traditional silicon technologies have actually reached the limit of information recording density and further miniaturization. One solution to this problem is to consider the electron as a charge carrier with two main "degrees of freedom" determined by its spin. Thus, due to giant and tunnel magnetoresistance effects, spin transfer effects and a number of other fundamental properties, spintronic devices, the basis of a new generation of information storage and processing technology, are now being actively developed. However, despite the proven high potential of spintronic technology (in terms of low power consumption and speed), it is still in its infancy in the consumer market. magnetoresistive random-access memory (MRAM) is expected to be able to compete with conventional flash memories. But to achieve this, a number of challenges must be met, requiring advances in the synthesis of stable nanoscale heterostructures and ways to control their properties at the atomic level. Two-dimensional materials can play a key role in solving these problems. Indeed, since the discovery of graphene and related materials, atomic-thick films have been viewed as a potential component of ultra-compact device architecture and radically new ways to process information. Scientific advances in spintronic devices based on 2D materials, as well as recent progress in large-scale co-integration of 2D structures with traditional microelectronic materials, have opened promising prospects for MRAM technology development. The project proposes the first comprehensive theoretical investigation of a range of promising magnetic tunneling junctions (MTJ) based on ferromagnetic and 2D materials, for which magnetoresistance and spin injection effects - the basis of spin valves and transistors - can be observed. For example, new interfaces based on iron and cobalt, including half-metallic Heusler alloys, and their heterojunction with two-dimensional structures such as graphene and transition metal dichalcogenides with different compositions will be investigated. Despite the wide popularity of these materials separately, heterostructures based on them are poorly understood, and experimental work and further applications for spintronic applications require a detailed theoretical analysis of the structure, properties and nature of the spintronic effects. In this project, quantum-chemical simulations and nonequilibrium transport methods will be used for the first time to obtain detailed information on the electronic and magnetic configuration of the most promising MTJs, to describe the equilibrium properties of heterojunctions, and to calculate the quantum conductivity and to study the tunneling magnetoresistance effect. Moreover, tunnel heterostructures with an embedded MoO3 oxide layer, a promising for efficient spin injection in two-dimensional materials due to the proximity effect, will be modelled and studied for the first time. The results will significantly extend the field of knowledge about the spin-transport properties of new magnetic heterostructures based on experimentally known ferromagnetic materials and two-dimensional films. The prospects for their application in magnetoresistive and other spintronic devices will also be substantiated in detail.

The project PI is Dr. Konstantin Larionov

Master thesis defence of the MIPT student Vladimir Prenas

Congratulations to Vladimir Prenas on the excellent defense of his master's thesis "Features of the atomic structure and mechanical properties of nanostructures of various dimensions containing mainly sp3-bonds"!

The defense took place on June 22, 2023 at the FSBI TISNCM at the base department of physics and chemistry of nanostructures of the Moscow Institute of Physics and Technology