Surface adsorption of nitrosourea on pristine and doped (Al, Ga and In) boron nitride nanosheets as anticancer drug carriers: the DFT and COSMO insights

Ab Initio Study of the Graphyne-like γ-SiC Nanoflake for Toxic Gas-Sensing Applications

This study focuses on the geometrical, electronic, and optical properties of the γ-graphyne-like novel γ-SiC nanoflake of the γ-silicon carbide (SiC) monolayer using density functional theory calculations. γ-SiC was revealed to be a stable semiconducting nanoflake confirmed by a negative cohesive energy, real vibrational frequencies, and a 1.749 eV energy gap. The adsorption of COCl2, HCN, PH3, AsH3, CNCl, and C2N2 toxic gases on the γ-SiC nanoflake is also studied, which revealed an attractive gas-nanoflake interaction with the adsorption energy ranging from -0.21 to -0.38 eV. The adsorption results in a significant charge transfer between gas-adsorbent complexes. A significant variation in the energy gap and electrical conductivity was observed due to gas adsorption. γ-SiC showed maximum sensitivity at room temperature for CNCl gas. The entire process of adsorption is exothermic and thermodynamically stable. γ-SiC showed a high absorption coefficient over 104 orders with a significant variation in the absorption peak intensity and blue peak shifting. According to the quantum theory and reduced density gradient analysis, all of the gases are physisorbed on the γ-SiC nanoflake due to van der Waals interactions. The obtained results signify the usability of γ-SiC as a potential toxic gas sensor.

Phosphorus-doped T-graphene nanocapsule toward O3 and SO2 gas sensing: a DFT and QTAIM analysis

Tetragonal graphene nano-capsule (TGC), a novel stable carbon allotrope of sp2 hybridization is designed and doped with phosphorus (P) to study the O3 and SO2 gas sensitivity via density functional theory calculation. Real frequencies verified the natural existence of both TGC and P-doped TGC (PTGC). Both TGC and PTGC suffer structural deformations due to interaction with O3 and SO2 gases. The amount of charge transfer from the adsorbent to the gas molecule is significantly greater for O3 adsorption than SO2 adsorption. The adsorption energies for TGC + O3 and PTGC + O3 complexes are - 3.46 and - 4.34 eV respectively, whereas for TGC + SO2 and PTGC + SO2 complexes the value decreased to - 0.29 and - 0.30 eV respectively. The dissociation of O3 is observed via interaction with PTGC. A significant variation in electronic energy gap and conductivity results from gas adsorption which can provide efficient electrical responses via gas adsorption. The blue/red shift in the optical response proved to be a way of detecting the types of adsorbed gases. The adsorption of O3 is exothermic and spontaneous whereas the adsorption of SO2 is endothermic and non-spontaneous. The negative change in entropy verifies the thermodynamic stability of all the complexes. QTAIM analysis reveals strong covalent or partial covalent interactions between absorbent and adsorbate. The significant variation in electrical and optical response with optimal adsorbent-gas interaction strength makes both TGC and PTGC promising candidates for O3 and SO2 sensing.

In silico investigation on sensing of tyramine by boron and silicon doped C60 fullerenes

The present communication deals with the adsorption of tyramine neurotransmitter over the surface of pristine, Boron (B) and Silicon (Si) doped fullerenes. Density functional theory (DFT) calculations have been used to investigate tyramine adsorption on the surface of fullerenes in terms of stability, shape, work function, electronic characteristics, and density of state spectra. The most favourable adsorption configurations for tyramine have been computed to have adsorption energies of - 1.486, - 30.889, and - 31.166 kcal/mol, respectively whereas for the rest three configurations, it has been computed to be - 0.991, - 6.999, and - 8.796 kcal/mol, respectively. The band gaps for all six configurations are computed to be 2.68, 2.67, 2.06, 2.17, 2.07, and 2.14 eV, respectively. The band gap of pristine, B and Si doped fullerenes shows changes in their band gaps after adsorption of tyramine neurotransmitters. However, the change in band gaps reveals more in B doped fullerene rather than pristine and Si doped fullerenes. The change in band gaps of B and Si doped fullerenes leads a change in the electrical conductivity which helps to detect tyramine. Furthermore, natural bond orbital (NBO) computations demonstrated a net charge transfer of 0.006, 0.394, and 0.257e from tynamine to pristine, B and Si doped fullerenes.

A first-principles investigation of Cr adsorption on C8 and B4N4 nanocages in aqueous mediums

Heavy metal removal from polluted environments is one of the vital research areas for better and healthier living. In this research, C8 and B4N4 nanocage-like quantum dots are investigated for heavy metal (Cr) removal applications via density functional theory calculations. The adsorption of up to two Cr atoms has been studied in both air and a water medium. The adsorption of Cr atoms results in significant structural deformation of the adsorbents with a high adsorption energy of -8.74 and -5.77 eV for C8 and B4N4 nanostructures, respectively, which is further increased with an increasing number of Cr atoms. All adsorbents and complex structures showed real vibrational frequencies. Mulliken charge and electrostatic potential analysis reveal a significant charge transfer between adsorbate-adsorbent. The adsorption process causes a decrease in the energy gap of the adsorbents. All the reactions in this study were spontaneous and thermodynamically ordered. QTAIM analysis verifies that the interactions of the adsorbents with Cr atoms are strong partial covalent. The study's findings make C8 and B4N4 nanostructures potential candidates for Cr-detection and removal applications.

Investigation of the adsorption behavior of the anti-cancer drug hydroxyurea on the graphene, BN, AlN, and GaN nanosheets and their doped structures via DFT and COSMO calculations

To reduce the direct side effects of chemotherapy, researchers are trying to establish a new approach of a drug-delivery system using nanomaterials. In this study, we investigated graphene and its derivative nanomaterials for their favorable adsorption behavior with the anti-cancer drug hydroxyurea (HU) using DFT calculations. Initially, different pristine and doped graphene and its derivatives were taken into consideration as HU drug carriers. Among them, AlN, GaN, GaN-doped AlN, and AlN-doped GaN nanosheets exhibited favorable adsorption behavior with HU. The HU adsorbed on these four nanosheets with adsorption energies of -0.92, -0.75, -0.83, and -0.69 eV, transferring 0.16, 0.032, 0.108, and 0.230 e charges to the nanosheets, respectively, in air medium. In water solvent media, these four nanosheets interacted with HU by -0.56, -0.45, -0.58, and -0.56 eV by accepting a significant amount of charge of about 0.125, 0.128, 0.192, and 0.126 e from HU. The dipole moment and COSMO analysis also indicated that these nanosheets, except for GaN-doped AlN, show high asymmetricity and solubility in water solvent media due to the increased values of the dipole moment by two or three times after the adsorption of the HU drug. Quantum molecular descriptors also suggest that the sensitivity and reactivity of the nanosheets are enhanced during the interaction with HU. Therefore, these nanosheets can be used as anti-cancer drug carriers.

Exploring the adsorption ability with sensitivity and reactivity of C12-B6N6, C12-Al6N6, and B6N6-Al6N6 heteronanocages towards the cisplatin drug: a DFT, AIM, and COSMO analysis

The DFT study on the adsorption behaviour of the C24, B12N12, and Al12N12 nanocages and their heteronanocages towards the anticancer drug cisplatin (CP) was performed in gas and water media. Among the three pristine nanocages, Al12N12 exhibited high adsorption energy ranging from -1.98 to -1.63 eV in the gas phase and -1.47 to -1.39 eV in water media. However, their heterostructures C12-Al6N6 and B6N6-Al6N6 showed higher interaction energies (-2.22 eV and -2.14 eV for C12-Al6N6 and B6N6-Al6N6) with a significant amount of charge transfer. Noteworthy variations in electronic properties were confirmed by FMO analysis and DOS spectra analysis after the adsorption of the cisplatin drug on B12N12 and B6N6-Al6N6 nanocages. Furthermore, an analysis of quantum molecular descriptors unveiled salient decrement in global hardness and increments in electrophilicity index and global softness occurred after the adsorption of CP on B12N12 and B6N6-Al6N6. On the other hand, the above-mentioned fluctuations are not so noteworthy in the case of the adsorption of CP on Al12N12, C12-B6N6, and C12-Al6N6. Concededly, energy calculation, FMO analysis, ESP map, DOS spectra, quantum molecular descriptors, dipole moment, COSMO surface analysis, QTAIM analysis, and work function analysis predict that B12N12 and B6N6-Al6N6 nanocages exhibit high sensitivity towards CP drug molecules.

Density Functional Theory Interaction Study of a Polyethylene Glycol-Based Nanocomposite with Cephalexin Drug for the Elimination of Wound Infection

In this paper, density functional theory (DFT) simulations are used to evaluate the possible use of a graphene oxide-based poly(ethylene glycol) (GO/PEG) nanocomposite as a drug delivery substrate for cephalexin (CEX), an antibiotic drug employed to treat wound infection. First, the stable configuration of the PEGylated system was generated with a binding energy of -25.67 kcal/mol at 1.62 Å through Monte Carlo simulation and DFT calculation for a favorable adsorption site. The most stable configuration shows that PEG interacts with GO through hydrogen bonding of the oxygen atom on the hydroxyl group of PEG with the hydrogen atom of the carboxylic group on GO. Similarly, for the interaction of the CEX drug with the GO/PEG nanocomposite excipient system, the adsorption energies are computed after determining the optimal and thermodynamically favorable configuration. The nitrogen atom from the amine group of the drug binds with a hydrogen atom from the carboxylic group of the GO/PEG nanocomposite at 1.75 Å, with an adsorption energy of -36.17 kcal/mol, in the most stable drug-excipient system. Drug release for tissue regeneration at the predicted target cell is more rapid in moist conditions than in the gas phase. The solubility of the suggested drug in the aqueous media around the open wound is shown by the magnitude of the predicted solvation energy. The findings from this study theoretically validate the potential use of a GO/PEG nanocomposite for wound treatment application as a drug carrier for sustained release of the CEX drug.

Trivalent and Pentavalent atoms doped Boron nitride nanosheets as Favipiravir drug carriers for the treatment of COVID-19 using computational approaches

In our DFT investigations, pristine BNNS as well as trivalent and pentavalent atoms doped BNNS have been taken into consideration for Favipiravir (FPV) drug carriers for the treatment of COVID-19. Among the nanosheets, In doped BNNS (BN(In)NS) interacts with FPV by favorable adsorption energies about −2.44 and −2.38 eV in gas and water media respectively. The charge transfer analysis also predicted that a significant amount of charge about 0.202e and 0.27e are transferred to BN(In)NS in gas and water media respectively. HOMO and LUMO energies are greatly affected by the adsorption of FPV on BN(In)NS and energy gap drastically reduced by about 38.80 % and 64.07 % in gas and water media respectively. Similar results are found from the global indices and work function analysis. Therefore, it is clearly seen that dopant In atom greatly modified the BNNS and enhanced the adsorption behavior along with sensitivity, reactivity, polarity towards the FPV.

Two-dimensionalcovalent triazine frameworks as superior nanocarriers for the delivery of thioguanine anti-cancer drugs: a periodic DFT study

This work aims to introduce a superior nanocarrier for thioguanine (TG) anti-cancer drug delivery, drug release, and cancer therapy through computational chemistry.