Reactivity of chitosan derivatives and their interaction with guanine: A computational study

Interaction of glucosamine with uracil and thymine: a computational study

The present study delves into the interaction of the monomer of glucosamine with uracil and thymine in vacuum and in different phases by density functional theory (DFT). Both the molecular geometries were optimized at B3LYP with a 6-31G(d,p) basis set. The binding energy, interaction energy, and solubility were calculated from the optimized molecular geometry. The dipole moment and the electronic energies were found of the optimized product in different solvents (water, ethanol, methanol, heptane, cyclohexane, and CCl₄) which describes the solubility of the interactive molecule in polar and non-polar solvents. The electronic energies are nearly the same for all the solvents. Observed theoretical results are expected to guide future relevant experimental research on gene delivery by glucosamine. This will also help in enhancing pharmaceutical research as carrier drug delivery, tissue repair, gene delivery, spermicidal activity, anti-tumor, and anti-microbial resistance.

Potential of B24O24 nanocluster for sensing and delivering chlormethine anticancer drug: a DFT study

In the present research, the adsorption and release of chlormethine (CM) drug on the B₂₄O₂₄ nanocage have been reported in the water media and gas phase at GGA/PBE/DNP computational level. The interaction between B₂₄O₂₄ nanocage and CM drug shows that adsorptions of the chlormethine on B₂₄O₂₄ nanocage for the most stable complexes are - 1.47 to - 1.36 eV in the gas phase and water media, respectively. The CM adsorption caused a notable change in the band gap (E_g) and work function (Φ) of the B₂₄O₂₄ nanocage in the studied complexes. The binding of chlormethine to B₂₄O₂₄ also significantly increased the polarity of the drug carrier, which is a desirable property for drug delivery in biological environments. CM drugs can be released from the nanocage in the presence of an external electric field along the X-axis direction. The present study results show that the B₂₄O₂₄ nanocage is a possible carrier for delivering chlormethine drugs.

The validation of molecular interaction among dimer chitosan with urea and creatinine using density functional theory: In application for hemodyalisis membrane

The formation of chitosan dimer and its interaction with urea and creatinine have been investigated at the density functional theory (DFT) level (B3LYP-D3/6-31++G**) to study the transport phenomena in hemodialysis membrane. The interaction energy of chitosan-creatinine and chitosan-urea complexes are in range -4 kcal/mol < interaction energy <-20 kcal/mol which were classified in medium hydrogen bond interaction. The chemical reactivity parameter proved that creatinine was more electrophilic and easier to bind chitosan than urea. The energy gap of HOMO-LUMO of chitosan-creatinine complex was lower than chitosan-urea complex that indicating chitosan-creatinine complex was more reactive and easier to transport electron than chitosan-urea complex. Moreover, the natural bond orbital (NBO) analysis showed a high contribution of hydrogen bond between chitosan-creatinine and chitosan-urea. The chitosan-creatinine interaction has a stronger hydrogen bond than chitosan-urea through the interaction O18-H34....N56 with stabilizing energy = -13 kcal/mol. The quantum theory atom in molecule (QTAIM) also supported NBO data. All data presented that creatinine can make hydrogen bond interaction stronger with chitosan than urea, that indicated creatinine easier to transport in the chitosan membrane than urea during hemodialysis process.

Radiation-induced curcumin release from curcumin–chitosan polymer films

The probability of human exposure to damaging radiation is increased in activities associated with long-term space flight, medical radiation therapies, and responses to nuclear accidents. However, the development of responsive countermeasures to combat radiation damage to biological tissue is lagging behind rates of human exposure. Herein, we report a radiation-responsive drug delivery system that releases doses of curcumin from a chitosan polymer/film in response to low level gamma radiation exposure. As a fibrous chitosan–curcumin polymer, 1 Gy gamma irradiation (¹³⁷Cs) released 5 ± 1% of conjugated curcumin, while 6 Gy exposure releases 98 ± 1% of conjugated curcumin. The same polymer was formed into a film through solvent casting. The films showed similar, albeit attenuated behavior in water (100% released) and isopropyl alcohol (32% released) with statistically significant drug release following 2 Gy irradiation. ATR FT-IR studies confirmed glycosidic bond cleavage in the chitosan–curcumin polymer in response to gamma radiation exposure. Similar behavior was noted upon exposure of the polymer to 20 cGy (1 GeV amu⁻¹, at 20 cGy min⁻¹) high linear energy transfer (LET) ⁵⁶Fe radiation based on FTIR studies. Density Functional Theory calculations indicate homolytic bond scission as the primary mechanism for polymer disintegration upon radiation exposure. Films did not change in thickness during the course of radiation exposure. The successful demonstration of radiation-triggered drug release may lead to new classes of radio-protective platforms for developing countermeasures to biological damage from ionizing radiation.

The probability of human exposure to damaging radiation is increased in activities associated with long-term space flight, medical radiation therapies, and responses to nuclear accidents.