Chemotherapy drug temozolomide adsorbed onto iron-oxide (Fe3O4) nanoparticles as nanocarrier: A simulation study

Computer-aided nanodrug discovery: recent progress and future prospects

Nanodrugs, which utilise nanomaterials in disease prevention and therapy, have attracted considerable interest since their initial conceptualisation in the 1990s. Substantial efforts have been made to develop nanodrugs for overcoming the limitations of conventional drugs, such as low targeting efficacy, high dosage and toxicity, and potential drug resistance. Despite the significant progress that has been made in nanodrug discovery, the precise design or screening of nanomaterials with desired biomedical functions prior to experimentation remains a significant challenge. This is particularly the case with regard to personalised precision nanodrugs, which require the simultaneous optimisation of the structures, compositions, and surface functionalities of nanodrugs. The development of powerful computer clusters and algorithms has made it possible to overcome this challenge through in silico methods, which provide a comprehensive understanding of the medical functions of nanodrugs in relation to their physicochemical properties. In addition, machine learning techniques have been widely employed in nanodrug research, significantly accelerating the understanding of bio-nano interactions and the development of nanodrugs. This review will present a summary of the computational advances in nanodrug discovery, focusing on the understanding of how the key interfacial interactions, namely, surface adsorption, supramolecular recognition, surface catalysis, and chemical conversion, affect the therapeutic efficacy of nanodrugs. Furthermore, this review will discuss the challenges and opportunities in computer-aided nanodrug discovery, with particular emphasis on the integrated "computation + machine learning + experimentation" strategy that can potentially accelerate the discovery of precision nanodrugs.

TiO2 nanorod arrays@PDA/Ag with biomimetic polydopamine as binary mediators for duplex SERS detection of illegal food dyes

Based on TiO2 nanorod arrays@PDA/Ag (TNRs@PDA/Ag), a better surface-enhanced Raman scattering (SERS) sensor with effective enrichment and enhancement was investigated for duplex SERS detection of illicit food dyes. Biomimetic PDA functions as binary mediators by utilizing the structural characteristics of polydopamine (PDA), which include the conjugated structure and abundant hydrophilic groups. One PDA functioned as an electron transfer mediator to enhance the efficiency of electron transfer, and the other as an enrichment mediator to effectively enrich rhodamine B (RhB) and crystal violet (CV) through hydrogen bonding, π-π stacking, and electrostatic interactions. Individual and duplex detection of illicit food dyes (RhB and CV) was performed using TNRs@PDA/Ag to estimate SERS applications. Their linear equations and limits of detection of 1 nM for RhB and 5 nM for CV were derived. Individual and duplex food colour detection was successfully accomplished even in genuine chili meal with good results. The bifunctional TNRs@PDA/Ag-based highly sensitive and duplex SERS dye detection will have enormous potential for food safety monitoring.

DFT investigation of temozolomide drug delivery by pure and boron doped C24 fullerene-like nanocages

In this paper, the DFT/M05-2X-D3/6-31+G(d,p) theoretical chemistry method is used to probe the adsorption ability of pure and boron doped C24 toward the temozolomide (TMZ) anticancer drug. The study is conducted in both gas and aqueous phases. The positive values of the Gibbs free energy of formation (12.03, 9.14 and 2.51 kcal mol-1) show that the adsorption of TMZ on C24 is not allowed. However, the boron-doped C24 (BC23) forms a very stable molecular complex with TMZ in the gas phase, characterized by the adsorption energy and Gibbs free energy values of -32.07 and -21.27 kcal mol-1 respectively. Analysis of Hirshfeld's atomic charge revealed the transfer of 0.6395e from TMZ to BC23, which is confirmed by the value of the dipole moment of the complex (13.42 D in the gas phase) as well as its molecular electrostatic potential map. The change in the frontier molecular orbital energy difference of BC23 is found to be 21.67% proving the good sensitivity of the cage toward the drug. The TMZ-BC23 molecular complex is very stable in water though the sensitivity of the cage is hugely reduced in that solvent. The reliability of these results was confirmed by checking the outcomes at both wB97XD/6-31+G(d,p) and B3LYP-D3/6-31+G(d,p) levels. This work shows that pristine BC23 is a better adsorbent of TMZ than some reported nanomaterials from the theoretical chemistry point of view.

DFT investigation on the application of pure and doped X12N12 (X = B and Al) fullerene-like nano-cages toward the adsorption of temozolomide

The sensitivity of pure and doped X₁₂N₁₂ (X = B and Al) fullerene-like nano-cages (FLNs) toward the anti-cancer drug temozolomide (TMZ) is probed herein at DFT/M06-2X-D3/6-311G(d,p) theoretical level in both gas phase and water. A noticeable affinity of the FLNs toward TMZ was observed along with the negative gas-phase adsorption energies -1.37 and -2.09 eV for the most stable configurations of pure B₁₂N₁₂ and Al₁₂N₁₂ pristines, respectively. Considerable charge transfer from TMZ to the FLNs was also revealed via NBO analysis and the Hirshfeld atomic charges, making the dipole moment vector of the molecular complexes to be oriented from the nano-cages to the TMZ moiety. Furthermore, a percentage decrease in the HOMO-LUMO energy gap (ΔE _g) of 38.09 and 17.72% was obtained for the B₁₂N₁₂ and Al₁₂N₁₂ nano-cages, respectively. The percentage change in ΔE _g was found to be reduced upon doping and solvation of the FLNs. Finally, a recovery time in vacuum ultraviolet light of 1.06 s is found for the complex with pure B₁₂N₁₂, which in addition to the above-mentioned parameters make this boron nitride cage the best sensor for TMZ, among the FLNs considered in the present work.

A molecular dynamics study concerning the effect of high-temperature and high-pressure on the structure and phase transition of Fe₂O₃ material

<abstract> <p>This paper uses Molecular Dynamics (MD) method to study the influence of high temperature (T) and high pressure (P) on the structure and phase transition of Fe₂O₃ materials. The results show that, when increasing the temperature from T = 300 K to T = 7000 K, P = 0.0 GPa, the size (1) of the Fe₂O₃ materials increases, the energy (E) increases, the length link (r) decreased, the number of structural units FeO₄, FeO₅ increased, and FeO₆ decreased. Similarly, as the pressure (P) is increased, from P = 0 GPa to P = 360 GPa at temperatures T, l decreases, E increases, r decreases, FeO₄ decreases and disappears, FeO₅ decreases, and FeO₆ increases at high P with P ≥ 150 GPa, FeO₅ disappeared at P ≥ 250 GPa and only FeO₆ appeared at T = 2300, 7000 K. In addition, when increasing T, P, the bond angle of Fe–O–Fe, O–Fe–O decreases, E increases, r decreases, l increases when T increases and l decreases when P increases, leading to the number of structural units FeO₄, FeO₅ increasing and FeO₆ decreasing when T increases and vice versa when P increases. In addition, the phase transition temperature (T_m), T_m = 2300 K was determined. All the obtained results will be the basis for future experimental studies of amorphous Fe₂O₃ materials.</p> </abstract>

Increasing DNA binding affinity of doxorubicin by loading on Fe3O4 nanoparticles: A multi-spectroscopic study

Magnetic Fe₃O₄ nanoparticles were synthesized successfully by co-precipitation method and characterized using XRD, SEM and EDS analyses. Then doxorubicin (DOX, a known anticancer drug) was loaded onto nanoparticles. In vitro DNA interaction of free DOX and loaded DOX onto Fe₃O₄ nanoparticles (DOX-Fe₃O₄) was investigated by DNA-viscosity measurements, UV-visible and fluorescence spectroscopies. The obtained values for binding constant of DOX and DOX-Fe₃O₄ compounds from UV-visible spectroscopies were 0.04 × 10⁵ and 0.68 × 10⁵ L mol^-1, respectively, which confirms DOX-Fe₃O₄ compound have a stronger interaction with CT-DNA compared to DOX. Considerable changes on viscosity of the compounds recommended that their binding mode with CT-DNA is intercalative binding. Fluorescence intensity of DOX and DOX-Fe₃O₄ was quenched via static process by regular addition of CT-DNA. Thermodynamic parameters suggest that Van der Waals forces and hydrogen bonding for DOX and electrostatic forces for DOX-Fe₃O₄ are predominantly responsible for interaction with CT-DNA. Competition fluorescence studies were done by Hoechst 33258 as a well-known groove binder and ethidium bromide (EtBr) as a known intercalator probe. Percentage of displacement for EtBr-DNA complex with DOX and DOX-Fe₃O₄ was 39% and 61%, and for Hoechst-DNA complex was 9% and 5%, respectively. These results confirmed that both compounds are intercalator binders, although DOX-Fe₃O₄ with a further 22% displacement is a stronger intercalator binder than DOX. The stronger interaction of DOX-Fe₃O₄ compared to DOX suggests that the current system can be used as a new and effective way to targeted therapy of anticancer drugs.