Folate conjugation improved uptake and targeting of porous hydroxyapatite nanoparticles containing epirubicin to cancer cells

As hydroxyapatite (HAp) with the hexagonal crystal structure is biocompatible and bioactive. In the present study, HAp nanoparticles were synthesized and functionalized with polyethylene glycol and folic acid. The anticancer drug, epirubicin, was loaded to the folic acid-conjugated polyethylene glycol-coated HAp (FA-PEG-HAp) nanoparticles. The prepared nanoparticles were used for in vitro and in vivo experiments. Particle size analyzer showed that the hydrodynamic size of PEG-HAp and FA-PEG-HAp nanoparticles was 150.3 ± 1.5 nm and 217.2 ± 14.9 nm, respectively. The release behavior of epirubicin from nanoparticles showed an increase in the rate of release in acidic pH. The released drug in acidic pH was 2.5 fold more than pH 7.4. The results of in vitro study indicated an increase in cellular uptake of nanoparticles due to folate ligand. In vivo treatment with both PEG-HAp and FA-PEG-HAp nanoparticles had notably higher inhibition efficacy towards tumor growth than free epirubicin. In conclusion, folate conjugation provided higher uptake and better targeting of hydroxyapatite nanoparticles to cancer cells.

Corrosion protection mechanism of Ce4+/organic inhibitor for AA2024 in 3.5% NaCl

Cerium is a rare earth element that has been widely proposed for the corrosion protection of aluminium alloys (AA). Both cerium salts, Ce³⁺ and Ce⁴⁺, have been used in combination with other compounds to offer synergistic inhibition, however, the inhibitive corrosion mechanism when using Ce⁴⁺ with organic compounds is still not clear. In this study, the synergistic inhibition effect of Ce⁴⁺ and melamine (M) on the corrosion of aluminium alloy 2024 (AA2024) in 3.5% NaCl solution was investigated. Potentiodynamic Polarization (PDP) and Electrochemical Impedance Spectroscopy (EIS) techniques were used to study the synergistic effect of different Ce⁴⁺/M ratios on the corrosion behaviour of AA2024. The PDP study showed that a combination of 50% Ce⁴⁺ and 50% M leads to the lowest corrosion rates, both acting as cathodic inhibitors. Both PDP and EIS results indicated that M or Ce⁴⁺ in isolation did not offer effective corrosion protection, while the combination of M and Ce⁴⁺ significantly enhances the corrosion protection with a synergism parameter equal to 3.5. SEM and EDX observations confirm the findings from the electrochemical techniques. XPS was used to investigate the mechanism of protection, revealing that the reduction of Ce⁴⁺ to Ce³⁺ occurs during protection of AA2024. A new mechanism of corrosion synergistic inhibition by Ce⁴⁺ and organic compounds is postulated where the role of the organic compounds is to enhance the reduction of Ce⁴⁺.

Proposed corrosion protection mechanism of Ce⁴⁺/ organic inhibitor for AA2024.

Synthesis of triblock copolymeric micelle based on poly (ethylene glycol) and poly (vinyl acetate) through reversible addition-fragmentation chain transfer polymerization

HYPOTHESIS

Polymeric micelles are fabricated by the self-aggregation of amphiphilic polymers in aqueous medium. Amphiphilic block copolymers consist of hydrophobic and hydrophilic blocks. The hydrophilic blocks form corona, while hydrophobic blocks produce core of the micelle.

EXPERIMENTS

In the present manuscript, a triblock copolymer derived from poly (ethylene glycol) and poly (vinyl acetate) (PVAc-b-PEG₂₀₀-b-PVAc) has been prepared via reversible addition-fragmentation chain transfer polymerization. Its structural properties as well as micellar stability have been studied and application as dye carrier has been discussed in details.

FINDINGS

The GPC analysis shows the low polydispersity of the developed copolymer that signifies the controlled nature of polymerization. The copolymer demonstrates long-term micellar stability, which has been determined by dynamic light scattering (DLS) analysis. The block copolymer reveals excellent pH-triggered release behavior of loaded Nile red, which ascertained the dye carrier feature of PVAc-b-PEG₂₀₀-b-PVAc.

High-Temperature and High-Pressure Pyrolysis of Hexadecane: Molecular Dynamic Simulation Based on Reactive Force Field (ReaxFF)

As important products of heavy oil pyrolysis, heavier components such as gasoline and diesel supply the vast majority of energy demand through combustion, and lighter components such as ethylene and propylene are the main sources of industrial chemicals and plastic products. In this work, pyrolysis of hexadecane, as the model compound, was studied by reactive force field (ReaxFF) molecular simulation at high temperatures and high pressures. It was confirmed by unimolecular simulations that there exist eight different initial mechanisms all starting with C-C bond dissociation. The biradical mechanism was verified, through which the pyrolysis process can be accomplished within a shorter time. The enthalpy of reaction was calculated by the QM method, which was well consistent with ReaxFF calculation results. Multimolecular simulations showed that there is a strong dependency relationship between products distribution and temperature, as well as that between reaction rates and temperature. The optimal condition for ethylene formation in our work is 11.6 MPa and 2000 K, whereas it is best for hydrogen formation at conditions of 11.6 MPa and 3500 K. Kinetic analysis was performed with the activation energy of 113.03 kJ/mol and pre-exponential factor of 4.55 × 10¹², and it is in good agreement with previous work.