Electronic Structure and Lithium Diffusion in LiAl2(OH)6Cl Studied by First Principle Calculations

Doxorubicin-Intercalated Li-Al-Based LDHs as Potential Drug Delivery Nanovehicle with pH-Responsive Therapeutic Cargo for Tumor Treatment

Clinical oncology is currently experiencing a technology bottleneck due to the expeditious evolution of therapy defiance in tumors. Although drugs used in chemotherapy work for a sort of cell death with potential clinical application, the effectiveness of chemotherapy-inducing drugs is subject to several endogenous conditions when used alone, necessitating the urgent need for controlled mechanisms. A tumor-targeted drug delivery therapy using Li-Al (M+/M3+)-based layered double hydroxide (LDHs) family has been proposed with the general chemical formula [M+1-x M3+x (OH)]2x+[(Am-)2x/m. n(H2O)]2x-, which is fully biodegradable and works in connection with the therapeutic interaction between LDH nanocarriers and anticancerous doxorubicin (DOX). Compositional variation of Li and Al in LDHs has been used as a nanoplatform, which provides a functional balance between circulation lifetime, drug loading capacity, encapsulation efficiency, and tumor-specific uptake to act as self-regulatory therapeutic cargo to be released intracellularly. First-principle analyses based on DFT have been employed to investigate the interaction of bonding and electronic structure of LDH with DOX and assess its capability and potential for a superior drug carrier. Following the internalization into cancer cells, nanoformulations are carried to the nucleus via lysosomes, and the mechanistic pathways have been revealed. Additionally, in vitro along with in vivo therapeutic assessments on melanoma-bearing mice show a dimensional effect of nanoformulation for better biocompatibility and excellent synergetic anticancer activity. Further, the severe toxic consequences associated with traditional chemotherapy have been eradicated by using injectable hydrogel placed just beneath the tumor site, and regulated release of the drug has been confirmed through protein expression applying various markers. However, Li-Al-based LDH nanocarriers open up new design options for multifunctional nanomedicine, which has intriguing potential for use in cancer treatment through sustained drug delivery.

The Effect of Lithium Ion Leaching from Calcined Li-Al Hydrotalcite on the Rapid Removal of Ni2+/Cu2+ from Contaminated Aqueous Solutions

A layered double hydroxide (LDH) calcined-framework adsorbent was investigated for the rapid removal of heavy metal cations from plating wastewater. Li-Al-CO₃ LDH was synthesized on an aluminum lathe waste frame surface to prepare the sorbent. The calcination treatment modified the LDH surface properties, such as the hydrophilicity and the surface pH. The change in surface functional groups and the leaching of lithium ions affected the surface properties and the adsorption capacity of the heavy metal cations. A zeta potential analysis confirmed that the 400 °C calcination changed the LDH surface from positively charged (+10 mV) to negatively charged (-17 mV). This negatively charged surface contributed to the sorbent instantly bonding with heavy metal cations in large quantities, as occurs during contact with wastewater. The adsorption isotherms could be fitted using the Freundlich model. The pseudo-second-order model and the rate-controlled liquid-film diffusion model successfully simulated the adsorption kinetics, suggesting that the critical adsorption step was a heterogeneous surface reaction. This study also confirmed that the recovered nickel and/or copper species could be converted into supported metal nanoparticles with a high-temperature hydrogen reduction treatment, which could be reused as catalysts.

Atomistic Insight into the Hydration States of Layered Double Hydroxides

Effective protective coatings are an essential component of lightweight engineering materials in a large variety of applications as they ensure structural integrity of the base material throughout its whole service life. Layered double hydroxides (LDHs) loaded with corrosion inhibitors depict a promising approach to realize an active corrosion protection for aluminum and magnesium. In this work, we employed a combination of density functional theory and molecular dynamics simulations to gain a deeper understanding of the influence of intercalated water content on the structure, the stability, and the anion-exchange capacity of four different LDH systems containing either nitrate, carbonate, or oxalate as potential corrosion inhibiting agents or chloride as a corrosion initiator. To quantify the structural change, we studied the atom density distribution, radial distribution function, and orientation of the intercalated anions. Additionally, we determined the stability of the LDH systems by calculating their respective hydration energies, hydrogen-bonded network connected to the intercalated water molecules, as well as the self-diffusion coefficients of the intercalated anions to provide an estimate for the probability of their release after intercalation. The obtained computational results suggest that the hydration state of LDHs has a significant effect on their key properties like interlayer spacing and self-diffusion coefficients of the intercalated anions. Furthermore, we conclude from our simulation results that a high self-diffusion coefficient which is linked to the mobility of the intercalated anions is vital for its release via an anion-exchange mechanism and to subsequently mitigate corrosion reactions. Furthermore, the presented theoretical study provides a robust force field for the computer-assisted design of further LDH-based active anticorrosion coatings.