Analgesic molecules interleaved between layered double hydroxide: Exchange versus in situ reaction and release properties

Nanoarchitectured two-dimensional layered double hydroxides-based nanocomposites for biomedical applications

Despite the exceptional physicochemical and morphological characteristics, the pristine layered double hydroxides (LDHs), or two-dimensional (2D) hydrotalcite clays, often suffer from various shortcomings in biomedicine, such as deprived thermal and chemical stabilities, acid-prone degradation, as well as lack of targeting ability, hampering their scale-up and subsequent clinical translation. Accordingly, diverse nanocomposites of LDHs have been fabricated by surface coating of organic species, impregnation of inorganic species, and generation of core-shell architectures, resulting in the complex state-of-the-art architectures. In this article, we initially emphasize various bothering limitations and the chemistry of these pristine LDHs, followed by discussions on the engineering strategies of different LDHs-based nanocomposites. Further, we give a detailed note on diverse LDH nanocomposites and their performance efficacy in various biomedical applications, such as drug delivery, bioimaging, biosensing, tissue engineering and cell patterning, deoxyribonucleic acid (DNA) extraction, as well as photoluminescence, highlighting the influence of various properties of installed supramolecular assemblies on their performance efficacy. In summary, we conclude with interesting perspectives concerning the lessons learned to date and the strategies to be followed to further advance their scale-up processing and applicability in medicine.

Specific lift-up behaviour of acetate-intercalated layered yttrium hydroxide interlayer in water: application for heterogeneous Brønsted base catalysts toward Knoevenagel reactions

The basal (00l) plane of acetate-intercalated layered yttrium hydroxide (CH3COO−/Y-LRH), synthesised by an anion exchange using Cl−/Y-LRH as a parent material, increased in water, and the lifted-up layered structure was generated immediately.

Layered Double Hydroxides as Promising Excipients for Drug Delivery Purposes

Layered Double Hydroxides (LDH) have received great attention in the development of drug carrier systems. LDHs have become intelligent excipients of high technological potential for the pharmaceutical industry due to their ability to intercalate biomaterials in the interlayer region, adsorb substances on its vast surface area, have flexible structure, swelling properties, high chemical and thermal stability, modulate drug release, have high biocompatibility and be easily synthesized. This article, using typical examples, mainly addresses the systems formed between LDHs and antimicrobial, antineoplastic and anti-inflammatory agents, which constitute the main pharmacological classes of wide interest due to the problems encountered with low solubility, control in administration, stability in body fluids and toxicity, among others. Additionally, the article also reports on the recent development of ternary or quaternary (multicomponent systems) compounds based on LDH, bringing the advantages of targeted therapy, improving the aqueous stability of nanohybrids and the performance of these inorganic carriers.

Solvent-Mediated and Mechanochemical Methods for Anion Exchange of Carbonate from Layered Double Hydroxides Using Ammonium Salts

Deintercalation of carbonate from layered double hydroxides (LDH) followed by intercalation of another anion (decarbonative intercalation) is a good method for the synthesis of crystalline LDH with different intercalated anions. We have carried out decarbonative intercalation of halides, nitrate, acetate, and sulfate by refluxing the carbonate-LDH with the corresponding ammonium salt in 1-butanol to obtain ordered LDH incorporating the desired anion. The crystallinity of the precursor LDH is retained in the anion-exchanged products, making this reaction a useful tool to prepare ordered LDH containing various anions. In addition, the morphology of the LDH is also retained after the exchange, making the reaction morphotactic. As the reaction is facilitated by the weak acidity of the ammonium salt, just grinding the carbonate-LDH with the ammonium salt of the desired anion also results in anion exchange. However, while the crystallinity of the LDH is retained, the morphology changes possibly due to breaking up of the crystals during the reaction.