Nanoclays in drug delivery systems

Synthesis and application of polyacrylamide hydrogels with incorporated acid-activated Laponite® for diagnosis of oncological diseases

Hydrogels with incorporated acid-activated Laponite® (LapA) platelets represent a new generation of biomaterials with promising biomedical application (e.g., diagnostics and therapy). The LapA nanomaterial have high specific surface area and demonstrate rather attractive hydrophilic properties. The physical cross-linking of hydrogels using the LapA allowed a significant improvement the systems homogeneity, transparency, and drug transport in these systems. In general incorporation of LapA may also affect the equilibrium degree of swelling at phase-transition from the swollen to the shrunken phase. In this work the effectiveness of using of polyacrylamide hydrogels (PAAG) with incorporated LapA for diagnosis of oncological diseases was studied. The synthesis procedure was performed using ultrasonication of aqueous dispersion of mixtures of monomer, crosslinking agent and initiators. The PAAG+LapA samples were characterized using SEM and PAAG swelling techniques. SEM images evidenced the presence of integration of LapA platelets into the hydrogel structure and formation of the shells of aggregated LapA particles. It can be explained by the formation of more active forms of LapA with stronger internal bonds. Effects of Lap, LapA concentration on the swelling kinetics and the maximal swelling degree were also evaluated. The the maximal equilibrium degree of swelling Qmax was reached within the first 5 hours. The concentration of platelets affected the value of Qmax, initially it decreased up to the minimum Qmax » 7.6 g/g at CLap » 0.04 % and then increased at higher concentrations. For these samples the protein separation spectrum of peripheral blood plasma was studied using the sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) technique. Peripheral blood plasma samples obtained from the donors, and colorectal cancer patients without distant metastases and with distant metastases were studied. The better separation of human plasma proteins was observed in hydrogels with incorporated LapA platelets. In future studies it is desirable to test these new SDS-PAGE materials for diagnostics of different forms of cancer diseases.

Chitosan-Clay Mineral Nanocomposites with Antibacterial Activity for Biomedical Application: Advantages and Future Perspectives

Polymers of natural origin, such as representatives of various polysaccharides (e.g., cellulose, dextran, hyaluronic acid, gellan gum, etc.), and their derivatives, have a long tradition in biomedical applications. Among them, the use of chitosan as a safe, biocompatible, and environmentally friendly heteropolysaccharide has been particularly intensively researched over the last two decades. The potential of using chitosan for medical purposes is reflected in its unique cationic nature, viscosity-increasing and gel-forming ability, non-toxicity in living cells, antimicrobial activity, mucoadhesiveness, biodegradability, as well as the possibility of chemical modification. The intuitive use of clay minerals in the treatment of superficial wounds has been known in traditional medicine for thousands of years. To improve efficacy and overcome the ubiquitous bacterial resistance, the beneficial properties of chitosan have been utilized for the preparation of chitosan-clay mineral bionanocomposites. The focus of this review is on composites containing chitosan with montmorillonite and halloysite as representatives of clay minerals. This review highlights the antibacterial efficacy of chitosan-clay mineral bionanocomposites in drug delivery and in the treatment of topical skin infections and wound healing. Finally, an overview of the preparation, characterization, and possible future perspectives related to the use of these advancing composites for biomedical applications is presented.

Nanoclay-Composite Hydrogels for Bone Tissue Engineering

Nanoclay-composite hydrogels represent a promising avenue for advancing bone tissue engineering. Traditional hydrogels face challenges in providing mechanical strength, biocompatibility, and bioactivity necessary for successful bone regeneration. The incorporation of nanoclay into hydrogel matrices offers a potential unique solution to these challenges. This review provides a comprehensive overview of the fabrication, physico-chemical/biological performance, and applications of nanoclay-composite hydrogels in bone tissue engineering. Various fabrication techniques, including in situ polymerization, physical blending, and 3D printing, are discussed. In vitro and in vivo studies evaluating biocompatibility and bioactivity have demonstrated the potential of these hydrogels for promoting cell adhesion, proliferation, and differentiation. Their applications in bone defect repair, osteochondral tissue engineering and drug delivery are also explored. Despite their potential in bone tissue engineering, nanoclay-composite hydrogels face challenges such as optimal dispersion, scalability, biocompatibility, long-term stability, regulatory approval, and integration with emerging technologies to achieve clinical application. Future research directions need to focus on refining fabrication techniques, enhancing understanding of biological interactions, and advancing towards clinical translation and commercialization. Overall, nanoclay-composite hydrogels offer exciting opportunities for improving bone regeneration strategies.

Physico-Chemical Properties of Laponite®/Polyethylene-oxide Based Composites

This review aims to provide a literature overview as well as the authors' personal account to the studies of Laponite® (Lap)/Polyethylene-oxide (PEO) based composite materials and their applications. These composites can be prepared over a wide range of their mutual concentrations, they are highly water soluble, and have many useful physico-chemical properties. To the readers' convenience, the contents are subdivided into different sections, related with consideration of PEO properties and its solubility in water, behavior of Lap systems(structure of Lap-platelets, properties of aqueous dispersions of Lap and aging effects in them), analyzing ofproperties LAP/PEO systems, Lap platelets-PEO interactions, adsorption mechanisms, aging effects, aggregation and electrokinetic properties. The different applications of Lap/PEO composites are reviewed. These applications include Lap/PEO based electrolytes for lithium polymer batteries, electrospun nanofibers, environmental, biomedical and biotechnology engineering. Both Lap and PEO are highly biocompatible with living systems and they are non-toxic, non-yellowing, and non-inflammable. Medical applications of Lap/PEO composites in bio-sensing, tissue engineering, drug delivery, cell proliferation, and wound dressings are also discussed.