Gelatin/Montmorillonite and Gelatin/Polyvinyl Alcohol/Montmorillonite Bionanocomposite Hydrogels: Microstructural, Swelling and Drying Properties

Advancements in gelatin-based hydrogel systems for biomedical applications: A state-of-the-art review

A gelatin-based hydrogel system is a stimulus-responsive, biocompatible, and biodegradable polymeric system with solid-like rheology that entangles moisture in its porous network that gradually protrudes to assemble a hierarchical crosslinked arrangement. The hydrolysis of collagen directs gelatin construction, which retains arginyl glycyl aspartic acid and matrix metalloproteinase-sensitive degeneration sites, further confining access to chemicals entangled within the gel (e.g., cell encapsulation), modulating the release of encapsulated payloads and providing mechanical signals to the adjoining cells. The utilization of various types of functional tunable biopolymers as scaffold materials in hydrogels has become highly attractive due to their higher porosity and mechanical ability; thus, higher loading of proteins, peptides, therapeutic molecules, etc., can be further modulated. Furthermore, a stimulus-mediated gelatin-based hydrogel with an impaired concentration of gellan demonstrated great shear thinning and self-recovering characteristics in biomedical and tissue engineering applications. Therefore, this contemporary review presents a concise version of the gelatin-based hydrogel as a conceivable biomaterial for various biomedical applications. In addition, the article has recapped the multiple sources of gelatin and their structural characteristics concerning stimulating hydrogel development and delivery approaches of therapeutic molecules (e.g., proteins, peptides, genes, drugs, etc.), existing challenges, and overcoming designs, particularly from drug delivery perspectives.

Preparation, properties, and applications of gelatin-based hydrogels (GHs) in the environmental, technological, and biomedical sectors

Gelatin's versatile functionalization offers prospects of facile and effective crosslinking as well as combining with other materials (e.g., metal nanoparticles, carbonaceous, minerals, and polymeric materials exhibiting desired functional properties) to form hybrid materials of improved thermo-mechanical, physio-chemical and biological characteristics. Gelatin-based hydrogels (GHs) and (nano)composite hydrogels possess unique functional features that make them appropriate for a wide range of environmental, technical, and biomedical applications. The properties of GHs could be balanced by optimizing the hydrogel design. The current review explores the various crosslinking techniques of GHs, their properties, composite types, and ultimately their end-use applications. GH's ability to absorb a large volume of water within the gel network via hydrogen bonding is frequently used for water retention (e.g., agricultural additives), and absorbency towards targeted chemicals from the environment (e.g., as wound dressings for absorbing exudates and in water treatment for absorbing pollutants). GH's controllable porosity makes its way to be used to restrict access to chemicals entrapped within the gel phase (e.g., cell encapsulation), regulate the release of encapsulated cargoes within the GH (e.g., drug delivery, agrochemicals release). GH's soft mechanics closely resembling biological tissues, make its use in tissue engineering to deliver suitable mechanical signals to neighboring cells. This review discussed the GHs as potential materials for the creation of biosensors, drug delivery systems, antimicrobials, modified electrodes, water adsorbents, fertilizers and packaging systems, among many others. The future research outlooks are also highlighted.

Magnetic κ-carrageenan/chitosan/montmorillonite nanocomposite hydrogels with controlled sunitinib release

This work aimed to design montmorillonite-incorporated pH-responsive and magnetic κ-carrageenan/chitosan hydrogels via a completely green route for controlled release of sunitinib anticancer drug. This was accomplished by ionic cross-linking of two biopolymers, κ-carrageenan and chitosan, in the presence of magnetic montmorillonite (mMMt) nanoplatelets. Interestingly, it was observed that the amount of mMMt affected not only the microstructure of hydrogels, but also the drug loading efficiency of nanocomposite hydrogels was noticeably increased by introducing mMMt (from 69 to 96%). The in vitro sunitinib release experiments showed that a low content of loaded sunitinib was released from all hydrogels in the buffered solution with pH 7.4. In contrast, a relatively sustained release with a high content of drug release was observed in the acidic solution of pH 5.5. During 48 h, the hydrogels nanocomposite containing a high content of mMMt showed cumulative release of 64.0 and 8.6% at pH 5.5 and 7.4, respectively. During two days, while the cumulative release of sunitinib was obtained 84.3% for the magnetic-free hydrogel, the magnetic ones showed 74.4 and 64% with the low and high contents of magnetic MMt, respectively. The developed κ-carrageenan/chitosan hydrogels with a high capacity of drug loading and subsequent pH-sensitive drug release can be considered in prolonged cancer therapy with reduced side effects.