Supramolecular Hydrogels Exhibiting Fast In Situ Gel Forming and Adjustable Degradation Properties (original) (raw)
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Supramolecular hydrogels as drug delivery systems
International Journal of Biological Macromolecules, 2015
Drug delivery from a hydrogel carrier implanted under the kidney capsule is an innovative way to induce kidney tissue regeneration and/or prevent kidney inflammation or fibrosis. We report here on the development of supramolecular hydrogels for this application. Chain-extended hydrogelators containing hydrogen bonding units in the main chain, and bifunctional hydrogelators end-functionalized with hydrogen bonding moieties, were made. The influence of these hydrogels on the renal cortex when implanted under the kidney capsule was studied. The overall tissue response to these hydrogels was found to be mild, and minimal damage to the cortex was observed, using the infiltration of macrophages, formation of myofibroblasts, and the deposition of collagen III as relevant read-out parameters. Differences in tissue response to these hydrogels could be related to the different physico-chemical properties of the three hydrogels.
Physicochemical Properties and the Gelation Process of Supramolecular Hydrogels: A Review
Gels, 2017
Supramolecular polysaccharide-based hydrogels have attracted considerable research interest recently due to their high structural functionality, low toxicity, and potential applications in foods, cosmetics, catalysis, drug delivery, tissue engineering and the environment. Modulation of the stability of hydrogels is of paramount importance, especially in the case of stimuli-responsive systems. This review will update the recent progress related to the rational design of supramolecular hydrogels with the objective of understanding the gelation process and improving their physical gelation properties for tailored applications. Emphasis will be given to supramolecular host-guest systems with reference to conventional gels in describing general aspects of gel formation. A brief account of the structural characterization of various supramolecular hydrogels is also provided in order to gain a better understanding of the design of such materials relevant to the nature of the intermolecular interactions, thermodynamic properties of the gelation process, and the critical concentration values of the precursors and the solvent components. This mini-review contributes to greater knowledge of the rational design of supramolecular hydrogels with tailored applications in diverse fields ranging from the environment to biomedicine.
Recent advances in the role of supramolecular hydrogels in drug delivery
Introduction: Supramolecular hydrogels, formed by noncovalent crosslinking of polymeric chains in water, constitute an interesting class of materials that can be developed specifically for drug delivery and biomedical applications. The biocompatibility, stimuli responsiveness to various external factors, and powerful functionalization capacity of these polymeric networks make them attractive candidates for novel advanced dosage form design. Areas covered: This review summarizes the significance of supramolecular hydrogels in various biomedical and drug delivery applications. The recent advancement of these hydrogels as potential advanced drug delivery systems (for gene, protein, anticancer and other drugs) is discussed. The importance of these hydrogels in biomedical applications, particularly in tissue engineering, biosensing, cell-culture research and wound treatment is briefly described. Expert opinion: The use of supramolecular hydrogels in drug delivery is still in very early stages. However, the potential of such a system is undeniably important and very promising. A number of recent studies have been conducted, which mainly focus on the use of cyclodextrin-based host–guest complex as well as other supramolecular motifs to form supramolecular hydrogels for delivery of various classes of drugs, therapeutic agents, proteins and genes. However, there are still plenty of opportunities for further development in this area for drug delivery and other biomedical applications.
Supramolecular Hydrogels for Protein Delivery in Tissue Engineering
Molecules
Therapeutic proteins, such as growth factors (GFs), have been used in tissue engineering (TE) approaches for their ability to provide signals to cells and orchestrate the formation of functional tissue. However, to be effective and minimize off-target effects, GFs should be delivered at the target site with temporal control. In addition, protein drugs are typically sensitive water soluble macromolecules with delicate structure. As such, hydrogels, containing large amounts of water, provide a compatible environment for the direct incorporation of proteins within the hydrogel network, while their release rate can be tuned by engineering the network chemistry and density. Being formed by transient crosslinks, afforded by non-covalent interactions, supramolecular hydrogels offer important advantages for protein delivery applications. This review describes various types of supramolecular hydrogels using a repertoire of diverse building blocks, their use for protein delivery and their fur...
Journal of Biomaterials Applications, 2015
In the present study, injectable hydrogels based on gum tragacanth–tyramine conjugate were prepared by enzymatic oxidation of tyramine radicals in the presence of hydrogen peroxide. Then, in vitro release of bovine serum albumin and insulin as model protein drugs from this polymeric network was investigated. Also, to improve the properties of this hydrogel, a blended hydrogel composed of tyramine-conjugated gelatin and tyramine-conjugated tragacanth was prepared. Experimental results showed that the gelation time ranged from 3 to 28 s depending on the polymer and enzyme concentrations. Results of morphological investigation of hydrogels indicated that the average pore size of hydrogels varied from 120 to 160 µm. Swelling degree of hydrogels and the rate of drug release decreased by increasing of hydrogen peroxide and polymer concentrations. The release profile of drug from hydrogels followed Higuchi and Fickian diffusion mechanism. Finally, it was shown that the swelling characteris...
International Journal of Pharmaceutics, 2017
In the current study, electrostatically-driven pH responsive, supramolecular hydrogels of the trilacunary Wells-Dawson-type 15-tungsto-2-phosphate polyanion (P 2 W 15) and chitosan hydrochloride (ChCl) were prepared, using methacrylic acid as pH responsive agent using benzoyl peroxide (BPO) as initiator. The prepared hydrogels were characterized by FT-IR, SEM, XRD and thermal analyses (TGA-DSC). The swelling and pH based P 2 W 15 release profile of the hydrogels showed maximum swellability and release at pH 7.4. Different mathematical models were applied, showing that P 2 W 15 release followed supercase transport-II mechanism and zero-order kinetics. The cytotoxicity results showed that free and embedded P 2 W 15 exhibited dose-dependent cytotoxicity against cancer cell lines (MCF-7; HeLa) with minimal effects on normal cells (Vero). The developed hydrogels were administered to the rabbits for determining the pharmacokinetic behavior of the polyanion. Moreover, the developed hydrogel system as well as polyanion concentration used were also checked for its oral tolerability and safety evaluation in rabbits. The histopathological studies, serum chemistry (except blood glucose level) and hematological investigations exhibited that administered hydrogel suspension at maximal tolerable dose (4000 mg/kg body weight) and polyanion concentration used (20 mg) were safe from in-vivo point of view. The developed hydrogels exhibited desirable qualities of a drug delivery system that can be used for the delivery of the embedded polyanion.
Cation Tuning of Supramolecular Gel Properties: A New Paradigm for Sustained Drug Delivery
Advanced materials (Deerfield Beach, Fla.), 2017
Hydrogels formed by the self-assembly of low-molecular-weight gelators (LMWGs) are promising scaffolds for drug-delivery applications. A new biocompatible hydrogel, resulting from the self-assembly of nucleotide-lipid salts can be safely injected in vivo. The resulting hydrogel provides sustained-release of protein for more than a week.
Journal of Biomaterials Science, Polymer Edition, 2012
Physical polymeric hydrogels have significant potential for use as injectable depot drug/protein-delivery systems. In this study, a series of novel injectable, biodegradable and pH/temperature-sensitive multiblock co-polymer physical hydrogels composed of poly(ethylene glycol) (PEG) and poly(β-amino ester urethane) (PEU) was synthesized by the polyaddition between the isocyanate groups of 1,6-diisocyanato hexamethylene and the hydroxyl groups of PEG and a synthesized monomer BTB (or ETE) in chloroform in the presence of dibutyltin dilaurate as a catalyst. The synthesized co-polymers were characterized by nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy and gel-permeation chromatography. Aqueous solutions of the co-polymers showed a sol-to-gel phase transition with increasing pH and a gel-to-sol phase transition with increasing temperature. The gel regions covered the physiological conditions (37°C, pH 7.4) and could be controlled by changing the molecular weight of PEG, PEG/PEU ratio and co-polymer solution concentration. A gel formed rapidly in situ after injecting the co-polymer solution subcutaneously into SD rats and remained for more than 2 weeks in the body. The cytotoxicity tests confirmed the non-cytotoxicity of this co-polymer hydrogel. The controlled in vitro release of the model anticancer drug, doxorubicin, from this hydrogel occurred over a 7-day period. This hydrogel is a potential candidate for biomedical applications and drug/protein-delivery systems.