Interpenetrating networks hydrogels based on hyaluronic acid for drug delivery and tissue engineering

Multifunctioning of carboxylic-cellulose nanocrystals on the reinforcement of compressive strength and conductivity for acrylic-based hydrogel

Simultaneously having competitive compressive properties, fatigue-resistant stability, excellent conductivity and sensitivity has still remained a challenge for acrylic-based conductive hydrogels, which is critical in their use in the sensor areas where pressure is performed. In this work, an integrated strategy was proposed for preparing a conductive hydrogel based on acrylic acid (AA) and sodium alginate (SA) by addition of carboxylic-cellulose nanocrystals (CNC-COOH) followed by metal ion interaction to reinforce its compressive strength and conductivity simultaneously. The CNC-COOH played a multifunctional role in the hydrogel by well-dispersing SA and AA in the hydrogel precursor solution for forming a uniform semi-interpenetrating network, providing more hydrogen bonds with SA and AA, more -COOH for metal ion interactions to form uniform multi-network, and also offering high modulus to the final hydrogel. Accordingly, the as-prepared hydrogels showed simultaneous excellent compressive strength (up to 3.02 MPa at a strain of 70 %) and electrical conductivity (6.25 S m-1), good compressive fatigue-resistant (93.2 % strength retention after 1000 compressive cycles under 50 % strain) and high sensitivity (gauge factor up to 14.75). The hydrogel strain sensor designed in this work is capable of detecting human body movement of pressing, stretching and bending with highly sensitive conductive signals, which endows it great potential for multi-scenario strain sensing applications.

Evaluation of hyaluronic acid-polymacrolactone hydrogels with 3D printing capacity

The implementation of personalized patches, tailored to individual genetic profiles and containing specific amounts of bioactive substances, has the potential to produce a transformative impact within the medical sector. There are several methods of designing scaffolds in the context of personalized medicine, with three-dimensional (3D) printing emerging as a pivotal technique. This innovative approach can be used to construct a wide variety of pharmaceutical dosage forms, characterized by variations in shape, release profile, and drug combinations, allowing precise dose individualization and the incorporation of multiple therapeutic agents. To expand the potential and applicability of personalized medicine, particularly with regards to indomethacin (IND), a drug necessitating individualized dosing, this study proposes the development of new transdermal delivery systems for IND based on hyaluronic acid and a polylactone synthesized within our research group, namely poly(ethylene brasilate-co-squaric acid) (PEBSA). The obtained systems were characterized in terms of their swelling capacity, rheological behavior, and morphological characteristics that highlighted the formation of stable three-dimensional networks. To impart specific shape and geometry to the structures, multi-component systems based on PEBSA, HA, and methacrylate gelatin were obtained. The scaffolds were loaded with IND and subsequently 3D printed. The release capacity of IND and its dependence on the relative ratios of the components comprising the scaffold composition were highlighted. The cytocompatibility studies revealed the successful development of biocompatible and noncytotoxic systems.

Recent Advances of Stimuli-Responsive Polysaccharide Hydrogels in Delivery Systems: A Review

Hydrogels obtained from natural polymers have received widespread attention for their excellent biocompatible property, nontoxicity, easy gelation, and functionalization. Polysaccharides can regulate the gut microbiota and improve the intestinal microenvironment, thus exerting the healthy effect of intestinal immunity. In an active substance delivery system, the extent and speed of the substance reaching its target are highly dependent on the carrier. Thus, the smart active substance delivery systems are gradually increasing. The smart polysaccharide-hydrogels possess the ability in response to external stimuli through changing their volume phase and structure, which are applied in various fields. Natural polysaccharide-based hydrogels possess excellent characteristics of environmental friendliness, good biocompatibility, and abundant sources. According to the response type, natural polysaccharide-based hydrogels are usually divided into stimulus-responsive hydrogels, including internal response (pH, temperature, enzyme, redox) and external response (light, electricity, magnetism) hydrogels. The delivery system based on polysaccharides can exert their effects in the gastrointestinal tract. At the same time, polysaccharides may also take part in regulating the brain signals through the microbiota-gut-brain axis. Therefore, natural polysaccharide-hydrogels are considered as promising biomaterials, which can be designed as delivery systems for regulating the gut-brain axis. This article reviews the research advance of stimulus-responsive hydrogels, which focus on the types, response characteristics, and applications for polysaccharide-based smart hydrogels as delivery systems.

Hyaluronic-Acid-Based Organic-Inorganic Composites for Biomedical Applications

Applications of natural hyaluronic acid (HYH) for the fabrication of organic-inorganic composites for biomedical applications are described. Such composites combine unique functional properties of HYH with functional properties of hydroxyapatite, various bioceramics, bioglass, biocements, metal nanoparticles, and quantum dots. Functional properties of advanced composite gels, scaffold materials, cements, particles, films, and coatings are described. Benefiting from the synergy of properties of HYH and inorganic components, advanced composites provide a platform for the development of new drug delivery materials. Many advanced properties of composites are attributed to the ability of HYH to promote biomineralization. Properties of HYH are a key factor for the development of colloidal and electrochemical methods for the fabrication of films and protective coatings for surface modification of biomedical implants and the development of advanced biosensors. Overcoming limitations of traditional materials, HYH is used as a biocompatible capping, dispersing, and structure-directing agent for the synthesis of functional inorganic materials and composites. Gel-forming properties of HYH enable a facile and straightforward approach to the fabrication of antimicrobial materials in different forms. Of particular interest are applications of HYH for the fabrication of biosensors. This review summarizes manufacturing strategies and mechanisms and outlines future trends in the development of functional biocomposites.

Drug Release Kinetics of Electrospun PHB Meshes

Microbial poly(3-hydroxybutyrate) (PHB) has several advantages including its biocompatibility and ability to degrade in vivo and in vitro without toxic substances. This paper investigates the feasibility of electrospun PHB meshes serving as drug delivery systems. The morphology of the electrospun samples was modified by varying the concentration of PHB in solution and the solvent composition. Scanning electron microscopy of the electrospun PHB scaffolds revealed the formation of different morphologies including porous, filamentous/beaded and fiber structures. Levofloxacin was used as the model drug for incorporation into PHB electrospun meshes. The entrapment efficiency was found to be dependent on the viscosity of the PHB solution used for electrospinning and ranged from 14.4–81.8%. The incorporation of levofloxacin in electrospun meshes was confirmed by Fourier-transform infrared spectroscopy and UV-VIS spectroscopy. The effect of the morphology of the electrospun meshes on the levofloxacin release profile was screened in vitro in phosphate-buffered saline solution. Depending upon the morphology, the electrospun meshes released about 14–20% of levofloxacin during the first 24 h. The percentage of drug released after 13 days increased up to 32.4% and was similar for all tested morphologies. The antimicrobial efficiency of all tested samples independent of the morphology, was confirmed by agar diffusion testing.