Chemical cross-linking on gelatin-hyaluronan loaded with hinokitiol for the preparation of guided tissue regeneration hydrogel membranes with antibacterial and biocompatible properties

Functional Hydrogel Interfaces for Cartilage and Bone Regeneration

Effective treatment of bone diseases is quite tricky due to the unique nature of bone tissue and the complexity of the bone repair process. In combination with biological materials, cells and biological factors can provide a highly effective and safe treatment strategy for bone repair and regeneration, especially based on these multifunctional hydrogel interface materials. However, itis still a challenge to formulate hydrogel materials with fascinating properties (e.g., biological activity, controllable biodegradability, mechanical strength, excellent cell/tissue adhesion, and controllable release properties) for their clinical applications in complex bone repair processes. In this review, we will highlight recent advances in developing functional interface hydrogels. We then discuss the barriers to  producing of functional hydrogel materials without sacrificing their inherent properties, and potential applications in cartilage and bone repair are discussed. Multifunctional hydrogel interface materials can serve as a fundamental building block for bone tissue engineering.

Alginate/hyaluronic acid/gelatin ternary blended films as pH-sensitive drug carriers: In vitro ampicillin release and kinetic studies

Researchers continuously focused on the fabrication of innovative drug delivery systems to prevent microbial infections while minimizing systemic side effects. Among these, pH-sensitive antibiotic release systems based on bio-based materials have gained great attention due to their ability to precisely modulate drug kinetics and enhance therapeutic efficacy. Herein, pH-sensitive alginate/hyaluronic acid/gelatin ternary blended films were fabricated for the controlled release of ampicillin. Swelling capacity, hydrolytic degradation profile, pH reversibility and in vitro ampicillin release behavior of produced films were investigated in both simulated gastric (pH 1.2) and intestinal (pH 7.4) environments. The cumulative release amount of ampicillin at pH 1.2 (61.0 ± 1.07 mg drug/g polymer) was greater than that of at pH 7.4 (43.0 ± 1.05 mg drug/g polymer) proved that release behavior of ampicillin for produced films is pH-dependent. Based on the fitted release data, best fit was found as the first-order kinetic model with the highest R2 values of 0.966 and 0.962 for both pH conditions. According to Korsmeyer-Peppas model, drug release mechanism is also controlled by case II-transport. Furthermore, produced films demonstrated excellent cytocompatibility. All results revealed that obtained films could be a promising drug carrier to traditional targeting systems for site-specific, pH-sensitive ampicillin delivery in both gastric and intestine.

Hydrogels promote periodontal regeneration

Periodontal defects involve the damage and loss of periodontal tissue, primarily caused by periodontitis. This inflammatory disease, resulting from various factors, can lead to irreversible harm to the tissues supporting the teeth if not treated effectively, potentially resulting in tooth loss or loosening. Such outcomes significantly impact a patient's facial appearance and their ability to eat and speak. Current clinical treatments for periodontitis, including surgery, root planing, and various types of curettage, as well as local antibiotic injections, aim to mitigate symptoms and halt disease progression. However, these methods fall short of fully restoring the original structure and functionality of the affected tissue, due to the complex and deep structure of periodontal pockets and the intricate nature of the supporting tissue. To overcome these limitations, numerous biomaterials have been explored for periodontal tissue regeneration, with hydrogels being particularly noteworthy. Hydrogels are favored in research for their exceptional absorption capacity, biodegradability, and tunable mechanical properties. They have shown promise as barrier membranes, scaffolds, carriers for cell transplantation and drug delivery systems in periodontal regeneration therapy. The review concludes by discussing the ongoing challenges and future prospects for hydrogel applications in periodontal treatment.

CSMP: A Self-Assembled Plant Polysaccharide-Based Hydrofilm for Enhanced Wound Healing

Wound management remains a critical healthcare issue due to the rising incidence of chronic diseases leading to persistent wounds. Traditional dressings have their limitations, such as potential for further damage during changing and suboptimal healing conditions. Recently, hydrogel-based dressings have gained attention due to their biocompatibility, biodegradability, and ability to fill wounds. Particularly, polysaccharide-based hydrogels have shown potential in various medical applications. This study focuses on the development of a novel hydrofilm wound dressing produced from a blend of chia seed mucilage (CSM) and polyvinyl alcohol (PVA), termed CSMP. While the individual properties of CSM and PVA are well-documented, their combined potential in wound management is largely unexplored. CSMP, coupled with sorbitol and glycerin, and cross-linked using ultraviolet light, results in a flexible, adhesive, and biocompatible hydrofilm demonstrating superior water absorption, moisturizing, and antibacterial properties. This hydrofilm promotes epithelial cell migration, enhanced collagen production, and outperforms existing commercial dressings in animal tests. The innovative CSMP hydrofilm offers a promising, cost-effective approach for improved wound care, bridging existing gaps in dressing performance and preparation simplicity. Future research can unlock further applications of such polysaccharide-based hydrofilm dressings.

A Metal-Organic Framework-Incorporated Hydrogel for Delivery of Immunomodulatory Neobavaisoflavone to Promote Cartilage Regeneration in Osteoarthritis

The treatment of osteoarthritis (OA)-related cartilage defects is a great clinical challenge due to the complex pathogenesis of OA and poor self-repair ability of cartilage tissue. Combining local and long-term anti-inflammatory therapies to promote cartilage repair is an effective method to treat OA. In this study, a zinc-organic framework-incorporated extracellular matrix (ECM)-mimicking hydrogel platform was constructed for the inflammatory microenvironment-responsive delivery of neobavaisoflavone (NBIF) to promote cartilage regeneration in OA. The NBIF was encapsulated in situ in zeolitic imidazolate frameworks (ZIF-8 MOFs). The NBIF@ZIF-8 MOFs were decorated with polydopamine and incorporated into a methacrylate gelatin/hyaluronic acid hybrid network to form the NBIF@ZIF-8/PHG hydrogel. The hydrogel featured excellent cell/tissue affinity, providing a favorable microenvironment for recruiting cells and cytokines to the defect sites. The hydrogel enabled the on-demand NBIF released in response to a weakly acidic microenvironment at the injured joint site to resolve inflammatory responses during the early stages of OA. Consequently, the cooperativity of the loaded NBIF and hydrogel synergistically modulated the immune response and assisted in cartilage defect repair. In summary, the NBIF@ZIF-8/PHG hydrogel delivery platform represents an effective treatment strategy for OA-related cartilage defects and may attract attentions for applications in other inflammatory diseases.

Chitosan/glycyrrhizic acid hydrogel: Preparation, characterization, and its potential for controlled release of gallic acid

In the present work, chitosan (CHT) as a biodegradable polymer was crosslinked using various amounts of glycyrrhizic acid (GLA) as a novel crosslinking agent to prepare biocompatible hydrogels. The prepared hydrogels were used for the controlled release of gallic acid (GA) in transdermal therapy application. FTIR, XRD, and SEM were used to characterize the prepared gels. The results indicated that the carboxylic acid groups of GLA react with the amine groups of the CHT in the presence of activating coupling reagents to form covalent amide linkage between the polymer chains of CHT and construct CHT cross-linked hydrogel (CCH) network structure. The prepared CCH samples were characterized and used for the controlled release of a drug, i.e. (GA). For this purpose, the swelling kinetic, loading and encapsulation efficiency, in vitro drug release, drug release kinetics, cell viability assay, and anti-bacterial activity of the samples were evaluated. The swelling ratio of CCH samples were in the range of 455-37 % depending on the pH of environment. Swelling kinetic results showed an aggregate to the non-linear second-order kinetic model. Drug release results were fitted by kinetic models while the Korsmeyer-Peppas model was fitted better. The CCH samples exhibited high biocompatibility for 5 mg/ml hydrogel concentration. In addition, the CHT and CCH sample without the GA did not show anti-bacterial properties for 1200 and 150 μg/ml concentrations, respectively. The CCH sample containing the GA exhibited enough anti-bacterial activity on the S. aureus bacteria strain at 150 μg/ml concentration. In contrast, the CCH sample containing the GA has a light anti-bacterial effect on the E. coli bacteria strain. The calculated mesh size of hydrogel networks, drug size, and kinetics models revealed that the CCH samples could release GA based on a diffusion mechanism. In conclusion, the designed CCH samples have enough ability for controlled drug release in transdermal applications.

Effects of Temoporfin-Based Photodynamic Therapy on the In Vitro Antibacterial Activity and Biocompatibility of Gelatin-Hyaluronic Acid Cross-Linked Hydrogel Membranes

This study was performed to design a hydrogel membrane that exhibits antibacterial properties and guides different tissues. Gelatin and hyaluronic acid were used as the main structures, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) was used as a cross-linker, and temoporfin was used as an antibacterial agent. The results revealed that the hydrogel membrane impregnated with temoporfin (HM-T) had a fixation index of >89%. Temoporfin was used in conjunction with a diode laser and did not significantly affect EDC-induced cross-linking. The inhibitory activity of temoporfin showed that HM-T15 and HM-T30 (light exposure for 15 and 30 min, respectively) had remarkable antibacterial properties. The cell survival rate of HM-T15 was 73% of that of the control group, indicating that temoporfin exposure for 15 min did not exert cytotoxic effects on L-929 cells. HM and HM-T15 hydrogel membranes showed good cell adhesion and proliferation after 14 days of dark incubation. However, the hydrogel membrane containing temoporfin significantly reduced pro-inflammatory gene expression. In summary, the HM-T15 group showed potential as a biodegradable material for biocompatible tissue-guarded regeneration membranes with antibacterial properties. This study demonstrated the potential of temoporfin for innovative biomaterials and delivery systems applied to new regenerative periodontal therapies.

Advances in modified hyaluronic acid-based hydrogels for skin wound healing

Hyaluronic acid (HA) is a natural linear anionic polysaccharide with many unique characteristics such as excellent biocompatibility and biodegradability, native biofunctionality, hydrophilicity, and non-immunoreactivity. HA plays crucial roles in numerous biological processes, including the inflammatory response, cell adhesion, migration, proliferation, differentiation, angiogenesis, and tissue regeneration. All these properties and biological functions of HA make it an appealing material for the synthesis of biomedical hydrogels for skin wound healing. Since HA is not able to be gelate alone, it must be processed and functionalized through chemical modifications and crosslinking to generate versatile HA-based hydrogels. In recent years, different physical and chemical crosslinking strategies for HA-based hydrogels have been developed and designed, such as radical polymerization, Schiff-base crosslinking, enzymatic crosslinking, and dynamic covalent crosslinking, and they have broad and promising applications in skin wound healing and tissue engineering. In this review, we focus on chemical modification and crosslinking strategies for HA-based hydrogels, aiming to provide an overview of the latest advances in the development of HA-based hydrogels for skin wound healing. We summarize and propose feasible measures for the application of HA-based hydrogels for skin treatment, and discuss future application trends, which may ultimately promote HA-based hydrogels as a promising biomaterial for clinical applications.

In situ forming hydrogel recombination with tissue adhesion and antibacterial property for tissue adhesive

In situ forming hydrogels with strong adhesive strength and antibacterial activity are of great interest to serve as tissue adhesive in fields like wound dressing and mass hemorrhage. In this study, hybrid hydrogel (GOHA) based on gelatin and oxidized hyaluronic acid was developed and endowed with excellent mechanical strength and tissue adhesion. According to our results, GOHA hydrogel exhibits a fast gelation time of around 60 s, robust compression strength of 223.43 ± 24.28 kPa, and strong adhesion of 14.33 ± 0.78 kPa to porcine skin, which is much higher than that of commercial fibrin glue (around 1.00 kPa). Meanwhile, through the loading of levofloxacin, obvious antibacterial activity can be obtained for wider applications. Notably, it would not compromise the hemocompatibility and cytocompatibility in vitro. In summary, this kind of hybrid hydrogel shows great potential as tissue adhesive in biomedical fields.

3D-Printed Hydrogels in Orthopedics: Developments, Limitations, and Perspectives

Three-dimensional (3D) printing has been used in medical research and practice for several years. Various aspects can affect the finished product of 3D printing, and it has been observed that the impact of the raw materials used for 3D printing is unique. Currently, hydrogels, including various natural and synthetic materials, are the most biologically and physically advantageous biological raw materials, and their use in orthopedics has increased considerably in recent years. 3D-printed hydrogels can be used in the construction of extracellular matrix during 3D printing processes. In addition to providing sufficient space structure for osteogenesis and chondrogenesis, hydrogels have shown positive effects on osteogenic and chondrogenic signaling pathways, promoting tissue repair in various dimensions. 3D-printed hydrogels are currently attracting extensive attention for the treatment of bone and joint injuries owing to the above-mentioned significant advantages. Furthermore, hydrogels have been recently used in infection prevention because of their antiseptic impact during the perioperative period. However, there are a few shortcomings associated with hydrogels including difficulty in getting rid of the constraints of the frame, poor mechanical strength, and burst release of loadings. These drawbacks could be overcome by combining 3D printing technology and novel hydrogel material through a multi-disciplinary approach. In this review, we provide a brief description and summary of the unique advantages of 3D printing technology in the field of orthopedics. In addition, some 3D printable hydrogels possessing prominent features, along with the key scope for their applications in bone joint repair, reconstruction, and antibacterial performance, are discussed to highlight the considerable prospects of hydrogels in the field of orthopedics.

Advances of Hydroxyapatite Hybrid Organic Composite Used as Drug or Protein Carriers for Biomedical Applications: A Review

Hydroxyapatite (HA), especially in the form of HA nanoparticles (HANPs), has excellent bioactivity, biodegradability, and osteoconductivity and therefore has been widely used as a template or additives for drug delivery in clinical applications, such as dentistry and orthopedic repair. Due to the atomically anisotropic distribution on the preferred growth of HA crystals, especially the nanoscale rod-/whisker-like morphology, HA can generally be a good candidate for carrying a variety of substances. HA is biocompatible and suitable for medical applications, but most drugs carried by HANPs have an initial burst release. In the adsorption mechanism of HA as a carrier, specific surface area, pore size, and porosity are important factors that mainly affect the adsorption and release amounts. At present, many studies have developed HA as a drug carrier with targeted effect, porous structure, and high porosity. This review mainly discusses the influence of HA structures as a carrier on the adsorption and release of active molecules. It then focuses on the benefits and effects of different types of polymer-HA composites to re-examine the proteins/drugs carry and release behavior and related potential clinical applications. This literature survey can be divided into three main parts: 1. interaction and adsorption mechanism of HA and drugs; 2. advantages and application fields of HA/organic composites; 3. loading and drug release behavior of multifunctional HA composites in different environments. This work also presents the latest development and future prospects of HA as a drug carrier.

Silk fibroin/polycaprolactone-polyvinyl alcohol directional moisture transport composite film loaded with antibacterial drug-loading microspheres for wound dressing materials

Drug delivery technology can prevent wound infection and inflammatory reactions and accelerate wound healing and quality. In this paper, we propose preparing a multifunctional medical dressing to meet the various needs of people for dressing. A multi-layered composite nanofiber membrane was constructed using silk fibroin as the substrate, and mesoporous silica nanoparticles (MSN) with high adsorption properties were first prepared and then electrosprayed on silk fibroin (SF)/chitosan (CS) microspheres to form MSN-SF/CS microspheres with uniform distribution. Then the MSN-SF/CS microspheres were sprayed on the silk fibroin (SF)/polycaprolactone (PCL)-polyvinyl alcohol (PVA) unidirectional water-conducting composite nanofiber membrane. The test results showed that the encapsulation rate of bovine serum albumin (BSA) by MSN-SF/CS drug-loaded microspheres was 65.53% and the cumulative release rate in vitro was 54.46%. The results of in vitro experiments also showed its good antibacterial effect and good biocompatibility. To eliminate excess wound exudate and reduce inflammation, the cumulative unidirectional transport capacity (AOTC) of 651.75% was achieved by spraying the microspheres on an SF/PCL- PVA unidirectional water conductive composite membrane. This study could stimulate and promote the use of additional wound healing biomaterials in clinical medicine.

Antibiotic-Loaded Polymeric Barrier Membranes for Guided Bone/Tissue Regeneration: A Mini-Review

Polymeric membranes are frequently used for bone regeneration in oral and periodontal surgery. Polymers provide adequate mechanical properties (i.e., Young’s modulus) to support oral function and also pose some porosity with interconnectivity to permit for cell proliferation and migration. Bacterial contamination of the membrane is an event that may lead to infection at the bone site, hindering the clinical outcomes of the regeneration procedure. Therefore, polymeric membranes have been proposed as carriers for local antibiotic therapy. A literature search was performed for papers, including peer-reviewed publications. Among the different membranes, collagen is the most employed biomaterial. Collagen membranes and expanded polytetrafluoroethylene loaded with tetracyclines, and polycaprolactone with metronidazole are the combinations that have been assayed the most. Antibiotic liberation is produced in two phases. A first burst release is sometimes followed by a sustained liberation lasting from 7 to 28 days. All tested combinations of membranes and antibiotics provoke an antibacterial effect, but most of the time, they were measured against single bacteria cultures and usually non-specific pathogenic bacteria were employed, limiting the clinical relevance of the attained results. The majority of the studies on animal models state a beneficial effect of these antibiotic functionalized membranes, but human clinical assays are scarce and controversial.

In Vitro Evaluation of a Composite Gelatin-Hyaluronic Acid-Alginate Porous Scaffold with Different Pore Distributions for Cartilage Regeneration

Although considerable achievements have been made in the field of regenerative medicine, since self-repair is not an advanced ability of articular cartilage, the regeneration of osteochondral defects is still a challenging problem in musculoskeletal diseases. Cartilage regeneration aims to design a scaffold with appropriate pore structure and biological and mechanical properties for the growth of chondrocytes. In this study, porous scaffolds made of gelatin, hyaluronic acid, alginate, and sucrose in different proportions of 2 g (S_L2) and 4 g (S_L4) were used as porogens in a leaching process. Sucrose with particle size ranges of 88–177 μm (Hμ) and 44–74 μm (SHμ) was added to the colloid, and the individually cross-linked hydrogel scaffolds with controllable pore size for chondrocyte culture were named Hμ-S_L2, Hμ-S_L4, SHμ-S_L2 and SHμ-S_L4. The perforation, porosity, mechanical strength, biocompatibility, and proliferation characteristics of the hydrogel scaffold and its influence on chondrocyte differentiation are discussed. Results show that the addition of porogen increases the porosity of the hydrogel scaffold. Conversely, when porogens with the same particle size are added, the pore size decreases as the amount of porogen increases. The perforation effect of the hydrogel scaffolds formed by the porogen is better at 88–177 μm compared with that at 44–74 μm. Cytotoxicity analysis showed that all the prepared hydrogel scaffolds were non-cytotoxic, indicating that no cross-linking agent residues that could cause cytotoxicity were found. In the proliferation and differentiation of the chondrocytes, the SHμ-S_L4 hydrogel scaffold with the highest porosity and strength did not achieve the best performance. However, due to the compromise between perforation pores, pore sizes, and strength, as well as considering cell proliferation and differentiation, Hμ-SL4 scaffold provided a more suitable environment for the chondrocytes than other groups; therefore, it can provide the best chondrocyte growth environment for this study. The development of hydrogels with customized pore properties for defective cartilage is expected to meet the requirements of the ultimate clinical application.

Health Benefits and Pharmacological Properties of Hinokitiol

Hinokitiol is a natural bioactive compound found in several aromatic and medicinal plants. It is a terpenoid synthetized and secreted by different species as secondary metabolites. This volatile compound was tested and explored for its different biological properties. In this review, we report the pharmacological properties of hinokitiol by focusing mainly on its anticancer mechanisms. Indeed, it can block cell transformation at different levels by its action on the cell cycle, apoptosis, autophagy via inhibiting gene expression and dysregulating cellular signaling pathways. Moreover, hinokitiol also exhibits other pharmacological properties, including antidiabetic, anti-inflammatory, and antimicrobial effects. It showed multiple and several effects through its inhibition, interaction and/or activation of the main cellular targets inducing these pathologies.

Effects of Hinokitiol and Dicalcium Phosphate on the Osteoconduction and Antibacterial Activity of Gelatin-Hyaluronic Acid Crosslinked Hydrogel Membrane In Vitro

Many hydrogel-based crosslinking membranes have been designed and tailored to meet the needs of different applications. The aim of this research is to design a bifunctional hydrogel membrane with antibacterial and osteoconducting properties to guide different tissues. The membrane uses gelatin and hyaluronic acid as the main structure, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride as the crosslinker, hinokitiol as the antibacterial agent, and dicalcium phosphate anhydrous (DCPA) micron particles for osteoconduction. Results show that the hydrogel membrane with added DCPA and impregnated hinokitiol has a fixation index higher than 88%. When only a small amount of DCPA is added, the tensile strength does not decrease significantly. The tensile strength decreases considerably when a large amount of modified DCPA is added. The stress–strain curve shows that the presence of a large amount of hinokitiol in hydrogel membranes results in considerably improved deformation and toughness properties. Each group impregnated with hinokitiol exhibits obvious antibacterial capabilities. Furthermore, the addition of DCPA and impregnation with hinokitiol does not exert cytotoxicity on cells in vitro, indicating that the designed amount of DCPA and hinokitiol in this study is appropriate. After a 14-day cell culture, the hydrogel membrane still maintains a good shape because the cells adhere and proliferate well, thus delaying degradation. In addition, the hydrogel containing a small amount of DCPA has the best cell mineralization effect. The developed hydrogel has a certain degree of flexibility, degradability, and bifunctionality and is superficial. It can be used in guided tissue regeneration in clinical surgery.