Thermosensitive Chitosan-based Hydrogel Research Articles

Injectable thermosensitive chitosan-based hydrogel containing ferulic acid for treating peripheral arterial disease.

Peripheral arterial disease (PAD) affects more than 200 million people worldwide. Recent studies suggest that oxidative stress-related inflammation can lead to the initiation and progression of PAD. Ferulic acid (FA) is a natural phenolic compound and has been proven to have antioxidant and angiogenesis effects. In this study, thermosensitive chitosan-gelatin-based hydrogel was used as a delivery vehicle of FA. The effects of hydrogel encapsulating FA (FA-gel) have been demonstrated in vitro and in vivo. The results revealed that the developed hydrogel with porous structure could provide a sustained release of FA. Post-treatment of FA-gel effectively decreased the oxidative stress-induced damage in human umbilical vein endothelial cells via decreasing endogenous reactive oxygen species production, inflammation-related gene expression and apoptosis level. In the mouse hindlimb ischemia model, the results revealed that FA-gel could improve blood flow, muscle regeneration and decreases inflammation in veins. These results suggested that FA-gel may have a therapeutic potential in PAD.

Thermosensitive Chitosan-Based Injectable Hydrogel as an Efficient Anticancer Drug Carrier.

A thermosensitive, physically cross-linked injectable hydrogel was formulated for the effective and sustained delivery of disulfiram (DSF) to the cancer cells as there is no hydrogel formulation available until now for the delivery of DSF. As we know, hydrogels have an advantage over other drug delivery systems because of their unique properties, so we proposed to formulate an injectable hydrogel system for the sustained delivery of an anticancer drug (DSF) to cancer cells. To investigate the surface morphology, a scanning electron microscope study was carried out, and for thermal stability of hydrogels, TGA (thermogravimetric analysis) and DSC (differential scanning calorimetry) were performed. The rheological behavior of hydrogels was evaluated with the increasing temperature and time. These developed hydrogels possessing excellent biocompatibility could be injected at room temperature following rapid gel formation at body temperature. The swelling index and in vitro drug release studies were performed at different pH (6.8 and 7.4) and temperatures (25 and 37 °C). The cell viability of the blank hydrogel, free DSF solution, and Ch/DSF (chitosan/DSF)-loaded hydrogel was studied by MTT assay on SMMC-7721 cells for 24 and 48 h, which exhibited higher cytotoxicity in a dose-dependent manner in contrast to the free DSF solution. Moreover, the cellular uptake of DSF-loaded hydrogels was observed stronger as compared with free DSF. Hence, chitosan-based hydrogels loaded with DSF possessing exceptional properties can be used as a novel injectable anticancer drug for the sustained delivery of DSF for long-term cancer therapy.

Synthesis and characterization of timolol maleate-loaded quaternized chitosan-based thermosensitive hydrogel: A transparent topical ocular delivery system for the treatment of glaucoma

The chitosan-based thermosensitive hydrogel is one of the attractive in situ forming drug delivery systems that are suggested for ophthalmic applications. However, the use of this thermogel has been limited by non-transparency, relatively low solubility and prolonged gelation time. In this study, a convenient approach has been reported to develop transparent thermosensitive hydrogel with suitable cytocompatibility and gelation properties for glaucoma treatment. After obtaining the optimum quaternization conditions, the developed in-situ gelling formulation of quaternized chitosan was achieved by mixing sodium hydrogen carbonate with β-glycerophosphate as a gelling agent. The formulation was a solution below or at room temperature and turned to a transparent hydrogel around ocular surface temperature within several minutes. The results of thermal and rheological evaluations demonstrated that adding sodium hydrogen carbonate has a synergic effect in enhancing the thermosensitivity of the hydrogel. Also, the prepared hydrogels based on quaternized chitosan presented obvious porous architectures, good swelling, and degradability. Hemolysis and cytotoxicity evaluations suggested that the developed hydrogels indicated good biocompatibility as a drug carrier. Finally, the in vitro release profile of timolol maleate as an anti-glaucoma model drug showed the initial burst release in the early hours and a steady linear release of drug from the hydrogel over 1 week. The obtained results confirmed that the developed hydrogel can be considered as an efficient drug delivery candidate for glaucoma therapy.

The interplay between chondrocyte spheroids and mesenchymal stem cells boosts cartilage regeneration within a 3D natural-based hydrogel

Articular cartilage (AC) lacks the ability to self-repair and cell-based approaches, primarily based on using chondrocytes and mesenchymal stem cells (MSCs), are emerging as effective technology to restore cartilage functionality, because cells synergic functionality may support the maintenance of chondrogenic phenotype and promote extracellular matrix regeneration. This work aims to develop a more physiologically representative co-culture system to investigate the influence of MSCs on the activity of chondrocytes. A thermo-sensitive chitosan-based hydrogel, ionically crosslinked with β–glycerophosphate, is optimised to obtain sol/gel transition at physiological conditions within 5 minutes, high porosity with pores diameter <30 µm, and in vitro mechanical integrity with compressive and equilibrium Young’s moduli of 37 kPa and 17 kPa, respectively. Live/dead staining showed that after 1 and 3 days in culture, the encapsulated MSCs into the hydrogels are viable and characterised by round-like morphology. Furthermore chondrocyte spheroids, seeded on top of gels that contained either MSCs or no cells, show that the encapsulated MSCs stimulate chondrocyte activity within a gel co-culture, both in terms of maintaining the coherence of chondrocyte spheroids, leading to a larger quantity of CD44 (by immunofluorescence) and a higher production of collagen and glycosaminoglycans (by histology) compared with the mono-culture.

Chitosan-based thermosensitive composite hydrogel enhances the therapeutic efficacy of human umbilical cord MSC in TBI rat model

Recently, stem cell–based therapy shows great promise in treating traumatic brain injury. However, the low rate of cell engraftment and survival are two major barriers for efficacy. To improve the therapeutic effect, a new thermosensitive hydrogel based on chitosan, hydroxyethyl cellulose, hyaluronic acid, and β-glycerophosphate (CS-HEC-HA/GP) was developed in this study. This CS-HEC-HA/GP hydrogel exhibits a faster gelation process and better biocompatibility to human umbilical cord mesenchymal stem cells (hUC-MSC) versus CS/GP or CS-HEC/GP hydrogels. The suitable rheological behavior similar to brain tissue supports that the CS-HEC-HA/GP hydrogel might be a preferable neural scaffold. In addition, CS-HEC-HA/GP hydrogel loaded with hUC-MSC could enhance the retention, survival, and migration of encapsulated hUC-MSC, improve survival and proliferation of endogenous neural cells probably by secreting neurotrophic factors and inhibiting apoptosis, and thereby accelerate remodeling of brain structure and neurological function recovery in TBI rats. Thus, this hydrogel shows enormous potentials in stem cell–based neural tissue repair and regeneration.

Enhanced cutaneous wound healing by functional injectable thermo-sensitive chitosan-based hydrogel encapsulated human umbilical cord-mesenchymal stem cells

Human umbilical cord-mesenchymal stem cells (hUCMSCs) can secrete a variety of cytokines and growth factors promoting wound repair. Hydrogel is suitable biomaterial to supply niche for cells adhesion and survival. This study constructed a functional injectable thermo-sensitive hydrogel (chitosan/glycerol phosphate sodium/cellulose nanocrystals, CS/GP/CNC) encapsulated hUCMSCs to repair full-thickness cutaneous wound. Addition of CNC to the CS/GP system not only accelerated the gel speed, but also greatly improved the mechanical properties of the gel and decreased degradation rate. The novel hydrogel was injectable and low toxicity. Histological detection showed that hydrogel-hUCMSCs combination significantly accelerated wound closure, microcirculation, tissue remodeling, re-epithelialization and hair follicle regeneration, and inhibited over-inflammation in the central and surrounding wounds. The hydrogel-hUCMSCs combination promoted collagen deposition and keratinocyte mature marker K1 expression, decreased inflammatory factors secretion namely TNF-α and IL-1β. The present data provides a potential strategy for treatment of non-healing chronic cutaneous wounds.

Sustained release of levofloxacin from thermosensitive chitosan-based hydrogel for the treatment of postoperative endophthalmitis.

In the field of ophthalmology, postoperative endophthalmitis (POE) is a serious surgical complication, which may lead to poor visual outcome even after the infection has been controlled. In the study, we develop a sustained drug releasing system loaded with levofloxacin which is expected to be effective against common pathogens responsible for POE for at least 7 days after single application at the end of surgery. The results of study showed that the sol-gel transition temperature of the levofloxacin-loaded chitosan-gelatin-based solution was ~34°C. The gelation time of the developed formulation was ~81 s at 34°C. The results showed that the osmolality of developed hydrogel was 304 mOsm/L. The in vitro drug release studies revealed that levofloxacin release from the developed hydrogel displayed a sustained-release profile. The long-term antibacterial property of the developed hydrogel has been demonstrated. The biocompatibility of the developed hydrogel was evaluated in vitro. These results suggest that the levofloxacin-containing hydrogel could be applied to ocular surface at the end of ophthalmic surgery, without the risks of intracameral injection of antibiotics. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:8-13, 2020.

A thermosensitive chitosan-based hydrogel for sealing and lubricating purposes in dental implant system.

Mechanical and biological complications associated with implant systems happen frequently in the clinic. To develop a chitosan (CS)-based thermosensitive hydrogel for sealing and lubricating purposes in dental implant system. In this study, a thermosensitive hydrogel made up of CS, β-glycerophosphate pentahydrate (β-GP), and povidone-iodine (PVP-I), called CS/β-GP/PVP-I thermosensitive hydrogel, was fabricated. Three experimental groups with different volume ratios of CS to β-GP were prepared, namely 16/4, 13/7, and 10/10 groups. The surface topography of the different groups and their physicochemical characteristics were examined by SEM, FTIR, and X-ray diffraction analysis. The cytotoxicity of the hydrogel was examined by CCK-8 test. In vitro antibacterial efficiency was analyzed by the spread plate method. Sealing ability was detected by incubating two-piece implants in Escherichia coli suspension. Lubricating ability of the hydrogel was evaluated by the removal torque test with a calibrated digital torque meter. The CS/β-GP/PVP-I thermosensitive hydrogel was fabricated and showed a highly porous structure under SEM. An in vitro cytotoxicity test demonstrated that 13/7 group displayed no cytotoxicity. Furthermore, all three groups showed obviously antibacterial effects. In the sealing ability test, 16/4 group showed the best sealing ability. The removal torque of 16/4 group and 13/7 group was significantly greater than control group. Based on our findings, it could be concluded that the thermosensitive and antibacterial CS/β-GP/PVP-I hydrogel with sealing and lubricating ability was successfully prepared. The hydrogel had better sealing and lubricating effects when the volume ratio of CS to β-GP was 16/4.

Injectable Chitosan Hydrogels with Enhanced Mechanical Properties for Nucleus Pulposus Regeneration.

A thermosensitive chitosan-based hydrogel was developed, which mimics the mechanical properties of the human nucleus pulposus (NP) tissue and provides a suitable environment for seeded NP cells to live and produce glycosaminoglycans. This scaffold is injectable through 25G needle and rapidly gels in vivo at body temperature. It has the potential to restore mechanical properties and stimulate biological repair of the degenerated intervertebral disc (IVD). It could therefore be used for the minimally invasive treatment of degenerated IVD, which affects more than one person out of five in the world.

Chitosan-based thermosensitive hydrogel for nasal delivery of exenatide: Effect of magnesium chloride

The aim of this research was to evaluate the potential of two chitosan (CS)-based hydrogel systems for nasal delivery of exenatide (EXT) in rats. Both of the EXT-loaded CS/glycerophosphate (GP)/CaCl2 (EXT/CS/GP/CaCl2) and EXT/CS/GP/MgCl2 hydrogel systems had similar in vitro release profiles. However, a difference in metal salt surprisingly resulted in multifaceted differences between the two hydrogel systems, such as EXT stability, gelation time, transepithelial transport, biodistribution and pharmacokinetics. The gelation time of the EXT/CS/GP/MgCl2 hydrogel (more than 110 min) at 37 °C was much longer than that of the EXT/CS/GP/CaCl2 hydrogel (8.0–20.4 min). Transepithelial transport analysis showed that the CS/GP/MgCl2 hydrogel enhanced EXT transport across the Calu-3 cell monolayers more than the CS/GP/CaCl2 hydrogel (P < 0.05). After nasal administration in the rats, the EXT/CS/GP/MgCl2 hydrogel increased the distribution of EXT in the targeting organs and the relative bioavailability of EXT in the rats more than the EXT/CS/GP/CaCl2 hydrogel. Moreover, both EXT/CS/GP/salt hydrogel formulation treatments in high-fat-fed rats significantly decreased food intake and body weight relative to the EXT solution within ten days (P < 0.05). The aforementioned results suggest that the EXT/CS/GP/MgCl2 hydrogel formulation is more suitable to be used as a nasally delivered EXT formulation for the treatment of weight loss.

Thermosensitive chitosan-based hydrogels releasing stromal cell derived factor-1 alpha recruit MSC for corneal epithelium regeneration.

The clarity of cornea is important for normal vision. The loss or dysfunction of LESCs leads to the impairment of corneal epithelium. The complete regeneration of corneal epithelium has not been achieved. Our study demonstrated that the incorporation of rhSDF-1 alpha with CHI hydrogel accelerated corneal epithelium reconstruction with more native structural and functional properties. The mechanism may involve in inducing proliferation and migration of the LESCs and MSCs to the injury site via the SDF-1/CXCR4 chemokine axis. Therefore, SDF-1 alpha/CHI hydrogel complexes could be a practical application for clinical therapy.

Evaluation on the anti-oxidation effects of a thermosensitive chitosan-based hydrogel loaded antioxidin-RL

Evaluation on the anti-oxidation effects of a thermosensitive chitosan-based hydrogel loaded antioxidin-RL

Accelerated bony defect healing based on chitosan thermosensitive hydrogel scaffolds embedded with chitosan nanoparticles for the delivery of BMP2 plasmid DNA.

Regeneration of alveolar bone is among the main purposes of periodontal treatment. However, it is a challenge for both dentists and patients. An injectable chitosan-based thermosensitive hydrogel scaffold (CS/CSn-GP) was successfully designed and prepared with the incorporation of bone morphogenetic protein-2 plasmid DNA (pDNA-BMP2)-loaded chitosan nanoparticles (CS/CSn(pDNA-BMP2)-GP) in this study. The aim of this study was to evaluate the regenerative effect of this scaffold on the endogenous repair of alveolar bone. Thermosensitive properties, SEM scans and in vivo inflammatory reactions and degradation were evaluated. The CS/CSn-GP solution was initially injected into the muscle pouches of rats, where it changed into a gel, resulting in non-specific inflammation. It effectively enhanced new bone formation in rat calvarial defects and enhanced bony defect healing in beagle dogs. All results indicated that the CS/CSn(pDNA-BMP2)-GP complex system is a potential candidate as a targeted, multi-effect scaffold for the endogenous repair of alveolar bone. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 265-273, 2017.

Preparation and properties of a novel thermo-sensitive hydrogel based on chitosan/hydroxypropyl methylcellulose/glycerol

Chitosan-based thermosensitive hydrogels are known as injectable in situ gelling thermosensitive polymer solutions which are suitable for biomaterials. In this study, a novel thermosensitive hydrogel gelling under physiological conditions was prepared using chitosan together with hydroxypropyl methylcellulose and glycerol. Hydroxypropyl methylcellulose is to facilitate the thermogelation through large amounts of hydrophobic interactions. Glycerol in heavy concentration destroys the polymer water sheaths promoting the formation of the hydrophobic regions, and lowering the phase transition temperature. The thermosensitive hydrogels showed a physiological pH ranging from 6.8 to 6.9 and gelation time within 15min at 37°C. The prepared hydrogels were characterized by FT-IR, XRD, SEM, and rheological studies, mechanical studies and contact angle studies. The properties of degradability, cytotoxicity and protein release behaviors of the hydrogels were investigated. The results indicate this thermosensitive hydrogel possess good fluidity, thermosensitivity and biodegradability, as well as low-cytotoxicity and controlled release, showing the potential use in biomedical applications.

Carbon nanotubes play an important role in the spatial arrangement of calcium deposits in hydrogels for bone regeneration.

Age related bone diseases such as osteoporosis are considered among the main causes of reduced bone mechanical stability and bone fractures. In order to restore both biological and mechanical function of diseased/fractured bones, novel bioactive scaffolds that mimic the bone structure are constantly under development in tissue engineering applications. Among the possible candidates, chitosan-based thermosensitive hydrogel scaffolds represent ideal systems due to their biocompatibility, biodegradability, enhanced antibacterial properties, promotion of osteoblast formation and ease of injection, which makes them suitable for less invasive surgical procedures. As a main drawback, these chitosan systems present poor mechanical performance that could not support load-bearing applications. In order to produce more mechanically-competent biomaterials, the combined addition of hydroxyapatite and carbon nanotubes (CNTs) is proposed in this study. Specifically, the aim of this work is to develop thermosensitive chitosan hydrogels containing stabilised single-walled and multi-walled CNTs, where their effect on the mechanical/physiochemical properties, calcium deposition patterns and ability to provide a platform for the controlled release of protein drugs was investigated. It was found that the addition of CNTs had a significant effect on the sol–gel transition time and significantly increased the resistance to compression for the hydrogels. Moreover, in vitro calcification studies revealed that CNTs played a major role in the spatial arrangements of newly formed calcium deposits in the composite materials studied, suggesting that they may have a role in the way the repair of fragile and/or fractured bones occurs in vivo.

Insight into the interactive effects of β-glycerophosphate molecules on thermosensitive chitosan-based hydrogels

The purpose of the present study was to provide insights into the interactive effects of β-glycerophosphate (β-GP) molecules on thermosensitive chitosan-based hydrogels, which experience sol–gel transformation around the physiological temperature. This study also investigated the influence of β-GP as a physical cross-linker and pH modifier on chitosan-based hydrogels by Fourier transform infrared spectroscopy with the aim of achieving a better understanding of the effect of β-GP action mechanism. For this purpose, some solutions with 2% (w/v) chitosan were mixed with different amounts of β-GP in the range of 0–20% (w/v) concentrations. It was shown that by further addition of β-GP, the anionic phosphate units of β-GP in combination with the cationic amine units of chitosan could provide electrostatic cross-linking for making chitosan-based hydrogels. All the β-GP–chitosan solutions remained at the physiological pH after complete mixing. In addition, the viability of 3T3 fibroblast cells determined by MTT assay and scanning suggested that the samples containing 12% β-GP would show optimum biological characteristics. This study demonstrated that the synthesized chitosan–β-GP is a biocompatible thermosensitive system, which can be potentially used for tissue engineering applications in different areas, such as cartilage injections, and that injectability and appropriate gelation behavior are important factors.

Chitosan-Based Thermosensitive Hydrogel for Controlled Drug Delivery to the Temporomandibular Joint.

Intra-articular injections of hyaluronic acid (HA) and corticosteroids have been extensively used in treating temporomandibular disorders. However, rapid clearance from the site of injection is a major concern that is commonly managed by frequent dosing, which is not without complications. This study aimed to determine the suitability of thermosensitive chitosan-based hydrogels for intra-articular controlled release of drugs in the rabbit temporomandibular joint (TMJ). A series of hydrogels were prepared using different chitosan (Ch) to β-glycerophosphate (β-GP) ratios. The gelation time, swelling ratio, the shape, and surface morphology of the prepared gels were investigated to select the formulation with optimum characteristics. The left TMJ in 13 adult male New Zealand white rabbits was injected with 0.2 mL of Chitosan/β-glycerophosphate/HA while the right TMJ was injected with 0.2 mL of control solution of HA. Hyaluronic acid concentrations in experimental and control groups were measured using Hyaluronan Quantikine Enzyme-Linked Immunosorbent Assay Kit. In vitro characterization showed that both the Ch:β-GP ratio and incorporation of HA had a significant effect on gelation time, degree of swelling, and surface morphology of the hydrogels. No morphological changes were observed in the joints in both groups. The mean concentration of HA in the experimental joints after 7 days (1339.79 ± 244.98 μg/g) was significantly higher than that in the control (474.52 ± 79.36 μg/g). In conclusion, the chitosan-based thermosensitive hydrogel can be considered as a promising controlled drug release system to the TMJ in a rabbit model that would potentially overcome many of the current limitations of intra-articular formulations.

Thermosensitive chitosan-based hydrogel as a topical ocular drug delivery system of latanoprost for glaucoma treatment

Ocular hypertension is a major risk factor for the development and progression of glaucoma. Frequent and long-term application of latanoprost often causes undesirable local side effects, which are a major cause of therapeutic failure due to loss of persistence in using this glaucoma medical therapy. In the present study, we developed a thermosensitive chitosan-based hydrogel as a topical eye drop formulation for the sustained release of latanoprost to control ocular hypertension. The developed formulation without preservatives may improve compliance and possibly even efficacy. The results of this study support its biocompatibility and sustained-release profile both in vitro and in vivo. After topical application of latanoprost-loaded hydrogel, triamcinolone acetonide-induced elevated intraocular pressure was significantly decreased within 7 days and remained at a normal level for the following 21 days in rabbit eyes. This newly developed chitosan-based hydrogel may provide a non-invasive alternative to traditional anti-glaucoma eye drops for glaucoma treatment.

Thermosensitive chitosan-based hydrogels for sustained release of ferulic acid on corneal wound healing

Oxidative damage to cornea can be induced by alkaline chemical burn which may cause vision loss or blindness. Recent studies showed that exogenous application of natural antioxidants may be a potential treatment for corneal wound healing. However, low ocular bioavailability and short residence time are the limiting factors of topically administered antioxidants. Ferulic acid (FA) is a natural phenolic compound and an excellent antioxidant. The study was aimed to investigate the effects of FA in corneal epithelial cells (CECs) under oxidative stress and evaluate the feasibility of use the thermosensitive chitosan-based hydrogel containing FA for corneal wound healing. The results demonstrated that post-treatment of FA on CECs could decrease the inflammation-level and apoptosis. In the rabbit corneal alkali burn model, post-treatment FA-loaded hydrogel may promote the corneal wound healing. The results of study suggest that FA-loaded hydrogel may have the potential applications in treating corneal alkali burn.

A thermosensitive chitosan-based hydrogel for controlled release of insulin

Present study aims at synthesizing a thermosensitive hydrogel for controlled release of insulin. According to a modified method, hydroxybutyl chitosan (HBC) hydrogel possessed thermal sensitivity is prepared which can form hydrogel at over 25°C. The HBC hydrogel is non-cytotoxic to mice fibroblasts cells (L929). Insulin is 100% entrapped in the hydrogel, 38% of which is released in vitro from the concentration of 5% hydrogel after 48 h, whereas by enzymolysis with lysozyme, 80% of the total insulin is released after 48 h. This study suggests that HBC hydrogel could be utilized for controlled release of insulin in a non-invasive manner.