Specific delivery of metronidazole using microparticles and thermosensitive in situ hydrogel for intrapocket administration as an alternative in periodontitis treatment

Periodontitis is a common chronic inflammatory disease primarily caused by the prevalence of bacterial overgrowth resulting in the development of an inflammatory condition that destroys the tooth's supporting tissues and eventual tooth loss. Comparatively, to other treatment methods, it is difficult for topical antibacterial drugs to effectively permeate the biofilm's physical barrier, making conventional therapy for periodontitis more challenging. This novel study combines thermosensitive in situ hydrogel with microparticles (MPs) to enhance the targeted delivery of metronidazole (MET) to the periodontal pocket. Polycaprolactone (PCL) polymer was utilized to produce bacteria-sensitive MPs. Additionally, the study assessed the attributes of MPs and demonstrated an enhancement in the in vitro antibacterial efficacy of MPs towards Staphylococcus aureus (SA) and Escherichia coli (EC). Subsequently, we incorporated MET-MPs into thermosensitive in situ hydrogel formulations using chitosan. The optimized formulations exhibited stability, appropriate gelation temperature, mucoadhesive strength, and viscosity. In vitro permeation tests showed selective and prolonged drug release against SA and EC. Ex vivo experiments demonstrated no significant differences between in situ hydrogel containing pure MET and MET-MPs in biofilm quantity, bacterial counts, and metabolic activity in biofilms. According to in vitro tests and the effectiveness of the antibacterial activity, this study has exhibited a novel methodology for more efficacious therapies for periodontitis. This study aims to utilize MET in MPs to improve its effectiveness, enhance its antibacterial activity, and improve patient treatment outcomes. In further research, the efficacy of the treatment should be investigated in vivo using an appropriate animal model.

Resveratrol-loaded microemulsion based thermosensitive hydrogel for potential topical treatment of the vaginal inflammation

BACKGROUND

Vaginal inflammation is a prevalent gynecological condition. If left untreated, it can potentially spread to the urinary and reproductive systems.

METHODS

In this study, we propose a resveratrol-loaded microemulsion-based thermosensitive hydrogel (Res-Me-Tsgel) and compare it with a chitosan hydrogel-based Res-Me-Cogel. We characterized the different characters of Res-Me-Tsgel. The safety of Res-Me-Tsgel was also evaluated in vitro and in vivo. Finally, we measured the retention of Res in the vagina after drug administration.

RESULTS

The Res-Me-Tsgel we prepared is a transparent liquid solution at room temperature that rapidly forms a gel at 37oC. Compared to Res solution and Res-Me, both Res-Me-Cogel and Res-Me-Tsgel demonstrate superior sustained release properties. Both in vitro and in vivo studies confirm the excellent biosafety profile of Res-Me-Cogel and Res-Me-Tsgel. Vaginal administration of these formulations in rats results in prolonged retention of resveratrol within the vagina. Notably, due to its improved flow into vaginal folds after administration, the retention of Resveratrol was approximately three times higher for the Res-Me-Tsgel group compared to the Res-Me-Cogel group at 24 h post-administration. Overall, these findings highlight the potential application of Res-Me-Tsgel as an effective means for vaginal inflammation.

CONCLUSIONS

We developed a novel micromulsion based thermosensitive hydrogel for the delivery of Res. The sustained release of Res and favorable vaginal retention from Res-Me-Tsgel make them promise as a potential candidate for local intravaginal therapy.

A Thermosensitive Bi-Adjuvant Hydrogel Triggers Epitope Spreading to Promote the Anti-Tumor Efficacy of Frameshift Neoantigens

Tumor-specific frameshift mutations encoding peptides (FSPs) are highly immunogenic neoantigens for personalized cancer immunotherapy, while their clinical efficacy is limited by immunosuppressive tumor microenvironment (TME) and self-tolerance. Here, a thermosensitive hydrogel (FSP-RZ-BPH) delivering dual adjuvants R848 (TLR7/8 agonist) + Zn2+ (cGAS-STING agonist) is designed to promote the efficacy of FSPs on murine forestomach cancer (MFC). After peritumoral injection, FSP-RZ-BPH behaves as pH-responsive sustained drug release at sites near the tumor to effectively transform the immunosuppressive TME into an inflammatory type. FSP-RZ-BPH orchestrates innate and adaptive immunity to activate dendritic cells in tumor-draining lymph nodes and increase the number of FSPs-reactive effector memory T cells (TEM) in tumor by 2.9 folds. More importantly, these TEM also exhibit memory responses to nonvaccinated neoantigens on MFC. This epitope spreading effect contributes to reduce self-tolerance to maintain long-lasting anti-tumor immunity. In MFC suppressive model, FSP-RZ-BPH achieves 84.8% tumor inhibition rate and prolongs the survival of tumor-bearing mice with 57.1% complete response rate. As a preventive tumor vaccine, FSP-RZ-BPH can also significantly delay tumor growth. Overall, the work identifies frameshift MFC neoantigens for the first time and demonstrates the thermosensitive bi-adjuvant hydrogel as an effective strategy to boost bystander anti-tumor responses of frameshift neoantigens.

Thermosensitive hydrogel with programmed dual-octenidine release combating biofilm for the treatment of apical periodontitis

The utilization of intracanal medicaments is an indispensable procedure in root-canal treatment. However, the conventional intracanal medicaments still need improvement regarding antimicrobial efficacy and ease of clinical operation. To address the above issues, OCT/PECT@OCT + ALK composite hydrogel characterized by programming sequential release of dual antimicrobial agents has been proposed. Thanks to the self-assemble ability of amphiphilic copolymer poly(ε-caprolactone-co-1,4,8-trioxa [4.6]spiro-9-undecanone)-poly(ethylene glycol)-poly(ε-caprolactone-co-1,4,8-trioxa[4.6]spiro-9-undecanone) (PECT), dual hydrophilic and hydrophobic antimicrobial agents could be easily encapsulated in the hydrogel system and tailored for sequential drug release for a better antibiofilm effect. The hydrophilic octenidine (Octenidine dihydrochloride, OCT-HCl) is encapsulated in the hydrophilic part of hydrogel for instantaneous elevating the drug concentration through bursting release, and the hydrophobic octenidine (Octenidine, OCT) is further loaded into the PECT nanoparticles to achieve a slower and sustained-release profile. Additionally, calcium hydroxide (Ca(OH)2) was incorporated into the system and evenly dispersed among PECT nanoparticles to create an alkaline (ALK) environment, synergistically enhancing the antibiofilm effect with higher efficiency and prolonged duration. The antibiofilm effect has been demonstrated in root-canal models and apical periodontitis rats, exhibiting superior performance compared to clinically used Ca(OH)2 paste. This study demonstrates that OCT/PECT@OCT + ALK composite thermosensitive hydrogel is a potential intracanal medicament with excellent antibiofilm effect and clinical operability.

Garlic-Derived Exosome-like Nanovesicles-Based Wound Dressing for Staphylococcus aureus Infection Visualization and Treatment

Garlic-derived exosome-like nanovesicles (GELNs) could function in interspecies communication and may serve as natural therapeutics to regulate the inflammatory response or as nanocarriers to efficiently deliver specific drugs. Staphylococcus aureus (S. aureus) is able to hide within host cells to evade immune clearance and antibiotics, leading to life-threatening infections. On-site detection and efficient treatment of intracellular S. aureus infection in wounds remain challenging. Herein, we report a thermosensitive, injectable, visible GELNs-based wound dressing, Van@GELNs/F127 hydrogel (gel Van@GELNs), which is H2O2-responsive and can slowly release vancomycin into host cells forS. aureus infection visualization and treatment in wounds. GELNs show inherent antibacterial activity, which is significantly enhanced after loading vancomycin. Both GELNs and Van@GELNs have the ability to be internalized by cells, so Van@GELNs are more effective than free vancomycin in killing S. aureus in RAW 264.7 macrophages. When applied to an S. aureus-infected wound on a mouse, the colorless HRP&ABTS/Van@GELNs/F127 solution immediately changes to a green hydrogel and shows better therapeutic effect than vancomycin. Thus, direct visualization by the naked eye and effective treatment of S. aureus infection in wounds are achieved by gel Van@GELNs. We anticipate gel Van@GELNs be applied for the theranostics of S. aureus infection diseases in the clinic in the near future.

Preparation and characterization of a novel composite acellular matrix/hyaluronic acid thermosensitive hydrogel for interstitial cystitis/bladder pain syndrome

Bladder mucosa damage that causes harm to the interstitium is a recognized pathogenesis of interstitial cystitis/bladder pain syndrome (IC/BPS). The intravesical instillation of drugs is an important second-line therapy, but it is often necessary to use drugs repeatedly in the clinic because of their short residence time in the bladder cavity, which alters the therapeutic effect. To overcome this drawback, this study developed a novel composite acellular matrix/hyaluronic acid (HA) thermosensitive hydrogel (HA-Gel) using rabbit small intestinal submucosa extracellular matrix (ECM) as the thermosensitive material and HA as the drug component and examined its composition, microstructure, thermodynamic properties, temperature sensitivity, rheological properties, biocompatibility, drug release, hydrogel residue, and bacteriostatic properties. The study showed HA-Gel was liquid at temperatures of 15-37.5°C and solid at 37.5-50°C, its swelling rate decreased with increasing temperature, and its lower critical solution temperature occurred at approximately 37.5°C. This property made the hydrogel liquid at room temperature convenient for intravesical perfusion and turned into a solid about 1 min after entering the body and rising to body temperature to increase its residence time. Subsequent experiments also proved that the gel residue time of HA-Gel in vivo and the drug release time of HA in vivo could reach more than 5 days, which was significantly higher than that of HA alone, and it had good biocompatibility and antibacterial properties. Therefore, this hydrogel possesses the proper characteristics to possibly make it an ideal dosage form for IC/BPS intravesical instillation therapy.

Chitosan-based thermosensitive hydrogel with long-term release of murine nerve growth factor for neurotrophic keratopathy

Neurotrophic keratopathy is a persistent defect of the corneal epithelium, with or without stromal ulceration, due to corneal nerve deficiency caused by a variety of etiologies. The treatment options for neurotrophic keratopathy are limited. In this study, an ophthalmic solution was constructed from a chitosan-based thermosensitive hydrogel with long-term release of murine nerve growth factor (CTH-mNGF). Its effectiveness was evaluated in corneal denervation (CD) mice and patients with neurotrophic keratopathy. In the preclinical setting, CTH-mNGF was assessed in a murine corneal denervation model. CTH-mNGF was transparent, thermosensitive, and ensured sustained release of mNGF for over 20 hours on the ocular surface, maintaining the local mNGF concentration around 1300 pg/mL in vivo. Corneal denervation mice treated with CTH-mNGF for 10 days showed a significant increase in corneal nerve area and total corneal nerve length compared with non-treated and CTH treated mice. A subsequent clinical trial of CTH-mNGF was conducted in patients with stage 2 or 3 neurotrophic keratopathy. Patients received topical CTH-mNGF twice daily for 8 weeks. Fluorescein sodium images, Schirmer's test, intraocular pressure, Cochet-Bonnet corneal perception test, and best corrected visual acuity were evaluated. In total, six patients (total of seven eyes) diagnosed with neurotrophic keratopathy were enrolled. After 8 weeks of CTH-mNGF treatment, all participants showed a decreased area of corneal epithelial defect, as stained by fluorescence. Overall, six out of seven eyes had fluorescence staining scores < 5. Moreover, best corrected visual acuity, intraocular pressure, Schirmer's test and Cochet-Bonnet corneal perception test results showed no significant improvement. An increase in corneal nerve density was observed by in vivo confocal microscopy after 8 weeks of CTH-mNGF treatment in three out of seven eyes. This study demonstrates that CTH-mNGF is transparent, thermosensitive, and has sustained-release properties. Its effectiveness in healing corneal epithelial defects in all eyes with neurotrophic keratopathy suggests CTH-mNGF has promising application prospects in the treatment of neurotrophic keratopathy, being convenient and cost effective.

Herbal Products-Powered Thermosensitive Hydrogel with Phototherapy and Microenvironment Reconstruction for Accelerating Multidrug-Resistant Bacteria-Infected Wound Healing

Wound healing and infection remain significant challenges due to the ineffectiveness against multidrug-resistant (MDR) bacteria and the complex oxidative wound microenvironments. To address these issues, thymoquinone-reinforced injectable and thermosensitive TQ@PEG-PAF-Cur hydrogels with dual functions of microenvironment reshaping and photodynamic therapy are developed. The hydrogel comprises natural compound thymoquinone (TQ) and poly (ethylene glycol)-block-poly (alanine-co-phenyl alanine) copolymers (PEG-PAF) conjugated with natural photosensitizer curcumin (Cur). The incorporation of TQ and Cur reduces the sol-to-gel transition temperature of TQ@PEG-PAF-Cur to 30°C, compared to PEG-PAF hydrogel (37°C), due to the formation of strong hydrogen bonding, matching the wound microenvironment temperature. Under blue light excitation, TQ@PEG-PAF-Cur generates significant amounts of reactive oxygen species such as H2 O2 , 1O2 , and ·OH, exhibiting rapid and efficient bactericidal capacities against methicillin-resistant Staphylococcus aureus and broad spectrum β-lactamases Escherichia coli via photodynamic therapy (PDT). Additionally, Cur effectively inhibits the expressions of proinflammatory cytokines in skin tissue-forming cells. As a result, the composite hydrogel can rapidly transform into a gel to cover the wound, reshape the wound microenvironment, and accelerate wound healing in vivo. This collaborative antibacterial strategy provides valuable insights to guide the development of multifunctional materials for efficient wound healing.

Sprayable hydroxypropyl chitin/collagen extract of Ampelopsis brevipedunculata hydrogel accelerates wound healing

OBJECTIVE

Keeping a wound moist can allow effective and rapid healing, and it can control the formation of scabs, thereby allowing cell proliferation and epithelial formation. When regularly changing a dressing, thermosensitive hydrogel as a moist dressing does not cause a secondary wound from adhesion. The main aim of this study was to evaluate the effect of a new sprayable thermosensitive hydrogel on wound healing.

METHOD

The hydrophobic N-acetyl group of chitin was removed by microwave reaction with lye until the degree of acetylation was 60%, followed by reaction with propylene oxide to obtain hydroxypropyl chitin (HPCH) with a degree of substitution of 40%. After mixing HPCH with fish scale collagen (FSC), a thermosensitive hydrogel with a gel temperature of 26.5°C was obtained. Ampelopsis brevipedunculata extracts (ABE), which have been found to accelerate wound repair and improve healing, were added. HPCH/FSC is not toxic to the mouse L929 cell line and forms a hydrogel at body surface temperature. It can be easily sprayed on a wound. The HPCH/FSC has a three-dimensional network porous structure with a swelling ratio of 10.95:1 and a water vapour transmission rate of 2386.03±228.87g/m2/day; it can facilitate the penetration of water and air, and promote absorption of wound exudate. Wound repair was performed on five Sprague-Dawley rats. Each rat had three wounds, which were treated with medical gauze, HPCH/FSC and HPCH/FSC/ABE, respectively.

RESULTS

The wounds in the HPCH/FSC/ABE group recovered the fastest in vivo, the mature wound site was smoother, the re-epithelialisation was even and thicker, and the angiogenesis developed rapidly to the mature stage.

CONCLUSION

In this study, HPCH/FSC/ABE thermosensitive hydrogel was shown to effectively accelerate wound healing and was convenient for practical application.

Thermosensitive Chitosan Hydrogels: A Potential Strategy for Prolonged Iron Dextran Parenteral Supplementation

Iron deficiency anemia (IDA) presents a global health challenge, impacting crucial development stages in humans and other mammals. Pigs, having physiological and metabolic similarities with humans, are a valuable model for studying and preventing anemia. Commonly, a commercial iron dextran formulation (CIDF) with iron dextran particles (IDPs) is intramuscularly administered for IDA prevention in pigs, yet its rapid metabolism limits preventive efficacy. This study aimed to develop and evaluate chitosan thermosensitive hydrogels (CTHs) as a novel parenteral iron supplementation strategy, promoting IDPs' prolonged release and mitigating their rapid metabolism. These CTHs, loaded with IDPs (0.1, 0.2, and 0.4 g of theoretical iron/g of chitosan), were characterized for IM iron supplementation. Exhibiting thermosensitivity, these formulations facilitated IM injection at ~4 °C, and its significant increasing viscosity at 25-37 °C physically entrapped the IDPs within the chitosan's hydrophobic gel without chemical bonding. In vitro studies showed CIDF released all the iron in 6 h, while CTH0.4 had a 40% release in 72 h, mainly through Fickian diffusion. The controlled release of CTHs was attributed to the physical entrapment of IDPs within the CTHs' gel, which acts as a diffusion barrier. CTHs would be an effective hydrogel prototype for prolonged-release parenteral iron supplementation.

Enhanced Chemo-Immunotherapy Strategy Utilizing Injectable Thermosensitive Hydrogel for The Treatment of Diffuse Peritoneal Metastasis in Advanced Colorectal Cancer

Patients with colorectal cancer (CRC) and diffuse peritoneal metastasis (PM) are not eligible for surgical intervention. Thus, palliative treatment remains the standard of care in clinical practice. Systemic chemotherapy fails to cause drug accumulation at the lesion sites, while intraperitoneal chemotherapy (IPC) is limited by high clearance rates and associated complications. Given the poor prognosis, a customized OxP/R848@PLEL hydrogel delivery system has been devised to improve the clinical benefit of advanced CRC with diffuse PM. This system is distinguished by its simplicity, security, and efficiency. Specifically, the PLEL hydrogel exhibits excellent injectability and thermosensitivity, enabling the formation of drug depots within the abdominal cavity, rendering it an optimal carrier for IPC. Oxaliplatin (OxP), a first-line drug for advanced CRC, is cytotoxic and enhances the immunogenicity of tumors by inducing immunogenic cell death. Furthermore, OxP and resiquimod (R848) synergistically enhance the maturation of dendritic cells, promote the expansion of cytotoxic T lymphocytes, and induce the formation of central memory T cells. Moreover, R848 domesticates macrophages to an anti-tumor phenotype. OxP/R848@PLEL effectively eradicates peritoneal metastases, completely inhibits ascites production, and significantly prolongs mice lifespan. As such, it provides a promising approach to managing diffuse PM in patients with CRC without surgical indications.

LuMA-Functionalized Thermosensitive Hydrogel: A Versatile and Robust Dopamine-Triggered Platform for Diverse Biomolecules Sensing

It is of great significance for the analysis of multiple biomarkers because a single biomarker is difficult to accurately achieve early diagnosis, disease course monitoring, and prognosis evaluation. Herein, a luminescence thermosensitive hydrogel was synthesized by radical polymerization using a methacrylic acid derivative monomer of luminol (LuMA) as luminescent, N-isopropylacrylamide (NIPAM) as thermosensitive monomer, and acrydite-oligonucleotides [dopamine (DA) aptamer, DNA C1, and DNA C2] as recognition elements. The combined DA based on the affinity interaction between the DA and the aptamer on the hydrogel polymer chain was electrochemically oxidized to dopamine quinone during the electrochemiluminescence (ECL) scanning, which effectively quenched the ECL signal of LuMA due to the resonance energy transfer (RET). In addition, the thermosensitive hydrogel showed swelling-collapse characteristics when the temperature was below and above the volume phase transition temperature. Undergoing the collapse process initiated by the temperature, the RET efficiency was further enhanced due to the shortened distance between the energy donor and acceptor, showing a 1.4 times signal amplification and achieving sensitive detection of DA with a limit of detection (LOD) of 1.7 × 10-10 M. For a proof of concept application, coupled with the target-induced release of DA from the DNA-magnetic beads bioconjugations based on duplex-specific nuclease (DSN)-assisted target recycling amplification strategy and DNAzyme cleavage reaction, this ECL-RET approach was successfully used to evaluate multiple targets including miRNA-141 and MUC1 with the LOD of 2.5 aM and 1.6 fg/mL, respectively. The excellent performances of the versatile and robust ECL-RET hydrogel in multiple target sensing showed potential applications in clinical diagnosis and disease therapeutic assay.

Novel Sprayable Thermosensitive Benzydamine Hydrogels for Topical Application: Development, Characterization, and In Vitro Biological Activities

Benzydamine hydrochloride (BZD) having analgesic, anesthetic, and anti-inflammatory effects is used orally or topically in the treatment of disorders such as joint inflammation and muscle pain. Within the scope of this study, sprayable thermosensitive BZD hydrogels were developed using thermoresponsive poloxamers to avoid systemic side effects and to provide better compliance for topical administration. Also, hydroxypropyl methyl cellulose (HPMC) was employed to improve the mechanical strength and bioadhesive properties of the hydrogel. The addition of BZD generally decreased the viscosity of the formulations (p < 0.05), while increasing the gelation temperature (p < 0.05). The formulations that did not have any clogs or leaks in the nozzle of the bottle during the spraying process were considered lead formulations. To spray the formulations easily, it was found that the viscosity at RT should be less than 200 mPa·s, and their gelation temperature should be between 26 and 34°C. Increasing HPMC and poloxamer improved bioadhesion. The amount of HPMC and poloxamers did not cause a significant change in the release characteristics of the formulations (p > 0.05); the release profiles of BZD from the formulations were similar according to model-independent kinetic (f2 > 50). HPMC and poloxamers had important roles in the accumulation of BZD in the skin. In vitro biological activity studies demonstrated that the formulations presented their anti-inflammatory activity with TNF-α inhibition but did not have any effect on the inhibition of COX enzymes as expected. As a result, thermosensitive hydrogels containing BZD might be an appropriate alternative, providing an advantage in terms of easier application compared to conventional gels.

Immunostimulant Hydrogel-Guided Tumor Microenvironment Reprogramming to Efficiently Potentiate Macrophage-Mediated Cellular Phagocytosis for Systemic Cancer Immunotherapy

Macrophage-mediated cellular phagocytosis (MMCP) plays a critical role in conducting antitumor immunotherapy but is usually impaired by the intrinsic phagocytosis evading ability of tumor cells and the immunosuppressive tumor microenvironment (TME). Herein, a MMCP-boosting hydrogel (TCCaGM) was elaborately engineered by encapsulating granulocyte-macrophage colony-stimulating factor (GM-CSF) and a therapeutic nanoplatform (TCCaN) that preloaded with the tunicamycin (Tuni) and catalase (CAT) with the assistance of CaCO3 nanoparticles (NPs). Strikingly, the hypoxic/acidic TME was efficiently alleviated by the engineered hydrogel, "eat me" signal calreticulin (CRT) was upregulated, while the "don't eat me" signal CD47 was downregulated on tumor cells, and the infiltrated DCs were recruited and activated, all of which contributed to boosting the macrophage-mediated phagocytosis and initiating tumor-specific CD8+ T cells responses. Meanwhile, the remodeled TME was beneficial to accelerate the polarization of tumor-associated macrophages (TAMs) to the antitumoral M1-like phenotype, further heightening tumoricidal immunity. With the combination of PD-1 antibody (αPD-1), the designed hydrogel significantly heightened systemic antitumor immune responses and long-term immunological effects to control the development of primary and distant tumors as well as suppress tumor metastasis and recurrence, which established an optimal strategy for high-performance antitumor immunotherapy.

Thermosensitive hydrogel-based GPR124 delivery strategy for rebuilding blood-spinal cord barrier

Spinal cord injury (SCI) causes blood-spinal cord barrier (BSCB) disruption, leading to secondary damage, such as hemorrhagic infiltration, inflammatory response, and neuronal cell death. It is of great significance to rebuild the BSCB at the early stage of SCI to alleviate the secondary injury for better prognosis. Yet, current research involved in the reconstruction of BSCB is insufficient. Accordingly, we provide a thermosensitive hydrogel-based G protein-coupled receptor 124 (GPR124) delivery strategy for rebuilding BSCB. Herein, we firstly found that the expression of GPR124 decreased post-SCI and demonstrated that treatment with recombinant GPR124 could partially alleviate the disruption of BSCB post-SCI by restoring tight junctions (TJs) and promoting migration and tube formation of endothelial cells. Interestingly, GPR124 could also boost the energy metabolism of endothelial cells. However, the absence of physicochemical stability restricted the wide usage of GPR124. Hence, we fabricated a thermosensitive heparin-poloxamer (HP) hydrogel that demonstrated sustained GPR124 production and maintained the bioactivity of GPR124 (HP@124) for rebuilding the BSCB and eventually enhancing functional motor recovery post-SCI. HP@124 hydrogel can encapsulate GPR124 at the lesion site by injection, providing prolonged release, preserving wounded tissues, and filling injured tissue cavities. Consequently, it induces synergistically efficient integrated regulation by blocking BSCB rupture, decreasing fibrotic scar formation, minimizing inflammatory response, boosting remyelination, and regenerating axons. Mechanistically, giving GPR124 activates energy metabolism via elevating the expression of phosphoenolpyruvate carboxykinase 2 (PCK2), and eventually restores the poor state of endothelial cells. This research demonstrated that early intervention by combining GPR124 with bioactive multifunctional hydrogel may have tremendous promise for restoring locomotor recovery in patients with central nervous system disorders, in addition to a translational approach for the medical therapy of SCI.

Mn3O4 Nanozyme Loaded Thermosensitive PDLLA-PEG-PDLLA Hydrogels for the Treatment of Inflammatory Bowel Disease

When reactive oxygen species (ROS) accumulate in the body, they can lead to inflammatory bowel disease (IBD) through their oxidative damages to DNA, proteins, and lipids. In this study, a thermosensitive hydrogel-based nanozyme was developed to treat IBD. We first synthesized a manganese oxide (Mn₃O₄) nanozyme with multienzyme activity followed by physically loading with a thermosensitive hydrogel poly(d,l-lactide)-poly(ethylene glycol)-poly(d,l-lactide)-based triblock copolymer (PDLLA-PEG-PDLLA). Then, a mouse model based on the inducement of dextran sulfate sodium (DSS) was built to assess the ROS targeting, scavenging, as well as anti-inflammatory ability of Mn₃O₄ nanozymes-loaded PDLLA-PEG-PDLLA (MLPPP). Because of the sharp gelation behavior of PDLLA-PEG-PDLLA in body temperature, the MLPPP nanozyme can easily target the inflamed colon after colorectal administration. Following the formation of a physical protection barrier and sustained release of manganese oxide nanozymes that had diverse enzymatic activities and can effectively scavenge ROS, the administration of the MLPPP nanozyme had a high efficacy for treating colitis mice; importantly, after the treatment with this novel nanoformulation, the levels of the pathological indicators in colons as well as in sera of colitis mice were even comparable to healthy mice. Therefore, the MLPPP nanozyme has a potential application for nanotherapy of IBD and would have great clinical translation prospects.

NIR-II Responsive Nanohybrids Incorporating Thermosensitive Hydrogel as Sprayable Dressing for Multidrug-Resistant-Bacteria Infected Wound Management

Developing an effective dressing against bacterial infection and synchronously addressing wound complications, such as bleeding, long-term inflammation, and reinfection, are highly desirable in clinical practice. In this work, a second near-infrared (NIR-II) responsive nanohybrid consisting of imipenem encapsulated liposome with gold-shell and lipopolysaccharide (LPS)-targeting aptamer, namely ILGA, is constructed for bacteria elimination. Benefiting from the delicate structure, ILGA exhibits strong affinity and a reliable photothermal/antibiotic therapeutic effect toward multidrug-resistant Pseudomonas aeruginosa (MDR-PA). Furthermore, by incorporating ILGA with a thermosensitive hydrogel poly(lactic-co-glycolic acid)-polyethylene glycol-poly(lactic-co-glycolic acid) (PLGA-PEG-PLGA), a sprayable dressing ILGA@Gel was prepared, which enables a quick on-demand gelation (10 s) for wound hemostasis and offers excellent photothermal/antibiotic efficacy to sterilize the infected wound. Additionally, ILGA@Gel provides satisfactory wound-healing environments by reeducating wound-associated macrophages for inflammation alleviation and forming a gel layer to block exogenous bacterial reinfection. This biomimetic hydrogel reveals excellent bacteria eradication and wound recovery effectiveness, demonstrating its promising potential for managing complicated infected wounds.

In-situ formed thermosensitive hydrogel amplifies statin-mediated immune checkpoint blockade for coordinated tumor chemo-immunotherapy

Small molecule drugs are the next-generation of immune checkpoint inhibitors (ICIs), but their in vivo therapeutic outcomes remain unsatisfactory for a long time. Herein, we proposed a combinatory regimen that delivered a small molecule ICI and an immunogenic cell death inducer in an in-situ formed hydrogel scaffold based on thermosensitive materials (Pluronic F127). This platform increased the tumor retention of administrated small molecules, creating more opportunities for the interaction between drugs and tumor cells. We found that atorvastatin (ATO) effectively downregulated the expression of programmed death ligand 1 (PD-L1) and reversed compensative PD-L1 upregulation after cyclophosphamide (CTX) chemotherapy on CT26 colon tumors. CTX not only killed tumor cells to reduce the tumor burden, but also release damage-associated molecular patterns (DAMPs) to stimulate T cell immunity, therefore amplifying statin-mediated immunotherapy. The platform reported in this study might be promising to overcome the limitation of small molecule ICIs with short retention time and potentiate tumor chemo-immunotherapy.

Photodynamic Alginate Zn-MOF Thermosensitive Hydrogel for Accelerated Healing of Infected Wounds

Antibiotic resistance reduces the effectiveness of infected wound healing, and it is necessary to develop a new strategy to promote infected wound healing without using antibiotics. Here, we develop a Chlorin e6 (Ce6)-loaded zinc-metal-organic framework (MOF) thermosensitive hydrogel (Ce6@MOF-Gel) based on alginate and poly(propylene glycol) 407, which enhances antibacterial effects and promotes infected wound healing by a novel strategy of combining zinc-MOF with photodynamic therapy (PDT). Zinc-MOF can realize acid-responsive release of Ce6 and improve antibacterial performance without drug resistance by destroying the integrity of bacterial cell membranes and enhancing the production of bacterial reactive oxygen species (ROS). Additionally, Ce6@MOF-Gel enhances the stability, solubility, and photodynamic properties of Ce6. More importantly, Ce6@MOF-Gel reduces inflammation and promotes collagen deposition and re-epithelialization to facilitate infected wound healing. Collectively, the photodynamic MOF-based hydrogel provides a new, efficient, and safe way for accelerated healing of infected wounds.

Quality by design driven development and evaluation of thermosensitive hydrogel loaded with IgY and LL37-SLNs to combat experimental periodontitis

Egg yolk immunoglobulin (IgY) and LL37, potent antibacterial substances, can fight against periodontitis. This work aimed to develop a locally injectable hydrogel for potential co-delivery of special IgY and LL37-loaded solid lipid nanoparticles (LL37-SLNs) to synergistically inhibit the proliferation of oral pathogens, thus relieving periodontal inflammation and redness. The formulation of thermosensitive hydrogel loaded with IgY and LL37-SLNs was developed by adopting the Quality by Design approach. Then the formulations were optimized by two-factor three-level full factorial design by Design-Expert software. Finally, the optimized formulation was characterized and estimated in vitro and in vivo. In vitro release and antibacterial activity studies have revealed that the optimized formulation was homogeneous and can be released slowly, with sustainably antibacterial power. And the physical and chemical composition analysis and morphological observations further confirmed the sustained-release capability. On the other hand, in vivo studies proved that the optimized formulation significantly decreased gingival redness, bleeding, and plaque formation, avoided excessive resorption of alveolar bone, and reduced the levels of inflammatory factor in periodontitis rats. In conclusion, the optimized thermosensitive hydrogel loaded with IgY and LL37-SLNs may be a promising local sustained-release preparation for the effective treatment of periodontal diseases.

Role of Berberine Thermosensitive Hydrogel in Periodontitis via PI3K/AKT Pathway In Vitro

Periodontitis is a long-term inflammatory illness and a leading contributor to tooth loss in humans. Due to the influence of the anatomic parameters of teeth, such as root bifurcation lesions and the depth of the periodontal pocket, basic periodontal treatment on its own often does not completely obliterate flora microorganisms. As a consequence, topical medication has become a significant supplement in the treatment of chronic periodontitis. Berberine (BBR) has various pharmacological effects, such as hypoglycemic, antitumor, antiarrhythmic, anti-inflammatory, etc. The target of our project is to develop a safe and non-toxic carrier that can effectively release berberine, which can significantly reduce periodontal tissue inflammation, and to investigate whether berberine thermosensitive hydrogel can exert anti-inflammatory and osteogenic effects by modulating phosphatifylinositol-3-kinase/Protein Kinase B (PI3K/AKT) signaling pathway. Consequently, firstly berberine temperature-sensitive hydrogel was prepared, and its characterizations showed that the mixed solution gelated within 3 min under 37 °C with a hole diameter of 10-130 µm, and the accumulation of berberine release amounted to 89.99% at 21 days. CCK-8 and live-dead cell staining results indicated that this hydrogel was not biotoxic, and it is also presumed that the optimum concentration of berberine is 5 µM, which was selected for subsequent experiments. Real-time polymerase chain reaction (qRT-PCR) and Western blotting (WB)results demonstrated that inflammatory factors, as well as protein levels, were significantly reduced in the berberine-loaded hydrogel group, and LY294002 (PI3K inhibitor) could enhance this effect (p < 0.05). In the berberine-loaded hydrogel group, osteogenesis-related factor levels and protein profiles were visibly increased, along with an increase in alkaline phosphatase expression, which was inhibited by LY294002 (p < 0.05). Therefore, berberine thermosensitive hydrogel may be an effective treatment for periodontitis, and it may exert anti-inflammatory and osteogenic effects through the PI3K/AKT signaling pathway.

Combined Silver Sulfadiazine Nanosuspension with Thermosensitive Hydrogel: An Effective Antibacterial Treatment for Wound Healing in an Animal Model

Introduction

Silver sulfadiazine (AgSD) is widely used in burn wound treatment due to its broad-spectrum antibacterial activity. However, its application in wound healing is greatly hindered by the low solubility of AgSD particles and their cellular cytotoxicity. Herein, we studied the safety and in vivo efficacy of nano-sized silver sulfadiazine loaded in poloxamer thermosensitive hydrogel (NS/Gel).

Methods

In NS/Gel, silver sulfadiazine was prepared into silver sulfadiazine nanosuspension (NS) to improve the solubility and enhance its antibacterial activity, whereas the poloxamer thermosensitive hydrogel was selected as a drug carrier of NS to achieve slow drug release and reduced cytotoxicity. The acute toxicity of silver sulfadiazine nanosuspension was first evaluated in healthy mice, and its median lethal dose (LD₅₀) was calculated by the modified Karber method. Furthermore, in vivo antibacterial effect and wound healing property of NS/Gel were evaluated on the infected deep second-degree burn wound mice model.

Results

The mortality ratio of mice was concentration-dependent, and the LD₅₀ for silver sulfadiazine nanosuspension was estimated to be 252.1 mg/kg (230.8 to 275.4 mg/kg, 95% confidence limit). The in vivo dosages used for burn wound treatment (40-50 mg/kg) were far below LD₅₀ (252.1 mg/kg). NS/Gel significantly accelerated wound healing in the deep second wound infection mice model, achieving > 85% wound contraction on day 14. Staphylococcus aureus in the wound region was eradicated after 7 days in NS/Gel group, while the bacterial colony count was still measurable in the control group. Histological analysis and cytokines measurement confirmed that the mice treated with NS/Gel exhibited well-organized epithelium and multiple keratinized cell layers compared to control groups with the modulated expression of IL-6, VEGF, and TGF-β.

Conclusion

The combination of silver sulfadiazine nanosuspension and thermo-responsive hydrogel has great potential in clinical burn wound treatment.

Thermosensitive Shape-Memory Poly(stearyl acrylate-co-methoxy poly(ethylene glycol) acrylate) Hydrogels

Stimuli-sensitive hydrogels are highly desirable candidates for application in intelligent biomaterials. Thus, a novel thermosensitive hydrogel with shape-memory function was developed. Hydrophobic stearyl acrylate (SA), hydrophilic methoxy poly(ethylene glycol) acrylate (MPGA), and a crosslinking monomer were copolymerized to prepare poly(SA-co-MPGA) gels with various mole fractions of SA (xSA) in ethanol. Subsequently, the prepared gels were washed, dried, and re-swelled in water at 50 °C. Differential scanning calorimetric (DSC) and compression tests at different temperatures revealed that poly(SA-co-MPGA) hydrogels with xSA > 0.5 induce a crystalline-to-amorphous transition, which is a hard-to-soft transition at ~40 °C that is based on the formation/non-formation of a crystalline structure containing stearyl side chains. The hydrogels stored in water maintained an almost constant volume, independent of the temperature. The poly(SA-co-MPGA) hydrogel was soft, flexible, and deformed at 50 °C. However, the hydrogel stiffened when cooled to room temperature, and the deformation was reversible. The shape-memory function of poly(SA-co-MPGA) hydrogels is proposed for potential use in biomaterials; this is partially attributed to the use of MPGA, which consists of relatively biocompatible poly(ethylene glycol).

Preparation and Optimization of Liposome Containing Thermosensitive In Situ Nasal Hydrogel System for Brain Delivery of Sumatriptan Succinate

Drug absorption is improved by the intranasal route's wide surface area and avoidance of first-pass metabolism. For the treatment of central nervous system diseases such as migraine, intranasal administration delivers the medication to the brain. The study's purpose was to develop an in situ nasal hydrogel that contained liposomes that were loaded with sumatriptan succinate (SS). A thin-film hydration approach was used to create liposomes, and a 3² factorial design was used to optimize them. The optimized liposomes had a spherical shape, a 171.31 nm particle size, a high drug encapsulation efficiency of 83.54%, and an 8-h drug release of 86.11%. To achieve in situ gel formation, SS-loaded liposomes were added to the liquid gelling system of poloxamer-407, poloxamer-188, and sodium alginate. The final product was tested for mucoadhesive strength, viscosity, drug content, gelation temperature, and gelation time. Following intranasal delivery, in vivo pharmacokinetic investigations showed a significant therapeutic concentration of the medication in the brain with a C_max value of 167 ± 78 ng/mL and an area under the curve value of 502 ± 63 ng/min·mL. For SS-loaded liposomal thermosensitive nasal hydrogel, significantly higher values of the nose-to-brain targeting parameters, that is, drug targeting index (2.61) and nose-to-brain drug direct transport (57.01%), confirmed drug targeting to the brain through the nasal route. Liposomes containing thermosensitive in situ hydrogel demonstrated potential for intranasal administration of SS.

In Vivo Sustained Release of the Retrograde Transport Inhibitor Retro-2.1 Formulated in a Thermosensitive Hydrogel

A recently developed inhibitor of retrograde transport, namely Retro-2.1, proved to be a potent and broad-spectrum lead in vitro against intracellular pathogens, such as toxins, parasites, intracellular bacteria and viruses. To circumvent its low aqueous solubility, a formulation in poly(ethylene glycol)-block-poly(D,L)lactide micelle nanoparticles was developed. This formulation enabled the study of the pharmacokinetic parameters of Retro-2.1 in mice following intravenous and intraperitoneal injections, revealing a short blood circulation time, with an elimination half-life of 5 and 6.7 h, respectively. To explain the poor pharmacokinetic parameters, the metabolic stability of Retro-2.1 was studied in vitro and in vivo, revealing fast cytochrome-P-450-mediated metabolism into a less potent hydroxylated analogue. Subcutaneous injection of Retro-2.1 formulated in a biocompatible and bioresorbable polymer-based thermosensitive hydrogel allowed for sustained release of the drug, with an elimination half-life of 19 h, and better control of its metabolism. This study provides a guideline on how to administer this promising lead in vivo in order to study its efficacy.

Application of Porous Polyetheretherketone Scaffold/ Vancomycin-Loaded Thermosensitive Hydrogel Composites for Antibacterial Therapy in Bone Repair

Polyetheretherketone (PEEK) has been widely used in bone repair, but it often fails due to bacterial infection. Herein, a high-strength porous polyetheretherketone scaffold (ps-PK) loaded with antibacterial drug-loaded hydrogel strategy is proposed. The prepared ps-PK possesses high porosity (30.8%-64.7%) and the compression modulus is between 0.4-0.98 GPa. The interconnected pore-type structure endows it with a drug loading capacity. Poly(_D,L -lactic acid-co-glycolic acid)-b-Poly(ethylene glycol)-b-Poly(_D,L -lactic acid-co-glycolic acid) (PLGA-PEG-PLGA) thermoresponsive hydrogels loaded with vancomycin are used as the drug sustained-release system. The vancomycin-loaded hydrogels in the solution state at a low temperature were filled into a porous polyetheretherketone scaffold (ps-PK-VGel) and formed a gel state after implantation in vivo. The antibacterial rate of ps-PK-VGel against methicillin-resistant staphylococcus aureus (MRSA) in vitro was 99.7% and histological observation in vivo demonstrates that the ps-PK-VGel shows obvious antibacterial activity. Given its excellent antibacterial ability and mechanical properties, the porous PEEK scaffold composite drug-loaded thermosensitive hydrogel has great potential in bone repair surgery applications. This article is protected by copyright. All rights reserved.

Multifunctional Hybrid Hydrogel System Enhanced the Therapeutic Efficacy of Treatments for Postoperative Glioma

Glioma is the most lethal brain tumor with a poor prognosis, and a combination of multiple therapeutic strategies is critical for postoperative glioma treatment. Herein, a multifunctional hybrid hydrogel system (designated as CP&CL@RNP_PTX-Gel) was developed for local treatment of postoperative glioma. The system was composed of self-illuminating chlorin e6 (Ce6) conjugated with luminol molecule (CL)-loaded glioma-targeting paclitaxel prodrug nanoparticles and copper peroxide nanodots (CP NDs) coembedded into a three-dimensional thermosensitive hydroxypropyl chitin hydrogel frame. After injection of CP&CL@RNP_PTX-Gel into the cavity of postoperative glioma, the solution could be cross-linked into the gel as a drug reservoir under body temperature stimulation. Then, the sustained-released CP NDs decomposed into Cu²⁺ and H₂O₂ in the acidic microenvironment of the glioma cells to exert chemodynamic therapy (CDT). Meanwhile, Cu²⁺ could catalyze the self-luminescence of CL to induce photodynamic therapy (PDT) without external excitation light. Moreover, paclitaxel prodrug nanoparticles degraded into paclitaxel to restrain residual glioma cells in response to intracellular reduced glutathione (GSH). The in vitro and in vivo results showed that CP&CL@RNP_PTX-Gel had great potential as a multifunctional hybrid hydrogel system with remarkable therapeutic effects for postoperative glioma treatment via a combination of chemotherapy, CDT, and PDT.

Thermosensitive Hydrogels and Advances in Their Application in Disease Therapy

Thermosensitive hydrogels, having unique sol–gel transition properties, have recently received special research attention. These hydrogels exhibit a phase transition near body temperature. This feature is the key to their applications in human medicine. In addition, hydrogels can quickly gel at the application site with simple temperature stimulation and without additional organic solvents, cross-linking agents, or external equipment, and the loaded drugs can be retained locally to improve the local drug concentration and avoid unexpected toxicity or side effects caused by systemic administration. All of these features have led to thermosensitive hydrogels being some of the most promising and practical drug delivery systems. In this paper, we review thermosensitive hydrogel materials with biomedical application potential, including natural and synthetic materials. We describe their structural characteristics and gelation mechanism and briefly summarize the mechanism of drug release from thermosensitive hydrogels. Our focus in this review was to summarize the application of thermosensitive hydrogels in disease treatment, including the postoperative recurrence of tumors, the delivery of vaccines, the prevention of postoperative adhesions, the treatment of nervous system diseases via nasal brain targeting, wound healing, and osteoarthritis treatment.

Novel Thermosensitive Hydrogel Promotes Spinal Cord Repair by Regulating Mitochondrial Function

The repair of spinal cord injury (SCI) is still a tough clinical challenge and needs innovative therapies. Mitochondrial function is significantly compromised after SCI and has emerged as an important factor causing neuronal apoptosis and hindering functional recovery. In this study, umbilical cord mesenchymal stem cells (UCMSC), which are promising seed cells for nerve regeneration, and basic fibroblast growth factor (bFGF) that have been demonstrated to have a variety of effects on neural regeneration were jointly immobilized in extracellular matrix (ECM) and heparin-poloxamer (HP) to create a polymer bioactive system that brings more hope and possibility for the treatment of SCI. Our results in vitro and in vivo showed that the UCMSC-bFGF-ECM-HP thermosensitive hydrogel has good therapeutic effects, mainly in reducing apoptosis and improving the mitochondrial function. It showed promising utility for the functional recovery of impaired mitochondrial function by promoting mitochondrial fusion, reducing pathological mitochondrial fragmentation, increasing mitochondrial energy supply, and improving the metabolism of MDA, LDH, and ROS. In addition, we uncovered a distinct molecular mechanism underlying the protective effects associated with activating p21-activated kinase 1 (PAK1) and mitochondrial sirtuin 4 (SIRT4) by the UCMSC-bFGF-ECM-HP hydrogel. The expansion of new insights into the molecular relationships between PAK1 and SIRT4, which links the mitochondrial function in SCI, can lay the foundation for future applications and help to provide promising interventions of stem-cell-based biological scaffold therapies and potential therapeutic targets for the clinical formulation of SCI treatment strategies.

Silk Fabric Decorated with Thermo-Sensitive Hydrogel for Sustained Release of Paracetamol

Paracetamol is a safe and widely used antipyretic and analgesic drug, however, with the drawbacks of gastrointestinal first-pass effect and short intervals of administration. Transdermal drug delivery system can effectively avoid the liver metabolism caused by excess oral ingestion of Paracetamol. Herein, we propose a silk fabric-based medical dressing decorated by a thermo-responsive hydrogel for sustained release of paracetamol. Genipin as a bio-safe cross-linker was applied to assist gelation of a thermo-responsive hydrogel system coupled of chitosan and glycerol-phosphate disodium salt (GP) around body temperature (37 °C), as well as densify the microporous gel to improve mechanical strength. The in-situ sol-gel transition enabled hydrogel well penetrate and coat the silk fabric, forming a hierarchical hydrogel structure capable of prolonging sustained release of drug to 12 h, twice as long as a blank fabric. The silk fabric with a thin gel coating maintains good water vapor transmission rate (WVTR), compatible for skin contact application. The drug release properties can be tuned by regulating the genipin content and fabric braiding structure. The silk fabric dressing exhibits temperature-dependent instant release behavior within the first two hours. The sustained release mechanism of paracetamol well matches with the Korsmeyer-Peppas model in a non-Fickian diffusion. This article is protected by copyright. All rights reserved.

A Tumor Microenvironments-Adapted Polypeptide Hydrogel/Nanogel Composite Boosts Antitumor Molecularly Targeted Inhibition and Immunoactivation

Various macro/microscopic biomaterials have been developed for controlled drug delivery in the combination therapy of malignancies. However, uncertain loading ratio, release sequence, and spatiotemporal distribution of drugs hinder their synergistic therapeutic effects and clinical applications. In this work, a tumor microenvironments-adapted composite consisting of a thermosensitive hydrogel and a reactive oxygen species (ROS)-responsive nanogel is developed for precisely sequential drug release to enhance molecularly targeted therapy and amplify immune activation. LY3200882 (LY), a selective transforming growth factor-β (TGF-β) inhibitor, is encapsulated in the ROS-responsive nanogel and dispersed uniformly with regorafenib (REG) in a thermosensitive hydrogel (Gel/(REG+NG/LY)). After in situ administration, REG is preferentially released from the hydrogel to inhibit tumor growth and promote ROS generation, which triggers the subsequent on-demand release of LY from the nanogel. LY contributes to preventing the epithelial-mesenchymal transition and immune escape of tumor cells induced by elevated TGF-β. In subcutaneous and orthotopic colorectal tumor bearing mouse models, Gel/(REG+NG/LY) effectively inhibits tumor growth and liver metastases by increasing the tumor infiltration of CD8⁺ T cells, reducing the recruitment of tumor-associated macrophages and myeloid-derived suppressor cells, and promoting the polarization of macrophages from M2 to M1 type, indicating the significant potential in improving the prognosis of advanced cancer patients.

Toward a Better Understanding of the Gelation Mechanism of Methylcellulose via Systematic DSC Studies

A methylcellulose (MC) is one of the materials representatives performing unique thermal-responsive properties. While reaching a critical temperature upon heating MC undergoes a physical sol-gel transition and consequently becomes a gel. The MC has been studied for many years and researchers agree that the MC gelation is related to the lower critical solution temperature (LCST). Nevertheless, a precise description of the MC gelation mechanism remains under discussion. In this study, we explained the MC gelation mechanism through examination of a wide range of MC concentrations via differential scanning calorimetry (DSC). The results evidenced that MC gelation is a multistep thermoreversible process, manifested by three and two endotherms depending on MC concentration. The occurrence of the three endotherms for low MC concentrations during heating has not been reported in the literature before. We justify this phenomenon by manifestation of three various transitions. The first one manifests water–water interactions, i.e., spanning water network breakdown into small water clusters. It is clearly evidenced by additional normalization to the water content. The second effect corresponds to polymer–water interactions, i.e., breakdown of water cages surrounded methoxy groups of MC. The last one is related to the polymer–polymer interactions, i.e., fibril hydrophobic domain formation. Not only did these results clarify the MC crosslinking mechanism, but also in the future will help to assess MC relevance for various potential application fields.

Controlled Liposome Delivery from Chitosan-Based Thermosensitive Hydrogel for Regenerative Medicine

This work describes the development of an injectable nanocomposite system based on a chitosan thermosensitive hydrogel combined with liposomes for regenerative medicine applications. Liposomes with good physicochemical properties are prepared and embedded within the chitosan network. The resulting nanocomposite hydrogel is able to provide a controlled release of the content from liposomes, which are able to interact with cells and be internalized. The cellular uptake is enhanced by the presence of a chitosan coating, and cells incubated with liposomes embedded within thermosensitive hydrogels displayed a higher cell uptake compared to cells incubated with liposomes alone. Furthermore, the gelation temperature of the system resulted to be equal to 32.6 °C; thus, the system can be easily injected in the target site to form a hydrogel at physiological temperature. Given the peculiar performance of the selected systems, the resulting thermosensitive hydrogels are a versatile platform and display potential applications as controlled delivery systems of liposomes for tissue regeneration.

Thermosensitive Poly(DHSe/PEG/PPG Urethane)-Based Hydrogel Extended Remdesivir Application in Ophthalmic Medication

The spread of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the coronavirus disease 2019 (COVID-19) outbreak beginning in March 2020. Currently, there is a lack of suitable dose formulations that interrupt novel coronavirus transmission via corneal and conjunctival routes. In the present study, we developed and evaluated a thermosensitive gelling system based on a selenium-containing polymer for topical ocular continuous drug release. In detail, di-(1-hydroxylundecyl) selenide (DHSe), poly(ethylene glycol) (PEG), and poly(propylene glycol) (PPG) were polymerized to form poly(DHSe/PEG/PPG urethane). The polymer was used to carry poorly water-soluble remdesivir (RDV) at room temperature to form the final thermosensitive in situ gel, which exhibited a typical sol-gel transition at 35 °C. The formed polymer was further characterized by rheology, thermology, and scanning electron microscopy. In vitro release studies and in vivo retention and penetration tests indicated that the thermogel provided the prolonged release of RDV. The RDV-loaded in situ gel was proven to be non-biotoxic against human corneal epithelial cells, with good ocular tolerance and biocompatibility in rabbit eyes.

Alginate nanogels-based thermosensitive hydrogel to improve antidepressant-like effects of albiflorin via intranasal delivery

Depression is a primary public health problem. However, current antidepressants work slowly, and together with side effects. Herein, the alginate nanogels were constructed to load albiflorin (albiflorin nanogels), which further formed albiflorin nanogel loaded self-assembled thermosensitive hydrogel system (albiflorin-NGSTH) and were used to improve its antidepressant effects. The nanogel showed a nano-scaled particle size and stronger antioxidant activity. Rheological studies showed that albiflorin-NGSTH had a sol-gel transition at approximately 28 °C. Albiflorin-NGSTH quickly entered the brain by intranasal delivery, and had a continuously release for albiflorin. Preliminary results of mice behavioral despair tests found that albiflorin-NGSTH had no effects on independent exploratory behavior and anxiety of the mice, and significantly decreased immobility duration of the mice in tail suspension test (TST). Moreover, the intranasally administrated albiflorin-NGSTH at a low dose improved depressive behavior, decreased levels of proinflammatory cytokines, and repaired neuronal damage of chronic unpredictable mild stress (CUMS) rats, which indicated an excellent potential for depression therapy. The treatment of albiflorin-NGSTH on depressive disorder was achieved by regulating signal pathway related to depression. Therefore, albiflorin-NGSTH has an excellent potential for clinical application in intranasal drug delivery systems.

Thermosensitive Bioadhesive Hydrogels Based on Poly(N-isopropylacrilamide) and Poly(methyl vinyl ether-alt-maleic anhydride) for the Controlled Release of Metronidazole in the Vaginal Environment

The development of thermosensitive bioadhesive hydrogels as multifunctional platforms for the controlled delivery of microbicides is a valuable contribution for the in situ treatment of vagina infections. In this work, novel semi-interpenetrating network (s-IPN) hydrogels were prepared by the entrapment of linear poly(methyl vinyl ether-alt-maleic anhydride) (PVME-MA) chains within crosslinked 3D structures of poly(N-isopropylacrylamide) (PNIPAAm). The multifunctional platforms were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermal techniques, rheological analysis, swelling kinetic measurements, and bioadhesion tests on porcine skin. The hydrogels exhibited an interconnected porous structure with defined boundaries. An elastic, solid-like behavior was predominant in all formulations. The swelling kinetics were strongly dependent on temperature (25 °C and 37 °C) and pH (7.4 and 4.5) conditions. The s-IPN with the highest content of PVME-MA displayed a significantly higher detachment force (0.413 ± 0.014 N) than the rest of the systems. The metronidazole loading in the s-IPN improved its bioadhesiveness. In vitro experiments showed a sustained release of the antibiotic molecules from the s-IPN up to 48 h (94%) in a medium simulating vaginal fluid, at 37 °C. The thermosensitive and bioadhesive PNIPAAm/PVME-MA systems showed a promising performance for the controlled release of metronidazole in the vaginal environment.

Injectable Nanosponge-Loaded Pluronic F127 Hydrogel for Pore-Forming Toxin Neutralization

PURPOSE

Pore-forming toxins (PFTs) perform important functions during bacterial infections. Among various virulence-targeting therapies, nanosponges (NSs) have excellent neutralization effects on multiple PFTs. To enhance treatment efficacy, NSs tend to be incorporated into other biomaterials, such as hydrogels.

METHODS

In the present work, red blood cell (RBC) vesicles were harvested to wrap polymer nanoparticles, leading to the formation of NSs, and the optimal Pluronic F127 hydrogel concentration was determined for gelation. Then, a novel detoxification system was constructed by incorporating NSs into an optimized Pluronic F127 hydrogel (NS-pGel). Next, the system was characterized by rheological and sustained release behavior as well as micromorphology. Then, the in vitro neutralization effect of NS-pGel on various PFTs was examined by a hemolysis protocol. Finally, therapeutic and prophylactic detoxification efficiency was evaluated in a mouse subcutaneous infection model in vivo.

RESULTS

A thermosensitive, injectable detoxification system was successfully constructed by loading NSs into a 30% Pluronic F127 hydrogel. Characterization results demonstrated that the NS-pGel hybrid system sustained an ideal fluidity and viscosity at lower temperatures but exhibited a quick sol-gel transition capacity near body temperature. In addition, this hybrid system had a sustained release behavior accompanied by good biocompatibility and biodegradability. Finally, the NS-pGel system showed neutralization effects similar to those of NSs both in vitro and in vivo, indicating a good preservation of NS functionality.

CONCLUSION

In conclusion, we constructed a novel temperature-sensitive detoxification system with good biocompatibility and biodegradability, which may be applied to the clinical treatment of PFT-induced local lesions and infections.

Physico-Chemical Properties and Biocompatibility of Thermosensitive Chitosan Lactate and Chitosan Chloride Hydrogels Developed for Tissue Engineering Application

Recently, the modification of the initial structure of biopolymers, mainly chitosan, has been gaining importance with a view to obtain functional forms with increased practicality and specific properties enabling their use in tissue engineering. Therefore, in this article, the properties (structural and biological) of thermosensitive hydrogels obtained from chitosan lactate/chloride and two types of crosslinking agents (β-glycerol phosphate disodium salt pentahydrate and uridine 5'-monophosphate disodium salt) are discussed. The aim of the research is to identify changes in the structure of the biomaterials during conditioning in water. Structural investigations were carried out by FTIR spectroscopy. The crystallinity of gels was determined by X-ray diffraction analysis. The biocompatibility (evaluation of cytotoxicity and genotoxicity) of chitosan hydrogels was investigated by contact with human colon adenocarcinoma cell line for 48 h. The cytotoxicity was verified based on the colorimetric resazurin assay, and the genotoxicity was checked by the comet assay (percentage of DNA in the comet tail). The conducted research showed that the analyzed types of chitosan hydrogels are non-cytotoxic and non-genotoxic materials. The good biocompatibility of chitosan hydrogels surfaces makes them interesting scaffolds with clinical potential in tissue regeneration engineering.

Characterization, antioxidant activity, and biocompatibility of selenium nanoparticle-loaded thermosensitive chitosan hydrogels

In this study, we recruited chitosan (CS) both for selenium nanoparticles (SeNPs) synthesis and for the development of a thermoresponsive nanocomposite hydrogel with the addition of glycerol phosphate (GP). Considering that SeNPs are toxic at high concentrations, five different ingredients of the nanocomposite hydrogel system with low concentrations of SeNPs (1.25-20 μg/mL) were prepared. The gelation conditions, structural characteristics, and mechanical properties of SeNPs-loaded thermosensitive CS/GP hydrogels were investigated. We also evaluated their antioxidizing activities and biocompatibility of the CS/GP/SeNPs hydrogels. Our study demonstrated that the incorporation of SeNPs in the hydrogel improved its mechanical properties, antioxidant activity, and degree of swelling. According to the properties of SeNPs and CS/GP thermosensitive hydrogels, the combination of these two technologies in an appropriate manner would be a promising antioxidant system for drug delivery and tissue engineering.

Molecular Targeted Agent and Immune Checkpoint Inhibitor Co-Loaded Thermosensitive Hydrogel for Synergistic Therapy of Rectal Cancer

Molecular targeted therapy has been proved effective in treatment of rectal cancer. Up-regulated expression of programmed death ligand-1 (PD-L1) was observed after the management of molecular targeted therapy, which made the therapeutic effect discounted. Tumors with higher PD-L1 expression were more sensitive and responsive to treatment of PD-L1 inhibitor. Therefore, the combination of molecular targeted therapy and immune checkpoint blockade makes sense. In this study, the copolymers of poly (ethylene glycol)-block-poly (_L-leucine) (PEG-PLLeu) were synthesized as a thermosensitive hydrogel composite for consecutive release of regorafenib (REG) and BMS202. The mechanical properties of PEG-PLLeu were investigated, confirming that PEG-PLLeu (5 wt.%) was suitable for in situ injection as drug-delivery composite at low temperature and stable after sol-gel transition at body temperature. Importantly, the double drug loaded hydrogel showed superior antitumour activity over single drugs in an orthotopic rectal cancer model (CT26-Luc). Further analysis of the tumor tissues suggested that REG upregulated the expression of PD-L1 in tumor tissues. In addition, the immunosuppressive tumor microenvironment of CT26-Luc tumor was distinctly relieved under the effect of BMS202, as characterized by increased infiltration of CD8⁺ T cells in tumors and enhanced secretion of antitumour cytokines (IFN-γ and TNF-α). Moreover, the drug-loaded composite showed no obvious toxicity in histological analysis. Taken together, the administration of REG and BMS202 in the PEG-PLLeu composite could induce a synergistic effect in in situ treatment of rectal cancer without obvious toxicity, and thus represented a potential strategy for enhanced in situ therapeutic modality.

Sustained-release of erythropoietin using a novel injectable thermosensitive hydrogel: in vitro studies, biological activity, and efficacy in rats

In the current study erythropoietin (EPO) loaded trimethyl chitosan/tripolyphosphate nanoparticles-embedded in a thermosensitive hydrogel was prepared. The influence of the main experimental factors on the properties of EPO-loaded nanoparticles were evaluated using a two-factors central composite design and the optimized formulation was then freeze dried. Sodium dodecyl sulfate-page and circular dichroismspectroscopy were used to confirm the structural stability of EPO following encapsulation and freeze drying. Rheological properties, and the release rate of EPO from the hydrogel were examined. Mean particle size, zeta potential, and entrapment efficiency of the optimized EPO-loaded nanoparticles were confirmed 151.5 ± 16 nm, 11.5 ± 1.8 mV, and 78.5 ± 5.9%, respectively. The hydrogel containing nanoparticles existed as a solution at room temperature converted to a semisolid upon increasing the temperature to 35 ± 1.2 °C and demonstrated controlled release of EPO for more than 10 days. The stability of EPO in the hydrogel system was further investigated using in vivo biological activity assay and the result revealed relative potency of 0.85 as calibrated with standard EPO. Finally, a single injection of the EPO-loaded nanoparticles-embedded in the hydrogel administered to Sprague-Dawley rats resulted in elevated reticulocytes for about 20 days compared to control group received blank hydrogel.

An Injectable Nano-Enabled Thermogel to Attain Controlled Delivery of p11 Peptide for the Potential Treatment of Ocular Angiogenic Disorders of the Posterior Segment

This investigation focused on the design of an injectable nano-enabled thermogel (nano-thermogel) system to attain controlled delivery of p11 anti-angiogenic peptide for proposed effective prevention of neovascularisation and to overcome the drawbacks of the existing treatment approaches for ocular disorders characterised by angiogenesis, which employ multiple intravitreal injections of anti-vascular endothelial growth factor (anti-VEGF) antibodies. Synthesis of a polyethylene glycol-polycaprolactone-polyethylene glycol (PEG-PCL-PEG) triblock co-polymer was undertaken, followed by characterisation employing Fourier-transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and differential scanning calorimetry (DSC) to ascertain the chemical stability and integrity of the co-polymer instituted for nano-thermogel formulation. The p11 anti-angiogenic peptide underwent encapsulation within poly(lactic-co-glycolic acid) (PLGA) nanoparticles via a double emulsion solvent evaporation method and was incorporated into the thermogel following characterisation by scanning electron microscopy (SEM), zeta size and zeta-potential analysis. The tube inversion approach and rheological analysis were employed to ascertain the thermo-sensitive sol-gel conversion of the nano-thermogel system. Chromatographic assessment of the in vitro release of the peptide was performed, with stability confirmation via Tris-Tricine PAGE (Polyacrylamide Gel Electrophoresis). In vitro biocompatibility of the nano-thermogel system was investigated employing a retinal cell line (ARP-19). A nanoparticle size range of 100–200 nm and peptide loading efficiency of 67% was achieved. Sol-gel conversion of the nano-thermogel was observed between 32–45 °C. Release of the peptide in vitro was sustained, with maintenance of stability, for 60 days. Biocompatibility assessment highlighted 97–99% cell viability with non-haemolytic ability, which supports the potential applicability of the nano-thermogel system for extended delivery of peptide for ocular disorder treatment.

Experimental Study on Thermosensitive Hydrogel Used to Extinguish Class A Fire

Hydrogels are crosslinked polymers that become fully swollen when placed in aqueous environments. They are widely used in the field of firefighting because they can remarkably increase the viscosity and wettability of water. In this study, a thermosensitive hydrogel used to effectively suppress class A fire was synthesized by using methylcellulose, sodium polyacrylate, and magnesium chloride. The structure, surface activity and viscosity of the hydrogel were characterized. Fire extinguishing performance was evaluated based on small-scale and large-scale experiments. The results showed that a phase transition of the hydrogel occurred when the temperature rose from 50 °C to 80 °C. After the phase transition, the hydrogel showed a higher viscosity and lower surface tension, which was conducive to attach to the surface of the burning material and acting as an effective barrier to isolate oxygen. The small-scale fire extinguishing tests indicated that the concentration of the hydrogel solution has an eminent influence on fire extinguishing performance. The optimum concentration for extinguishing performance was around 6 wt%. The large-scale experiments demonstrated that the fire-extinguishing performance of this thermosensitive hydrogel was superior to the two other commercial water-based fire extinguishing agents, as it prevented re-ignition highly efficiently.

Corrigendum: Tissue-engineered nerve grafts using a scaffold-independent and injectable drug delivery system: a novel design with translational advantages (2019 J. Neural Eng. 16 036030)

OBJECTIVE

Currently commercially available nerve conduits have demonstrated suboptimal clinical efficacy in repairing peripheral nerve defects. Although tissue-engineered nerve grafts (TENGs) with sustained release of neurotrophic factors (NTFs) are experimentally proved to be more effective than these blank conduits, there remains a lack of clinical translation. NTFs are typically immobilized onto scaffold materials of the conduit via adsorption, specific binding or other incorporation techniques. These scaffold-based delivery strategies increase complexity and cost of conduit fabrication and lack flexibility in choosing different drugs. Therefore, to facilitate clinical translation and commercialization, we construct a TENG using a scaffold-independent drug delivery system (DDS).

APPROACH

This study adopted a scaffold-independent DDS based on methoxy-poly (ethylene glycol)-b-poly(γ-ethyl-Lglutamate) (mPEG-PELG) thermosensitive hydrogels that undergo sol-to-gel transition at body temperature. In addition, TENG, a chitosan scaffold filled with nerve growth factor (NGF)-loaded mPEG-PELG that gel in the lumen upon injection during surgery and function as a drug-releasing conduit-filler, was designed. Subsequently, the efficacy of DDS and therapeutic effects of TENG were assessed.

MAIN RESULTS

The results demonstrated that NGFloaded mPEG-PELG controllably and sustainably released bioactive NGF for 28 d. When bridging a 10 mm rat sciatic nerve gap, the morphological, electrophysiological, and functional analyses revealed that NGF-releasing TENG (Scaffold + NGF/mPEG-PELG) achieved superior regenerative outcomes compared to plain scaffolds and those combined with systemic delivery of NGF (daily intramuscular injection (IM)), and its effects were relatively similar to autografts.

SIGNIFICANCE

This study has proposed a TENG using thermosensitive hydrogels as an injectable implant to controllably release NGF, which has promising therapeutic potential and translatability. Such TENGs obviate the need for conduit modification, complex preloading or binding mediators, therefore they allow the ease of drug switching in clinical practice and greatly simplify the manufacturing process due to the independent preparation of drug delivery system.

Injectable Thermosensitive Hydrogel Containing Erlotinib-Loaded Hollow Mesoporous Silica Nanoparticles as a Localized Drug Delivery System for NSCLC Therapy

Erlotinib (ERT), oral administration agents, is one of the most pivotal targeted drugs in the treatment of non-small cell lung cancer (NSCLC); however, its poor solubility, low oral bioavailability, and capricious toxicity limit broader clinical applications. In this paper, a novel injectable matrix is prepared based on hollow mesoporous silica nanoparticles (HMSNs) and thermosensitive poly(d,l-lactide)-poly(ethylene glycol)-poly(d,l-lactide) (PDLLA-PEG-PDLLA, PLEL) hydrogel to encapsulate and localize the sustained release of ERT for improved efficacy against NSCLC. The test-tube-inversion method shows that this ERT-loaded hydrogel composite (ERT@HMSNs/gel) presents as an injectable flowing solution under room temperature and transfers into a physically crosslinked non-flowing gel structure at physiological temperature.The ERT@HMSNs/gel composite shows a much longer intratumoral and peritumoral drug retention by in vivo imaging study. Notably, this injectable drug delivery system (DDS) provides an impressive balance between antitumor efficacy and systemic safety in a mice xenograft model. The novel ERT loaded HMSNs/gel system may be a promising candidate for the in situ treatment of NSCLC. Moreover, this study provides a prospective platform for the design and fabrication of a nano-scaled delivery system for localized anticancer therapies.

Effects of beta-tricalcium phosphate nanoparticles on the properties of a thermosensitive chitosan/collagen hydrogel and controlled release of quercetin

In the present study, an inorganic matrix of beta-tricalcium phosphate (bTCP) nanoparticles and quercetin was incorporated into an organic matrix of 2:1 (w/w) chitosan/collagen composite to fabricate thermosensitive bTCP-chitosan/collagen-quercetin hydrogels. A sol-gel transition of the hydrogels was stimulated by beta-glycerophosphate (bGP) and temperature changes at physiological temperature and pH levels. Thereafter, the effects of 1%-3% (w/v) bTCP on properties of the bTCP-bGP-2:1 (w/w) chitosan/collagen hydrogels were investigated. Notably, the incorporation of 1%-3% (w/v) bTCP in the hydrogels did not interfere with the gelation process and time of the hydrogels at physiological temperature and pH levels. The bTCP-hydrogels exhibited a porous structure, interconnecting pore architecture, and median pore size of 100-200 μm. The incorporation of 3% bTCP increased the mechanical strength but decreased the swelling and degradation rates, pore size, permeability, and quercetin release rate of the hydrogels. The hydrogels were noncytotoxic and able to support cell encapsulation. A sustained quercetin release profile of the 3% bTCP-hydrogel further suggested the applicability of the hydrogel as a delivery vehicle of natural flavonoids for bone regeneration.

Thermosensitive Polysaccharide Hydrogel As a Versatile Platform for Prolonged Salmon Calcitonin Release and Calcium Regulation

The common pathological characteristic of osteoporosis and hypercalcemia is the disorder of calcium homeostasis. Currently, salmon calcitonin (sCT), a clinical regenerative medicine, is an attractive chioice to regulate calcium metabolism for alleviation of osteoporosis and hypercalcemia. Unfortunately, serum sCT is quickly cleared in vivo, leading to its short half-life. Here, we designed a versatile hydrogel, based on salmon calcitonin-oxidized calcium alginate (sCT-OCA) conjugate and hydroxypropyl chitin (HPCH). The release profile showed that sCT could be released from HPCH hydrogels loaded with sCT-OCA conjugate (sCT-OCA-HPCH) for at least 28 days with conformation stability. The cellular test demonstrated that the biocompatible sCT-OCA-HPCH, compared with sCT formulation, had capacity in up-regulating alkaline phosphatase activity (∼63% increase) and promoting calcium to deposit into extracellular matrix (∼42% increase). These results indicated that thermosensitive sCT-OCA-HPCH hydrogel herein is a versatile platform for many applications such as calcium metabolism regulation, osteoporosis treatment, and hypercalcemia therapy.

Doxorubicin Loaded Poloxamer Thermosensitive Hydrogels: Chemical, Pharmacological and Biological Evaluation

(1) Background: doxorubicin is a potent chemotherapeutic agent, but it has limitations regarding its side effects and therapy resistance. Hydrogels potentially deal with these problems, but several characterizations need to be optimized to better understand how hydrogel assisted chemotherapy works. Poloxamer 407 (P407) hydrogels were mixed with doxorubicin and physico-chemical, biological, and pharmacological characterizations were considered. (2) Methods: hydrogels were prepared by mixing P407 in PBS at 4 °C. Doxorubicin was added upon solutions became clear. Time-to-gelation, hydrogel morphology, and micelles were studied first. The effects of P407-doxorubicin were evaluated on MC-38 colon cancer cells. Furthermore, doxorubicin release was assessed and contrasted with non-invasive in vivo whole body fluorescence imaging. (3) Results: 25% P407 had favorable gelation properties with pore sizes of 30–180 µm. P407 micelles were approximately 5 nm in size. Doxorubicin was fully released in vitro from 25% P407 hydrogel within 120 h. Furthermore, P407 micelles strongly enhanced the anti-neoplastic effects of doxorubicin on MC-38 cells. In vivo fluorescence imaging revealed that hydrogels retained fluorescence signals at the injection site for 168 h. (4) Conclusions: non-invasive imaging showed how P407 gels retained drug at the injection site. Doxorubicin P407 micelles strongly enhanced the anti-tumor effects.

Sustained release of human platelet lysate growth factors by thermosensitive hydroxybutyl chitosan hydrogel promotes skin wound healing in rats

This study evaluated the effect of thermosensitive hydroxybutyl chitosan (HBC) hydrogel loaded with human platelet lysate (hPL) on skin wound healing in rats. hPLs were generated by freeze-thaw method of platelet-rich plasma from healthy donors. Successful grafting of hydroxybutyl group to chitosan molecular chain to obtain HBC hydrogel was confirmed by Fourier-transform infrared spectroscopy. HBC/hPL was prepared by combining 10% (vol/vol) hPL with HBC solution. Surface morphologies were determined by Scanning Electron Microscopy, rheological properties were measured by rheometer, and sustained release of factors from HBC/hPL was measured by enzyme-linked immunoassay. We evaluated the in vitro effect of HBC/hPL on human umbilical cord vein endothelial cell (HUVEC) proliferation, migration, and tube formation. The effect of growth factors released from HBC/hPL in promoting skin wound healing was evaluated by gross observation, histology, immunohistochemistry, and immunofluorescence in vivo. Rheological analyses indicated the gelation temperatures of HBC and HBC/hPL were 17 and 14°C, respectively. ELISA showed sustained release of human platelet-derived growth factor, basic fibroblast growth factor, and transforming growth factor-β1 from HBC/hPL hydrogel. In vitro studies revealed HBC/hPL promoted greater levels of HUVECs proliferation, migration, and tube formation than the HBC and control groups. In vivo studies showed better wound healing, greater amounts of newly formed collagen, as well as neovascular and neo-epidermis markers in the wound site of HBC/hPL-treated group compared to the HBC and control groups. HBC/hPL is a promising potential therapeutic agent for promoting skin wound healing via the sustained release of growth factors.

Pharmacotechnical Development of a Nasal Drug Delivery Composite Nanosystem Intended for Alzheimer's Disease Treatment

Direct nose-to-brain delivery has been raised as a non-invasive powerful strategy to deliver drugs to the brain bypassing the blood-brain barrier (BBB). This study aimed at preparing and characterizing an innovative composite formulation, associating the liposome and hydrogel approaches, suitable for intranasal administration. Thermosensitive gel formulations were obtained based on a mixture of two hydrophilic polymers (Poloxamer 407, P407 and Poloxamer 188, P188) for a controlled delivery through nasal route via liposomes of an active pharmaceutical ingredient (API) of potential interest for Alzheimer’s disease. The osmolarity and the gelation temperature (T° sol-gel) of formulations, defined in a ternary diagram, were investigated by rheometry and visual determination. Regarding the issue of assays, a mixture composed of P407/P188 (15/1%, w/w) was selected for intranasal administration in terms of T° sol-gel and for the compatibility with the olfactory mucosal (280 ± 20 mOsmol, pH 6). Liposomes of API were prepared by the thin film hydration method. Mucoadhesion studies were performed by using mucin disc, and they showed the good natural mucoadhesive characteristics of in situ gel formulations, which increased when liposomes were added. The study demonstrated successful pharmacotechnical development of a promising API-loaded liposomes in a thermosensitive hydrogel intended for nasal Alzheimer’s disease treatment.