Freeze-Dried Matrices Based on Polyanion Polymers for Chlorhexidine Local Release in the Buccal and Vaginal Cavities

UV cross-linked injectable non-swelling dihydrocaffeic acid grafted chitosan hydrogel for promoting wound healing

Hydrogels are widely used as wound dressings for wound healing, but when hydrogels absorb wound exudate, swelling occurs and compresses the surrounding tissue, affecting healing. A chitosan injectable (CS/4-PA/CAT) hydrogel based on catechol and 4-glutenoic acid was prepared to avoid swelling and promote wound healing. After cross-linking by UV light, pentenyl groups formed hydrophobic alkyl chains which give the hydrogel a hydrophobic network and thus control its swelling. CS/4-PA/CAT hydrogels retained their non-swelling for a long time in PBS solution at 37 °C. CS/4-PA/CAT hydrogels had good injectable and adhesive properties, and had a good killing effect on E. coli and S. aureus and could remove the bacterial biofilms of E. coli and S. aureus. CS/4-PA/CAT hydrogels had good in vitro coagulation function by absorbing red blood cells and platelets. When used in a whole skin injury model, CS/4-PA/CAT-1 hydrogel stimulated fibroblast migration, promoted epithelialization and accelerated collagen deposition to promote defect healing, and showed good hemostatic effects in liver and femoral artery defects in mice. In summary, the non-swelling injectable hydrogel with free radical scavenging, rapid hemostasis, and antibacterial effects would be a promising treatment for defect repair.

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.

Freeze-Dried Matrices Composed of Degradable Polymers with Surfactant-Loaded Microparticles Based on Pectin and Sodium Alginate

Gelatin/polyvinylpyrrolidone/hydroxyethyl cellulose/glycerol porous matrices with microspheres made of sodium alginate or pectin and sodium alginate were produced. A surfactant was loaded into these microparticles. The microspheres were characterized using optical microscopy, scanning electron microscopy SEM, and laser diffraction particle size analyzer. For the matrices, the density, porosity, swelling capacity, dissolution in phosphate saline buffer were determined and SEM, mechanical, and thermogravimetric studies were applied. The results showed that the size of the two-component microspheres was slightly larger than that of single-ingredient microparticles. The images confirmed the spherical shape of the microparticles. The prepared matrices had high water uptake ability and porosity due to the presence of hydrophilic polymers. The presence of microparticles in the matrices caused a decrease in these parameters. Degradation of the composites with the microspheres was significantly faster than the matrix without them. The addition of microparticles increased the stiffness and toughness of the prepared materials. The efficiency of the thermal decomposition main stage was reduced in the samples with microspheres, whereas a char residue increased in these composites.

Anti-Candida Activity of Hyaluronic Acid Combined with Lactobacillus crispatus Lyophilised Supernatant: A New Antifungal Strategy

Vulvovaginal candidiasis (VVC) and recurrencies are common in reproductive-aged women. The emergence of Candida strains resistant to conventional antimycotic drugs prompted the search for alternative therapies. Hyaluronic acid (HA), a uniform and linear glycosaminoglycan, has been proposed as an anti-Candida agent. Vaginal lactobacilli and their derivatives, including cell free culture supernatants (CFS), represent potential strategies for the treatment of Candida infections. In the present paper, the anti-Candida potential of HA and lyophilised CFS (LCFS), obtained from the vaginal strain Lactobacillus crispatus BC5, was investigated. HA and LCFS proved to be active towards a panel of clinical Candida isolates belonging to different species in a dose dependent manner and their association maintained the antifungal activity. Notably, also Candida species generally resistant to conventional antifungals resulted sensitive. A vaginal matrix based on microcrystalline cellulose and containing effective doses of both agents was developed and characterised. This vaginal formulation showed mucoadhesive ability and almost abrogated Candida albicans growth. In conclusion, HA and LCFS from L. crispatus BC5 are thus good candidates to design a new therapeutic strategy to counteract VVC, and the proposed vaginal matrix represents a promising prototype.

Marine-inspired molecular mimicry generates a drug-free, but immunogenic hydrogel adhesive protecting surgical anastomosis

Herein, we report the synthesis of a biomimic hydrogel adhesive that addresses the poor healing of surgical anastomosis. Dopamine-conjugated xanthan gum (Da-g-Xan) is fabricated using deep insights into the molecular similarity between mussels' adhesive and dopamine as well as the structural similarity between barnacle cement proteins and xanthan gum. The hydrogel mimics marine animals’ adherence to wet tissue surfaces. Upon applying this adhesive to colonic anastomosis in a rat model, protective effects were shown by significantly improving the bursting pressure. Mechanistically, the architecture of Da-g-Xan hydrogel is maintained by dynamic intermolecular hydrogen bonds that allow the quick release of Da-g-Xan. The free Da-g-Xan can regulate the inflammatory status and induce type 2 macrophage polarization (M2) by specifically interacting with mannose receptors (CD206) revealed by RNA-sequencing and molecular binding assays. Consequently, an appropriate microenvironment for tissue healing is created by the secretion of chemokines and growth factors from M2 macrophages, strengthening the fibroblast migration and proliferation, collagen synthesis and epithelial vascularization. Overall, this study demonstrates an unprecedented strategy for generating an adhesive by synergistic mimicry inspired by two marine animals, and the results show that the Da-g-Xan adhesive augments native tissue regenerative responses, thus enabling enhanced recovery following surgical anastomosis.

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Dual-biomimic conjugates, Da-g-Xan, are synthesized.

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Da-g-Xan adhesive hydrogels are degradable, self-healing, and injectable.

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Released Da-g-Xan induces type 2 macrophage polarizations by specifically interacting with mannose receptors.

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Paracrine action by the type 2 macrophage polarizations promotes the surgical anastomosis healing.

Utilizing Liposomal Quercetin and Gallic Acid in Localized Treatment of Vaginal Candida Infections

Vulvovaginal candidiasis (VVC) is a widely spread fungal infection that causes itching, pain and inflammation at the vaginal site. Although common, currently available treatment suffers from limited efficacy and high recurrence. In addition, the growing problem of resistance to azole drugs used in current treatments emphasizes the need for superior treatment options. Antimicrobial polyphenols are an attractive approach offering multitargeting therapy. We aimed to develop novel liposomes for simultaneous delivery of two polyphenols (quercetin, Q, and gallic acid, GA) that, when released within the vaginal cavity, act in synergy to eradicate infection while alleviating the symptoms of VVC. Q was selected for its anti-itching and anti-inflammatory properties, while GA for its reported activity against Candida. Novel liposomes containing only Q (LP-Q), only GA (LP-GA) or both polyphenols (LP-Q+GA) were in the size range around 200 nm. Q was efficiently entrapped in both LP-Q and in LP-Q+GA (85%) while the entrapment of GA was higher in LP-Q+GA (30%) than in LP-GA (25%). Liposomes, especially LP-Q+GA, promoted sustained release of both polyphenols. Q and GA acted in synergy, increasing the antioxidant activities of a single polyphenol. Polyphenol-liposomes were not cytotoxic and displayed stronger anti-inflammatory effects than free polyphenols. Finally, LP-GA and LP-Q+GA considerably reduced C. albicans growth.