Agarose Cryogels Loaded with Polydopamine Microspheres for Sustainable Wound Care with Enhanced Hemostatic and Antioxidant Properties.

Excessive bleeding presents a grave risk to life, especially in scenarios involving deep wounds such as those inflicted by gunshots and accidental stabs. Despite advancements in wound care management, existing commercial hemostatic agents have limitations, necessitating the development of enhanced solutions. In this study, we developed cryogels using agarose and polydopamine microspheres as a hemostatic dressing to effectively manage profuse bleeding. The resulting cryogels demonstrated impressive attributes, such as high absorption capacity (>4000%), shape recovery ability, antioxidant properties, and excellent biocompatibility in mammalian cell lines. Particularly noteworthy was the rapid blood clotting observed in vitro, with the agarose/PDA cryogels achieving complete clotting within just 90 s. Subsequent validation in the rat trauma model further underscored their hemostatic efficacy, with clotting times of 40 and 53 s recorded in tail amputation and liver puncture models, respectively. The porous structure and hydrophilicity of the cryogels facilitated superior blood absorption and retention, while the amine groups of polydopamine played a pivotal role in enhancing blood clotting activity. This study represents a significant step forward in utilizing agarose/polydopamine cryogels as advanced materials for hemostatic wound dressings, promising an impactful contribution to wound therapy.

Multifunctional 58S Bioactive Glass/Silver/Cerium Oxide-Based Biocomposites with Effective Antibacterial, Cytocompatibility, and Mechanical Properties.

58S bioactive glass (BG) has effective biocompatibility and bioresorbable properties for bone tissue engineering; however, it has limitations regarding antibacterial, antioxidant, and mechanical properties. Therefore, we have developed BGAC biocomposites by reinforcing 58S BG with silver and ceria nanoparticles, which showed effective bactericidal properties by forming inhibited zones of 2.13 mm (against Escherichia coli) and 1.96 mm (against Staphylococcus aureus; evidenced by disc diffusion assay) and an increment in the antioxidant properties by 39.9%. Moreover, the elastic modulus, hardness, and fracture toughness were observed to be increased by ∼84.7% (∼51.9 GPa), ∼54.5% (∼3.4 GPa), and ∼160% (∼1.3 MPam1/2), whereas the specific wear rate was decreased by ∼55.2% (∼1.9 × 10-11 m3/Nm). X-ray diffraction, high-resolution transmission electron microscopy, and field emission scanning electron microscopy confirmed the fabrication of biocomposites and the uniform distribution of the nanomaterials in the BG matrix. The addition of silver nanoparticles in the 58S BG matrix (in BGA) increased mechanical properties by composite strengthening and bactericidal properties by damaging the cytoplasmic membrane of bacterial cells. The addition of nanoceria in 58S BG (BGC) increased the antioxidant properties by 44.5% (as evidenced by the 2,2-diphenyl-1-picrylhydrazyl assay). The resazurin reduction assay and MTT assay confirmed the effective cytocompatibility for BGAC biocomposites against mouse embryonic fibroblast cells (NIH3T3) and mouse bone marrow stromal cells. Overall, BGAC resulted in mechanical properties comparable to those of cancellous bone, and its effective antibacterial and cytocompatibility properties make it a good candidate for bone healing.

Preparation and assessment of agar/TEMPO-oxidized bacterial cellulose cryogels for hemostatic applications.

In this work, we have demonstrated agar and oxidized bacterial cellulose cryogels as a potential hemostatic dressing material. TEMPO-oxidized bacterial cellulose (OBC) was incorporated into the agar matrix, improving its mechanical and hemostatic properties. The oxidation of bacterial cellulose (BC) was evidenced by chemical characterization studies, confirming the presence of carboxyl groups. The in vitro blood clotting test conducted on agar/OBC composite cryogels demonstrated complete blood clotting within 90 seconds, indicating their excellent hemostatic efficacy. The cryogels exhibited superabsorbent properties with a swelling degree of 4200%, enabling them to absorb large amounts of blood. Moreover, the compressive strength of the composite cryogels was appreciably improved compared to pure agar, resulting in a more stable physical structure. The platelet adhesion test proved the significant ability of the composite cryogels to adhere to and aggregate platelets. Hemocompatibility and cytocompatibility tests have verified the safety of these cryogels for hemostatic applications. Finally, the material exhibited remarkable in vivo hemostatic performance, achieving clotting times of 64 seconds and 35 seconds when tested in the rat tail amputation model and the liver puncture model, respectively. The experiment results were compared with those of commercial hemostat, Axiostat, and Surgispon, affirming the potential of agar/OBC composite cryogel as a hemostatic dressing material.