Multifunctional natural microneedles based methacrylated Bletilla striata polysaccharide for repairing chronic wounds with bacterial infections.

The expeditious healing of chronic wounds with bacterial infections poses a formidable challenge in clinical practice because of the persistent bacterial presence, excessive inflammation, and the accumulation of reactive oxygen species (ROS) in clinical practice. Thus, in this study, natural antimicrobial material microneedles (MNs) with multifunctional properties were prepared by adding peony leaf extract (PLE) into a matrix of methacrylated Bletilla striata polysaccharide (BSPMA) and methacrylated chitosan (CSMA) via cross-linking under ultra-violet light to accelerate the rapid healing of chronic wounds with bacterial infections. Results showed that BCP-MNs effectively inhibited the growth of Escherichia coli, Staphylococcus aureus, and methicillin-resistant S. aureus (MRSA) by disrupting bacterial cell membranes and accelerated the healing of infected wounds by enhancing cell migration, epidermal regeneration, pro-collagen deposition, and angiogenesis and reducing inflammation. Furthermore, BCP-MNs not only possessed good mechanical properties, stability, and biocompatibility but also showed potent antioxidant effects to eliminate excessive ROS accumulation in the wound bed. In conclusion, BCP-MNs possess multifunctional wound-healing properties and can serve as excellent wound dressing in to treat infected wounds.

Multifunctional Bletilla striata polysaccharide/copper/peony leaf sponge for the full-stage wound healing.

Conventional wound dressings fail to satisfy the requirements and needs of wounds in various stages. It is challenging to develop a multifunctional dressing that is hemostatic, antibacterial, anti-inflammatory, and promotes wound healing. Therefore, this study aimed to develop a multifunctional sponge dressing for the full-stage wound healing based on copper and two natural products, Bletilla striata polysaccharide (BSP) and peony leaf extract (PLE). The developed BSP-Cu-PLE sponges were characterized by SEM, XRD, FTIR, and XPS to assess micromorphology and elemental composition. Their properties and bioactivities were also verified by the further experiments, whereby the findings revealed that the BSP-Cu-PLE sponges had improved water absorption and porosity while exhibiting excellent antioxidative, biocompatible, and biodegradable properties. Moreover, the antibacterial test revealed that BSP-Cu-PLE sponges had superior antibacterial activity against S. aureus and E. coli. Furthermore, the hemostatic activity of BSP-Cu-PLE sponges was significantly enhanced in a rat liver trauma model. Most notably, further studies have demonstrated that the BSP-Cu-PLE sponges could significantly (p < 0.05) accelerate the healing process of skin wounds by stimulating collagen deposition, promoting angiogenesis, and decreasing inflammatory cells. In summary, the BSP-Cu-PLE sponges could provide a new strategy for application in clinical setting for full-stage wound healing.

Preparation of chitosan/peony (Paeonia suffruticosa Andr.) leaf extract composite film and its application in sustainable active food packaging.

Considering the problem of food perishability and the environmental pollution of plastic packaging, the natural active packaging prepared by incorporating plant leaf (e.g. peony leaf) extract into biodegradable food packaging materials may be a key to addressing these issues. In the study, a novel green bioactive composite film (CS-PLE) with antioxidant and antibacterial propertiese was developed by blending peony leaf extract (PLE) into chitosan (CS) film through the solution casting method. The physical properties and biological activities of a series of films, including CS film and CS-PLEs incorporated with different concentrations of PLE, were studied by appropriate experimental protocols. The results demonstrated that addition of PLE improved thermal stability, the barrier performance of UV-A and total phenolic content of CS film, and the antioxidant activities of CS-PLEs increased by 60.6 % ~ 73.2 % with the appending proportion of PLE from 0.1 wt% ~ 0.7 wt% compared to CS film. Furthermore, CS-PLEs had better inhibiting effect on bacteria. Notably, CS-PLE (0.7 wt%) wrapping apples showed the least degree of browning among all the groups. Hence, the study of CS-PLEs can provide a new strategy for the preparation of food packaging materials that are green alternatives and reduce environmental pollution.