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.

A pH-responsive chiral mesoporous silica nanoparticles for delivery of doxorubicin in tumor-targeted therapy.

The purpose of this study was to develop a nano-drug delivery system with intelligent stimuli-responsive drug delivery in tumor microenvironment (TME). Based on chiral mesoporous silica nanoparticles (CMSN) with a chiral recognition function in our previous research, a pH-responsive CMSN (CS-CMSN) was successfully prepared by chemical modification of chitosan (CS), and the related physicochemical properties, drug release performance, potential anti-tumor effect, and biological safety were studied. The results showed that the CS-CMSN were successfully modified by CS. Moreover, CS-CMSN displayed superior encapsulation ability for doxorubicin (DOX) and exhibited controllable pH-responsive drug release properties. In particular, in a physiological environment (pH 7.4/6.5), CS shielded the nanopores, prevented DOX release, and minimized side effects on normal cells. Once the CS-CMSN was exposed to the TME (pH 5.0), the pH-sensitive moiety of CS was cleaved in an acidic environment, along with the rapid release of DOX. In vitro cell experiments further proved that DOX@CS-CMSN was more strongly taken up by 4T1 cells and could enhance the toxicity to 4T1 tumor cells as well as promote cell apoptosis. More importantly, CS-CMSN were shown to have good biosafety in vitro and in vivo. Overall, the delivery of DOX by CS-CMSN nanocarriers is a promising strategy for tumor-targeted therapy.

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.

In-situ synthesis silver nanoparticles in chitosan/Bletilla striata polysaccharide composited microneedles for infected and susceptible wound healing.

A novel antibacterial strategy is urgently required to develop for solving bacterial biofilm obstruction and bacterial drug resistance in the infected wound healing process. Herein, the Chitosan/Bletilla striata polysaccharide composited microneedles were prepared by chitosan, tannic acid, AgNO3 and Bletilla striata polysaccharide through step centrifugation. In our design system, the porous structure of microneedles gradually disappeared, and the mechanical properties were significantly improved after multiple fillings. Ag+ is reduced in-situ to silver nanoparticles by the abundant polyphenols of tannic acid, displaying antibacterial effects both in vitro and vivo, even for methicillin resistant Staphylococcus aureus. The addition of Bletilla striata polysaccharide increased the ability of piercing biofilm and promoted wound healing. The microneedles exhibited good biocompatibility and with function of piercing the bacterial biofilms, scavenging excessive free radicals, inhibiting inflammatory factors, and promoting wound healing. Therefore, the multifunctional composited microneedles show great potential to promote infected and susceptible wound healing.

Development of the mussel-inspired pH-responsive hydrogel based on Bletilla striata polysaccharide with enhanced adhesiveness and antioxidant properties.

Recently, smart hydrogels have attracted much attention for their abilities to respond to subtle changes in external and internal stimuli. Also, natural polysaccharide-based biomaterials are more appealing for their biocompatibility and biodegradability. However, limitations owing to their complex compositions and mechanisms, cumbersome synthetic routes, and single function call for a simple and effective strategy to develop novel multifunctional smart hydrogels. Herein, this developed work was achieved based on Bletilla striata polysaccharide (BSP), a kind of natural glucomannan with diverse bioactivities and biocompatibility, we fabricated a low-cost multifunctional hydrogel by oxidizing the catechol groups of carboxymethylated BSP(CBSP)-dopamine(DA) conjugate with adhesion, antioxidant, and pH-responsive properties. In this hydrogel system, CBSP as the backbone material, was negatively charged and conferred the hydrogel with pH sensitivity. The presence of catechol groups greatly enhanced the tissue adhesion and antioxidant capacities of the hydrogel. Meanwhile, the highly porous structure of hydrogel allowed berberine to be encapsulated and released to exhibit excellent and long-lasting antibacterial activity. In summary, the adhesion, antioxidant, pH-sensitive, and antibacterial multifunctional hydrogel showed massive potential in the biomedical field.

Antioxidant mechanism of Rutin on hypoxia-induced pulmonary arterial cell proliferation.

Reactive oxygen species (ROS) are involved in the pathologic process of pulmonary arterial hypertension as either mediators or inducers. Rutin is a type of flavonoid which exhibits significant scavenging properties on oxygen radicals both in vitro and in vivo. In this study, we proposed that rutin attenuated hypoxia-induced pulmonary artery smooth muscle cell (PASMC) proliferation by scavenging ROS. Immunofluorescence data showed that rutin decreased the production of ROS, which was mainly generated through mitochondria and NADPH oxidase 4 (Nox4) in pulmonary artery endothelial cells (PAECs). Western blot results provided further evidence on rutin increasing expression of Nox4 and hypoxia-inducible factor-1α (HIF-1α). Moreover, cell cycle analysis by flow cytometry indicated that proliferation of PASMCs triggered by hypoxia was also repressed by rutin. However, N-acetyl-L-cysteine (NAC), a scavenger of ROS, abolished or diminished the capability of rutin in repressing hypoxia-induced cell proliferation. These data suggest that rutin shows a potential benefit against the development of hypoxic pulmonary arterial hypertension by inhibiting ROS, subsequently preventing hypoxia-induced PASMC proliferation.