RESUMO
Understanding the interaction between biomaterials and blood is critical in the design of novel biomaterials for use in biomedical applications. Depending on the application, biomaterials can be designed to promote hemostasis, slow or stop bleeding in an internal or external wound, or prevent thrombosis for use in permanent or temporary medical implants. Bacterial nanocellulose (BNC) is a natural, biocompatible biopolymer that has recently gained interest for its potential use in blood-contacting biomedical applications (e.g., artificial vascular grafts), due to its high porosity, shapeability, and tissue-like properties. To promote hemostasis, BNC has been modified through oxidation or functionalization with various peptides, proteins, polysaccharides, and minerals that interact with the coagulation cascade. For use as an artificial vascular graft or to promote vascularization, BNC has been extensively researched, with studies investigating different modification techniques to enhance endothelialization such as functionalizing with adhesion peptides or extracellular matrix (ECM) proteins as well as tuning the structural properties of BNC such as surface roughness, pore size, and fiber size. While BNC inherently exhibits comparable mechanical characteristics to endogenous blood vessels, these mechanical properties can be enhanced through chemical functionalization or through altering the fabrication method. In this review, we provide a comprehensive overview of the various modification techniques that have been implemented to enhance the suitability of BNC for blood-contacting biomedical applications and different testing techniques that can be applied to evaluate their performance. Initially, we focused on the modification techniques that have been applied to BNC for hemostatic applications. Subsequently, we outline the different methods used for the production of BNC-based artificial vascular grafts and to generate vasculature in tissue engineered constructs. This sequential organization enables a clear and concise discussion of the various modifications of BNC for different blood-contacting biomedical applications and highlights the diverse and versatile nature of BNC as a natural biomaterial.
RESUMO
Despite significant progress in developing diabetic wound dressing, the fabrication of an ideal one that fulfills all virtual criteria, such as promoting angiogenesis, is still lacking. Given the low vascularization in chronic diabetic wounds, they have a severe and non-healing nature. In this study, Nitric oxide (NO) was used as an angiogenic agent, which also has antibacterial properties. Briefly, S-nitrosoglutathione (GSNO) as a NO-donor was physically loaded into the carboxymethyl chitosan (CMC)/sodium alginate (ALg) composite film (CMC-ALg-GSNO). The morphological evaluation via scanning electron microscope confirms the homogeneous and porous structure of the wound dressing. The water uptake and water vapor transmission for the wound dressing were 4354.1% ± 179.3% and 2753.8 ± 54.6 g m-2per day, respectively. Anin-vitrorelease study showed a continuous delivery of NO during 168 h. Besides, the result from thein-vivotest reveals that the CMC-ALg-GSNO wound dressing developed diabetic wound healing in a rat model compared to the CMC-ALg and gauze. Thus, this study showed that CMC-ALg-GSNO wound dressing could lead to novel therapeutic invasions to treat diabetic wounds.