Characteristic Synthesis of a Covalent Organic Framework and Its Application in Multifunctional Tumor Therapy.

For decades, covalent organic frameworks (COFs) have attracted wide biomedical interest due to their unique properties including ease of synthesis, porosity, and adjustable biocompatibility. Versatile COFs can easily encapsulate various therapeutic drugs due to their extremely high payload and porosity. COFs with abundant functional groups can be surface-modified to achieve active targeting and enhance biocompatibility. In this paper, the latest developments of COFs in the biomedical field are summarized. First, the classification and synthesis of COFs are discussed. Cancer diagnosis and treatment based on COFs are studied, and the advantages and limitations of each method are discussed. Second, the specific preparation methods to obtain specific therapeutic properties are summarized. Finally, based on the combination and modification of COFs with various components, this review system summarizes different combination therapies. In addition, the main challenges faced in COF research and prospects for applying COFs to cancer diagnosis and treatment are evaluated. This review provides enlightening insights into the interdisciplinary research on COFs and applications in biomedicine, which highlight the great expectations for their further clinical transformation.

Biomimetic cartilage scaffold with orientated porous structure of two factors for cartilage repair of knee osteoarthritis.

A dual-layer biomimetic cartilage scaffold was prepared by mimicking the structural design, chemical cues and mechanical characteristics of mature articular cartilage. The surface layer was made from collagen (COL), chitosan (CS) and hyaluronic acid sodium (HAS). The transitional layer with microtubule array structure was prepared with COL, CS and silk fibroin (SF). The PLAG microspheres containing kartogenin (KGN) and the polylysine-heparin sodium nanoparticles containing TGF-ß1 (TPHNs) were constructed for the surface, transitional layer, respectively. The SEM result showed that the dual-layer composite scaffold had a double structure similar to natural cartilage. The vitro biocompatibility experiment showed that the biomimetic cartilage scaffold with orientated porous structure was more conducive to the proliferation and adhesion of BMSCs. A rabbit KOA cartilage defect model was established and biomimetic cartilage scaffolds were implanted in the defect area. Compared with the surface layer and transitional layer scaffolds group, the results of dual-layer biomimetic cartilage scaffold group showed that the defects had been completely filled, the boundary between new cartilage and surrounding tissue was difficult to identify, and the morphology of cells in repair tissue was almost in accordance with the normal cartilage after 16 weeks. All those results indicated that the biomimetic cartilage scaffold could effectively repair the defect of KOA, which is related to the fact that the scaffold could guide the morphology, orientation, and proliferation and differentiation of BMSCs. This work could potentially lead to the development of multilayer scaffolds mimicking the zonal organization of articular cartilage.

Silk fibroin/collagen/hyaluronic acid scaffold incorporating pilose antler polypeptides microspheres for cartilage tissue engineering.

A silk fibroin/collagen/hyaluronic acid (SF/COL/HA) composite scaffold was prepared via admixing, crosslinking, and lyophilizing processes. We studied its physicochemical and biological properties, such as water absorption, porosity, weight loss, and biocompatibility. The optimal ratio of SF/COL/HA scaffold was 3:6.5:0.5. Then, the optimal ratio of scaffold incorporating pilose antler polypeptides (PAPs)-PLGA microspheres was prepared, and their compatibility was studied. PAP-SF/COL/HA scaffold had favorable adhesion and proliferation. A rabbit cartilage defect model was established. The repair effect of cartilage defects was observed and evaluated among PAP-SF/COL/HA, SF/COL/HA, and sham operation groups. The defects were almost completely repaired after 13 weeks in the PAP-SF/COL/HA group, thereby indicating that the PAP-SF/COL/HA composite had a favorable effect on articular cartilage repair.

Management of a Steel Bar Injury Penetrating the Head and Neck: A Case Report and Review of the Literature.

BACKGROUND: Nonmissile penetrating injuries to the head and neck caused by a steel bar are rare, and a standard management strategy is lacking. CASE DESCRIPTION: A 42-year-old woman sustained a steel bar injury with penetration of the head and neck. Computed tomography and three-dimensional reconstruction were performed for preoperative evaluation. Digital subtraction angiography was performed to confirm potential vascular injury. The steel bar was successfully removed through an open surgical procedure by a multidisciplinary team. CONCLUSIONS: Relevant literature regarding nonmissile penetrating injuries involving a steel bar was reviewed to propose appropriate management strategies. Comprehensive imaging evaluation and prompt surgery by a multidisciplinary team contributed to the successful removal of the steel bar.

Vascular endothelial growth factor is neuroprotective against ischemic brain injury by inhibiting scavenger receptor A expression on microglia.

Vascular endothelial growth factor (VEGF) is a secreted mitogen associated with angiogenesis. VEGF has long been thought to be a potent neurotrophic factor for the survival of spinal cord neurons. However, the role of VEGF in the regulation of ischemic brain injury remains unclear. In this study, rats were subjected to MCAO (middle cerebral artery occlusion) followed by intraperitoneal injection of VEGF165 (10 mg/kg) immediately after surgery and once daily until the day 10. The expression of target genes was assayed using qPCR, western blot and immunofluorescence to investigate the role of VEGF165 in regulating ischemic brain injury. We found that VEGF165 significantly inhibited MCAO-induced up-regulation of Scavenger receptor class A (SR-A) on microglia in a VEGFR1-dependent manner. VEGF165 inhibited lipopolysaccharide (LPS)-induced expression of proinflammatory cytokines IL-1ß, tumor necrosis factor alpha (TNF-α) and iNOS in microglia. More importantly, the role of VEGF165 in inhibiting neuroinflammation is partially abolished by SR-A over-expression. SR-A further reduced the protective effect of VEGF165 in ischemic brain injury. These data suggest that VEGF165 suppresses neuroinflammation and ischemic brain injury by inhibiting SR-A expression, thus offering a new target for prevention of ischemic brain injury.