No abstract

The results demonstrated that the robotic system with the designed controller was effective in both position control and trajectory tracking.

Tracheal stenosis is one of major challenging issues in clinical medicine because of the poor intrinsic ability of tracheal cartilage for repair. Tissue engineering provides an alternative method for the treatment of tracheal defects by generating replacement tracheal structures. In this study, we fabricated coaxial electrospun fibers using poly(L-lactic acid-co-caprolactone) and collagen solution as shell fluid and kartogenin solution as core fluid. Scanning electron microscope and transmission electron microscope images demonstrated that nanofibers had uniform and smooth structure. The kartogenin released from the scaffolds in a sustained and stable manner for about 2 months. The bioactivity of released kartogenin was evaluated by its effect on maintain the synthesis of type II collagen and glycosaminoglycans by chondrocytes. The proliferation and morphology analyses of mesenchymal stems cells derived from bone marrow of rabbits indicated the good biocompatibility of the fabricated nanofibrous scaffold. Meanwhile, the chondrogenic differentiation of bone marrow mesenchymal stem cells cultured on core-shell nanofibrous scaffold was evaluated by real-time polymerase chain reaction. The results suggested that the core-shell nanofibrous scaffold with kartogenin could promote the chondrogenic differentiation ability of bone marrow mesenchymal stem cells. Overall, the core-shell nanofibrous scaffold could be an effective delivery system for kartogenin and served as a promising tissue engineered scaffold for tracheal cartilage regeneration.

This study explored a new rosuvastatin calcium- and heparin-loaded poly­(l-lactide-co-caprolactone) (PLCL) scaffold for covered stents for treating aneurysms. The mechanism of rosuvastatin-induced endothelialization via vascular endothelial growth factor (VEGF)-A elevation was further explored. Rosu50, Rosu75, Rosu100, and phosphate-buffered saline (PBS) nanofibrous scaffolds were fabricated by coaxial electrospinning and observed by electron microscopy. Anticoagulation and pro-endothelialization properties were tested. Sixteen rabbits were selected for an in vivo assay and underwent microsurgery to establish a carotid aneurysm model. The animals were treated with covered stents and followed for 4 months using digital subtraction angiography (DSA), electron microscopy, and histology. Rosuvastatin-treated human umbilical vein endothelial cell (HUVEC) viability, function, and VEGF-A modulation were further studied to elucidate the pro-endothelialization mechanism of rosuvastatin. Our study demonstrates that rosuvastatin and heparin can be incorporated into PLCL nanofibers via electrospinning. Rosu100 nanofiber scaffolds exhibited significant anticoagulation properties. The viability of HUVECs transferred to Rosu100 nanofiber scaffolds was increased significantly. In vivo, DSA revealed that the Rosu100 group had better outcomes than the PBS group. In addition, the Rosu100 stents induced more integrated endothelialization. Further study demonstrated that rosuvastatin promoted HUVEC viability and function in vitro. The effects of rosuvastatin may be attributed to an elevation in VEGF-A. We demonstrated that rosuvastatin- and heparin-loaded PLCL-covered stents show favorable anticoagulation and pro-endothelialization properties in vitro and in vivo in a rabbit aneurysm model. VEGF-A elevation played a crucial role in rosuvastatin-promoted endothelialization. This work provides an additional option for treating cerebral aneurysms with covered stents.

Heparin and rosuvastatin calcium cause P(LLA-CL) nanofibers to exhibit good cell viability and anticoagulation ability.