Fabrication and characterization of TGF-ß1-loaded electrospun poly (lactic-co-glycolic acid) core-sheath sutures.

It is difficult for traditional sutures, which are usually braided by microfibers, to load drugs or growth factors. To develop a novel species of suture, in this study, a core-sheath yarn was fabricated by surrounding Poly (lactic-co-glycolic acid) (PLGA) microfibers with electrospun PLGA nanofibers using a custom electrospinning equipment with two needles and a rotating funnel. The resulting yarn shows enough mechanical strength to be used as sutures. The capillary action, which is caused by the structure of the core-sheath yarn, enabled the PLGA yarn to easily absorb a growth factor. Thus TGF-ß1 was loaded to the core-sheath yarn ensuring that the suture has a tissue repairing function. Human umbilical vein endothelial cells grew faster on TGF-ß1 loaded core-sheath yarn than on the core-sheath yarn without growth factor. This core-sheath yarn fabrication method has the potential to be used in the development of functional sutures.

Restoring tracheal defects in a rabbit model with tissue engineered patches based on TGF-ß3-encapsulating electrospun poly(l-lactic acid-co-ε-caprolactone)/collagen scaffolds.

Long segment tracheal stenosis often has a poor prognosis due to the limited availability of materials for tracheal reconstruction. Tissue engineered tracheal patches based on electrospun scaffolds and stem cells present ideal solutions to this medical challenge. However, the established engineering process is inefficient and time-consuming. In our research, to optimize the engineering process, core-shell nanofilms encapsulating TGF-ß3 were fabricated as scaffolds for tracheal patches. The morphological and mechanical characteristics, degradation and biocompatibility of poly(l-lactic acid-co-ε-caprolactone)/collagen (PLCL/collagen) scaffolds with different compositions (PLCL:collagen 75:25, 50:50 and 25:75, respectively) were comparatively evaluated to determine the preferable compositional ratio. Then the chondrogenesis-inducing potential is investigated, and tracheal patches based on electrospun scaffolds and bone marrow mesenchymal stem cells (BMSCs) were constructed to restore tracheal defects in rabbit models. The results indicated that core-shell scaffolds with a PLCL/collagen proportion of 75:25 were eligible for tracheal patches. The stable and sustained release of TGF-ß3 from scaffolds could efficiently promote the chondrogenic differentiation of BMSCs and shorten the incubation time. Tracheal integrity was well maintained for 2 months after restoration; meanwhile, re-epithelialization also achieved. In conclusion, TGF-ß3-encapsulating core-shell electrospun scaffolds with a PLCL/collagen proportion of 75:25 could be used to optimize engineering process of tracheal patches.

Evaluation of the potential of kartogenin encapsulated poly(L-lactic acid-co-caprolactone)/collagen nanofibers for tracheal cartilage regeneration.

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.