A novel small diameter nanotextile arterial graft is associated with surgical feasibility and safety and increased transmural endothelial ingrowth in pig.

Globally, millions of patients are affected by myocardial infarction or lower limb gangrene/amputation due to atherosclerosis. Available surgical treatment based on vein and synthetic grafts provides sub-optimal benefits. We engineered a highly flexible and mechanically robust nanotextile-based vascular graft (NanoGraft) by interweaving nanofibrous threads of poly-L-lactic acid to address the unmet need. The NanoGrafts were rendered impervious with selective fibrin deposition in the micropores by pre-clotting. The pre-clotted NanoGrafts (4 mm diameter) and ePTFE were implanted in a porcine carotid artery replacement model. The fibrin-laden porous milieu facilitated rapid endothelization by the transmural angiogenesis in the NanoGraft. In-vivo patency of NanoGrafts was 100% at 2- and 4-weeks, with no changes over time in lumen size, flow velocities, and minimal foreign-body inflammatory reaction. However, the patency of ePTFE at 2-week was 66% and showed marked infiltration, neointimal thickening, and poor host tissue integration. The study demonstrates the in-vivo feasibility and safety of a thin-layered vascular prosthesis, viz., NanoGraft, and its potential superiority over the commercial ePTFE.

Injectable Nano Whitlockite Incorporated Chitosan Hydrogel for Effective Hemostasis.

Uncontrolled bleeding can lead to many complications that might cause multiple organ failures and even death. Of all the hemostatic agents used, chitosan has been reported to show better hemostatic potential. It acts through one mechanism involved in hemostasis that is plug formation by adhering to the injured site. Hence our focus is to enhance the hemostatic potential of chitosan (Ch) hydrogel by incorporating nano whitlockite (nWH: Ca18Mg2(HPO4)2(PO4)12) that would release Ca2+, Mg2+, and PO43- ions that would simultaneously initiate the coagulation cascade. Ch-nWH composite hydrogel can act simultaneously on different mechanisms involved in hemostasis and bring about rapid bleeding control. The nWH particles were synthesized using precipitation technique and were characterized. Particle size of nWH was found to be 75 ± 5 nm. Composite hydrogel was characterized using FTIR and XRD to confirm the presence of different constituents of the hydrogel. Rheological studies showed the shear-thinning property and increased elastic modulus of the composite hydrogel compared to Ch hydrogel. 2%Ch-4%nWH hydrogel was observed to be cytocompatible with Human Umbilical Vein Endothelial Cells (HUVEC). In the in vitro blood clotting analysis using citrated human whole blood, 2%Ch-4%nWH hydrogel showed rapid blood clot formation compared to control 2%Ch hydrogel. Further in vivo experiments performed on liver and femoral artery injuries created on Sprague-Dawley (S.D) rat model reveals that 2%Ch-4%nWH hydrogel promoted rapid bleeding control and less volume of blood loss compared to Ch hydrogel. These in vitro and in vivo results showed that incorporation of nWH has enhanced the hemostatic potential of Ch hydrogel. Therefore, the synthesized 2%Ch-4%nWH hydrogel may be a promising system that could bring about rapid hemostasis during life threatening bleeding.