Electrospinning Device for Nanofibers| Bilayer vascular grafts separately composited with nitric oxide-releasingkeratin conjugates and hydrogen sulfide-releasing heparin conjugates

Prof. Yuan Jiang/Shen Jian from Nanjing Normal University & Prof. Yin Meng from Shanghai Children's Medical Center: Construction of Keratin/Heparin Bilayer-Modified Vascular Grafts with Dual NO/H2S Release Function

Small-diameter tissue-engineered vascular grafts hold great potential for cardiovascular disease treatment, but their clinical application is often limited by thrombosis, inflammatory responses, and intimal hyperplasia. Modifying vascular materials can positively regulate vascular cell growth and promote vascular regeneration and remodeling.

To address this, Prof. Shen Jian/Yuan Jiang's research group at Nanjing Normal University employed a spatiotemporal regulation strategy. They synthesized a nitric oxide donor (KMA) from keratin and a hydrogen sulfide donor (HAT) from heparin, then prepared a bilayer tissue-engineered vascular graft with dual NO/H2S release capability through electrospinning with PCL for vascular cell regulation. The research titled "Bilayer vascular grafts separately composited with nitric oxide-releasing keratin conjugates and hydrogen sulfide-releasing heparin conjugates" was published in International Journal of Biological Macromolecules.The NO donor and H2S donor retained keratin's excellent biocompatibility and heparin's anticoagulant properties. Beyond their individual effects, these two gas signaling molecules synergistically regulated vascular regeneration. 

Fig. 1: Schematic of PCL/KMA//PCL/HAT vascular graft preparation

The team first synthesized methacrylated arginine (M-Arg) and grafted it to keratin's sulfhydryl groups via Michael addition to obtain the macromolecular NO donor KMA, which was electrospun with PCL as the graft's inner layer. Subsequently, the small molecule H2S donor 4-aminothiobenzamide was conjugated with heparin through amidation to obtain the macromolecular H2S donor HAT, which was coaxially electrospun with PCL as the graft's outer layer.This bilayer vascular graft selectively promoted HUVEC proliferation while inhibiting abnormal HUASMC proliferation. Importantly, NO and H2S release could stimulate each other's secretion, creating synergistic effects. Additionally, these grafts exhibited antibacterial, antioxidant, and anti-inflammatory properties.

Fig. 2: Characterization of PCL/KMA graft inner layer

Fig. 3: Characterization of PCL/HAT graft outer layer

Fig. 4: NO/H2S release profiles and cell viability characterization

The electrospun PCL/KMA//PCL/HAT vascular scaffold possessed a porous structure conducive to cell adhesion and growth. The inner layer's NO donor KMA could sustain NO release under high reactive oxygen species conditions. The outer layer, prepared by coaxial electrospinning, showed distinct core-shell structure that effectively delayed H2S and heparin release rates, achieving long-term anticoagulation effects.

Fig. 5: Tissue staining after one month of PCL/KMA//PCL/HAT graft implantation

After one month of implantation in rat abdominal aortas, Doppler ultrasound showed clear blood flow signals in PCL/KMA//PCL/HAT grafts without obstruction. The grafts promoted rapid endothelialization while enhancing anticoagulation and anti-calcification properties. These findings suggest these bilayer grafts are promising candidates for small-diameter tissue-engineered vascular grafts.

Paper Link: https://doi.org/10.1016/j.ijbiomac.2025.141887