Three layer PLA/PU/collagen electrospun vascular stent with enhanced mechanical and hydrophilic properties after EDC/NHS crosslinking

Three layer structure design and material division

According to a study published in Polymers for Advanced Technologies, researchers used polylactic acid (PLA), polyurethane (PU), and collagen (COL) as raw materials to prepare a small diameter three-layer artificial vascular stent through sequential electrospinning technology, in order to simulate the structural and functional characteristics of natural blood vessels. Among them, the inner layer is composed of PLA, PU and COL composite, and the surface is relatively smooth; The middle layer is composed of PU and COL, mainly providing mechanical strength and elasticity; The outer layer is composed of PLA and COL, responsible for structural support and integration with surrounding tissues.

Performance changes caused by crosslinking treatment

The study used the EDC/NHS system to crosslink the scaffold.

. The results showed that the mechanical properties of the cross-linked scaffold were significantly improved: the longitudinal tensile performance increased by 43.35%, and the transverse performance increased by 29.36%; The hydrophilicity is synchronously enhanced, and the water contact angle decreases from 61.6 ° to 54.7 °. In terms of biological evaluation, the survival rate of L929 cells cultured in scaffold extract solution exceeded 80% after 1 day, and the cells maintained stable growth after 7 days of cultivation, indicating low toxicity and good biocompatibility. The hemolysis rate of all samples was below 5%, indicating that the rupture of red blood cells after contact with the scaffold was effectively limited.

Reference significance for the field of electronic and electrical materials

Although the application scenario of this research is vascular implants, its material combination and processing ideas have reference value for the development of electronic and electrical materials.

. Both PLA and PU are common engineering plastic substrates in the field of electronics and electrical engineering. The rigidity of PLA, the flexibility and elastic characteristics of PU have potential applications in cable sheaths, connector housings, and potting components. In the study, a multi-layer structure was constructed through sequential electrospinning, and then crosslinked and modified with EDC/NHS, demonstrating the pathway of controlling mechanical strength and surface hydrophilicity without changing the chemical composition of the matrix. This is consistent with the idea of balancing rigidity, toughness, and interfacial properties through formulation and post-treatment in electronic and electrical materials. It is worth noting that crosslinking modification not only improves mechanical properties but also changes the surface polarity of the material. For electronic and electrical applications, changes in surface hydrophilicity may affect the material’s moisture absorption behavior, which in turn is associated with electrical stability and weather resistance. The limited range of change in contact angle from 61.6 ° to 54.7 ° in the study suggests that the crosslinking density and surface modification degree need to be finely controlled. In addition, PLA and PU systems face thermal oxidative aging problems during long-term use, and the selection and addition of antioxidants are crucial for maintaining mechanical and electrical properties; If such multi-layer spinning structures are extended to electronic and electrical scenarios, the introduction of flame retardant systems also needs to be compatible with cross-linking processes to avoid weakening flame retardant efficiency during post-processing. The mechanical enhancement data, cell compatibility, and hemolysis rate results provided by this study have established a relatively complete testing framework for the performance evaluation of multi-layer polymer scaffolds. For practitioners engaged in the development of engineering plastic modification, packaging materials, and cable materials, their cross-linking process and performance characterization methods can be used as references in the material design stage. However, it should be noted that this study does not involve flame retardancy, weather aging, or electrical performance testing, and the relevant conclusions cannot be directly extrapolated to electronic and electrical applications.

Information source:Cross‐Linking of a Triple‐Layered Polymeric‐Collagen Vascular Graft by Carbodiimide for Enhanced Mechanical Properties and Biocompatibility， Organized by Herun Chemical.