Effect of fiber orientation of collagen-based electrospun meshes on human fibroblasts for ligament tissue engineering applications

Abstract

Within the past two decades polylactic-co-glycolic acid (PLGA) has gained considerable attention as a biocompatible and biodegradable polymer that is suitable for tissue engineering and regenerative medicine. In this present study, we have investigated the potential of PLGA, collagen I (ColI), and polyurethane (PU) scaffolds for ligament tissue regeneration. Two different ratios of PLGA (50:50 and 85:15) were used to determine the effects on mechanical tensile properties and cell adhesion. The Young's modulus, tensile stress at yield, and ultimate tensile strain of PLGA(50:50)-ColI-PU scaffolds demonstrated similar tensile properties to that of ligaments found in the knee. Whereas, scaffolds composed of PLGA(85:15)-ColI-PU had lower tensile properties than that of ligaments. Furthermore, we investigated the effect of fiber orientation on mechanical properties and our results indicate that aligned fiber scaffolds demonstrate higher tensile properties than scaffolds with random fiber orientation. Also, human fibroblasts attached and proliferated with no need for additional surface modifications to the presented electrospun scaffolds in both categories. Collectively, our investigation demonstrates the effectiveness of electrospun PLGA scaffolds as a suitable candidate for regenerative medicine, capable of being manipulated and combined with other polymers to create three-dimensional microenvironments with adjustable tensile properties to mimic native tissues.

Keywords: collagen I; electrospinning; ligament tissue engineering; polylactic-co-glycolic acid; polyurethane.

FIGURE 1.

Schematic set-up of two-syringe system for electrospinning bicomponent fiber scaffolds. A: chemical fume hood. B: Support beams used to holster electrospinning syringe pumps. C: Syringe pumps. D: Electrospun fibers. E: Rotating drill system for aligned fiber production. F: 5 w/v % PU. G: 15 w/v % PLGA and 10 w/v % ColI. H: Static collector.

FIGURE 2.

(A and C): Scanning electron micrograph of aligned fiber scaffolds. (B and D): Cell-seeded scaffolds (2 weeks in culture). (E and G): Scanning electron micrograph of random fiber scaffolds. (F and H): Cell-seeded scaffolds (2 weeks in culture).

FIGURE 3.

A: Cell adhesion assay measured at days 4, 7, and 14. Bars represented as mean ± standard error of mean. Figure legend indicates scaffold composition as well as fiber orientation: A—Aligned and R—Random. Asterisks represent statistical significance: *p < 0.05, ** p < 0.005, and *** p < 0.0005. B: HFF seeded on scaffolds for 4, 7, and 14 days and nuclei stained using DAPI (blue), scale bar 20 µm. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]