3D printed mesh reinforcements enhance the mechanical properties of electrospun scaffolds

Abstract

Background: There is substantial interest in electrospun scaffolds as substrates for tissue regeneration and repair due to their fibrous, extracellular matrix-like composition with interconnected porosity, cost-effective production, and scalability. However, a common limitation of these scaffolds is their inherently low mechanical strength and stiffness, restricting their use in some clinical applications. In this study we developed a novel technique for 3D printing a mesh reinforcement on electrospun scaffolds to improve their mechanical properties. Methods: A poly (lactic acid) (PLA) mesh was 3D-printed directly onto electrospun scaffolds composed of a 40:60 ratio of poly(ε-caprolactone) (PCL) to gelatin, respectively. PLA grids were printed onto the electrospun scaffolds with either a 6 mm or 8 mm distance between the struts. Scanning electron microscopy was utilized to determine if the 3D printing process affected the archtitecture of the electrospun scaffold. Tensile testing was used to ascertain mechanical properties (strength, modulus, failure stress, ductility) of both unmodified and reinforced electrospun scaffolds. An in vivo bone graft model was used to assess biocompatibility. Specifically, reinforced scaffolds were used as a membrane cover for bone graft particles implanted into rat calvarial defects, and implant sites were examined histologically. Results: We determined that the tensile strength and elastic modulus were markedly increased, and ductility reduced, by the addition of the PLA meshes to the electrospun scaffolds. Furthermore, the scaffolds maintained their matrix-like structure after being reinforced with the 3D printed PLA. There was no indication at the graft/tissue interface that the reinforced electrospun scaffolds elicited an immune or foreign body response upon implantation into rat cranial defects. Conclusion: 3D-printed mesh reinforcements offer a new tool for enhancing the mechanical strength of electrospun scaffolds while preserving the advantageous extracellular matrix-like architecture. The modification of electrospun scaffolds with 3D-printed reinforcements is expected to expand the range of clinical applications for which electrospun materials may be suitable.

Adipose-Derived Stem Cells Based on Electrospun Biomimetic Scaffold Mediated Endothelial Differentiation Facilitating Regeneration and Repair of Abdominal Wall Defects via HIF-1α/VEGF Pathway

“…Currently, scaffolds fabricated by the electrospinning method have gained prominence for soft tissue reconstruction ( Liu et al, 2015 ; Mori da Cunha et al, 2019 ; Kaya et al, 2020 ). Electrospun scaffolds have the advantages of light weight, high surface area/volume ratio, and a three-dimensional (3D) fibrous matrix with interconnected pores, which mimic the native extracellular matrix ( James and Laurencin, 2016 ; Pensa et al, 2019 ; Kaya et al, 2020 ). Poly (N-isopropylacrylamide) (PNIPAAm), a thermoresponsive hydrogel, self-assembles at the lower critical solution temperature (LCST) of 32°C without a chemical crosslinking agent and is extensively applied in drug-controlled release and tissue engineering ( Donderwinkel et al, 2017 ; Suntornnond et al, 2017 ; Bordat et al, 2018 ).…”

3D printing of tissue engineering scaffolds: a focus on vascular regeneration

“…Depositions of the bioink on the support were controlled by extrusion-based 3D printing technology. Also, extrusion-based 3D printing of biomaterial inks can be used as support materials for vascular cells [ 141 ]. Uniaxially micropatterned struts were fabricated by Yeo et al [ 142 ] using extrusion-based 3D printing of the compositive material of PCL and collagen.…”

The 3D Printing of Freestanding PLLA Thin Layers and Improving First Layer Consistency through the Introduction of Sacrificial PVA

“…PLA filament can be blended or mixed with additional biomaterials components such as chitosan [13], antibacterial alloys [14], lignin [15], structural metals [16], and hydroxyapatite [17][18][19]. The ability to extrude controllable thin depositions is desirable 2 of 16 in tissue engineering, where 3D-printed meshes have recently been used to improve the mechanical properties of electrospun biomaterial scaffolds [20]. The generation of reproducible thin mesh structures would be of interest in biomedical engineering and in the pursuit of controlling localised cell interaction through printing microfeatures.…”