PLA short sub-micron fiber reinforcement of 3D bioprinted alginate constructs for cartilage regeneration

Abstract

In this study, we present an innovative strategy to reinforce 3D printed hydrogel constructs for cartilage tissue engineering by formulating composite bioinks containing alginate and short sub-micron polylactide (PLA) fibers. We demonstrate that Young's modulus obtained for pristine alginate constructs (6.9 ± 1.7 kPa) can be increased threefold (up to 25.1 ± 3.8 kPa) with the addition of PLA short fibers. Furthermore, to assess the performance of such materials in cartilage tissue engineering, we loaded the bioinks with human chondrocytes and cultured in vitro the bioprinted constructs for up to 14 days. Live/Dead assays at day 0, 3, 7 and 14 of in vitro culture showed that human chondrocytes were retained and highly viable (~80%) within the 3D deposited hydrogel filaments, thus confirming that the fabricated composites materials represent a valid solution for tissue engineering applications. Finally, we show that the embedded chondrocytes during all the in vitro culture maintain a round morphology, a key parameter for a proper deposition of neocartilage extra cellular matrix (ECM).&#13.

Chemical insights into bioinks for 3D printing

“…For example, nano-hydroxyapatite 63 was added to alginate bioink to allow high throughput printing with laser-induced forward transfer. PLA-sub-micro fibers 148 were added to a cell embedded alginate bioink to improve rheological properties.…”

Processing of (Co)Poly(2-oxazoline)s by Electrospinning and Extrusion from Melt and the Postprocessing Properties of the (Co)Polymers

“…Such matrices are of great interest in materials science because of their multiple applications in different fields, like electronic [1], or controlled drug delivery [2]. Especially, a great interest in recent years is the processing of polymers into materials that can be applied as scaffolds in tissue regeneration [3][4][5][6][7][8]. Among synthetic and natural polymers, mainly polycaprolactone (PCL) [9], poly(l-lactic acid) (PLA) [10], poly(lactic-co-glycolic) acid (PLGA) [11], silk [12], collagen [13], hyaluronic acid [14] or chitosan [15], were utilised for the fabrication of matrices applied as scaffolds for tissue regeneration.…”

Recent progress in extrusion 3D bioprinting of hydrogel biomaterials for tissue regeneration: a comprehensive review with focus on advanced fabrication techniques

“…According to the ECM composition, cartilage tissue can be classified in three categories, including elastic cartilage (if elastic fibres are present in the ECM), fibrous cartilage (if the matrix is rich in collagenous fibres), and hyaline cartilage (if the matrix is mainly composed of glycosaminoglycans (GAGs)) [169]. From the microscopic point of view, human cartilage composed of a hydrated ECM, which is made of proteoglycans consisting of a core protein with covalently attached GAGs (accountable for the cartilages' capacity to maintain high compressive loads), mainly chondroitin sulphates, and collagen type II fibrils (provide its high tensile strength and capability of tolerating shear stresses) [170,171].…”