Enhanced Biochemical and Biomechanical Properties of Scaffolds Generated by Flock Technology for Cartilage Tissue Engineering

Abstract

Natural cartilage shows column orientation of cells and anisotropic direction of collagen fibers. However, matrices presently used in matrix-assisted autologous chondrocyte implantation do not show any fiber orientation. Our aim was to develop anisotropic scaffolds with parallel fiber orientation that were capable to support a cellular cartilaginous phenotype in vitro. Scaffolds were created by flock technology and consisted of a membrane of mineralized collagen type I as substrate, gelatine as adhesive, and parallel-oriented polyamide flock fibers vertically to the substrate. Confocal laser scan microscopy demonstrated that mesenchymal stem cells (MSCs) adhered and proliferated well in the scaffolds and cell vitality remained high over time. Articular chondrocytes seeded in a collagen type I gel into flock scaffolds deposited increasing amounts of proteoglycans and collagen type II over time. MSC-seeded flock scaffold constructs under chondrogenic conditions deposited significantly more proteoglycans and collagen type II than MSC collagen type I gel constructs only. Biomechanical testing revealed higher initial hardness of flock scaffolds than that of a clinically applied collagen type I/III scaffold combined with superior relaxation and an increasing hardness in MSC-loaded flock biocomposites during chondrogenesis. In conclusion, flock technology allows fabrication of scaffolds with anisotropic fiber orientation that mediates superior biomechanical and biochemical composition of tissue engineering constructs for cartilage repair.

Application of cell and biomaterial-based tissue engineering methods in the treatment of cartilage, menisci and ligament injuries

“…In vitro studies of type I collagen hydrogel scaffolds has shown that the cells embedded in the hydrogel easily adhere and proliferate well and the MSCs seeded on type I collagen matrix, retain their differentiation potential for a long time. In one of the studies, it was reported that proteoglycan and type II collagen content were similar to that obtained by the same number of cells seeded on clinically used type I/III collagen scaffolds and cultured under the same conditions for 42 days [61]. Yuan et al [62] demonstrated the immunomodulatory properties of type I collagen hydrogel.…”

Treatment of rabbit growth plate injuries with oriented ECM scaffold and autologous BMSCs

“…Scaffolds could possess superior biomechanical properties and protect cells from early critical compression. Furthermore, oriented scaffolds fabricated from various materials using diverse techniques have been shown to possess superior strength and compressive modulus compared with typical non-oriented scaffolds in the dry state in vitro 21.…”

Bilayered bioactive glass scaffolds incorporating fibrous morphology by flock technology

“…4 (C) and 4(D) show the FTIR spectra of the scaffolds flocked for 10 s and 30 s, respectively, and after immersion in SBF for 7, 14 and 21 days. The HA formation is confirmed by the appearance of bands at $ 567, 600 and 1017-1090 cm À 1 corresponding to the bending and stretching vibration of phosphate groups (PO 4 3 À ). The band at 878 cm À 1 corresponds to the vibration mode of carbonate groups (CO 3 2 À ) and suggests the formation of carbonated HA.…”

“…Driven by increasing demand, new strategies for osteochondral TE are fast developing which involve the fabrication of bilayered scaffolds [3]. In case of cartilage damage, anisotropic scaffolds with parallel fiber orientation which provide columnar pore channels represent a suitable approach [4]. These types of scaffolds can be developed by flock technology [5].…”

“…Despite its suitable application for fabricating ordered fibrous structures, electroflocking has not been yet widely considered to produce scaffolds for TE. Only few studies are available in literature [4,5,7]. Walther et al [7], for example, showed that chondrogenesis of mesenchymal stem cells (MSC), which is determined by the synthesis of proteoglycan and deposition of collagen type II, was significantly higher on flock scaffolds than when cultivated in collagen gels.…”