In vitro generation of mechanically functional cartilage grafts based on adult human stem cells and 3D-woven poly(ɛ-caprolactone) scaffolds

Abstract

Three-dimensionally woven poly(ε-caprolactone)(PCL) scaffolds were combined with adult human mesenchymal stem cells (hMSC) to engineer mechanically functional cartilage constructs in vitro. The specific objectives were to: (i) produce PCL scaffolds with cartilage-like mechanical properties, (ii) demonstrate that hMSCs formed cartilage after 21-days of culture on PCL scaffolds, and (iii) study effects of scaffold structure (loosely vs. tightly woven), culture vessel (static dish vs. oscillating bioreactor), and medium composition (chondrogenic additives with or without serum). Aggregate moduli of 21-day constructs approached normal articular cartilage for tightly woven PCL cultured in bioreactors, were lower for tightly woven PCL cultured statically, and lowest for loosely woven PCL cultured statically (p<0.05). Construct DNA, total collagen, and glyocosaminoglycans (GAG) increased in a manner dependent on time, culture vessel, and medium composition. Chondrogenesis was verified histologically by rounded cells within a hyaline-like matrix that immunostained for collagen type II but not type I. Bioreactors yielded constructs with higher collagen content (p<0.05) and more homogenous matrix than static controls. Chondrogenic additives yielded constructs with higher GAG (p<0.05) and earlier expression of collagen II mRNA if serum was not present in medium. These results show feasibility of functional cartilage tissue engineering from hMSC and 3D woven PCL scaffolds.

Scaffold-mediated lentiviral transduction for functional tissue engineering of cartilage

“…By nearly all measures of gene regulation, protein content, and biomechanical properties, the level of chondrogenic differentiation achieved at D28 by immobilizing LVT was indistinguishable from that using rhTGF-β3. The observed increase in sGAG and collagen content is consistent with previous reports from our group and others when using hMSCs for chondrogenesis (24)(25)(26).…”

Mechanical response of 3D Insert® PCL to compression

“…Due to the absence of plastic deformation noticed applying loading ramps at 8% of strain, such value was used to induce complete relaxation from pre-stresses on all samples before further mechanical testing. PCL scaffolds with an architecture similar to 3D PCL relaxed under constant strain conditions over periods ranging from few hundreds of seconds [19] up to 33 min [20], while requiring about 180 min in this study. The differences with the literature are believed to be due to the molecular weight and the degree of crystallinity of samples [27].…”

“…In order to obtain reproducibility of the response to compression, pre-stresses existing in the scaffolds must be prevented. For this purpose, static pre-conditioning was proposed in multiple studies [18]- [20] as a method to prevent progressive relaxation of the structure undergoing dynamic cycles. Environmental conditions are known to affect the mechanical response of scaffolds [21] as demonstrated by Dynamic Mechanical Analysis (DMA) in previous literature studies [14], [15], [17].…”

Bioengineering of Articular Cartilage: Past, Present and Future

“…[92]; [206]; [207]; [208]; [209]; [210]; [211]; [212]; [209]; [213] Poly(ethylene glycol) Hydrophilicity [218]; [219] …”