RESUMEN
An electrically conductive polypyrrole (PPy) doped with a bioactive agent is an emerging functional biomaterial for tissue engineering. We therefore used chondroitin sulfate (CS)-doped PPy coating to modify initially electrically insulating polylactide resulting in novel osteogenic scaffolds. In situ chemical oxidative polymerization was used to obtain electrically conductive PPy coating on poly-96L/4D-lactide (PLA) nonwoven scaffolds. The coated scaffolds were characterized and their electrical conductivity was evaluated in hydrolysis. The ability of the coated and conductive scaffolds to enhance proliferation and osteogenic differentiation of human adipose stem cells (hASCs) under electrical stimulation (ES) in three-dimensional (3D) geometry was compared to the noncoated PLA scaffolds. Electrical conductivity of PPy-coated PLA scaffolds (PLA-PPy) was evident at the beginning of hydrolysis, but decreased during the first week of incubation due to de-doping. PLA-PPy scaffolds enhanced hASC proliferation significantly compared to the plain PLA scaffolds at 7 and 14 days. Furthermore, the alkaline phosphatase (ALP) activity of the hASCs was generally higher in PLA-PPy seeded scaffolds, but due to patient variation, no statistical significance could be determined. ES did not have a significant effect on hASCs. This study highlights the potential of novel PPy-coated PLA scaffolds in bone tissue engineering.
Asunto(s)
Tejido Adiposo/citología , Diferenciación Celular/efectos de los fármacos , Osteogénesis/efectos de los fármacos , Poliésteres/farmacología , Polímeros/farmacología , Pirroles/farmacología , Células Madre/citología , Andamios del Tejido/química , Adulto , Anciano , Fosfatasa Alcalina/metabolismo , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Materiales Biocompatibles Revestidos/farmacología , Medios de Cultivo/farmacología , ADN/metabolismo , Espectroscopía Dieléctrica , Estimulación Eléctrica , Electrodos , Femenino , Humanos , Hidrólisis/efectos de los fármacos , Microscopía de Fuerza Atómica , Microscopía Electrónica de Rastreo , Espectrometría de Masa por Ionización de Electrospray , Células Madre/efectos de los fármacos , Células Madre/enzimologíaRESUMEN
A poly-70L/30DL-lactide (PLA70)-ß-tricalcium phosphate (ß-TCP) composite implant reinforced by continuous PLA-96L/4D-lactide (PLA96) fibers was designed for in vivo spinal fusion. The pilot study was performed with four sheep, using titanium cage implants as controls. The composite implants failed to direct bone growth as desired, whereas the bone contact and the proper integration were evident with controls 6 months after implantation. Therefore, the PLA70/ß-TCP composite matrix material was further analyzed in the in vitro experiment by human and ovine adipose stem cells (hASCs and oASCs). The composites proved to be biocompatible as confirmed by live/dead assay. The proliferation rate of oASCs was higher than that of hASCs at all times during the 28 d culture period. Furthermore, the composites had only a minor osteogenic effect on oASCs, whereas the hASC osteogenesis on PLA70/ß-TCP composites was evident. In conclusion, the composite implant material can be applied with hASCs for tissue engineering but not be evaluated in vivo with sheep.