Introduction: The main problems of cartilage tissue engineering are to get a scaffold with god cell interaction, good transport properties since it is not vascularized, and to avoid fibrous tissue. This paper discusses scaffold based on electrospinning polylactic acid (PLA)-polycaprolactone (PCL), surface modified with plasma polimerized polypyrrole-iodine (PPy-I) to improve their interaction with cells, and coated with Aggrecan (AG) which is a important component of the extracellular matrix of native cartilage. This protein is essential for normal tissue function and their concentration favors hidratation and tissues development during the early stage[1],[2].
Materials and Methods: The polymer scaffolds were produced by the electrospinning technique of with polymer solutions of PLA and PCL 12% (w/v) in chloroform. Distance from the collector was 20cm, voltage of 20kV and jet flow 2ml/h.
Membranes surface was modified using plasma polymerization of pirrole with Iodine PPy-I. The operating parameters of the reactor were: 8cm electrode spacing, power of 20Watts, 1.2x10-1mmHg pressure. The coated substrates with PPy-I were immersed in a solution of aggrecan (AG) from bovine articular cartilage (Sigma Aldrich) for 24 hours. Subsequently rinsed with distilled water for 10 minutes and allowed to dry at room temperature in a vacuum desiccator for 24 hours. Samples were characterized by Fourier transform infrared spectroscopy (FTIR-ATR) and scanning electron microscopy (SEM). For in vivo culture, cells were obtained from an auricular cartilage biopsy using a New Zealand white rabbit and a cell expansion cultures for 3 weeks was conducted. Approximately 1.2x106 cells were deposited on the scaffolds and cultured in vivo for 30 days in the dorsal region of the rabbit.
Results and Discussion: After the PPy-I treatment FTIR showed characteristic chemical variety in the surface showing primary and secondary amines aliphatic chains, pirrole rings, hidroxyles and nitriles FTIR-ATR also confirmed the presence of the AG protein on the scaffold[3],[4]. The materials were tested for in vivo culture in a rabbit model, showing excellent biocompatibility and cell growth, the immunohistochemical shows the presence of proteins aggrecan and collagen in the neotissue.
Conclusion: According to the findings, the scaffolding PLA-PCL-PPy-I-AG could be used for the regeneration of cartilage tissue.
The first author thanks CONACyT for Ph.D. scholarship No. 265465
References:
[1] Puppi, D., Chiellini, F., Piras, A., & Chiellini, E. (2010). Polymeric materials for bone and cartilage repair. Progress in Polymer Science, 35(4), 403-440.
[2] Domowicz, M. S., Cortes, M., Henry, J. G., & JudiSchwartz, N. B. (2009). Aggrecan modulation of growth plate morphogenesis. Developmental Biology, 329(2), 242-257.
[3] Morales, J.; Osorio, C.; Montiel, R.; Vázquez, H.; Olayo, R.; Olayo, M.G.; Cruz, G.J.; Pérez, E (2008). Autoensamble de capas de polímeros iónicos sobre polietileno funcionalizado por plasma de pirrol. Superficies y vacío, 21(3), 1-4.
[4] N. P. Camcho, P. West, P. A. Torzilli y R. Mendelson. (2000). FTIR Microscopic Imaging of Collagen and Proteoglycan in Bovine Cartilage. Biopolymers, 62(1),1-8.