A biodegradable porous composite scaffold of PCL/BCP containing Ang-(1-7) for bone tissue engineering

Abstract

Highly porous three-dimensional biodegradable scaffolds was obtained from beta-tricalcium phosphate-hydroxyapatite bioceramic (BCP), PCL, and Angiotensin-(1-7). We used the solvent casting and particulate leaching methods (SC/PL). The processed scaffolds were characterized by X-ray microtomography (µ-CT). Biocompatibility tests in vitro were performed during three and seven days using MTT and Alkaline Phosphatase Activity (APA) assays. Both the MTT activity and APA were evaluated using a one-way ANOVA test. The µ-CT results showed that the increase of the PCL:BCP weight ratio leads to structures with lower pore sizes. The pore interconnectivity of the processed scaffolds was evaluated in terms of the fragmentation index (FI). We observed that the obtained composites present poorly connected structures, with close values of FI. However, as the polymer phase is almost transparent to the X-rays, it was not taken into consideration in the µ-CT tests. The MTT activity assay revealed that scaffolds obtained with and without Angiotensin-(1-7) present mild and moderate cytotoxic effects, respectively. The APA assay showed that the rat osteoblasts, when in contact for three days with the PCL composites, presented an APA similar to that observed for the control cells. Nevertheless, for an incubation time of seven days we observed a remarkable decrease in the alkaline phosphatase activity. In conclusion, using the solvent casting and salt leaching method we obtained 3D porous that are composites of PCL, BC and Ang-(1-7), which have suitable shapes for the bone defects, a high porosity and interconnect pores. Furthermore, the viability in vitro showed that the scaffolds have potential for drug delivery system and could be used in future in vivo tests. Keywords: angiotensin-(1-7), composite, scaffold, tissue engineering. Resumo A estrutura de um biomaterial para regeneração óssea é fator chave para seu sucesso clínico. Não existe um único biomaterial usado para reparo e regeneração óssea capaz de preencher todos os requisitos para um enxerto ósseo ideal. Assim, optou-se por utilizar neste estudo dois biomateriais largamente utilizados na engenharia de tecido ósseo, a policaprolactona (PCL) e cerâmica bifásica (BCP). Neste estudo, compósitos porosos tridimensionais de PCL:BCP (3:1 e 1:1 p:p) foram fabricados utilizando a combinação das técnicas de evaporação do solvente e lavagem de partículas de sal com ou sem a adição de Angiotensina (Ang)-(1-7). Os compósitos de PCL:BCP com alta porosidade e interconectividade obtidos foram analisados usando microtomografia computadorizada (µ-CT). A viabilidade dos compósitos com e sem a adição da Ang-(1-7) foram analisados utilizando osteoblastos de cultura primária nos períodos de 3 e 7 dias utilizando o teste de MTT e secreção de Fosfatase Alcalina. Diferenças significativas de todas as variáveis foram testadas através de análises multivariáveis (p<0,05). Demonstrou-se uma estrutura mais uniformemente distribuída quando a razão PCL/BCP foi aumentada. A conectividade dos poros f...

Effect of Electron Beam Sterilization on Three-Dimensional-Printed Polycaprolactone/Beta-Tricalcium Phosphate Scaffolds for Bone Tissue Engineering

“…[13][14][15][16][17] In particular, PCL and b-tricalcium phosphate (b-TCP) composites have attracted extensive attention due to their high biocompatibility, long-term degradation, appropriate mechanical performances, and osteoconductivity. [18][19][20][21] Moreover, PCL/ b-TCP composites can be processed using AM techniques such as fused deposition modeling (FDM). 17,22 A critical step toward the translation and clinical applications of PCL/b-TCP-based 3D-printed constructs and devices is terminal sterilization.…”

Ex Vivo and In Vivo Analyses of Novel 3D-Printed Bone Substitute Scaffolds Incorporating Biphasic Calcium Phosphate Granules for Bone Regeneration

“…With respect to the chosen fabrication method, a composite made of PCL and BCP should combine the advantages of both material classes [ 43 , 44 ]. Previous studies have reported the combination of BCP and PCL creates a material with a high biocompatibility, mechanical stability, and a stable degradation.…”

Targeting the Protective Arm of the Renin-Angiotensin System: Focused on Angiotensin-(1–7)

“…Incorporating Ang-(1-7) in the bone structure may counteract Ang II and eventually decrease interleukin-6 (IL-6) levels that act as a boneresorbing factor and also induce osteoclast formation that stimulates bone resorption. Viability, in vitro, demonstrates that the scaffolds may hold promise as a drug delivery system (Macedo et al, 2012). et al, 2017).…”