Biocompatibility and biodegradation of polyester and polyfumarate based-scaffolds for bone tissue engineering

Biodegradable and biocompatible polymeric scaffolds have been recently introduced for tissue regeneration purpose. In the present study we aimed to develop polymeric-based scaffolds for bone regeneration. Two polyesters, poly-β-propiolactone (PBPL), poly-ε-caprolactone (PCPL) and two polyfumarates, polydiisopropyl fumarate (PDIPF), polydicyclohexyl fumarate (PDCF) were chosen to prepare films which can support osteoblastic growth. Scanning electron microscopy and water contact angle were used to characterize the matrices. Biodegradation studies were performed both in PBS buffer and using an in vitro macrophage degradation assay. Mouse calvaria-derived MC3T3E1 cells and UMR106 rat osteosarcoma cell lines were used to perform biocompatibility and cytotoxicity studies. The polyesters, the most hydrophilic polymers studied, showed a rougher and more porous surfaces than the polyfumarates. Under acellular conditions, only PBPL was degraded by hydrolytic mechanisms. However, macrophages performed an active degradation of all polymeric films. Osteoblasts developed well-defined actin fibres without evidence of cytotoxicity when growing on the films. The number of UMR106 osteoblasts that adhered to the PBPL-based film was higher than that of the cells attached to the PECL and polyfumarates (PDIPF and PDCF) matrices. Both UMR106 and MC3T3E1 osteoblastic lines showed protein levels comparable to control conditions, demonstrating that they grew well on all surfaces. However, UMR106 cells showed a significant increase in proliferation on polyester-derived scaffolds (PBPL and PECL). The alkaline phosphatase activity of UMR106, an osteoblastic marker, was significantly higher than that of control plastic dishes. MC3T3E1 cells expressed similar levels of this differentiation marker in all polymeric matrices. We found similar collagen protein content after 48 h culture of UMR106 cells on all surfaces. However, important differences were evident in the MC3T3E1 line. In conclusion, the synthetic polymeric-based scaffold we have developed and studied supports adhesion, growth and differentiation of two osteoblastic cell lines, suggesting that they could be useful in bone tissue regeneration. Copyright 2008 John Wiley & Sons, Ltd

Biocompatibility and biodegradation of polyester and polyfumarate based-scaffolds for bone tissue engineering

Biodegradable and biocompatible polymeric scaffolds have been recently introduced for tissue regeneration purpose. In the present study we aimed to develop polymeric-based scaffolds for bone regeneration. Two polyesters, poly-β-propiolactone (PBPL), poly-ε-caprolactone (PCPL) and two polyfumarates, polydiisopropyl fumarate (PDIPF), polydicyclohexyl fumarate (PDCF) were chosen to prepare films which can support osteoblastic growth. Scanning electron microscopy and water contact angle were used to characterize the matrices. Biodegradation studies were performed both in PBS buffer and using an in vitro macrophage degradation assay. Mouse calvaria-derived MC3T3E1 cells and UMR106 rat osteosarcoma cell lines were used to perform biocompatibility and cytotoxicity studies. The polyesters, the most hydrophilic polymers studied, showed a rougher and more porous surfaces than the polyfumarates. Under acellular conditions, only PBPL was degraded by hydrolytic mechanisms. However, macrophages performed an active degradation of all polymeric films. Osteoblasts developed well-defined actin fibres without evidence of cytotoxicity when growing on the films. The number of UMR106 osteoblasts that adhered to the PBPL-based film was higher than that of the cells attached to the PECL and polyfumarates (PDIPF and PDCF) matrices. Both UMR106 and MC3T3E1 osteoblastic lines showed protein levels comparable to control conditions, demonstrating that they grew well on all surfaces. However, UMR106 cells showed a significant increase in proliferation on polyester-derived scaffolds (PBPL and PECL). The alkaline phosphatase activity of UMR106, an osteoblastic marker, was significantly higher than that of control plastic dishes. MC3T3E1 cells expressed similar levels of this differentiation marker in all polymeric matrices. We found similar collagen protein content after 48 h culture of UMR106 cells on all surfaces. However, important differences were evident in the MC3T3E1 line. In conclusion, the synthetic polymeric-based scaffold we have developed and studied supports adhesion, growth and differentiation of two osteoblastic cell lines, suggesting that they could be useful in bone tissue regeneration.Facultad de Ciencias Exacta

Biocompatibility and biodegradation of polyester and polyfumarate based-scaffolds for bone tissue engineering

Biodegradable and biocompatible polymeric scaffolds have been recently introduced for tissue regeneration purpose. In the present study we aimed to develop polymeric-based scaffolds for bone regeneration. Two polyesters, poly-β-propiolactone (PBPL), poly-ε-caprolactone (PCPL) and two polyfumarates, polydiisopropyl fumarate (PDIPF), polydicyclohexyl fumarate (PDCF) were chosen to prepare films which can support osteoblastic growth. Scanning electron microscopy and water contact angle were used to characterize the matrices. Biodegradation studies were performed both in PBS buffer and using an in vitro macrophage degradation assay. Mouse calvaria-derived MC3T3E1 cells and UMR106 rat osteosarcoma cell lines were used to perform biocompatibility and cytotoxicity studies. The polyesters, the most hydrophilic polymers studied, showed a rougher and more porous surfaces than the polyfumarates. Under acellular conditions, only PBPL was degraded by hydrolytic mechanisms. However, macrophages performed an active degradation of all polymeric films. Osteoblasts developed well-defined actin fibres without evidence of cytotoxicity when growing on the films. The number of UMR106 osteoblasts that adhered to the PBPL-based film was higher than that of the cells attached to the PECL and polyfumarates (PDIPF and PDCF) matrices. Both UMR106 and MC3T3E1 osteoblastic lines showed protein levels comparable to control conditions, demonstrating that they grew well on all surfaces. However, UMR106 cells showed a significant increase in proliferation on polyester-derived scaffolds (PBPL and PECL). The alkaline phosphatase activity of UMR106, an osteoblastic marker, was significantly higher than that of control plastic dishes. MC3T3E1 cells expressed similar levels of this differentiation marker in all polymeric matrices. We found similar collagen protein content after 48 h culture of UMR106 cells on all surfaces. However, important differences were evident in the MC3T3E1 line. In conclusion, the synthetic polymeric-based scaffold we have developed and studied supports adhesion, growth and differentiation of two osteoblastic cell lines, suggesting that they could be useful in bone tissue regeneration.Facultad de Ciencias Exacta

Interaction studies of mixed matrices of Chitosanpoly- ε -Caprolactone and Alendronate for bone tissue engineering

Tissue engineering actual tendencies leads to the development of biocompatible matrices with accurate physical and mechanical properties in bone reconstruction. As a regeneration of a new tissue is achieved, the scaffold is no longer needed and so it is reasonable to use biodegradable scaffolds [1]. The rate of degradation must be in parallel with the tissue regeneration, and is very important to provide long term construct biocompatibility, because only natural tissue will remain in the body–a neo-organ. In this context one of the most common compound used is the natural polymer chitosan, whose mechanical properties can be improved by adding synthetic polymers [2]. The great interest in this macromolecule is due to its proved biocompatibility and biodegradation properties [3]. Matrix also requires the capacity to transport osteogenic agents which enhance bone regeneration. Bisphosphonates are a new class of synthetic compounds structurally related to pyrophosphate, an endogenous modulator in homeostasis of calcium, and they are clinically used for various metabolic bone disorders such as Paget’s disease, hypercalcemia of malignancy, bone metastasis and osteoporosis [4]. The reduced targetability of some bisphosphonates in relationship to the dose increased and its hepatosplenic accumulation has been reported [5]. It is due to high precipitability with divalent ions in the circulation in blood plasma, which may be taken up by reticuloendothelial system as foreign substances [6]. Therefore, new drug delivery systems are needed to overcome these problems. The aim of our work is the development of a scaffold for tissue engineering based in chitosan/poly-ε-caprolactone blend which contains an adequate concentration of alendronate (a nitrogen bisphosphonate) for osteoblastic bone growth without toxic effects

A vanadium/aspirin complex controlled release using a poly(ß-propiolactone) film : Effects on osteosarcoma cells

A delivery system for vanadium was developed using poly(ß-propiolactone)(PßPL) films. The release kinetics of a complex of vanadium (IV) with aspirin (VOAspi) was evaluated with lms prepared from polymers of different molecular weights, as well as with variable drug load. A sustained release of vanadium over 7 days was achieved. The drug release kinetics depends on contributions from two factors: (a) diffusion of the drug; and (b) erosion of the PßPL lm. The experimental data at an early stage of release were tted with a diffusion model, which allowed determination of the diffusion coef cient of the drug. VOAspi does not show strong interaction with the polymer, as demonstrated by the low apparent partition coef cient (approximately 10-2). UMR106 osteosarcoma cells were used as a model to evaluate the anticarcinogenic effects of the VOAspi released from the PßPL lm. VOAspi–PßPL lm inhibited cell proliferation in a dose-response manner and induced formation of approximately half of the thiobarbituric acid reactive substances (TBARS), an index of lipid peroxidation, compared to that with free VOAspi in solution. The unloaded PßPL lm did not generate cytotoxicity, as evaluated by cell growth and TBARS. Thus, the polymer-embedded VOAspi retained the antiproliferative effects showing lower cytotoxicity than the free drug. Results with VOAspi–PßPL lms suggest that this delivery system may have promising biomedical and therapeutic applications.Facultad de Ciencias Exacta

Interaction studies of mixed matrices of chitosanpoly-ε-caprolactone and alendronate for bone tissue engineering

Tissue engineering actual tendencies leads to the development of biocompatible matrices with accurate physical and mechanical properties in bone reconstruction. As a regeneration of a new tissue is achieved, the scaffold is no longer needed and so it is reasonable to use biodegradable scaffolds. The rate of degradation must be in parallel with the tissue regeneration, and is very important to provide long term construct biocompatibility, because only natural tissue will remain in the body–a neo-organ. In this context one of the most common compound used is the natural polymer chitosan, whose mechanical properties can be improved by adding synthetic polymers. The great interest in this macromolecule is due to its proved biocompatibility and biodegradation properties. Matrix also requires the capacity to transport osteogenic agents which enhance bone regeneration. Bisphosphonates are a new class of synthetic compounds structurally related to pyrophosphate, an endogenous modulator in homeostasis of calcium, and they are clinically used for various metabolic bone disorders such as Paget’s disease, hypercalcemia of malignancy, bone metastasis and osteoporosis. The reduced targetability of some bisphosphonates in relationship to the dose increased and its hepatosplenic accumulation has been reported. It is due to high precipitability with divalent ions in the circulation in blood plasma, which may be taken up by reticuloendothelial system as foreign substances. Therefore, new drug delivery systems are needed to overcome these problems. The aim of our work is the development of a scaffold for tissue engineering based in chitosan/poly-ε-caprolactone blend which contains an adequate concentration of alendronate (a nitrogen bisphosphonate) for osteoblastic bone growth without toxic effects.Facultad de Ciencias Exacta

A vanadium/aspirin complex controlled release using a poly(ß-propiolactone) film : Effects on osteosarcoma cells

A delivery system for vanadium was developed using poly(ß-propiolactone)(PßPL) films. The release kinetics of a complex of vanadium (IV) with aspirin (VOAspi) was evaluated with lms prepared from polymers of different molecular weights, as well as with variable drug load. A sustained release of vanadium over 7 days was achieved. The drug release kinetics depends on contributions from two factors: (a) diffusion of the drug; and (b) erosion of the PßPL lm. The experimental data at an early stage of release were tted with a diffusion model, which allowed determination of the diffusion coef cient of the drug. VOAspi does not show strong interaction with the polymer, as demonstrated by the low apparent partition coef cient (approximately 10-2). UMR106 osteosarcoma cells were used as a model to evaluate the anticarcinogenic effects of the VOAspi released from the PßPL lm. VOAspi–PßPL lm inhibited cell proliferation in a dose-response manner and induced formation of approximately half of the thiobarbituric acid reactive substances (TBARS), an index of lipid peroxidation, compared to that with free VOAspi in solution. The unloaded PßPL lm did not generate cytotoxicity, as evaluated by cell growth and TBARS. Thus, the polymer-embedded VOAspi retained the antiproliferative effects showing lower cytotoxicity than the free drug. Results with VOAspi–PßPL lms suggest that this delivery system may have promising biomedical and therapeutic applications.Facultad de Ciencias Exacta

A vanadium / aspirin complex controlled release using a poly(ß-propiolactone) lm.

A delivery system for vanadiumwas developed using poly(¯-propiolactone)(P¯PL) lms. The release kinetics of a complex of vanadium (IV) with aspirin (VOAspi) was evaluated with lms prepared from polymers of differentmolecularweights, as well as with variable drug load. A sustained release of vanadium over 7 days was achieved. The drug release kinetics depends on contributions from two factors: (a) diffusion of the drug; and (b) erosion of the P¯PL lm. The experimental data at an early stage of release were tted with a diffusion model, which allowed determination of the diffusion coef cient of the drug. VOAspi does not show strong interaction with the polymer, as demonstrated by the low apparent partition coef cient (approximately 10¡2). UMR106 osteosarcoma cells were used as a model to evaluate the anticarcinogenic effects of the VOAspi released from the P¯PL lm. VOAspi–P¯PL lm inhibited cell proliferation in a dose-response manner and induced formation of approximately half of the thiobarbituric acid reactive substances (TBARS), an index of lipid peroxidation, compared to that with free VOAspi in solution. The unloaded P¯PL lm did not generate cytotoxicity, as evaluated by cell growth and TBARS. Thus, the polymer-embedded VOAspi retained the antiproliferative effects showing lower cytotoxicity than the free drug. Results with VOAspi–P¯PL lms suggest that this delivery system may have promising biomedical and therapeutic applications

Interaction studies of mixed matrices of chitosanpoly-ε-caprolactone and alendronate for bone tissue engineering

Tissue engineering actual tendencies leads to the development of biocompatible matrices with accurate physical and mechanical properties in bone reconstruction. As a regeneration of a new tissue is achieved, the scaffold is no longer needed and so it is reasonable to use biodegradable scaffolds. The rate of degradation must be in parallel with the tissue regeneration, and is very important to provide long term construct biocompatibility, because only natural tissue will remain in the body–a neo-organ. In this context one of the most common compound used is the natural polymer chitosan, whose mechanical properties can be improved by adding synthetic polymers. The great interest in this macromolecule is due to its proved biocompatibility and biodegradation properties. Matrix also requires the capacity to transport osteogenic agents which enhance bone regeneration. Bisphosphonates are a new class of synthetic compounds structurally related to pyrophosphate, an endogenous modulator in homeostasis of calcium, and they are clinically used for various metabolic bone disorders such as Paget’s disease, hypercalcemia of malignancy, bone metastasis and osteoporosis. The reduced targetability of some bisphosphonates in relationship to the dose increased and its hepatosplenic accumulation has been reported. It is due to high precipitability with divalent ions in the circulation in blood plasma, which may be taken up by reticuloendothelial system as foreign substances. Therefore, new drug delivery systems are needed to overcome these problems. The aim of our work is the development of a scaffold for tissue engineering based in chitosan/poly-ε-caprolactone blend which contains an adequate concentration of alendronate (a nitrogen bisphosphonate) for osteoblastic bone growth without toxic effects.Facultad de Ciencias Exacta

Propiedades biológicas de matrices porosas y no porosas de PCL/PFIP

Actualmente existe un alto interés en el estudio de polímeros sintéticos biodegradables para su aplicación como andamiajes biocompatibles en distintas áreas de ingeniería de tejidos. Poli(e-caprolactona) (PCL) y poli(diisopropilfumarato) (PDIPF) han demostrado ser buenos sustratos para la adhesión, el crecimiento y la diferenciación de dos líneas de células osteoblásticas, MC3T3E1 derivadas de células de calvaria ratón y UMR106 osteosarcoma de rata, sugiriendo que estos polímeros pueden ser útiles en la regeneración de tejido óseo. Para obtener un material con buenas propiedades mecánicas y una tasa de degradación intermedia entre ambos homopolímeros se ha preparado una mezcla de PCL y PDIPF compatibilizada por ultrasonido de alta intensidad. Esta mezcla ha demostrado poseer mejores propiedades mecánicas y mayor biocompatibilidad que los homopolímeros correspondientes. El objetivo de este trabajo es evaluar la actividad de células UMR106 frente a matrices porosas y no porosas de la mezcla de PCL-PFIP compatibilizadas. Las matrices porosas se obtuvieron mediante electrospraying de una solución de la mezcla en cloroformo. Las matrices no porosas se obtuvieron por casting de una solución en cloroformo. Las películas obtenidas se evaluaron por SEM y microscopia óptica, usando el software “Image J” para caracterizarlas morfológicamente. En ambas matrices se realizaron ensayos de adhesión (a 1h), proliferación (a 24 h) y actividad de Fosfatasa Alcalina (ALP) (a 24 y 48 h, control: superficie de placa de cultivo). La técnica de electrospraying permitió la obtención de matrices porosas formadas por microgotas tal como se observa mediante SEM. La adhesión y proliferación y la actividad de ALP de las células crecidas sobre las películas aumento significativamente sobre la matriz porosa respecto a la matriz no porosa. El aumento del área superficial proporcionada por la estructura porosa incrementó los marcadores de actividad celular