ß-TCP/S53P4 Scaffolds Obtained by Gel Casting: Synthesis, Properties, and Biomedical Applications.

The objective of this study was to investigate the osteogenic and antimicrobial effect of bioactive glass S53P4 incorporated into ß-tricalcium phosphate (ß-TCP) scaffolds in vitro and the bone neoformation in vivo. ß-TCP and ß-TCP/S53P4 scaffolds were prepared by the gel casting method. Samples were morphologically and physically characterized through X-ray diffraction (XRD) and scanning electron microscope (SEM). In vitro tests were performed using MG63 cells. American Type Culture Collection reference strains were used to determine the scaffold's antimicrobial potential. Defects were created in the tibia of New Zealand rabbits and filled with experimental scaffolds. The incorporation of S53P4 bioglass promotes significant changes in the crystalline phases formed and in the morphology of the surface of the scaffolds. The ß-TCP/S53P4 scaffolds did not demonstrate an in vitro cytotoxic effect, presented similar alkaline phosphatase activity, and induced a significantly higher protein amount when compared to ß-TCP. The expression of Itg ß1 in the ß-TCP scaffold was higher than in the ß-TCP/S53P4, and there was higher expression of Col-1 in the ß-TCP/S53P4 group. Higher bone formation and antimicrobial activity were observed in the ß-TCP/S53P4 group. The results confirm the osteogenic capacity of ß-TCP ceramics and suggest that, after bioactive glass S53P4 incorporation, it can prevent microbial infections, demonstrating to be an excellent biomaterial for application in bone tissue engineering.

Regeneração óssea induzida por scaffold ß-TCP/S53P4 produzido por gel casting: estudo in vitro e in vivo / Bone regeneration induced by ß-TCP/S53P4 scaffolds produced by gel casting: in vitro and in vivo study

Os materiais biocerâmicos são promissores em cirurgias de substituição óssea, tanto para aplicações odontológicas quanto ortopédicas. Estes materiais apresentam excelente compatibilidade biológica, osteocondutividade, degradação, além de exibirem atividade antimicrobiana. Neste presente trabalho, o objetivo foi avaliar in vitro a efetividade de scaffolds ß-fosfato tricálcico (ß-TCP) incorporado com biovidro (S53P4), produzidos por meio do processo de gel casting, na atividade celular, diferenciação osteoblástica e ação antibacteriana sobre biofilmes monotípicos, e avaliar in vivo seu efeito sobre a neoformação óssea. Os scaffolds foram confeccionados com diferentes materiais: a) ß-TCP; b) ß-TCP incorporado com biovidro. Na etapa in vitro, foram realizados os testes de MTT, proteína total, atividade de fosfatase alcalina, nódulos de mineralização, interação celular e expressão dos genes relacionados à osteogênese por RT-PCR. Na etapa in vivo, dois scaffolds de cada biomaterial foram implantados nas tíbias direita e esquerda de coelhos. Após 21 dias, os animais foram eutanasiados e a neoformação óssea foi avaliada por meio de análise histológica e análise histomorfométrica. Por fim, avaliou a formação de biofilmes em cepas de Candida albicans, Pseudomonas aeruginosa e Staphylococcus aureus. Os resultados in vitro, mostraram que os scaffolds ß-TCP/S53P4 não apresentaram efeito citotóxico e permitiram a interação de células de aspecto alongado sobre os scaffolds. Na avaliação da proteína total os scaffolds ß-TCP/S53P4 apresentaram valores mais altos, sendo significativamente maior em comparação ao ß-TCP (p<0,05) no período de 7 dias. Na atividade de fosfatase alcalina, os scaffolds foram semelhantes estatisticamente (p>0,05). Na quantificação de nódulos de mineralização, os scaffolds ß-TCP/S53P4 expressaram maior quantidade de nódulos de mineralização com diferença estatística significativa (p<0,05) com os scaffolds ß-TCP. No período de 7 dias, os genes osteopontina (Osp), fator relacionado ao Runt (Runx2), osteocalcina (Bglap), fator estimulador de colônias de macrófagos (M-csf), prostaglandina E2 (PgE2), osteonectina (Osn) e fator de crescimento de transformador Beta (Tgf-ß1) foram expressos em todos os scaffolds, sem diferença estatística entre os grupos (p>0,05). Contudo a expressão de integrina ß1 (Itg ß1) no scaffold ß-TCP foi maior do que no scaffold ß-TCP/S53P4, diferindo estatisticamente (p<0,05), houve maior expressão de colágeno I (Col-1) em ß-TCP/S53P4 com diferença estatística (p<0,05). Os defeitos preenchidos por ß-TCP/S53P4 tiveram maior formação e preenchimento por tecido ósseo neoformado (p<0,05) conforme a análise histomorfométrica. ß-TCP/S53P4 inibiu o crescimento bacteriano e fúngico em comparação ao ß-TCP (p<0,05). Desse modo, os resultados confirmam a capacidade osteogênica da cerâmica ß-TCP e sugere que após a incorporação do biovidro S53P4, pode reduzir infecções microbianas. O novo biomaterial demonstrou-se um excelente material para aplicação na engenharia de tecido ósseo.

Bioceramic materials are promising in bone replacement surgeries, both for dental and orthopedic applications. These materials have excellent biological compatibility, osteoconductivity, degradation, in addition to exhibiting antimicrobial activity. The objective of this study was to investigate the effects of bioglass (S53P4) incorporated into ß-tricalcium phosphate (ß-TCP) scaffolds on cell activity, osteoblast differentiation and antibacterial activity in monotypic biofilms in vitro, and to evaluate the influence of this new biomaterial on in vivo bone neoformation. The scaffolds were made with different materials: a) ß-TCP; b) ß-TCP incorporated with bioglass. MTT test, total protein, alkaline phosphatase activity, mineralization nodules, cell interaction and expression of genes related to osteogenesis by RT-PCR were performed. Two scaffolds of each biomaterial were implanted in the right and left tibiae of rabbits. After 21 days, the animals were euthanized and bone neoformation was evaluated through histological and histomorphometric analysis. Finally, the formation of biofilms in Candida albicans, Pseudomonas aeruginosa and Staphylococcus aureus strains. The in vitro results showed that the ß-TCP/S53P4 scaffolds did not show cytotoxic effect and allowed the interaction of elongated cells on the scaffolds. In the evaluation of total protein, the ß-TCP/S53P4 scaffolds showed better results, being significantly higher compared to ß-TCP (p<0.05) in the 7-day period. In alkaline phosphatase activity, the scaffolds were statistically similar (p>0.05). In the quantification of mineralization nodules, the ß-TCP/S53P4 scaffolds expressed a greater amount of mineralization nodules with a significant difference (p<0.05) with the ß-TCP scaffolds. Within 7 days, genes Osp, Runx2, Bglap, M-csf, PgE2, Osn and Tgf-ß1 were expressed in all scaffolds, with no significant difference between groups (p>0.05). The expression of Itg ß1 in the ß-TCP scaffold was higher than in the ß-TCP/S53P4 scaffold, differing statistically (p<0.05), but there was a higher expression of Col-1 in ß-TCP/S53P4 with statistical difference (p<0.05). In the histological analysis, neoformed bone tissue filling the defect was observed in both scaffolds, but greater formation was observed in ß-TCP/S53P4 (p<0.05). ßTCP/S53P4 inhibited bacterial and fungal growth compared to ß-TCP (p<0.05). Thus, the results confirm the osteogenic capacity of the ß-TCP ceramic and suggest that after its incorporation into the S53P4 bioglass, it can prevent microbial infections. An excellent biomaterial for application in bone tissue engineering

Synergistic effect of adding bioglass and carbon nanotubes on poly (lactic acid) porous membranes for guided bone regeneration.

Polymer membranes have been widely used in guided bone regeneration (GBR), especially when it comes to their use in dentistry. Poly (lactic acid) (PLA) have good mechanical properties such as flexibility, which allows the material to be moldable and also has biocompatibility and biodegradation. Besides that, bioglass (BG) incorporated into the polymer matrix can promote osteoinduction properties and osteoconduction properties to the polymer-ceramic biocomposite. The membranes are also required to exhibit antimicrobial activity to prevent or control the proliferation of pathogenic microorganisms, and the addition of carbon nanotubes (CNT) can assist in this property. The porous membranes of PLA with the addition of different contents of BG and CNT were obtained by solvent casting in controlled humidity method, and the synergistic effect of the addition of both fillers were investigated. The membranes showed pores (3-11 µm) on their surface. The addition of 5 wt% BG causes an increase in the surface porosity and bioactivity properties of the PLA. The agar diffusion test showed antimicrobial activity in the membranes with addition of CNT. In vitro results showed that the porous membranes were not cytotoxic and allowed cell activity and differentiation. Thus, BG collaborated to increase biological activity while CNT contributed to microbial activity, creating a synergistic effect on PLA porous membranes, being this effect more evident for PLA/5BG/1.0CNT. These results indicated a promising use of this new biomaterial for the production of porous membranes for GBR.

Membranas porosas de polímeros de PLA e PCL: estudo in vitro microbiológico e da osteogênese / Porous membranes of PLA and PCL polymers: in vitro microbiological study and osteogenesis

O objetivo do trabalho foi analisar in vitro o comportamento de osteoblastos MG-63 em contato com membranas reabsorvíveis porosas de poli (ácido lático) (PLA) e policaprolactona (PCL), incorporadas com fibras cerâmicas de silicato de cálcio (CaSiO3), visando aplicação na regeneração óssea guiada. Foram utilizados seis grupos experimentais, a partir da concentração do teor de CaSiO3, PLA P; PLA + 5% CaSiO3; PLA + 10% CaSiO3; PCL P; PCL + 5% CaSiO3; PCL + 10% CaSiO3, e o grupo controle. Foram avaliadas viabilidade celular, genotoxicidade; produção de proteína total, atividade de fosfatase alcalina e formação matriz mineralizada. Bem como, a influência das membranas poliméricas na redução de biofilmes monotípicos de Enterococcus faecalis quando associadas ou não a solução de gluconato de clorexidina a 0,12%. Os dados foram analisados por ANOVA e Tukey (p<0.05%). Os resultados mostraram que nenhum grupo experimental foi citotóxico, mas os grupos PCL P, PLA 5%, PLA P e PCL 10% apresentaram maior viabilidade celular com diferença estatística dos grupos PCL 5% e PLA 10% (p<0.05). No teste de genotoxicidade os grupos experimentais não foram genotóxicos, já que apresentaram números de micronúcleos semelhantes ou menores ao grupo controle (p>0.05). Todos os grupos experimentais apresentaram proteína total e atividade de fosfatase alcalina semelhante estatisticamente ao controle (p>0.05) e permitiram a formação de matriz mineralizada. Com relação à redução de biofilme, os grupos experimentais PCL P e PCL 10% apresentaram maior redução de biofilme para Enterococcus faecalis com diferença estatística (p<0.05) do PCL 5% e do controle. Nos grupos experimentais de PLA, todas as membranas promoveram maior redução de biofilme com diferença estatística (p<0.05) do grupo controle. Entretanto quando os grupos experimentais de PCL, bem como de PLA foram tratados com gluconato de clorexidina, observou-se redução do biofilme em todos os grupos, sem diferença estatística do grupo controle (p>0.05). Concluiu-se que as membranas poliméricas são biomateriais adequados para o uso em regeneração óssea guiada. Da mesma maneira, pareceram contribuir para a osteogênese e redução de biofilme de Enterococcus faecalis(AU)

The objective of this study was to analyze the behavior of MG-63 osteoblasts in contact with poly (lactic acid) (PLA) and polycaprolactone (PCL) porous resorbable membranes, incorporated with calcium silicate ceramic fibers (CaSiO3), aiming application in bone regeneration guided in periapical lesions. Six experimental groups were used, from the concentration of CaSiO3, PLA P; PLA + 5% CaSiO3; PLA + 10% CaSiO3; PCL P; PCL + 5% CaSiO3; PCL + 10% CaSiO3, and the control group. Cell viability, genotoxicity; total protein production, alkaline phosphatase activity and mineralized matrix formation. As well as the influence of polymer membranes on the reduction of monotypic biofilms of Enterococcus faecalis when associated with 0.1% chlorhexidine gluconate solution. Data were analyzed by ANOVA and Tukey (p <0.05%). The results showed that no experimental group was cytotoxic, but the PCL P, PLA 5%, PLA P and PCL 10% groups presented higher cell viability with a statistical difference between PCL 5% and PLA 10% (p <0.05). In the genotoxicity test, the experimental groups were not genotoxic, since they had similar or smaller numbers of micronuclei to the control group (p> 0.05). All experimental groups presented total protein and alkaline phosphatase activity statistically similar to the control (p> 0.05) and allowed the formation of mineralized matrix. Regarding the biofilm reduction, the PCL P and PCL 10% experimental groups showed a higher biofilm reduction for Enterococcus faecalis with a statistical difference (p <0.05) in PCL 5% and control. In the PLA experimental groups, all membranes promoted a higher biofilm reduction with a statistical difference (p <0.05) in the control group. However, when the PCL and PLA groups were treated with chlorhexidine gluconate, biofilm reduction was observed in all groups, with no statistical difference in the control group (p> 0.05). It was concluded that the polymer membranes are biomaterials suitable for use in guided bone regeneration. In the same way, they appeared to contribute to the osteogenesis and biofilm reduction of Enterococcus faecalis(AU)