Navegando por Autor "Santos, Kennedy Wallace dos"

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    Biocomposite macrospheres based on strontium-bioactive glass for application as bone fillers
    (American Chemical Society) Oliveira, Ivone Regina de; Gonçalves, Isabela dos Santos; Santos, Kennedy Wallace dos; Lança, Maria Carmo; Vieira, Tânia; Silva, Jorge Carvalho; Cengiz, Ibrahim Fatih; Reis, Rui Luís; Oliveira, Joaquim Miguel; Borges, João Paulo Miranda Ribeiro
    Traditional bioactive glass powders are typically composed of irregular particles that can be packed into dense configurations presenting low interconnectivity, which can limit bone ingrowth. The use of novel biocomposite sphere formulations comprising bioactive factors as bone fillers are most advantageous, as it simultaneously allows for packing the particles in a 3-dimensional manner to achieve an adequate interconnected porosity, enhanced biological performance, and ultimately a superior new bone formation. In this work, we develop and characterize novel biocomposite macrospheres of Sr-bioactive glass using sodium alginate, polylactic acid (PLA), and chitosan (CH) as encapsulating materials for finding applications as bone fillers. The biocomposite macrospheres that were obtained using PLA have a larger size distribution and higher porosity and an interconnectivity of 99.7%. Loose apatite particles were observed on the surface of macrospheres prepared with alginate and CH by means of soaking into a simulated body fluid (SBF) for 7 days. A dense apatite layer was formed on the biocomposite macrospheres’ surface produced with PLA, which served to protect PLA from degradation. In vitro investigations demonstrated that biocomposite macrospheres had minimal cytotoxic effects on a human osteosarcoma cell line (SaOS-2 cells). However, the accelerated degradation of PLA due to the degradation of bioactive glass may account for the observed decrease in SaOS-2 cells viability. Among the biocomposite macrospheres, those composed of PLA exhibited the most promising characteristics for their potential use as fillers in bone tissue repair applications.
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    Development and characterization of ceramic-polymeric hybrid scaffolds for bone regeneration: incorporating of bioactive glass BG-58S into PDLLA matrix
    (Taylor & Francis) Aguiar, Veronica Cristina Pêgo Fiebig; Bezerra, Rayssa do Nascimento; Santos, Kennedy Wallace dos; Gonçalves, Isabela dos Santos; Costa, Karen Julie Santos Grancianinov; Lauda, Diogo Ponte; Campos, Tiago Moreira Bastos; Prado, Renata Falchete do; Vasconcellos, Luana Marotta Reis de; Oliveira, Ivone Regina de
    In recent years, there has been a notable surge of interest in hybrid materials within the biomedical field, particularly for applications in bone repair and regeneration. Ceramic-polymeric hybrid scaffolds have shown promising outcomes. This study aimed to synthesize bioactive glass (BG-58S) for integration into a bioresorbable poly- meric matrix based on PDLLA, aiming to create a bioactive scaffold featuring stable pH levels. The synthesis involved a thermally induced phase separation process followed by lyophilization to ensure an appropriate porous structure. BG-58S characterization revealed vitreous, bioactive, and mesoporous structural properties. The scaffolds were analyzed for morphology, interconnectivity, chemical groups, porosity and pore size distribution, zeta potential, pH, in vitro degradation, as well as cell viability tests, total protein content and mineralization nodule production. The PDLLA scaffold displayed a homogeneous morphology with interconnected mac- ropores, while the hybrid scaffold exhibited a heterogeneous mor- phology with smaller diameter pores due to BG-58S filling. The hybrid scaffold also demonstrated a pH buffering effect on the polymer surface. In addition to structural characteristics, degrada- tion tests indicated that by incorporating BG-58S modified the acidic degradation of the polymer, allowing for increased total pro- tein production and the formation of mineralization nodules, indi- cating a positive influence on cell culture.
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    Estudo e otimização da produção de Vidro Bioativo (BG) por fusão
    (2022) Santos, Kennedy Wallace dos; Costa, Karen Julie Santos Grancianinov; Lauda, Diogo Ponte; Oliveira, Ivone Regina de
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    Estudo e otimização da produção de vidro bioativo (BG) por fusão
    (2022) Santos, Kennedy Wallace dos; Costa, Karen Julie Santos Grancianinov; Lauda, Diogo Ponte
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    Estudo e otimização da produção de vidro bioativo 45S5 por fusão
    (2022-12-09) Oliveira, Ivone Regina de; Ortega, Fernando dos Santos; Carvalho, Paulo Henrique Salles de; Campos, Tiago Moreira Bastos; Cardenas, José Edgar Valdivia; Santos, Kennedy Wallace dos; São José dos Campos
    O tecido ósseo apresenta uma habilidade rara de regeneração e reparação. Contudo, em algumas situações, devido à extensão do defeito, devido a doenças ou traumas, o tecido ósseo não se regenera completamente, sendo necessário o uso de enxerto ósseo. Entre as biocerâmicas, os vidros bioativos (BG) apresentam potencial para osteocondução e osteoindução. Uma compreensão das suas propriedades e método de produção permite o desenvolvimento de melhores materiais para a regeneração do tecido ósseo. A luz disto, o presente trabalho teve como objetivo estudar e otimizar a produção do BG-45S5 pelo método de fusão, por intermédio da variação de diferentes parâmetros. Parâmetros estes que controlam esse processo, visando a otimização do processo de produção de um produto para uso em reparo e reconstrução óssea. Inicialmente foi estudado o processo de fusão variando diferentes parâmetros como, tipo de cadinho, ambiente de vertimento, precursor de fósforo e tempo de fusão, quanto às características e propriedades do BG obtido como estrutura cristalina, grupos químicos característicos, distribuição de tamanho de partículas, temperatura de transição vítrea e composição química. O BG selecionado foi posteriormente caracterizado quanto à bioatividade, comportamento em cultivo celular e ensaios preliminares in vivo e, por fim, foi estudada a forma de apresentação do produto desenvolvido. Os materiais vertidos em molde de grafite ou aço apresentaram tamanhos de partículas mais adequados para aplicação na forma de grânulos. O uso de cadinho de platina resultou em composição química mais próxima à composição nominal. O uso de fosfato de sódio resultou em maiores temperaturas de transição vítrea e cristalização apresentando vantagens quanto à estabilidade térmica se comparado ao pentóxido de fósforo. O material produzido com fosfato de sódio, 1 hora de fusão (FS1), também apresentou composição mais próxima à nominal e bioatividade comprovada pelo recobrimento superficial em SBF. Esse material também apresentou a maior quantia de nódulos de mineralização, obtendo diferença estatística em relação a hidroxiapatita, o que mostra sua capacidade de diferenciação celular das células mesenquimais em osteoblastos. O estudo microbiológico durante a fase de produção e embalagem do produto indicou a dose de validação de esterilização por radiação gama de 1,7 kGy seguido da irradiação com 15 kGy, para garantia de esterilidade com um nível de segurança de 10 elevado a menos 6.
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    Properties of strontium-containing BG 58S produced by alkali-mediated sol-gel process
    (Elsevier) Oliveira, Ivone Regina de; Barbosa, Ana Maria; Santos, Kennedy Wallace dos; Lança, Maria Carmo; Lima, Maria Margarida Rolim Augusto; Vieira, Tânia; Silva, Jorge Carvalho; Borges, João Paulo
    Among many bioglass (BG) compositions, gel-BG 58S has been indicated in the literature for applications as bone graft due to its promising use to repair bone defects. However, its physical and biological properties also depend of choice of precursors. The use of phosphoric acid as a source of P2O5 changes the thermal behavior of BG and in the presence of HNO3 increases the rate of hydrolysis and reduces the size of sol particles, thus influencing the surface area and in turn rate of apatite formation of bioactive glasses. In addition, the addition of concentrated NH4OH decreases the gelation time and new bioactive materials have been produced using Ca/Sr substitution in BG compositions. Thus, the aim of this work was to prepare BG 58S by the sol-gel technique at room temperature using phosphoric acid (PA) as the phosphorus precursor compared with conventional precursor triethylphosphate (TEP) and to evaluate the effect of the adding NH4OH (1 or 2 M) as gelation catalyst in order to select the better route to Sr incorporate. The products were characterized using XRD, FTIR and confocal Raman spectroscopy. The composition prepared with 1M NH4OH (PA-1M) presented more evidence of NBO bonds, and the absence of crystallinity. Thus, BG 58S-5 wt% Sr was prepared using the alkali-mediated sol-gel process (PA-1M) and characterized as the techniques mentioned in addition to bioactivity and cytotoxicity assays. Both compositions showed the development of a layer of apatite when treated in a simulated body fluid (SBF). Strontium composition showed higher cell viability and more evidence of calcium phosphate formation while calcium carbonate is mainly identified in strontium-free composition.
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    Synthesis and characterization of photosensitive gelatin-based hydrogels for photodynamic therapy in HeLa-CCL2 cell line
    (Elsevier) Ambrósio, Jéssica Aparecida Ribeiro; Pinto, Bruna Cristina dos Santos; Marmo, Vitor Luca Moura; Santos, Kennedy Wallace dos; Beltrame Junior, Milton; Pinto, Juliana Guerra; Ferreira-Strixino, Juliana; Raniero, Leandro José; Simioni, Andreza Ribeiro
    Background: Hydrogel systems are increasingly gaining visibility involving biomedicine, tissue engineering, environmental treatments, and drug delivery systems. These systems have a three-dimensional network composition and high-water absorption capacity, are biocompatible, allowing them to become an option as photosensitizer carriers (PS) for applications in Photodynamic Therapy (PDT) protocols. Methods: A nanohydrogel system (NAHI), encapsulated with chloroaluminium phthalocyanine (ClAlPc) was synthesized for drug delivery.. NAHI was synthesized using gelatin as based polymer by the chemical cross-linking technique. The drug was encapsulated by immersing the hydrogel in a 1.0 mg.mL􀀀 1 ClAlPc solution. The external morphology of NAHI was examined by scanning electron microscopy (SEM). The degree of swelling of the synthesized system was evaluated to determine the water absorption potential. The produced nanohydrogel system was characterized by photochemical, photophysical and photobiologial studies. Results: The images from the SEM analysis showed the presence of three-dimensional networks in the formulation. The swelling test demonstrated that the nanohydrogel freeze-drying process increases its water holding capacity. All spectroscopic results showed excellent photophysical parameters of the drug studied when served in the NAHI system. The incorporation efficiency was 70%. The results of trypan blue exclusion test have shown significant reduction (p < 0.05) in the cell viability for all groups treated with PDT, in all concentrations tested. In HeLa cells, PDT mediated by 0,5 mg.mL􀀀 1 ClAlPc encapsulated in NAHI showed a decrease in survival close to 95%. In the internalization cell study was possible to observe the internalization of phthalocyanine after one hour of incubation, at 37 ◦C, with the the accumulation of PS in the cytoplasm and inside the nucleus at both concentrations tested. Conclusions: Given the peculiar performance of the selected system, the resulting nanohydrogel is a versatile platform and display potential applications as controlled delivery systems of photosensitizer for photodynamic therapy application.