This study evaluated the biocompatibility of Bio- silicate V R scaffolds by means of histopatholo... more This study evaluated the biocompatibility of Bio- silicate V R scaffolds by means of histopathological, cytotoxicity, and genotoxicity analysis. The histopathologic analysis of the biomaterial was performed using 65 male rats, distributed into the groups: control and Biosilicate V R , evaluated at 7, 15, 30, 45, and 60 days after implantation. The cytotoxicity analy- sis was performed by the methyl thiazolyl tetrazolium (MTT) assay, with various concentrations of extracts from the bio- material in culture of osteoblasts and fibroblasts after 24, 72, and 120 h. The genotoxicity analysis (comet assay) was per- formed in osteoblasts and fibroblasts after contact with the biomaterial during 24, 72, and 96 h. In the histopathology analysis, we observed a foreign body reaction, characterized by the presence of granulation tissue after 7 days of implan- tation of the biomaterial, and fibrosis connective tissue and multinucleated giant cells for longer periods. In the cytotoxic- ity analysi...
Magnetic hyperthermia (MHT) is a therapy that uses the heat generated by a magnetic material for ... more Magnetic hyperthermia (MHT) is a therapy that uses the heat generated by a magnetic material for cancer treatment. Magnetite nanoparticles are the most used materials in MHT. However, magnetite has a high Curie temperature (Tc~580 °C), and its use may generate local superheating. To overcome this problem, strontium-doped lanthanum manganite could replace magnetite because it shows a Tc near the ideal range (42–45 °C). In this study, we developed a smart composite formed by an F18 bioactive glass matrix with different amounts of Lanthanum-Strontium Manganite (LSM) powder (5, 10, 20, and 30 wt.% LSM). The effect of LSM addition was analyzed in terms of sinterability, magnetic properties, heating ability under a magnetic field, and in vitro bioactivity. The saturation magnetization (Ms) and remanent magnetization (Mr) increased by the LSM content, the confinement of LSM particles within the bioactive glass matrix also caused an increase in Tc. Calorimetry evaluation revealed a temperat...
The Ti6Al4V alloy is usually employed as a biomaterial, however, when in use, exhibits a few draw... more The Ti6Al4V alloy is usually employed as a biomaterial, however, when in use, exhibits a few drawbacks such as corrosion, caused by the release of aluminum and vanadium ions besides the bioinert behavior. Bioactive coatings offer a barrier effect and bioactivity, promoting biocompatibility and osseointegration processes. The present work aims to study the biocompatibility behavior of a bioglass-containing silane film deposited on a titanium alloy (Ti6Al4V) substrate. The effect of the surface roughness of the metallic substrate was also evaluated. Film/substrate systems were characterized as their morphological, chemical, physical, electrochemical behavior, and cell cytotoxicity and cell viability. The main results pointed out that silane films augment corrosion resistance of titanium alloy substrates. The biological results indicated a growth of osteoblast cells (MG-63), for all the test conditions. The bioglass film deposited on the ground substrate exhibits the highest cell density.
The development of bioactive glass-ceramic materials has been a topic of great interest aiming at... more The development of bioactive glass-ceramic materials has been a topic of great interest aiming at enhancing the mechanical strength of traditional bioactive scaffolds. In the present study, we test and demonstrate the use of Biosilicate R glass-ceramic powder to fabricate bone scaffolds by the foam replica method. Scaffolds possessing the main requirements for use in bone tissue engineering (95% porosity, 200‐500µm pore size) were successfully produced. Gelatine coating was investigated as a simple approach to increase the mechanical competence of the scaffolds. The gelatine coating did not affect the interconnectivity of the pores and did not significantly affect the bioactivity of the Biosilicate R scaffold. The gelatine coating significantly improved the compressive strength (i.e. 0.80±0.05MPa of coated versus 0.06±0.01MPa of uncoated scaffolds) of the Biosilicate R scaffold. The combination of Biosilicate R glass-ceramic and gelatine is attractive for producing novel scaffolds f...
Biosilicate® glass-ceramics are among the most valid alternatives to 45S5 Bioglass. They combine ... more Biosilicate® glass-ceramics are among the most valid alternatives to 45S5 Bioglass. They combine a similar bioactivity and bioresorbability as the 45S5 with superior mechanical strength, owing to the crystallization of a Na–Ca silicate phase. This crystallization may be experienced upon viscous flow sintering of fine glass powders, thus configuring a sinter-crystallization process. As crystallization is seldom complete, sintering can also be applied to semicrystalline powders. The sintering/crystallization combination may be exploited for shaping highly porous bodies, to be used as scaffolds for bone tissue engineering, in the form of foams. The present study aims at exploring a gel-casting process, based on the room temperature foaming of powders suspended in a “weakly alkaline” (1 M NaOH) aqueous solution, followed by sintering at 1,000°C. The gelation of suspensions is attributed to the formation of hydrated compounds, later decomposed upon firing. Amorphous powders provided more...
This study evaluatedthe gene expression profile ofthe human adipose-derived stem cells (hASCs)gro... more This study evaluatedthe gene expression profile ofthe human adipose-derived stem cells (hASCs)grown onthe Biosilicate®/F18 glass (BioS-2P/F18) scaffolds. hASCswere cultured using the osteogenic medium (control),the scaffolds, and their ionic extract. We observed that ALP activity was higher inhASCs grown onthe BioS-2P/F18 scaffolds than inhASCs cultured withtheionic extractorthe osteogenic mediumon day 14. Moreover, the dissolution product group and the control exhibited deposited calcium, which peaked on day 21. Gene expression profiles of cell cultured using the BioS-2P/F18 scaffolds and their extract wereevaluated in vitrousing the RT2 Profiler Polymerase Chain Reaction(PCR) microarray on day 21. Mineralizing tissue-associated proteins, differentiation factors, and extracellular matrix enzyme expressions were measured using quantitativePCR. The gene expression of different proteins involved inosteoblast differentiation was significantlyup-regulated inhASCsgrown on the scaffolds,especiallyBMP1, BMP2,SPP1, BMPR1B, ITGA1, ITGA2, ITGB1, SMAD1, and SMAD2, showing that both the composition and topographic features of the biomaterial could stimulate osteogenesis. This study demonstrated that gene expression of hASCs grown on the scaffold surfaceshowed significantlyincreased gene expression related tohASCs cultured with the ionic extract or the osteogenic medium, evidencing that the BioS-2P/F18 scaffoldshave asubstantial effect on cellular behavior of hASCs.
After five decades of research on bioactive glasses and glass-ceramics, these materials became of... more After five decades of research on bioactive glasses and glass-ceramics, these materials became of considerable interest due to their revolutionary potential for numerous health applications, including cancer treatment. One advantage of glass-ceramics compared with other materials – such as metallic alloys and polymers – is their capability of being highly bioactive and, if desired, containing magnetic phases. Hyperthermia (HT) is an alternative for treating cancer; the strategy is to increase the temperature of the tumor using an external magnetic field that increases the temperature of an implanted magnetic material, which works as an internal heat source. This local increase of temperature, ideally to ~43°C, could kill cancer cells in situ without damaging the healthy surrounding tissue. To achieve such goal, a material that presents a balance between proper magnetic properties and bioactivity is necessary for the safe applicability and successful performance of the HT treatment. ...
This study aimed to investigate the in vivo tissue response of the Biosilicate® scaffolds in a mo... more This study aimed to investigate the in vivo tissue response of the Biosilicate® scaffolds in a model of tibial bone defect. Sixty male Wistar rats were distributed into bone defect control group (CG) and Biosilicate® scaffold group (BG). Animals were euthanized 15, 30 and 45 days post-surgery. Stereomicroscopy, scanning electron microscopy, histopathological, immunohistochemistry and biomechanical analysis were used. Scaffolds had a total porosity of 44%, macroporosity of 15% with pore diameter of 230 μm. Higher amount of newly formed bone was observed on days 30 and 45 in BG. Immunohistochemistry analysis showed that the COX-2 expression was significantly higher on days 15 and 30 in BG compared with the CG. RUNX-2 immunoexpression was significantly higher in BG on days 15 and 45. No statistically significant difference was observed in RANKL immunoexpression in all experimental groups. BMP-9 immunoexpression was significantly upregulated in the BG on day 45. Biomechanical analysis showed a decrease in the biomechanical properties of the bone callus on days 30 and 45. The implantation of the Biosilicate® scaffolds was effective in stimulating newly bone formation and produced an increased immunoexpression of markers related to the bone repair.
This study evaluated the biocompatibility of Bio- silicate V R scaffolds by means of histopatholo... more This study evaluated the biocompatibility of Bio- silicate V R scaffolds by means of histopathological, cytotoxicity, and genotoxicity analysis. The histopathologic analysis of the biomaterial was performed using 65 male rats, distributed into the groups: control and Biosilicate V R , evaluated at 7, 15, 30, 45, and 60 days after implantation. The cytotoxicity analy- sis was performed by the methyl thiazolyl tetrazolium (MTT) assay, with various concentrations of extracts from the bio- material in culture of osteoblasts and fibroblasts after 24, 72, and 120 h. The genotoxicity analysis (comet assay) was per- formed in osteoblasts and fibroblasts after contact with the biomaterial during 24, 72, and 96 h. In the histopathology analysis, we observed a foreign body reaction, characterized by the presence of granulation tissue after 7 days of implan- tation of the biomaterial, and fibrosis connective tissue and multinucleated giant cells for longer periods. In the cytotoxic- ity analysi...
Magnetic hyperthermia (MHT) is a therapy that uses the heat generated by a magnetic material for ... more Magnetic hyperthermia (MHT) is a therapy that uses the heat generated by a magnetic material for cancer treatment. Magnetite nanoparticles are the most used materials in MHT. However, magnetite has a high Curie temperature (Tc~580 °C), and its use may generate local superheating. To overcome this problem, strontium-doped lanthanum manganite could replace magnetite because it shows a Tc near the ideal range (42–45 °C). In this study, we developed a smart composite formed by an F18 bioactive glass matrix with different amounts of Lanthanum-Strontium Manganite (LSM) powder (5, 10, 20, and 30 wt.% LSM). The effect of LSM addition was analyzed in terms of sinterability, magnetic properties, heating ability under a magnetic field, and in vitro bioactivity. The saturation magnetization (Ms) and remanent magnetization (Mr) increased by the LSM content, the confinement of LSM particles within the bioactive glass matrix also caused an increase in Tc. Calorimetry evaluation revealed a temperat...
The Ti6Al4V alloy is usually employed as a biomaterial, however, when in use, exhibits a few draw... more The Ti6Al4V alloy is usually employed as a biomaterial, however, when in use, exhibits a few drawbacks such as corrosion, caused by the release of aluminum and vanadium ions besides the bioinert behavior. Bioactive coatings offer a barrier effect and bioactivity, promoting biocompatibility and osseointegration processes. The present work aims to study the biocompatibility behavior of a bioglass-containing silane film deposited on a titanium alloy (Ti6Al4V) substrate. The effect of the surface roughness of the metallic substrate was also evaluated. Film/substrate systems were characterized as their morphological, chemical, physical, electrochemical behavior, and cell cytotoxicity and cell viability. The main results pointed out that silane films augment corrosion resistance of titanium alloy substrates. The biological results indicated a growth of osteoblast cells (MG-63), for all the test conditions. The bioglass film deposited on the ground substrate exhibits the highest cell density.
The development of bioactive glass-ceramic materials has been a topic of great interest aiming at... more The development of bioactive glass-ceramic materials has been a topic of great interest aiming at enhancing the mechanical strength of traditional bioactive scaffolds. In the present study, we test and demonstrate the use of Biosilicate R glass-ceramic powder to fabricate bone scaffolds by the foam replica method. Scaffolds possessing the main requirements for use in bone tissue engineering (95% porosity, 200‐500µm pore size) were successfully produced. Gelatine coating was investigated as a simple approach to increase the mechanical competence of the scaffolds. The gelatine coating did not affect the interconnectivity of the pores and did not significantly affect the bioactivity of the Biosilicate R scaffold. The gelatine coating significantly improved the compressive strength (i.e. 0.80±0.05MPa of coated versus 0.06±0.01MPa of uncoated scaffolds) of the Biosilicate R scaffold. The combination of Biosilicate R glass-ceramic and gelatine is attractive for producing novel scaffolds f...
Biosilicate® glass-ceramics are among the most valid alternatives to 45S5 Bioglass. They combine ... more Biosilicate® glass-ceramics are among the most valid alternatives to 45S5 Bioglass. They combine a similar bioactivity and bioresorbability as the 45S5 with superior mechanical strength, owing to the crystallization of a Na–Ca silicate phase. This crystallization may be experienced upon viscous flow sintering of fine glass powders, thus configuring a sinter-crystallization process. As crystallization is seldom complete, sintering can also be applied to semicrystalline powders. The sintering/crystallization combination may be exploited for shaping highly porous bodies, to be used as scaffolds for bone tissue engineering, in the form of foams. The present study aims at exploring a gel-casting process, based on the room temperature foaming of powders suspended in a “weakly alkaline” (1 M NaOH) aqueous solution, followed by sintering at 1,000°C. The gelation of suspensions is attributed to the formation of hydrated compounds, later decomposed upon firing. Amorphous powders provided more...
This study evaluatedthe gene expression profile ofthe human adipose-derived stem cells (hASCs)gro... more This study evaluatedthe gene expression profile ofthe human adipose-derived stem cells (hASCs)grown onthe Biosilicate®/F18 glass (BioS-2P/F18) scaffolds. hASCswere cultured using the osteogenic medium (control),the scaffolds, and their ionic extract. We observed that ALP activity was higher inhASCs grown onthe BioS-2P/F18 scaffolds than inhASCs cultured withtheionic extractorthe osteogenic mediumon day 14. Moreover, the dissolution product group and the control exhibited deposited calcium, which peaked on day 21. Gene expression profiles of cell cultured using the BioS-2P/F18 scaffolds and their extract wereevaluated in vitrousing the RT2 Profiler Polymerase Chain Reaction(PCR) microarray on day 21. Mineralizing tissue-associated proteins, differentiation factors, and extracellular matrix enzyme expressions were measured using quantitativePCR. The gene expression of different proteins involved inosteoblast differentiation was significantlyup-regulated inhASCsgrown on the scaffolds,especiallyBMP1, BMP2,SPP1, BMPR1B, ITGA1, ITGA2, ITGB1, SMAD1, and SMAD2, showing that both the composition and topographic features of the biomaterial could stimulate osteogenesis. This study demonstrated that gene expression of hASCs grown on the scaffold surfaceshowed significantlyincreased gene expression related tohASCs cultured with the ionic extract or the osteogenic medium, evidencing that the BioS-2P/F18 scaffoldshave asubstantial effect on cellular behavior of hASCs.
After five decades of research on bioactive glasses and glass-ceramics, these materials became of... more After five decades of research on bioactive glasses and glass-ceramics, these materials became of considerable interest due to their revolutionary potential for numerous health applications, including cancer treatment. One advantage of glass-ceramics compared with other materials – such as metallic alloys and polymers – is their capability of being highly bioactive and, if desired, containing magnetic phases. Hyperthermia (HT) is an alternative for treating cancer; the strategy is to increase the temperature of the tumor using an external magnetic field that increases the temperature of an implanted magnetic material, which works as an internal heat source. This local increase of temperature, ideally to ~43°C, could kill cancer cells in situ without damaging the healthy surrounding tissue. To achieve such goal, a material that presents a balance between proper magnetic properties and bioactivity is necessary for the safe applicability and successful performance of the HT treatment. ...
This study aimed to investigate the in vivo tissue response of the Biosilicate® scaffolds in a mo... more This study aimed to investigate the in vivo tissue response of the Biosilicate® scaffolds in a model of tibial bone defect. Sixty male Wistar rats were distributed into bone defect control group (CG) and Biosilicate® scaffold group (BG). Animals were euthanized 15, 30 and 45 days post-surgery. Stereomicroscopy, scanning electron microscopy, histopathological, immunohistochemistry and biomechanical analysis were used. Scaffolds had a total porosity of 44%, macroporosity of 15% with pore diameter of 230 μm. Higher amount of newly formed bone was observed on days 30 and 45 in BG. Immunohistochemistry analysis showed that the COX-2 expression was significantly higher on days 15 and 30 in BG compared with the CG. RUNX-2 immunoexpression was significantly higher in BG on days 15 and 45. No statistically significant difference was observed in RANKL immunoexpression in all experimental groups. BMP-9 immunoexpression was significantly upregulated in the BG on day 45. Biomechanical analysis showed a decrease in the biomechanical properties of the bone callus on days 30 and 45. The implantation of the Biosilicate® scaffolds was effective in stimulating newly bone formation and produced an increased immunoexpression of markers related to the bone repair.
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Papers by Murilo Crovace