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Meet The Team

With each orientation, new learning. Thank you for being part of this story. Together we are more!

Lucas R. dos Santos

Master Degree

The present work proposes to develop a novel biomaterial based on chitosan (CHT) with 0, 15, 30, 45, 60 and 75% (w/w) additions of functionalized Biosilicate® (BG), as microparticles (particle size ~3 μm), obtained by solid-state reaction, for future applications in Tissue Engineering. The composites were fabricated in the form of membranes by solvent casting. The materials were characterized in terms of composition and morphology using FTIR, XRD and optical microscopy, swelling under phosphate buffered saline (PBS) solution, wettability by sessile drop method, mechanical properties in a tensile test, in vitro bioactivity test and Cell viability by MTT assay. Besides, statistical analyses were performed in some characterization stages (ANOVA, T student, and Tukey tests), and the results were considered significantly different when p-value <0.05. The results showed that the functionalized Biosilicate® allows us to incorporate high fractions of reinforcement in composites and good dispersion of the microparticles in the chitosan matrix. The addition of BG to CHT increased the wettability of these membranes, due to high hydrophilicity of the Biosilicate microparticle. The membranes containing the BG demonstrated a lower degree of swelling when compared with pure chitosan membrane, on the other hand, better elastic modulus and tensile strength. Moreover, the results suggest that Biosilicate could ionically cross-link composites since this crosslinking generates an increase in strength and a reduction in the degree of swelling. Finally, after seven days, the membranes containing the BG induced the precipitation of bone-like apatite in simulated body fluid (SBF). Pure chitosan and composite membranes were not cytotoxicities. In conclusion, the functionalization of Biosilicate allowed developing innovative bioactive composite using high concentrations of micrometric glass-ceramic reinforcements, never before reported in the literature.


Mariana T. B. Milesi

Master Degree

Glass-ceramics based on Li2O.SiO2 system, containing lithium disilicate as a major phase, has already been used clinically as almost inert biomaterials due to good mechanical strength, although sometimes they do not have entirely satisfactory biocompatibility and biofunctionality. Therefore, bioactive Li2O.SiO2 glass-ceramics appear as a promising alternative. This study aims to evaluate the in vitro biocompatibility of three experimental groups: a base glass and glass-ceramics - containing lithium metasilicate and lithium disilicate, looking for bone repair. Samples of the three experimental groups were characterized by X-Ray Diffraction (XRD). After analyzing the phases, these materials were subjected to in vitro bioactivity and biodegradation tests as well as cytotoxicity and adhesion and proliferation in cellular medium tests. The bioactivity test evaluated the formation of hydroxycarbonate apatite (HCA) on the surface of the material after immersion in Simulated Body Fluid (SBF) for periods up to 14 days with the aid of Fourier Transform Infrared Spectroscopy (FTIR). The biodegradation test was used to quantify the release of lithium (for Flame Atomic Absorption Spectrometry - FAAS) and the weight loss of the material in TRIS-HCl buffer solution, for periods up to 28 days. After several periods of immersion, the samples were analyzed by Scanning Electron Microscopy (SEM). Surprisingly, only the glass ceramic containing lithium disilicate as majority phase (Crystallinity Index ~ 79%) proved to be bioactive after 14 days of immersion in SBF. Regarding the evaluation of biodegradation, there was a more significant weight loss for glass after 28 days, and only this group showed the concentration of Li+ ions in the solution within the range considered toxic, after 14 days of immersion in TRIS –HCl. About the cytotoxicity, none of the groups showed to be cytotoxic. Regarding cellular adhesion and proliferation, the lithium disilicate showed the best results, being able to verify the formation of a mineralized matrix after 21 days. The results showed that, between the 3 experimental groups analyzed, the lithium disilicate glassceramic have great potential to be used as a biomaterial for bone repair.


Aline F. Weber

Master Degree

The search for functional materials that repair and/or regenerate of biological tissues satisfactorily has continually risen in the past few years. For such applications, composite materials are each time being better accepted, capable of merge properties from different materials. Between all the bio-resorbable, one can find the Poly(ε-caprolactone), which shows to be suitable to be used as implants, due to its biocompatibility and widespread use. The Biosilicate® is a glass-ceramic highly bioactive that has also shown to be an excellent alternative to bone healing, among other applications. In this context, the purpose of this study is the development and characterization of bioactive composite films based on Poly(ε-caprolactone) and Biosilicate®, originally for bone tissue regeneration. Associating these to materials a composite was developed (PCL/BS) from two different routes. This study has two main stages, the first was a pilot study, to define the processing conditions, and the second one analyzed the materials performance. Route 1 uses the solvent casting technique, and route 2 consists in phase precipitation followed by solvent casting. The characterization was made using OM, SEM, XRD, and DSC. For performance evaluation, in vitro bioactivity and degradation and mechanical properties had been analyzed. The two routes produced films with different morphology, showing a particular degree of crystallinity (from 30 to 67%). Route 2 presented higher crystallinity and porosity, and route 1 produced denser films. The SBF tests show that the BS addition allowed the formation of HCA phase in the composite, after seven days immersion, proving their bioactivity, but, at the same time, it doesn’t significantly improve the degradation of the polymeric phase, at least for 21 days tests. The mechanical tests show that route 1 presents samples more resistant than route 2, probably due to its high porosity levels. The addition of BSyielded an increase in Young’s modulus of around 46%, although the maximum stress and yield strength were reduced. Nevertheless, the mechanical properties of the developed materials are compatible with the biological tissues. Therefore, it is possible to conclude that the processing parameters to obtain PCL-BS composites were well-established, allowing the development of materials with different characteristics, according to the used route, and with biomedical applications interest.


Amanda C. Juraski

Master Degree

Spinal Cord Injury (SCI) is a severe condition that had been a significant concern for neural tissue engineering for several years. Current efforts focus on the combination of nerve guides loaded with therapeutic molecules. Chitosan is a biocompatible, biodegradable hydrogel that has been explored both as a scaffold for axonal repair and as a drug delivery system. Ibuprofen is an anti-inflammatory drug already used for pain management as well as a model drug for drug delivery systems. Recent studies have explored Ibuprofen’s effect in axonal regeneration post-SCI. In this study, chitosan (CH) and 28% (m/m) Ibuprofen-loaded chitosan (ICH) films were prepared through the solvent cast, envisioning the application of Ibuprofen loaded chitosan as films for SCI repair. The two groups were characterized through FTIR, SEM, TGA, and in vitro weight loss, swelling degree, drug release profile, and cytotoxicity. FTIR qualitative and semi-quantitative analyses showed that both groups had a similar composition. SEM images showed that ICH films have a higher apparent roughness and that Ibuprofen particles were entrapped on the surface and inside the polymeric matrix. TGA results showed that 5% of the initial mass of ICH films is due to Ibuprofen, that means approximately 23% of drug loaded was lost during the process. In vitro weight loss (WL) and swelling degree (SD) indicated that both CH and ICH films are stable in physiological pH (7.4) and will absorb enough fluid to interact with a physiological environment appropriately. In vitro drug release profile showed that over 60% of drug loaded is released within the first 24 hours of immersion in PBS, and that drug release remains until 30 days later. Mathematical models indicated that, within the first 24 hours, the drug release profile is best fitted by the Higuchi model. For times after the first day, the data is best fitted by the Kors- Peppas model. Therefore, Ibuprofen is first released through diffusion process of the particles found on the surface, and later through a combination of diffusion and erosion of the chitosan matrix. In vitro cell viability was evaluated through MTT assay, and showed that both CH and ICH films are nontoxic. Statistical analysis was performed to compare the intensity of characteristic peaks evaluated in FTIR, as well as in vitro WL, SD, and cell viability. The analyses showed that only FTIR results were statistically different, indicating that Ibuprofen was entrapped inside the polymeric matrix and electrostatically interacted with chitosan. Based on the performed evaluations, it was possible to confirm ICH films as applicable as materials for nerve guides for spinal cord injury treatment.


Daniela C. Figueredo

Master Degree (in progress)

EFFECTS OF ASSOCIATION OF BIOSILICATE® AND HIGH-INTENSITY LASER IN THE PARALYSIS OF THE RADIATION CARIES


Karina F. Santos

Master Degree (in progress)

PRODUCTION BY ADDITIVE MANUFACTURE OF SCAFFOLDS FROM THE COMPOSITE PEG -LAPONITE FOR INCORPORATION OF TISSUE SPHEROIDS


Mayara Mendes Roloff

Undergraduate

Techniques based on biomaterials for the treatment of bone lesions have been developed in an attempt to supply the required properties. This research aimed to create a composite biomaterial based on Chitosan and Biosilicate®, combining the desired features for its application in the engineering of bone tissues. Membranes of chitosan 1.0% (m / v) with additions of 60% and 75% of Biosilicate® were studied. Thus, the structural, mechanical, and biological characterization of such membranes becomes relevant to evaluate the influence of the composition on the composite. The degree of swelling of the membranes was carried out in Phosphate Buffered Solution (PBS). SEM and FTIR analyzed the bioactivity of the samples after the immersion in the Simulated Body Fluid solution (SBF) for up to 7 days. Mechanical tests were conducted to determine the elastic modulus, tensile strength, and deformation until rupture. The results showed that a higher concentration of Biosilicate® in the chitosan membranes interfered negatively in the water absorption capacity. The in vitro bioactivity test characterized the formation of a layer of carbonated hydroxyapatite (HCA) by MEV and FTIR in times of 1 and 3 days on the surface of membranes, respectively for composites with additions of 60 and 75% Biosilicate. The elastic modulus of the Qui-60% Biosilicate membrane increases considerably over the pure membrane, but for Qui-75% Biosilicate this property reduces because of defects in the microstructure. The results show a great potential of the composite membranes of Chitosan and with additions of 60% of Biosilicate® in the development of bioactive materials for applications in Tissue Engineering.


Leandro dos Santos

Undergraduate

Based on the current success of the use of glass-ceramics for biomedical applications, and the increasing trend of aesthetic valorization, this study aims to develop high performance aesthetic brackets for the orthodontic appliance. A product produced at a lower cost to meet the unique market perspective that today is supplied only by-products from sapphire, generating substantial costs and consequently restricting the target market. In this work, four groups of samples were characterized and submitted to a mechanical and in vitro biological evaluation to determine and verify the possibility of their use in brackets. These characterizations were the identification of phases by X-ray diffraction (XRD), analysis of the microstructure by optical microscopy, mechanical characterization by the Vickers indentation method, in vitro evaluation of the cytotoxicity by the technique of indirect contact and biodegradation in artificial saliva for periods of up to 28 days. Three groups of samples had a high fraction, and crystallized presence of lithium disilicate phase, characterized by acicular crystal morphology and an average size of 5 m. These groups had a Hardness between 5.0 and 5.2 GPa and fracture toughness 1.1 to 1.8 MPa.m-1/2. A mechanism of tenacification in the materials due to the shape and size of these crystals were observed. The fourth group showed low crystallized fraction and presence of lithium metasilicate phase, with acicular crystals, the Hardness of 7.4 GPa and fracture toughness of 1.6 MPa.m1/2. The two compositions best evaluated in their mechanical properties and cytocompatibility were submitted to a biodegradation test in artificial saliva, which did not compromise the features as mentioned earlier. In conclusion, an essential step for the future of orthodontic biomaterials was given, since it opened its doors for the manufacture of these devices through a dental ceramic enshrined in the middle, which is produced at low costs and returns excellent characteristics.


G abriel V. Scocca

Undergraduate

Although of known etiology, caries is still a disease of high prevalence and incidence in the world population. The polarization of this disease, which presents increased rates in children and the elderly, requires the search for more durable and effective treatments. The best way is mainly acting in inhibiting the neoformation of cariogenic biofilm, which would avoid the formation of secondary caries. This study aims to evaluate the potential of bioactive glass-ceramic, when associated or not to the laser irradiation in high intensity, in the progression of lesions of root caries in vitro. For this, 40 blocks of bovine root dentin were prepared and demineralized in order to create an initial artificial carious lesion (Group A). Then, of these 40 blocks of dentin, 30 blocks were treated with Biosilicate® (bioactive glass-ceramic) seeking the remineralization of these lesions (Group B). After immersion in artificial saliva for 48 h, the samples were submitted to the chemical caries process for 7 days. The samples were again distributed in 4 different experimental groups, namely: Group 1: samples of group A, maintained without any further treatment (negative control group); Group 2: Group B samples without any further treatment; Group 3: Group B samples, treated again with Biosilicate®; Group 4: Group B samples, with subsequent laser irradiation. The irradiations were performed with Er, Cr: YSGG laser (2780 nm, 0.25 W, 2.8 J/cm 2, 20 Hz). The compositional evaluation of the samples was made from Fourier Transform Infrared Spectroscopy (FTIR) at different stages of the project. The present research revealed the potential of Biosilicate® to act as a prevention against the caries process, and that the subsequent application of laser (in the conditions used here) eventually removed part of the Biosilicate®, which would make the teeth again susceptible to caries. It is necessary that further studies be conducted regarding the application techniques of Biosilicate® on the dental surface to improve the adhesion of the biomaterial.


Rodrigo S. Monteiro

Undergraduate

The request to improve the quality of life, coupled with an increasing life expectancy for the world's population, makes it necessary to advance medicine. Thus, it is sought to develop new biomaterials, capable of restoring or replacing tissues and organs with insufficient functionality. This work studies the synthesis of poly (ε-caprolactone) - PCL and PCL composite with Biosilicate (BS), in film format, so that it can be applied in bone recoveries. In this way, samples obtained through the solvent evaporation technique were characterized by bioactivity test (immersion test in SBF), X-ray Diffraction, Scanning Electron Microscopy, and mechanical tensile test. The results are satisfactory and point in the direction of confirming that the PCL / BS composite has sufficient characteristics to become a bioactive material and to serve for bone repair and recovery.


Leonardo J. Messias

Undergraduate (in progress)

ASSESSMENT OF BIOSILICATE® ASSOCIATION TO ND:YAG LASER FOR CARIE TREATMENT


Henrique M. Urbano

Undergraduate (in progress)

EVALUATION OF IN VITRO DEGRADATION OF DENTAL CERAMICS BASED ON LITHIUM DISILICATE SYSTEM BY THE RIETVELD METHOD