PEDRO RODRIGO DE SOUSA REIS

PEDRO RODRIGO DE SOUSA REIS

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Development of biocomposite materials from biodegradable polymer and bio-hydroxyapatite derived from eggshells for biomedical applications
2019 - REIS, PEDRO R.S.; SANTANA, JULYANA G.; OLIVEIRA, RENE R.; RANGARI, VIJAYA K.; LOURENÇO, FELIPE R.; MOURA, ESPERIDIANA A.B.
Nowadays, significant advances have been made in the development of biodegradable polymeric materials for biomedical applications. This study aims to prepare and characterize composite materials based on PLA/PBAT, a biodegradable polymer blend, reinforced with bio-hydroxyapatite (bio-HAp). First, bio-HAp was obtained from eggshell residues by the wet precipitation method. PLA/PBAT blend with 1.5 wt% of bio-HAp was prepared by melt extrusion and injection molding process. Part of composite samples was irradiated with gamma radiation dose of 25 kGy, at room temperature and presence of air. The effects of the bio-HAp addition into the biodegradable blend were investigated by mechanical tests, XRD, DSC, FESEM, and cytotoxicity “in vitro” analysis and the correlation between the properties was discussed. In addition, the microbiological tests were carried out at irradiated and non-irradiated composite samples in order to evaluate the efficiency of the radiation dose of 25 kGy at composite materials sterilization.
Synthesis and characterization of nanocrystalline hydroxyapatite derived from eggshell for biomedical applications
2018 - MOURA, ESPERIDIANA; LODIS, ALINE; REIS, PEDRO; WELLEN, RENATE
Hydroxyapatite(HAP) a crystal-chemical analog of the bone tissue mineral component has been intensively studied in recent years as a potential bone substitute in orthopedic and dentistry because of its biocompatibility, biodegradability, bioactivity, and osteoconductive properties. Hydroxyapatite in a nanocrystalline state with uniform size and morphology has many applications in different fields of medicine ranging from targeted drug delivery to designed load-bearing implants. This work presents the synthesis and characterization of nanocrystalline hydroxyapatite derived from hen’s eggshell waste for biomedical applications. Firstly, bio-hydroxyapatite was synthesized by the wet precipitation method in which white hen’s eggshell waste was used. The white hen`s eggshells were washed, dried and reduced to powder with particle size ≤ 30 μm. Then, the eggshell powder was subjected to a heating cycle at 800 ° C for 3 hours to obtain calcium oxide. Calcium oxide was converted to bio-hydroxyapatite by the addition of a solution of distilled water and phosphoric acid under magnetic stirring at 100 ° C, until a viscous slurry was formed, which was oven dried at 110 ° C for 24 hours. The dried material was disintegrated and calcined at 900 ° C for 2 hours to obtain the hydroxyapatite phase. The bio-hydroxyapatite was irradiated with a high intensity ultrasonic (20 kHz, and 450W/cm2) in order to obtain nanocrystalline hydroxyapatite. These synthesized nanocrystalline hydroxyapatites have been characterized by XRD, FE-SEM, FTIR, and TG analyzes.
Biodegradable polymer blends reinforced with bio-hydroxyapatite nanoparticle - preparation and characterization
2017 - REIS, PEDRO R.S.; SANTANA, JULYANA G.; OLIVEIRA, RENE R.; RANGARI, VIJAYA K.; MOURA, ESPERIDIANA A.B.
Nowadays significant advances have been made in the development of biodegradable polymeric materials for biomedical applications. The purpose of this study was to preparation and characterization of biodegradable polymer blend reinforced with bio-hydroxyapatite nanoparticle from eggshell by sonochemical method. Biodegradable polymer blends based on PLA (Poly(lactic acid)) and the PBAT (butylene adipate-co-terepthalate)) reinforced with 1-5 wt. % of bio-hydroxyapatite were prepared by melt extrusion, using a twin screw extruder and injection molding machine to obtain specimen test. The effects of the bio-hydroxyapatite addition on properties of PLA/PBAT biodegradable blend were investigated by tensile tests, XRD, DSC, TG and SEM-FEG analysis and the correlation between the results was discussed.
Effects of bio-CaCO3 nanoparticles and graphene nanosheets on properties of PBAT/PLA flexible films treated by ionizing radiation
2016 - REIS, PEDRO R.S.; CARDOSO, ELIZABETH C.L.; LOURENÇO, FELIPE R.; ORTIZ, ANGEL V.; RANGARI, VIJAY K.; MOURA, ESPERIDIANA A.B.