Navegação IPEN por Autores IPEN "VARCA, GUSTAVO H.C."

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  • IPEN-DOC 23707

    GONÇALVES, LIVIA de S.; ARTIOLI, GUILHERME G.; MATHOR, MONICA B. ; LUGAO, ADEMAR B. ; VARCA, GUSTAVO H.C. . An approach to the sterilization of B-alanine by ionizing radiation. In: MEETING OF THE IONIZING RADIATION AND POLYMERS SYMPOSIUM, 12th, September 25-30, 2016, Peninsula of Giens, France. Abstract... 2016. p. 96-96.

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  • IPEN-DOC 25206

    FREITAS, LUCAS F. de ; VARCA, GUSTAVO H.C. ; BATISTA, JORGE G. dos S. ; LUGAO, ADEMAR B. . An overview of the synthesis of gold nanoparticles using radiation technologies. Nanomaterials, v. 8, n. 11, 2018. DOI: 10.3390/nano8110939

    Abstract: At a nano-level, optical properties of gold are unique and gave birth to an emerging platform of nanogold-based systems for diverse applications, because gold nanoparticle properties are tunable as a function of size and shape. Within the available techniques for the synthesis of gold nanoparticles, the radiolytic synthesis allows proper control of the nucleation process without the need for reducing agents, in a single step, combined or not with simultaneous sterilization. This review details and summarizes the use of radiation technologies for the synthesis and preparation of gold nanoparticles concerning fundamental aspects, mechanism, current pathways for synthesis and radiation sources, as well as briefly outlines final applications and some toxicity aspects related to nanogold-based systems.

    Palavras-Chave: gold; nanoparticles; gamma radiation; electron beams; x-ray sources; radiolysis; nanotechnology; medicine; diagnostic uses; ionizing radiations

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  • IPEN-DOC 27582

    LIMA, CAROLINE S.A. de ; BALOGH, TATIANA S. ; VARCA, JUSTINE P.R.O. ; VARCA, GUSTAVO H.C. ; LUGAO, ADEMAR B. ; CAMACHO-CRUZ, LUIS A.; BUCIO, EMILIO; KADLUBOWSKI, SLAWOMIR S.. An updated review of macro, micro, and nanostructured hydrogels for biomedical and pharmaceutical applications. Pharmaceutics, v. 12, n. 10, p. 1-28, 2020. DOI: 10.3390/pharmaceutics12100970

    Abstract: Hydrogels are materials with wide applications in several fields, including the biomedical and pharmaceutical industries. Their properties such as the capacity of absorbing great amounts of aqueous solutions without losing shape and mechanical properties, as well as loading drugs of different nature, including hydrophobic ones and biomolecules, give an idea of their versatility and promising demand. As they have been explored in a great number of studies for years, many routes of synthesis have been developed, especially for chemical/permanent hydrogels. In the same way, stimuli-responsive hydrogels, also known as intelligent materials, have been explored too, enhancing the regulation of properties such as targeting and drug release. By controlling the particle size, hydrogel on the micro- and nanoscale have been studied likewise and have increased, even more, the possibilities for applications of the so-called XXI century materials. In this paper, we aimed to produce an overview of the recent studies concerning methods of synthesis, biomedical, and pharmaceutical applications of macro-, micro, and nanogels.

    Palavras-Chave: hydrogels; drugs; synthesis; cross-linking; skin; animal tissues; gamma radiation

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  • IPEN-DOC 25707

    BOARO, LETICIA C.C. ; CAMPOS, LUIZA M. ; VARCA, GUSTAVO H.C. ; SANTOS, TAMIRIS M.R. dos ; MARQUES, PAMELA A.; SUGII, MARI M.; SALDANHA, NATHALIA R.; COGO-MULLER, KARINA; BRANDT, WILLIAM C.; BRAGA, ROBERTO R.; PARRA, DUCLERC F. . Antibacterial resin-based composite containing chlorhexidine for dental applications. Dental Materials, v. 35, n. 6, p. 909-918, 2019. DOI: 10.1016/j.dental.2019.03.004

    Abstract: Objeticve. The aim of this study was to develop a composite material with antibacterial activ-ity using MMT loaded with clorhexidine (CHX). For that it was used a BisGMA/TEGDMAmatrix and added low concentration of MMT/CHX. The aim was to evaluate the drug releasecapacity of MMT, and not to provide reinforcement.Methods. Six experimental composites were made with organic matrix of BisGMA/TEGDMAin equal proportions by weight. The composites received organophlizated montmorillonitewith or without CHX. The concentrations were 2,5; 5 or 10% by weight. Degree of conversion(DC) was evaluated using FTIR (peak 6165 cm-1; n = 5). Specimens for flexural properties(10×2×1 mm) were immediate tested (24h). Elastic modulus(E) and flexural strength (FS)was measured using the three point bending test (n = 10). Inibition halo was used to test theantibacterial activity against Staphylococcus aureus, Streptococcus mutans, and Porphyromonasgingivalis (n = 5 for each bacteria). The inhibition of biofilm formation (BF) was evaluated byinserting polymerized disc of composite in to a culture media colonized with Streptococcusmutans (n = 10). The release of CHX was measured using ultraviolet (255 nm) for 10 days(n = 5). The data of degree of conversion was analysed using Kruskal–Wallis/ Mann–Whitney,and the other variables using two-way ANOVA/Tukey, always considering a global level ofsignificance of 5%.Results. DC ranged from 71% to 74%. E ranged from 5.7 to 8.1 GPa. FS ranged from 61.4 to74.7 MPa. There were no statistical differences among the groups for all the variables. Forthe three bacteria tested the composites with CHX loaded presented inhibition of growthfor all concentration, except for 2,5% that did not inihibited the growth of P. gingivalis. BFwas lower for the groups with 10% MMT/CHX, all groups presented BF, even those withoutCHX loaded. All concentrations presented release off CHX during all the 28 days analyzed. Conclusions. Within the limitation of this study it can be concluded that: all concentrations tested presented release of CHX and reduced BF. All concentration presented antibacterial activity for the three bacteria tested, except for 2,5% that did not inhibit the growth of P. gingivalis. The presence of MMT with CHX loaded did not interfere in the properties evaluated.

    Palavras-Chave: composite materials; germicides; dentistry; manganese compounds; chlorine compounds; bacteria; staphylococcus; streptococcus; antimicrobial agents; resins

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  • IPEN-DOC 27589

    GONCALVES, FLAVIA; CAMPOS, LUIZA M. de P. ; SANCHES, LUCIANA K.F.; SILVA, LARISSA T.S.; SANTOS, TAMIRIS M.R. dos ; VARCA, GUSTAVO H.C. ; LOPES, DIANA P.; COGO-MULLER, KARINA; PARRA, DUCLERC F. ; BRAGA, ROBERTO R.; SANTOS, MARCELO dos; BOARO, LETICIA C.C.. Antimicrobial activity and physicochemical performance of a modified endodontic sealer / Atividade antimicrobiana e desempenho físico-químico de um cimento endodôntico modificado. Research, Society and Development, v. 9, n. 11, p. 1-16, 2020. DOI: 10.33448/rsd-v9i11.9401

    Abstract: Introduction: this study aimed to evaluate the antimicrobial and physicochemical properties of a commercial endodontic sealer modified by the addition of montmorillonite (MMT) nanoparticles loaded with two different drugs: chlorhexidine (CHX) or metronidazole (MET). Methods: 5 wt% MMT/CHX or MMT/MET nanoparticles were added to the sealer AH-Plus. The experimental materials were evaluated for drug release, antimicrobial activity, flow, flexural strength, and flexural modulus. Data were subjected to one-way ANOVA, Kruskal-Wallis, and Mann-Whitney tests. Results: The drug incorporation into MMT particles was 9% and 10% for CHX and MET, respectively. At 20 days after manipulation, 16.5% of the drug was released by the sealer with MMT/MET and 0.4% by MMT/CHX. The addition of both nanoparticles decreased the flow of materials, but they were still in compliance with ISO 6876-2012. The conversion, flexural strength, and flexural modulus of MMT/MET (87%, 37±7 MPa, 2.3 GPa) and MMT/CHX (78%, 29±2 MPa, 2.7 GPa) were similar in both groups but lower than in the control group (100%, 54±7 MPa, 4.0±0.7 GPa). Both experimental materials were able to form an inhibition halo for E. faecalis bacteria (CHX: 4.8±1.4 and MET: 4.0±1.6 mm), whereas the control group did not inhibit the microorganism. Conclusion: both formulations proposed as endodontic sealer presented effective antimicrobial activity and acceptable flow. The addition of MMT/CHX and MMT/MET particles decreased the conversion and mechanical properties, but further studies are required to clarify the clinical relevance of these properties.

    Palavras-Chave: antimicrobial agents; metronidazole; organic chlorine compounds; dentistry; drugs; sealing materials; montmorillonite; nanoparticles; teeth; seals

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  • IPEN-DOC 27726

    LOPEZ-SAUCEDO, FELIPE; FLORES-ROJAS, GUADALUPE G.; VARCA, JUSTINE P.R.O. ; VARCA, GUSTAVO H.C. ; BUCIO, EMILIO. Antimicrobial materials and devices for biomedical applications. In: UR-RAHMAN, ATTA (Ed.). Frontiers in Clinical Drug Research: Anti-Infectives. Singapore: Bentham Science Publishers, 2020. p. 78-126, v. 6, cap. 3. DOI: 10.2174/9789811425745120060005

    Abstract: Bioaccumulation in sanitary devices, caused by opportunistic pathogens, intervenes negatively in the recovery of a patient since these are able to provoke a mild or life-threatening infection. Thus, surfaces of certain materials such as gauzes, catheters, sutures, etc., which are adjacent or directly exposed to a healing zone, are prone to become sites for the growth, proliferation, and spread of pathogenic microorganisms. Although in surgical or healing processes, sterile materials are usually applied, the time of contact with biological interfaces is long enough to make the sterilization but not enough to control and prevent an infection since pathogens abound in the surroundings. Air, water, and soil can be potential vectors, without considering those factors related to iatrogenesis that also play a role in the opportunities for the patient's recovery. Within this context, engineered materials are currently being developed and explored towards devices and biomaterials with improved design, performance, duration, biocompatibility aiming to be safer for the user. The surface functionalization of materials with antimicrobial agents is a highlighted alternative to overcome this issue. This chapter addresses current antimicrobial materials, as well as strategies for obtaining antimicrobial surfaces and coating as well as their properties. In addition, the safety assessment of biomedical applications and international standards are discussed.

    Palavras-Chave: safety analysis; risk assessment; antimicrobial agents; coatings; surface properties; standardization

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  • IPEN-DOC 27201

    FREITAS, LUCAS F. de ; CRUZ, CASSIA P.C. da ; CAVALCANTE, ADRIANA K. ; BATISTA, JORGE G. dos S. ; VARCA, GUSTAVO H.C. ; MATHOR, MONICA B. ; LUGAO, ADEMAR B. . Comparison between gold nanoparticles synthesized by radiolysis and by EGCG-driven gold reduction. Radiation Physics and Chemistry, v. 174, p. 1-9, 2020. DOI: 10.1016/j.radphyschem.2020.108959

    Abstract: Radiolytic synthesis and phytochemical-driven gold reduction for the generation of nanoparticles are successful examples of Green Chemistry applied for nanomaterials. The present work compares these two green approaches focusing on hydrodynamic size, stability over time, optical properties and toxicity in NIH 3T3 (ATCC® CRL- 1658™) cells and Danio rerio (Zebra Fish). The radiolytic synthesis was performed by mixing 1 mM NaAuCl4; polyvinyl pyrrolidone 0.5%, AgNO3 6×10−5 M, propan-2-ol 0.2 M and acetone 0.06 M, followed by irradiation at 15 kGy (5 kGy h−1, 60Co source). The EGCG-functionalized nanoparticles were synthesized by mixing 1.6 mM of Au with 0.8 mM of EGCG in phosphate buffer (10 mM) for 2 h. Both methods yield the formation of gold nanoparticles featuring plasmon resonance bands at 520–530 nm, polydispersity above 0.3 was relevant only for the radiolytic protocol. Regarding stability over time, after 30 days, the nanoparticles synthesized radiolytically presented no relevant size changes, while some aggregation was observed for the EGCG-particles. The same nanoparticles demonstrated a lack of stability in high ionic strength medium. Slight toxicity was observed for the EGCG-nanoparticles in Danio rerio, with an IC50 calculated as 40.49%, while no IC50 was established within the concentration range of radiolysis-AuNPs used in this study. In conclusion, both green methods generated nanoparticles with good control of size and optical properties, especially via reduction by EGCG. However, the stability and toxicity results were found to be more promising for the radiolytically synthesized gold nanoparticles.

    Palavras-Chave: gold; nanoparticles; synthesis; chemistry; ecology; polyphenols; fishes

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  • IPEN-DOC 25125

    OLIVEIRA, JUSTINE P.R. ; MELENDEZ-ORTIZ, H.I.; BUCIO, EMILIO; ALVES, PATRICIA T.; LIMA, MAYARA I.S.; GOULART, LUIZ R.; MATHOR, MONICA B. ; VARCA, GUSTAVO H.C. ; LUGAO, ADEMAR B. . Current methods applied to biomaterials – characterization approaches, safety assessment and biological international standards. Current Topics in Medicinal Chemistry, v. 18, n. 4, p. 256-274, 2018. DOI: 10.2174/1568026618666180410151518

    Abstract: Safety and biocompatibility assessment of biomaterials are themes of constant concern as advanced materials enter the market as well as products manufactured by new techniques emerge. Within this context, this review provides an up-to-date approach on current methods for the characterization and safety assessment of biomaterials and biomedical devices from a physical-chemical to a biological perspective, including a description of the alternative methods in accordance with current and established international standards.

    Palavras-Chave: biological materials; bioassay; medicine; in vitro; in vivo; compatibility; composite materials; sterilization; standardization; iso; recommendations; physical chemistry

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  • IPEN-DOC 23368

    VARCA, GUSTAVO H.C. . Desenvolvimento de hidrogel nanoestruturado contendo complexo de papaína e ciclodextrina / Development of a nanostructured hydrogel containing papain and cyclodextrin complex . 2014. Tese (Doutorado em Tecnologia Nuclear) - Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP, São Paulo. 154 p. Orientador: Ademar Benévolo Lugão. DOI: 10.11606/T.85.2017.tde-30062017-114133

    Abstract: A papaína é uma enzima proteolítica empregada no debridamento e cicatrização de feridas. Contudo, problemas de estabilidade na forma farmacêutica, bem como reações alérgicas reportadas por pacientes submetidos à tratamentos com a enzima, culminaram na restrição aos produtos contendo papaína para uso tópico por órgãos regulatórios internacionais. Este trabalho objetivou desenvolver hidrogel nanoestruturado contendo complexo de papaína e ciclodextrina visando obter forma farmacêutica estável e eficaz como curativo dérmico, com redução da resposta imunológica. A síntese do hidrogel foi realizada combinando fenômenos de cristalização e/ou reticulação e esterilização simultânea induzida por radiação gama, de modo a promover nanoestruturação adequada da membrana para veiculação da papaína nativa e do complexo. O complexo e o produto final tiveram suas propriedades biológicas e físico-químicas avaliadas. O hidrogel a base de PVA contendo complexo de papaína-ciclodextrina apresentou características adequadas para aplicação como curativo, além de apresentar indícios de redução na resposta imunológica e melhora na citocompatibilidade quando comparado à papaína nativa, isso devido ao encapsulamento molecular com a ciclodextrina e à alta retenção do complexo por parte da matriz. Por outro lado, a irradiação, não alterou o perfil citotóxico da enzima, mas acarretou leve diminuição em seu potencial imunogênico. O hidrogel se mostrou promissor para uso como curativo e demonstrou potencial redução nas reações adversas desencadeadas pelo uso da papaína.

    Palavras-Chave: antimitotic drugs; enzymes; papain; nanomaterials; sh-proteinases; hydrolases; oligosaccharides; saccharides; synthetic materials; polymers; polyvinyls; potting materials; gamma radiation; in vitro; immunity; immunoassay; physical chemistry; synthesis; process development units

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  • IPEN-DOC 27247

    VARCA, JUSTINE P.R.O. ; MARTINS, ELAINE A.J. ; VARCA, GUSTAVO H.C. ; ROMANO, RENATO L.; LEBRE, DANIEL T.; LAINETTI, PAULO E.O. ; BUSTILLOS, JOSE O.V. . Determination of organochlorines in soil of a suburban area of São Paulo Brazil. International Journal of Environmental Research and Public Health, v. 17, n. 16, p. 1-16, 2020. DOI: 10.3390/ijerph17165666

    Abstract: Technological advances have promoted improvements in several science fields, especially related to environmental and analytical areas with the improvement of detection and development of environmentally friendly extraction techniques. This study applied Quick, Easy, Cheap, Effective, Rugged and Safe method (QuEChERS) for soil extraction and assessed its performance through a validation study using samples from the soil of a contaminated area in Caieiras, SP, Brazil. Nine organochlorine pesticides, including the isomers alpha, beta, gamma and delta- hexachlorocyclohexane; cis- and trans-heptachlor epoxide; cis- and trans-chlordane and heptachlor were analyzed by gas chromatography coupled to electron capture detector. The method was validated according to ISO 5725-4 (2020), EURACHEM (2014) and DOQ-CGCRE-008 (2016). The limits of detection and quantification of the method for the nine organochlorines were α-HCH (1.2 and 12.6 µg kg−1), β-HCH (1.7 and 12.0 µg kg−1), γ-HCH (1.5 and 11.6 µg kg−1), δ-HCH (0.8 and 11.6 µg kg−1), heptachlor (1.0 and 10.8 µg kg−1), cis-heptachlor epoxide (0.9 and 11.5 µg kg−1), trans-heptachlor epoxide (0.9 and 11.5 µg kg−1), cis-chlordane (0.4 and 7.9 µg kg−1) and trans-chlordane (0.5 and 10.9 µg kg−1), respectively, and all of them were within the maximum limits recommended by the EPA for the compounds α-HCH (86.0 and 360.0 µg kg−1), β-HCH (300.0 and 1.3 × 103 µg kg−1), γ-HCH (570.0 and 2.5 × 103 µg kg−1), δ-HCH (not defined), heptachlor (130.0 and 630.0 µg kg−1), cis-/trans-heptachlor epoxide (7.0 and 330.0 µg kg−1), cis-/trans-chlordane (1.77 × 103 and 7.7 × 103 µg kg−1) in residential and industrial soil, respectively. Recovery results were between 65% and 105% for almost all compounds, which is an optimum result for multi-residue analytical methods, considering the complexity of the matrix used in the study. Caieiras presented contamination levels of α-HCH in the range of 2.0 to 66.0 µg g−1, which was higher than the limits established by EPA, corresponding to 0.077 µg g−1 for residential soil and 0.27 µg g−1 for industrial soil. According to the validation study, the analytical method proposed was reliable for organochlorine quantification, and the QuEChERS was considered efficient for organochlorine extraction from soil.

    Palavras-Chave: organic chlorine compounds; soils; urban areas; pollution; sanitary landfills; land pollution; pesticides; environmental impacts; validation; electron-capture detectors

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  • IPEN-DOC 25541

    VARCA, JUSTINE P.R.O. ; FERRARI, ANDRE ; PIGNATA, DANILO R. ; GUAZZELLI, STEFANE K. ; KLINGBEIL, MARIA F.G. ; VARCA, GUSTAVO H.C. ; LUGAO, ADEMAR B. ; MATHOR, MONICA B. . Development of gelatin based scaffold by gamma radiation for application as platelet rich plasma support for wound treatment. Regenerative Research, v. 7, n. 2, p. 44-44, 2018.

    Abstract: Gelatin is a natural polymer originated from the collagen, and presents poor mechanical properties, however it is a natural and biocompatible polymer, and collagen is the main component of the extracellular matrix1. Poly-vynil (alcohol) is an artificial polymer with interesting mechanical properties and biocompatibility. Such polymers have been largely scientific studied for biomedical application2. Platelet Rich Plasma (PRP) has been widely scientific explored in many medical fields in the last decades, especially in orthopedic area and in athletic treatments3. Based on the PRP desired properties regarded to the tissue regeneration, the present work aimed to develop a scaffold to support PRP release for wound treatment and study the influence of different radiation doses on a scaffold formation to apply as support for PRP release for wound treatment. In specific terms, the impact of radiation will be evaluated through physicochemical and morphologic characteristics. In the study, two polymers of different characteristics were applied, and scaffolds were prepared based on two formulations, one composed by gelatin (7%, w/w) and PVA (5%, w/w), and the second by gelatin (10%, w/w) and PVA (5%, w/w). The formulations were solubilized together in distilled water and heated up to 80 ºC under constant stirring for 1 hour. Posteriorly, the blends were disposed in circular glass molds. The samples were cooled at 4 ºC for at least 24 h and then irradiated at 15, 25 and 50 kGy. After irradiation, the samples were frozen and freeze dried. The scaffolds were characterized in terms of structure and morphology by mechanical assays, differential scanning calorimetry, scanning electron microscopy, optical coherence tomography and infrared spectroscopy. In addition, platelet adhesion and release, and cytotoxic assays were also performed. Samples irradiated at 15 kGy presented pore size diameter of around 1.4 μm and porosity of 54%, while samples irradiated at 25 kGy, presented pore size diameter of around 1.1 μm and porosity of 49%. Optical coherence tomography showed that gelatin control samples presented more superficial degradation as irradiation dose increased, while PVA control sample presented higher integrity, indicating that this polymer is less sensitive to gamma radiation. The system presented suitable mechanical properties and the platelet adhesion and release assays showed that the scaffold presented adequate pore size range to host and release the platelets, and non-cytotoxic to platelets, featuring adequate properties to be applied as dressing for wound treatments.

    Palavras-Chave: polymers; gelatin; gamma radiation; mechanical properties; wounds; therapy; animal tissues; biological regeneration

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  • IPEN-DOC 27687

    LIMA, CAROLINE S.A. de; VARCA, GUSTAVO H.C. ; COSTA, SIRLENE M. da; FERRAZ, HUMBERTO G.; SANTOS, ANA C. da S.; LOPES, PATRICIA S.; COSTA, SILGIA A. da. Development of natural polymeric microcapsules for antimicrobial drug delivery: triclosan loaded chitosan and alginate-based microcapsules. Drug Development and Industrial Pharmacy, v. 46, n. 9, p. 1477-1486, 2020. DOI: 10.1080/03639045.2020.1809445

    Abstract: The goal of this work was the development of natural polymeric microcapsules for antimicrobial drug delivery – triclosan loaded alginate and chitosan-based microcapsules for potential coating applications in substrates such as textiles or plastics. Microcapsules containing 2.5% (w/w) or 3% (w/w) triclosan in both core and matrix were synthesized and evaluated by Fourier-transform infrared spectroscopy, scanning electron microscopy, confocal microscopy, differential scanning calorimetry, thermogravimetry, and antimicrobial activity. The microcapsules produced featured spherical and mostly irregularly-shaped surfaces composed by an alginate core in a chitosan outer matrix, as revealed by confocal microscopy, and antimicrobial activity against S. aureus and E. coli with inhibition halos up to 60 mm and 25 mm respectively, granted by a triclosan loading of 61.66%. The thermal analysis suggested that the polymers protected the active substance from temperature-induced degradation. In conclusion, these microcapsules may be applied toward antimicrobial functionalization of plastics, textiles and other materials.

    Palavras-Chave: polysaccharides; oligosaccharides; antimicrobial agents; drugs; antiseptics; sodium; alginates; polymers

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  • IPEN-DOC 24323

    AL-SHEIKHLY, MOHAMAD; VARCA, GUSTAVO H.C. . Editorial. Radiation Physics and Chemistry, v. 143, n. SI, p. 1-2, 2018. DOI: 10.1016/j.radphyschem.2017.11.011

    Palavras-Chave: electron beams; radiation chemistry; physical chemistry; linear momentum transfer; irradiation

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  • IPEN-DOC 27301

    KADLUBOWSKI, SLAWOMIR S.; VARCA, GUSTAVO H.C. . Editorial. Radiation Physics and Chemistry, v. 169, SI, 2020. DOI: 10.1016/j.radphyschem.2019.108542

    Palavras-Chave: nanoparticles; radiations; nanomaterials; electron beams

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  • IPEN-DOC 27356

    CORAZZA, FULVIO G.; ERNESTO, JULIA V.; NAMBU, FELIPE A.N.; CALIXTO, LEANDRO A.; VARCA, GUSTAVO H.C. ; VIEIRA, DANIEL P. ; LEITE-SILVA, VANIA R.; ANDREO-FILHO, NEWTON; LOPES, PATRICIA S.. Enhancing the furosemide permeability by papain minitablets through a triple co-culture in vitro intestinal cell model. AAPS PharmSciTech, v. 21, n. 7, p. 1-10, 2020. DOI: 10.1208/s12249-020-01796-9

    Abstract: The administration of medicines by the oral route is the most used approach for being very convenient. Although it is the most popular, this route also has absorption, and consequently, bioavailability limitations. In this sense, several pharmacotechnical strategies have been used to improve drug absorption, one of which is the use of permeation promoters. Papain is a very versatile plant enzyme that can be used as a permeation promoter of various active compounds. This study aimed to evaluate the safety of papain and the formulation of native papain minitablets to promote in vitro permeation of furosemide through an innovative biomimetic triple co-culture model of Caco-2, HT29-MTX, and Raji cells. Regarding permeation, furosemide and metaprolol concentrations are determined with HPLC; those are used to calculate Papp. Monolayer integrity was evaluated using TEER and Lucifer Yellow. In the presence of papain, TEER decreased two-fold and the Papp of furosemide increased six-fold. The results suggest that native papain minitablets can be used as therapeutic adjuvants to enhance the permeation of drugs significantly improving bioavailability.

    Palavras-Chave: drugs; diuretics; papain; permeability; in vitro; animal cells; intestines; mucous membranes; cell cultures; electrical properties

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  • IPEN-DOC 24825

    BATISTA, JORGE G.S. ; BARROS, JANAINA A.G. ; VARCA, GUSTAVO H.C. ; ROGERO, SIZUE O. ; CAVALCANTE, ADRIANA K. ; MAZIERO, JOANA S. ; ROGERO, JOSE R. ; LUGAO, ADEMAR B. . Evaluation of the in vitro and in vivo toxicity of gold nanoparticles synthesized by green nanotechnology. In: PAN AMERICAN CONGRESS OF NANOTECHNOLOGY, 1st, 27-30 de novembro, 2017, Guarujá, SP. Abstract... 2017.

    Abstract: Researchers and laboratories around the world have studied gold nanoparticles. In medicine, several studies demonstrate the applicability of gold nanoparticles (AuNPs) in the treatment and diagnosis of cancer. Green nanotechnology uses phytochemical agents to synthesize and stabilize nanoparticles. The phytochemical epigallocatechin-gallate (EGCG) reduces and stabilize gold nanoparticles by functionalizing the surface of the molecule. Such chemical groups allow binding to overexpressed receptors on some types of tumors as demonstrated in studies performed with PC3 prostate cancer cells. With the advancement of nanotechnology, a large number of nanoparticles are produced on a daily basis. However apart from their possible applications it is necessary to evaluate the environmental impact of these molecules as well as find ways for proper disposal. The embryonic zebrafish (Danio rerio) trial has recently emerged as an interesting method for evaluating in vivo nanotoxicity providing a more complex system analysis than in typical cell cultures and less expensive if compared to large-scale biocompatibility studies performed in rats and mice. The objective of this study was to evaluate the in vitro and in vivo toxicity of EGCG-AuNPs by means of the cytotoxicity by neutral red uptake methodology according to the International Standard Organization [ISO 10993-5, 2009] and in vivo test based on the OECD guideline on Fish Embryo Toxicity Test (FET) (OECD, 2013). The spectrophotometric band at 535 nm observed is characteristic of the formation of AuNPs. Nanoparticles synthesized with EGCG presented a size of 32 ± 4 nm as determined by transmission electron microscopy and the hydrodynamic diameter of these particles was about 60 ± 18 nm obtained by dynamic light scattering. The EGCG-AuNPs showed no cytotoxicity up to 4.2 μg.L-1. In the FET test regarding the acute ecotoxicity assay the LC50/96 hours revealed no toxicity at concentrations up to 1.8 mM.

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  • IPEN-DOC 28434

    ZAHARESCU, TRAIAN; MATEESCU, CARMEN; DIMA, ANDREEA; VARCA, GUSTAVO H.C. . Evaluation of thermal and radiation stability of EPDM in the presence of some algal powders. Journal of Thermal Analysis and Calorimetry, v. 147, n. 1, p. 327-336, 2022. DOI: 10.1007/s10973-020-10319-4

    Abstract: In this paper, ecological-friendly materials based on ethylene–propylene–diene terpolymer (EPDM) with improved thermal and radiation stabilities by Chlorella vulgaris (CV) and Spirulina platensis (SP) powders were investigated by complementary procedures: FTIR spectroscopy and isothermal and nonisothermal chemiluminescence (CL). The stabilization potential of microalgae was evaluated at several degrees of γ-radiolysis by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, while the polymer resistances were studied on a large range of algal concentrations (1, 3, 5 and 10 mass%). The carbonyl and hydroxyl indices of all degraded EPDM formulations were found to be two times smaller in the presence of algal powders, if compared to the pristine material. Some dissimilarities between the oxidation development in pristine and modified EPDM appeared, especially in unirradiated samples. The activation energies required for the oxidation of EPDM and the lifetime of these samples at various temperatures between room temperature and 100 °C were calculated. The antioxidant compounds existing in the studied microalgae proved a significant influence on the stability of EPDM, mainly in the presence of SP, which was confirmed by the activation energies calculated from our CL results. The investigation of cycling thermal degradation revealed the obvious contribution of additives towards delaying EPDM ageing.

    Palavras-Chave: antioxidants; chlorella; ethylene propylene diene polymers; stability; thermal analysis; radiations

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  • IPEN-DOC 24928

    BARROS, JANAINA A.G. ; MAZIERO, JOANA S. ; MAMEDE, FERNANDA C.S. ; CAVALCANTE, ADRIANA K. ; ROGERO, SIZUE O. ; BATISTA, JORGE G.S. ; VARCA, GUSTAVO H.C. ; ROGERO, JOSE R. ; LUGAO, ADEMAR B. . In vitro and in vivo toxicity evaluation of resveratrol assisted gold nanoparticles. In: CONGRESSO DA SOCIEDADE LATINO AMERICANA DE BIOMATERIAIS, ORGAOS ARTIFICIAIS E ENGENHARIA DE TECIDOS, 14.; EDICAO DO WORKSHOP DE BIOMATERIAIS, ENGENHARIA DE TECIDOS E ORGAOS ARTIFICIAIS, 5., 20-24 de agosto, 2017, Maresias, SP. Anais... 2017. p. 926-933.

    Abstract: Gold nanoparticles (AuNP) are being investigated for diagnostic and therapeutic nanomedicines considering their low toxicity and stability against oxidation, among other features. The increasing production and use of AuNP can result in release of them into aquatic environment and the impacts on the aquatic organisms are not clear and the safety of AuNPs are still under investigation. This work aimed analyze the toxicity of resveratrol assisted AuNP synthesized in buffer phosphate pH 7.0 with approximately 47 nm in DLS and 15 nm in TEM analysis and gold ionic solution (Au+3). Cytotoxicity by neutral red uptake method and acute ecotoxicological assay on Daphnia similis were used. AuNP presented no cytotoxicity up to 246 mg L-1 while Au+3 showed IC50=7.95 mg L-1. AuNP CE50 was 113.15 mg L-1 and for Au+3 0.05 mg L-1. More studies can be conducted for the determination of safety ionic Au+3 and AuNP concentrations in aquatic environment.

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  • IPEN-DOC 27033

    OLIVEIRA, JUSTINE P.R. de ; OLIVEIRA, MARIA J.A. de ; SILVA, ISABELA C. da ; VARCA, GUSTAVO H.C. ; LUGAO, ADEMAR B. . Influence of different gamma radiation doses on PVA/gelatin based scaffolds. In: DUDALA, JOANNA (Ed.); CIECHANOWSKI, MAREK (Ed.) INTERNATIONAL CONFERENCE ON DEVELOPMENTS AND APPLICATIONS OF NUCLEAR TECHNOLOGIES, September 10-13, 2017, Kraków, Poland. Abstract... Kraków, Poland: AGH University of Science and Technology - Faculty of Science and Applied Computer Science, 2017. p. 27-27.

    Abstract: The present work aimed to study the influence of different radiation doses on a polymer blend at cryogenic and room temperature by means of crosslinking formation, pore size, morphology, topography and mechanical properties. The scaffold was prepared based on two formulations, one composed by gelatin (7%, w/w) and PVA (5%, w/w), and the second by gelatin (10%, w/w) and PVA (5%, w/w). The formulations were separately solubilized in distilled water and heated up to 80 ºC under constant stirring for 1 hour. Posteriorly, both blends were disposed in circular glass moulds. Half of samples was frozen for at least 24 h and then irradiated at 15, 25 and 50 kGy. The other half was cooled at 4 ºC for at least 24 h and then irradiated using the same doses. After irradiation both sample groups were frozen and freeze dried. The scaffold was characterized in terms of structure and morphology by mechanical assays, differential scanning calorimetry, scanning electron microscopy, optical coherence tomography and infrared spectroscopy. In addition, platelet adhesion and release, and cytotoxic assays were also performed. Samples irradiated at 15 kGy presented pore size diameter of around 1.4 μm and porosity of 54%, while samples irradiated at 25 kGy, presented pore size diameter of around 1.1 μm and porosity of 49%. Optical coherence tomography showed that gelatin control samples presented more superficial degradation as irradiation dose increased, while PVA control sample presented higher integrity, indicating that this polymer is less sensitive to gamma radiation. The system presented suitable mechanical properties and the platelet adhesion and release assays showed that the scaffold presented adequate pore size range to host and release the platelets, and non-cytotoxic to platelets, featuring adequate properties to be applied as dressing for wound treatments.

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  • IPEN-DOC 21674

    VARCA, GUSTAVO H.C. ; QUEIROZ, RODRIGO G. ; LUGAO, ADEMAR B. . Irradiation as an alternative route for protein crosslinking: Cosolvent free BSA nanoparticles. Radiation Physics and Chemistry, v. 124, p. 111-115, 2016.

    Palavras-Chave: gamma radiation; cross-linking; nanoparticles; albumins; synthesis; solvents; spectroscopy; fluorescence spectroscopy; proteins

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A pesquisa no RD utiliza os recursos de busca da maioria das bases de dados. No entanto algumas dicas podem auxiliar para obter um resultado mais pertinente.

✔ É possível efetuar a busca de um autor ou um termo em todo o RD, por meio do Buscar no Repositório , isto é, o termo solicitado será localizado em qualquer campo do RD. No entanto esse tipo de pesquisa não é recomendada a não ser que se deseje um resultado amplo e generalizado.

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Exemplo:

Buscar os artigos apresentados em um evento internacional de 2015, sobre loss of coolant, do autor Maprelian.

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Ano de publicação: 2015

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O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.

A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

1. Portaria IPEN-CNEN/SP nº 387, que estabeleceu os princípios que nortearam a criação do RDI, clique aqui.


2. A experiência do Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP) na criação de um Repositório Digital Institucional – RDI, clique aqui.

O Repositório Digital do IPEN é um equipamento institucional de acesso aberto, criado com o objetivo de reunir, preservar, disponibilizar e conferir maior visibilidade à Produção Científica publicada pelo Instituto, desde sua criação em 1956.

Operando, inicialmente como uma base de dados referencial o Repositório foi disponibilizado na atual plataforma, em junho de 2015. No Repositório está disponível o acesso ao conteúdo digital de artigos de periódicos, eventos, nacionais e internacionais, livros, capítulos, dissertações, teses e relatórios técnicos.

A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.