ABSTRACT The X-ray diffraction data of l-serine anhydrous crystals was taken into account to init... more ABSTRACT The X-ray diffraction data of l-serine anhydrous crystals was taken into account to initialize the total energy minimization process of their unit cell through density functional theory (DFT) computations, which were performed within both the local density and generalized gradient approximations with dispersion, LDA, and GGA+D, respectively. The calculated lattice parameters are in good agreement with the experimental results for the dispersion corrected generalized gradient approximation functional, with a unit cell volume larger by only about 0.32%; the Mulliken and Hirschfield charges show the zwitterionic state of the l-serine molecules in the DFT converged crystals. The electronic (band structure, density of states) and optical absorption properties were calculated to explain the light absorption of the l-serine anhydrous crystalline powder we have measured at room temperature. The optical absorption related to transitions between the top of the valence band and the bottom of the conduction band involves O-2p valence states and H-1s conduction states. The LDA (4.74 eV) and GGA+D (4.75 eV) estimated energy gaps are about 1 eV below the estimated value from optical absorption measurements (5.90 eV). Small values were obtained for the electron effective masses, which are almost isotropic, whereas large anisotropic values were found for hole effective masses, suggesting that the l-serine anhydrous crystal behaves like an n-type wide gap semiconductor. Different dielectric function profiles obtained for some of the most important symmetry directions also demonstrate the optical anisotropy of l-serine anhydrous crystals.
Due to their excellent surface properties, gold nanoparticles have been used in a wide range of a... more Due to their excellent surface properties, gold nanoparticles have been used in a wide range of applications from optics and catalysis to biology and cancer treatment by thermal therapy. Gold nanoparticles can absorb a large amount of radiation according to their geometry, such as nanospheres and nanorods. The importance of gold nanoparticles geometry is based on the electromagnetic spectrum wavelength where exists a greater absorption of radiation, which belongs to the visible region for nanospheres and ranges between visible and near infrared regions for nanorods, conferring greater biomedical applicability to the latter. When using photochemical synthesis method, which consists of reducing gold atoms to their metallic state with UV radiation, the geometry of gold nanoparticles depends on different variables such as: 1) pH, 2) concentration of chloroauric acid, 3) the surfactant, 4) concentration of silver nitrate, 5) temperature and 6) irradiation time. Therefore, in this study the geometry of the gold nanoparticles obtained by photochemical synthesis was determined as a function of solution pH and chloroauric acid concentration, using Spectrophotometry in the Ultraviolet Visible region (UV-vis) as characterization technique. From the analysis of the UVvis spectra, it was determined that at an acidic pH the particles have two absorption bands corresponding to nanorods geometry, while at a basic pH only nanospheres are found and at a neutral pH the lower relative intensity of the second band indicates the simultaneous existence of the two geometries. The increase in the concentration of chloroauric acid produces a decrease in the amount of synthesized nanorods, seen as a decrease of the relative intensity of the second absorption band. Therefore, obtaining gold nanoparticles with nanorods geometry favours fields such as biomedicine, because they are capable of absorbing infrared radiation and can be used as photosensitive agents in localized thermal therapy against cancer.
Physica E-low-dimensional Systems & Nanostructures, May 1, 2017
For the first time, patterned growth of boron nitride nanostructures (BNNs) is achieved by therma... more For the first time, patterned growth of boron nitride nanostructures (BNNs) is achieved by thermal chemical vapor deposition (TCVD) technique at 1150 °C using a mixture of FeS/Fe2O3 catalyst supported in alumina nanostructured, boron amorphous and ammonia (NH3) as reagent gas. This innovative catalyst was synthesized in our laboratory and systematically characterized. The materials were characterized by X-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The X-ray diffraction profile of the synthesized catalyst indicates the coexistence of three different crystal structures showing the presence of a cubic structure of iron oxide and iron sulfide besides the gamma alumina (γ) phase. The results show that boron nitride bamboo-like nanotubes (BNNTs) and hexagonal boron nitride (h-BN) nanosheets were successfully synthesized. Furthermore, the important contribution of this work is the manufacture of BNNs from FeS/Fe2O3 mixture.
Abstract In this letter, we study the electronic structure and optical properties of the active m... more Abstract In this letter, we study the electronic structure and optical properties of the active medicinal component γ -aminobutyric acid (GABA) and its cocrystals with oxalic (OXA) and benzoic (BZA) acid by means of the density functional theory formalism. It is shown that the cocrystallization strongly weakens the zwitterionic character of the GABA molecule leading to striking differences among the electronic band structures and optical absorption spectra of the GABA crystal and GABA:OXA, GABA:BZA cocrystals, originating from distinct sets of hydrogen bonds. Calculated band widths and Δ -sol band gap estimates indicate that both GABA and GABA:OXA, GABA:BZA cocrystals are indirect gap insulators.
Visceral leishmaniasis (VL) is a systemic parasitic disease that leads to high rates of morbidity... more Visceral leishmaniasis (VL) is a systemic parasitic disease that leads to high rates of morbidity and mortality in humans worldwide. There is a great need to develop new drugs and novel strategies to make chemotherapy for this disease more efficacious and well tolerated. Recent reports on the immunomodulatory effects and the low toxicity of the spherical carbon nanostructure fullerol led us to investigate in vitro and in vivo antileishmanial activity in free and encapsulated forms in liposomes. When assayed against intramacrophagic Leishmania amastigotes, fullerol showed a dose-dependent reduction of the infection index with IC50 of 0.042 mg/mL. When given daily by i.p. route for 20 days (0.05 mg/kg/d) in a murine model of acute VL, fullerol promoted significant reduction in the liver parasite load. To improve the delivery of fullerol to the infection sites, liposomal formulations were prepared by the dehydration-rehydration method. When evaluated in the acute VL model, liposomal fullerol (Lip-Ful) formulations given i.p. at 0.05 and 0.2 mg/kg with 4-days intervals were more effective than the free form, with significant parasite reductions in both liver and spleen. Lip-Ful at 0.2 mg/kg promoted complete parasite elimination in the liver. The antileishmanial activity of Lip-Ful was further confirmed in a chronic model of VL. Lip-Ful was also found to induce secretion of pro-inflammatory TNF-α, IFN-γ and IL-1β cytokines. In conclusion, this work reports for the first time the antileishmanial activity of fullerol and introduces an innovative approach for treatment of VL based on the association of this nanostructure with liposomes.
Neste trabalho, foram sintetizados e caracterizados nanofios de prata que posteriormente foram us... more Neste trabalho, foram sintetizados e caracterizados nanofios de prata que posteriormente foram usados para produção de uma tinta condutora cuja, caracterização elétrica foi medida através de valores de tensão versus corrente. A primeira fase do trabalho consiste na obtenção dos nanofios pelo método poliol. Nesta fase, fez-se uma análise da estrutura dos fios, com o objetivo de verificar a uniformidade (forma e tamanho). Para estudos da estrutura utilizou-se a microscopia ótica (MO) e microscopia eletrônica de varredura (MEV). Também utilizou-se a espectroscopia de Ultravioleta-Visível (Uv-Vis) para identificação dos nanofios no produto obtido. A segunda fase, consiste no desenvolvimento da tinta condutora, onde nanofios foram redispersados em uma mistura de solventes e CTAB em banho de ultrassom, para obtenção de valores de tensão superficial e viscosidade. Por fim, medidas de corrente contínua da tinta, permitiram a construção da curva tensão versus corrente, da qual se obteve o valor da resistência elétrica. Através da curva foi possível comprovar o caráter condutor da tinta e pela linearidade da curva, verificou-se que a tinta produzida é considerada um material ôhmico. Palavras-chave: Nanofios de prata; Tinta condutora; Resistência elétrica; Lei de ohms.
Particle & Particle Systems Characterization, Feb 6, 2022
In this paper, a localized surface plasmon resonance (LSPR)‐based biosensor, computationally guid... more In this paper, a localized surface plasmon resonance (LSPR)‐based biosensor, computationally guided to detect selectively the four Dengue virus (DENVx) serotypes in seropositive patients, is presented. The behavior of gold nanoparticles in the shape of nanorods is theoretically and numerically studied as a function of induced structural variations, which are experimentally evidenced due to the bio‐interaction between the target analytes and its surface during the detection process. Additionally, with the implementation of the largest Lyapunov exponent, it is possible to calculate the notion of predictability for the experimental results, observing chaotic systems with a very low probability of repetition. Due to the above, when analyzing the recurrence map associated with the obtained resonance curve generated by the LSPR system, the genetic similarity of DENV3/DENV2 and DENV4/DENV1 is evidenced. Finally, the biosensors are validated by analyzing samples of seronegative patients for DENVx and seropositive ones for other Flaviviruses such as Zika virus, Yellow Fever virus, and Saint Louis Encephalitis virus.
Environmental Nanotechnology, Monitoring and Management, Dec 1, 2021
Abstract In recent years, studies using the green chemistry approach for the synthesis of metalli... more Abstract In recent years, studies using the green chemistry approach for the synthesis of metallic nanoparticles (Nps) have been increasingly explored. Gold Nps (GNps) produced from natural compounds, such as hydroalcoholic extracts or essential oils from plants, can have greater stability, monodispersion, faster and more efficient synthesis, and can be an interesting alternative to conventional synthesis. In this work the seedless synthesis of gold nanorods (GNRs) using resveratrol (RSV), gallic acid (GA) and a fraction of the hydroalcoholic extract of Stryphnodendron obovatum was explored. The main objective was to characterize their stability and surface chemistry to demonstrate the natural products presence. Characterizations were made by Ultaviolet-Visible Absorption Spectrophotometry (UV-Vis), Transmission Electron Microscopy (TEM), Zeta Potential, Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Photoelectron Spectroscopy (XPS). The results showed that the natural compounds used in the synthesis of GNRs favor the production of more stable particles, in addition to remaining anchored on its surface which reinforces, and allows us to suggest, several applications in the biomedical area of the GNRs thus produced.
Particle & Particle Systems Characterization, Mar 1, 2022
In this paper, a localized surface plasmon resonance (LSPR)‐based biosensor, computationally guid... more In this paper, a localized surface plasmon resonance (LSPR)‐based biosensor, computationally guided to detect selectively the four Dengue virus (DENVx) serotypes in seropositive patients, is presented. The behavior of gold nanoparticles in the shape of nanorods is theoretically and numerically studied as a function of induced structural variations, which are experimentally evidenced due to the bio‐interaction between the target analytes and its surface during the detection process. Additionally, with the implementation of the largest Lyapunov exponent, it is possible to calculate the notion of predictability for the experimental results, observing chaotic systems with a very low probability of repetition. Due to the above, when analyzing the recurrence map associated with the obtained resonance curve generated by the LSPR system, the genetic similarity of DENV3/DENV2 and DENV4/DENV1 is evidenced. Finally, the biosensors are validated by analyzing samples of seronegative patients for DENVx and seropositive ones for other Flaviviruses such as Zika virus, Yellow Fever virus, and Saint Louis Encephalitis virus.
Gold nanoparticles enhance antibody-fluorescence detection by flow cytometry reducing the signal ... more Gold nanoparticles enhance antibody-fluorescence detection by flow cytometry reducing the signal to noise ratio and improving cell biology assessments.
Resonance Raman spectroscopy with an energy tunable system is used to analyze the 600-1100 cm ÿ1 ... more Resonance Raman spectroscopy with an energy tunable system is used to analyze the 600-1100 cm ÿ1 spectral region in single-wall carbon nanotubes. Sharp peaks are associated with the combination of zone folded optic and acoustic branches from 2D graphite. These combination modes exhibit a peculiar dependence on the excitation laser energy that is explained on the basis of a highly selective resonance process that considers phonons and electrons in low dimensional materials.
Journal of controlled release : official journal of the Controlled Release Society, Jan 8, 2018
Schistosomiasis is an important parasitic disease affecting >207 million people in 76 countrie... more Schistosomiasis is an important parasitic disease affecting >207 million people in 76 countries around the world and causing approximately 250,000 deaths per year. At present, the main strategy adopted for the control of schistosomiasis is the use of safe chemotherapy, such as praziquantel. However, the high rates of reinfection after treatment restrict the use of this treatment approach and assume the need for other forms of control such as vaccination. Sm29 is a protein that is localized in the Schistosoma mansoni tegument of adult worms and schistosomula and is considered a powerful vaccine candidate. Because of the chemical, physical and immunological characteristics of nanoparticles, nanocarriers have received increasing attention. In the field of nanotechnology, gold nanorods are considered potential vaccine carriers. In this study, we bound S. mansoni rSm29 protein to gold nanorods either directly or by cysteamine functionalization. When the worm burden was evaluated, the ...
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Irradiation of tumor cell lines is a useful way to investigate the effects of ionizing radiation ... more Irradiation of tumor cell lines is a useful way to investigate the effects of ionizing radiation on biological molecules. We designed an easy and reproducible approach for in vitro experimental high dose rate brachytherapy, which was simulated by a Monte Carlo code and dosimetrically characterized by experimental methods to evaluate the correspondence between planned doses and doses absorbed by the cells. This approach is an acrylic platform containing T25 tissue culture flasks and multiwell tissue culture plates. It allows nine parallel needles carrying an 192Ir source to irradiate the adherent cells. The whole system composed of the acrylic platform, tissue culture flasks and 192Ir source tracking was simulated by the Monte Carlo N-Particle transport code (MCNPX). Dosimetric measurements were taken by well ionization chamber and radiochromic films. There was a slight difference, averaging from 2% to 7%, between the MCNPX results and film dosimetry results regarding uniform radiation created by the source arrangement. The results showed different values for planned and measured doses in each cell culture plate, which was attributed to the non-equivalent water material used and to the lack of full scattering coming from the top of the platform. This last contribution was different for each tissue culture plate and an individual dose correction factor was calculated. The dose correction factor must be applied to match the planned dose and the actual doses absorbed by the cells. The designed approach is an efficient tool for in vitro brachytherapy experiments for most commercial cell culture plates.
ABSTRACT The X-ray diffraction data of l-serine anhydrous crystals was taken into account to init... more ABSTRACT The X-ray diffraction data of l-serine anhydrous crystals was taken into account to initialize the total energy minimization process of their unit cell through density functional theory (DFT) computations, which were performed within both the local density and generalized gradient approximations with dispersion, LDA, and GGA+D, respectively. The calculated lattice parameters are in good agreement with the experimental results for the dispersion corrected generalized gradient approximation functional, with a unit cell volume larger by only about 0.32%; the Mulliken and Hirschfield charges show the zwitterionic state of the l-serine molecules in the DFT converged crystals. The electronic (band structure, density of states) and optical absorption properties were calculated to explain the light absorption of the l-serine anhydrous crystalline powder we have measured at room temperature. The optical absorption related to transitions between the top of the valence band and the bottom of the conduction band involves O-2p valence states and H-1s conduction states. The LDA (4.74 eV) and GGA+D (4.75 eV) estimated energy gaps are about 1 eV below the estimated value from optical absorption measurements (5.90 eV). Small values were obtained for the electron effective masses, which are almost isotropic, whereas large anisotropic values were found for hole effective masses, suggesting that the l-serine anhydrous crystal behaves like an n-type wide gap semiconductor. Different dielectric function profiles obtained for some of the most important symmetry directions also demonstrate the optical anisotropy of l-serine anhydrous crystals.
Due to their excellent surface properties, gold nanoparticles have been used in a wide range of a... more Due to their excellent surface properties, gold nanoparticles have been used in a wide range of applications from optics and catalysis to biology and cancer treatment by thermal therapy. Gold nanoparticles can absorb a large amount of radiation according to their geometry, such as nanospheres and nanorods. The importance of gold nanoparticles geometry is based on the electromagnetic spectrum wavelength where exists a greater absorption of radiation, which belongs to the visible region for nanospheres and ranges between visible and near infrared regions for nanorods, conferring greater biomedical applicability to the latter. When using photochemical synthesis method, which consists of reducing gold atoms to their metallic state with UV radiation, the geometry of gold nanoparticles depends on different variables such as: 1) pH, 2) concentration of chloroauric acid, 3) the surfactant, 4) concentration of silver nitrate, 5) temperature and 6) irradiation time. Therefore, in this study the geometry of the gold nanoparticles obtained by photochemical synthesis was determined as a function of solution pH and chloroauric acid concentration, using Spectrophotometry in the Ultraviolet Visible region (UV-vis) as characterization technique. From the analysis of the UVvis spectra, it was determined that at an acidic pH the particles have two absorption bands corresponding to nanorods geometry, while at a basic pH only nanospheres are found and at a neutral pH the lower relative intensity of the second band indicates the simultaneous existence of the two geometries. The increase in the concentration of chloroauric acid produces a decrease in the amount of synthesized nanorods, seen as a decrease of the relative intensity of the second absorption band. Therefore, obtaining gold nanoparticles with nanorods geometry favours fields such as biomedicine, because they are capable of absorbing infrared radiation and can be used as photosensitive agents in localized thermal therapy against cancer.
Physica E-low-dimensional Systems & Nanostructures, May 1, 2017
For the first time, patterned growth of boron nitride nanostructures (BNNs) is achieved by therma... more For the first time, patterned growth of boron nitride nanostructures (BNNs) is achieved by thermal chemical vapor deposition (TCVD) technique at 1150 °C using a mixture of FeS/Fe2O3 catalyst supported in alumina nanostructured, boron amorphous and ammonia (NH3) as reagent gas. This innovative catalyst was synthesized in our laboratory and systematically characterized. The materials were characterized by X-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The X-ray diffraction profile of the synthesized catalyst indicates the coexistence of three different crystal structures showing the presence of a cubic structure of iron oxide and iron sulfide besides the gamma alumina (γ) phase. The results show that boron nitride bamboo-like nanotubes (BNNTs) and hexagonal boron nitride (h-BN) nanosheets were successfully synthesized. Furthermore, the important contribution of this work is the manufacture of BNNs from FeS/Fe2O3 mixture.
Abstract In this letter, we study the electronic structure and optical properties of the active m... more Abstract In this letter, we study the electronic structure and optical properties of the active medicinal component γ -aminobutyric acid (GABA) and its cocrystals with oxalic (OXA) and benzoic (BZA) acid by means of the density functional theory formalism. It is shown that the cocrystallization strongly weakens the zwitterionic character of the GABA molecule leading to striking differences among the electronic band structures and optical absorption spectra of the GABA crystal and GABA:OXA, GABA:BZA cocrystals, originating from distinct sets of hydrogen bonds. Calculated band widths and Δ -sol band gap estimates indicate that both GABA and GABA:OXA, GABA:BZA cocrystals are indirect gap insulators.
Visceral leishmaniasis (VL) is a systemic parasitic disease that leads to high rates of morbidity... more Visceral leishmaniasis (VL) is a systemic parasitic disease that leads to high rates of morbidity and mortality in humans worldwide. There is a great need to develop new drugs and novel strategies to make chemotherapy for this disease more efficacious and well tolerated. Recent reports on the immunomodulatory effects and the low toxicity of the spherical carbon nanostructure fullerol led us to investigate in vitro and in vivo antileishmanial activity in free and encapsulated forms in liposomes. When assayed against intramacrophagic Leishmania amastigotes, fullerol showed a dose-dependent reduction of the infection index with IC50 of 0.042 mg/mL. When given daily by i.p. route for 20 days (0.05 mg/kg/d) in a murine model of acute VL, fullerol promoted significant reduction in the liver parasite load. To improve the delivery of fullerol to the infection sites, liposomal formulations were prepared by the dehydration-rehydration method. When evaluated in the acute VL model, liposomal fullerol (Lip-Ful) formulations given i.p. at 0.05 and 0.2 mg/kg with 4-days intervals were more effective than the free form, with significant parasite reductions in both liver and spleen. Lip-Ful at 0.2 mg/kg promoted complete parasite elimination in the liver. The antileishmanial activity of Lip-Ful was further confirmed in a chronic model of VL. Lip-Ful was also found to induce secretion of pro-inflammatory TNF-α, IFN-γ and IL-1β cytokines. In conclusion, this work reports for the first time the antileishmanial activity of fullerol and introduces an innovative approach for treatment of VL based on the association of this nanostructure with liposomes.
Neste trabalho, foram sintetizados e caracterizados nanofios de prata que posteriormente foram us... more Neste trabalho, foram sintetizados e caracterizados nanofios de prata que posteriormente foram usados para produção de uma tinta condutora cuja, caracterização elétrica foi medida através de valores de tensão versus corrente. A primeira fase do trabalho consiste na obtenção dos nanofios pelo método poliol. Nesta fase, fez-se uma análise da estrutura dos fios, com o objetivo de verificar a uniformidade (forma e tamanho). Para estudos da estrutura utilizou-se a microscopia ótica (MO) e microscopia eletrônica de varredura (MEV). Também utilizou-se a espectroscopia de Ultravioleta-Visível (Uv-Vis) para identificação dos nanofios no produto obtido. A segunda fase, consiste no desenvolvimento da tinta condutora, onde nanofios foram redispersados em uma mistura de solventes e CTAB em banho de ultrassom, para obtenção de valores de tensão superficial e viscosidade. Por fim, medidas de corrente contínua da tinta, permitiram a construção da curva tensão versus corrente, da qual se obteve o valor da resistência elétrica. Através da curva foi possível comprovar o caráter condutor da tinta e pela linearidade da curva, verificou-se que a tinta produzida é considerada um material ôhmico. Palavras-chave: Nanofios de prata; Tinta condutora; Resistência elétrica; Lei de ohms.
Particle & Particle Systems Characterization, Feb 6, 2022
In this paper, a localized surface plasmon resonance (LSPR)‐based biosensor, computationally guid... more In this paper, a localized surface plasmon resonance (LSPR)‐based biosensor, computationally guided to detect selectively the four Dengue virus (DENVx) serotypes in seropositive patients, is presented. The behavior of gold nanoparticles in the shape of nanorods is theoretically and numerically studied as a function of induced structural variations, which are experimentally evidenced due to the bio‐interaction between the target analytes and its surface during the detection process. Additionally, with the implementation of the largest Lyapunov exponent, it is possible to calculate the notion of predictability for the experimental results, observing chaotic systems with a very low probability of repetition. Due to the above, when analyzing the recurrence map associated with the obtained resonance curve generated by the LSPR system, the genetic similarity of DENV3/DENV2 and DENV4/DENV1 is evidenced. Finally, the biosensors are validated by analyzing samples of seronegative patients for DENVx and seropositive ones for other Flaviviruses such as Zika virus, Yellow Fever virus, and Saint Louis Encephalitis virus.
Environmental Nanotechnology, Monitoring and Management, Dec 1, 2021
Abstract In recent years, studies using the green chemistry approach for the synthesis of metalli... more Abstract In recent years, studies using the green chemistry approach for the synthesis of metallic nanoparticles (Nps) have been increasingly explored. Gold Nps (GNps) produced from natural compounds, such as hydroalcoholic extracts or essential oils from plants, can have greater stability, monodispersion, faster and more efficient synthesis, and can be an interesting alternative to conventional synthesis. In this work the seedless synthesis of gold nanorods (GNRs) using resveratrol (RSV), gallic acid (GA) and a fraction of the hydroalcoholic extract of Stryphnodendron obovatum was explored. The main objective was to characterize their stability and surface chemistry to demonstrate the natural products presence. Characterizations were made by Ultaviolet-Visible Absorption Spectrophotometry (UV-Vis), Transmission Electron Microscopy (TEM), Zeta Potential, Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Photoelectron Spectroscopy (XPS). The results showed that the natural compounds used in the synthesis of GNRs favor the production of more stable particles, in addition to remaining anchored on its surface which reinforces, and allows us to suggest, several applications in the biomedical area of the GNRs thus produced.
Particle & Particle Systems Characterization, Mar 1, 2022
In this paper, a localized surface plasmon resonance (LSPR)‐based biosensor, computationally guid... more In this paper, a localized surface plasmon resonance (LSPR)‐based biosensor, computationally guided to detect selectively the four Dengue virus (DENVx) serotypes in seropositive patients, is presented. The behavior of gold nanoparticles in the shape of nanorods is theoretically and numerically studied as a function of induced structural variations, which are experimentally evidenced due to the bio‐interaction between the target analytes and its surface during the detection process. Additionally, with the implementation of the largest Lyapunov exponent, it is possible to calculate the notion of predictability for the experimental results, observing chaotic systems with a very low probability of repetition. Due to the above, when analyzing the recurrence map associated with the obtained resonance curve generated by the LSPR system, the genetic similarity of DENV3/DENV2 and DENV4/DENV1 is evidenced. Finally, the biosensors are validated by analyzing samples of seronegative patients for DENVx and seropositive ones for other Flaviviruses such as Zika virus, Yellow Fever virus, and Saint Louis Encephalitis virus.
Gold nanoparticles enhance antibody-fluorescence detection by flow cytometry reducing the signal ... more Gold nanoparticles enhance antibody-fluorescence detection by flow cytometry reducing the signal to noise ratio and improving cell biology assessments.
Resonance Raman spectroscopy with an energy tunable system is used to analyze the 600-1100 cm ÿ1 ... more Resonance Raman spectroscopy with an energy tunable system is used to analyze the 600-1100 cm ÿ1 spectral region in single-wall carbon nanotubes. Sharp peaks are associated with the combination of zone folded optic and acoustic branches from 2D graphite. These combination modes exhibit a peculiar dependence on the excitation laser energy that is explained on the basis of a highly selective resonance process that considers phonons and electrons in low dimensional materials.
Journal of controlled release : official journal of the Controlled Release Society, Jan 8, 2018
Schistosomiasis is an important parasitic disease affecting >207 million people in 76 countrie... more Schistosomiasis is an important parasitic disease affecting >207 million people in 76 countries around the world and causing approximately 250,000 deaths per year. At present, the main strategy adopted for the control of schistosomiasis is the use of safe chemotherapy, such as praziquantel. However, the high rates of reinfection after treatment restrict the use of this treatment approach and assume the need for other forms of control such as vaccination. Sm29 is a protein that is localized in the Schistosoma mansoni tegument of adult worms and schistosomula and is considered a powerful vaccine candidate. Because of the chemical, physical and immunological characteristics of nanoparticles, nanocarriers have received increasing attention. In the field of nanotechnology, gold nanorods are considered potential vaccine carriers. In this study, we bound S. mansoni rSm29 protein to gold nanorods either directly or by cysteamine functionalization. When the worm burden was evaluated, the ...
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Irradiation of tumor cell lines is a useful way to investigate the effects of ionizing radiation ... more Irradiation of tumor cell lines is a useful way to investigate the effects of ionizing radiation on biological molecules. We designed an easy and reproducible approach for in vitro experimental high dose rate brachytherapy, which was simulated by a Monte Carlo code and dosimetrically characterized by experimental methods to evaluate the correspondence between planned doses and doses absorbed by the cells. This approach is an acrylic platform containing T25 tissue culture flasks and multiwell tissue culture plates. It allows nine parallel needles carrying an 192Ir source to irradiate the adherent cells. The whole system composed of the acrylic platform, tissue culture flasks and 192Ir source tracking was simulated by the Monte Carlo N-Particle transport code (MCNPX). Dosimetric measurements were taken by well ionization chamber and radiochromic films. There was a slight difference, averaging from 2% to 7%, between the MCNPX results and film dosimetry results regarding uniform radiation created by the source arrangement. The results showed different values for planned and measured doses in each cell culture plate, which was attributed to the non-equivalent water material used and to the lack of full scattering coming from the top of the platform. This last contribution was different for each tissue culture plate and an individual dose correction factor was calculated. The dose correction factor must be applied to match the planned dose and the actual doses absorbed by the cells. The designed approach is an efficient tool for in vitro brachytherapy experiments for most commercial cell culture plates.
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Papers by Luiz Orlando Ladeira