Hygroscopic behavior of lyophilized products can be visualized starting from the construction of ... more Hygroscopic behavior of lyophilized products can be visualized starting from the construction of Moisture Sorption Isotherms (MSI). Such curves show the relationship between the maximum amount of absorbed water for a substance, with the equilibrium vapor pressure or water activity, at a given constant temperature. Aimed to study later the reconstitution and use of biological materials of lyophilized bovine pericardium, it was plot adsorption and desorption curves, at temperatures of 15, 25 and 35°C, on HydrosorbTM 1000 - water vapor sorption analyzer. The results showed MSI type II, according BET classification, typical reaction of hydrophilic surfaces with monolayer and multilayer formation. Histerese phenomenon was observed during the whole MSI interval. The mathematical models of BET and GAB fitted well the experimental data and allowed the water monolayer calculation, estimate the critical level of residual moisture that assures more stability to the product.O comportamento higr...
Chitosan, a chitin-derivative polysaccharide, known for its non-toxicity, biocompatibility and bi... more Chitosan, a chitin-derivative polysaccharide, known for its non-toxicity, biocompatibility and biodegradability, presents limited applications due to its low solubility in neutral or basic pH medium. Quaternization stands out as an alternative to modify this natural polymer, aiming to improve its solubility over a wide pH range and, consequently, expand its range of applications. Quaternization occurs by introducing a quaternary ammonium moiety onto or outside the chitosan backbone, via chemical reactions with primary amino and hydroxyl groups, under vast experimental conditions. The oldest and most common forms of quaternized chitosan involve N,N,N-trimethyl chitosan (TMC) and N-[(2-hydroxy-3-trimethyl ammonium) propyl] chitosan (HTCC) and, more recently, quaternized chitosan by insertion of pyridinium or phosphonium salts. By modifying chitosan through the insertion of a quaternary moiety, permanent cationic charges on the polysaccharide backbone are achieved and properties such a...
The increasing need for point-of-care diagnosis has sparked the development of label-free sensing... more The increasing need for point-of-care diagnosis has sparked the development of label-free sensing platforms, some of which are based on impedance measurements with biological cells. Here, interdigitated electrodes were functionalized with layer-by-layer (LbL) films of hyaluronan (HA) and chitosan (CHI) to detect prostatic tumor cells (PC3 line). The deposition of LbL films was confirmed with atomic force microscopy and polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS), which featured the vibrational modes of the HA top layer capable of interacting specifically with glycoprotein CD44 receptors overexpressed in tumor cells. Though the CHI/HA LbL films cannot be considered as a traditional biosensor due to their limited selectivity, it was possible to distinguish prostate tumor cells in the range from 50 to 600 cells/µL in in vitro experiments with impedance spectroscopy. This was achieved by treating the impedance data with information visualization methods...
Silk fibroin (SF) and konjac glucomannan (KGM) are promising materials in the biomedical field du... more Silk fibroin (SF) and konjac glucomannan (KGM) are promising materials in the biomedical field due to their low toxicity, biocompatibility, biodegradability and low immune response. Beads of these natural polymers are interesting scaffolds for biomedical applications, but their fabrication is a challenge due to their low stability and the necessary adaptation of their chemical and mechanical properties to be successfully applied. In that sense, this study aimed to synthesize a blend of silk fibroin and konjac glucomannan (SF/KGM) in the form of porous beads obtained through dripping into liquid nitrogen, with a post-treatment using ethanol. Intermolecular hydrogen bonds promoted the integration of SF and KGM. Treated beads showed higher porous size, crystallinity, and stability than untreated beads. Characterization analyses by Fourier-transform infrared spectroscopy (FTIR), thermogravimetric (TGA), and X-ray diffraction (XDR) evidenced that ethanol treatment allows a conformational...
Revista dos Trabalhos de Iniciação Científica da UNICAMP, 2019
Este trabalho foi dedicado ao desenvolvimento de filmes finos de ácido hialurônico e quitosana pa... more Este trabalho foi dedicado ao desenvolvimento de filmes finos de ácido hialurônico e quitosana para a captura de células tumorais prostáticas. Os recobrimentos foram feitos com a técnica Layer-by-Layer, por meio da qual são construídas camadas alternadas de polieletrólitos de cargas opostas. Devido à interação dos receptores CD44, superexpressos em células tumorais, com o ácido hialurônico, este configurou a última camada depositada nos filmes. Foram utilizadas condições variadas de pH e número de bicamadas, de forma a investigar tais fatores nas propriedades físico-químicas e no potencial seletivo dos recobrimentos. As caracterizações foram feitas através das técnicas de Perfilometria, Ângulo de Contato,UV-Visível e Microscopia de Força Atômica. Já os testes de adesão foram realizados com células tumorais prostáticas da linhagem PC3.
Langmuir : the ACS journal of surfaces and colloids, Jan 6, 2018
Chitosan-based thin films were assembled using the layer-by-layer technique and the axial composi... more Chitosan-based thin films were assembled using the layer-by-layer technique and the axial composition was accessed using X-ray photoelectron spectroscopy with depth profiling. Chitosan (CHI) samples possessing different degree of acetylation (DA) and molecular weight (Mv) produced via ultrasound assisted deacetylation reaction were used in this study as well as two different polyanions, namely sodium polystyrene sulfonate (SPS) and carboxymethylcellulose (CMC). When chitosan, a positively charged polymer in aqueous acid medium, was combined with a strong polyanion (SPS), the total positive charge of chitosan, directly related to its D), was the key factor affecting the film formation. However, for CMC/CHI films, the pH of the medium and Mv of chitosan strongly affected film structure and composition. Consequently, the structure and the axial composition of chitosan-based films can be finely adjusted by choosing the polyanion and defining the chitosan to be used according to its DA a...
Miscibility is an important issue in biopolymer blends for analysis of the behavior of polymer pa... more Miscibility is an important issue in biopolymer blends for analysis of the behavior of polymer pairs through the detection of phase separation and improvement of the mechanical and physical properties of the blend. This study presents the formulation of a stable and one-phase mixture of collagen and regenerated silk fibroin (RSF), with the highest miscibility ratio between these two macromolecules, through inducing electrostatic interactions, using salt ions. For this aim, a ternary phase diagram was experimentally built for the mixtures, based on observations of phase behavior of blend solutions with various ratios. The miscibility behavior of the blend solutions in the miscible zones of the phase diagram was confirmed quantitatively by viscosimetric measurements. Assessing the effects of biopolymer mixing ratio and salt ions, before and after dialysis of blend solutions, revealed the importance of ion-specific interactions in the formation of coacervate-based materials containing ...
Silk fibroin (SF) and sodium alginate (SA) offer promising properties for application as biomater... more Silk fibroin (SF) and sodium alginate (SA) offer promising properties for application as biomaterials, especially as artificial skin and wound dressing. By blending SF and SA, it is possible to conjugate their properties, producing a material with suitable mechanical properties and good efficiency for wound healing applications. Degree of swelling in water, water contact angle, water vapor transmission, tensile strength and in vitro cytotoxicity tests were performed on blend membranes and in the pure component membranes. The blend membrane presented intermediate values for all tests when compared to pure SF and pure SA. SA membrane presented the highest degree of swelling (310%), while SF presented 59.5% of swelling. The water vapor transmission was also higher for SA membrane. SA presented the lowest water contact angle. It is known that the cellular adhesion and growth is enhanced in hydrophilic surfaces. The tensile strength of SA, blend and SF membranes were 95.70 MPa, 73.00 MPa...
O comportamento higroscópico de produtos desidratados pode ser visualizado a partir da construção... more O comportamento higroscópico de produtos desidratados pode ser visualizado a partir da construção de curvas denominadas Isotermas de Sorção de Umidade (ISU). Esse tipo de curva relaciona a quantidade máxima de água absorvida por uma substância, com a pressão de vapor de equilíbrio ou a atividade de água, numa dada temperatura mantida constante. Com o objetivo de estudar posteriormente a reconstituição, material de embalagem e utilização de implantes feitos a partir de pericárdio bovino liofilizado, foram traçadas curvas de adsorção e dessorção de umidade em um analisador de sorção de vapor de água, HydrosorbTM 1000, nas temperaturas de 15, 25 e 35°C. Os resultados obtidos mostraram ISU tendendo ao tipo II, segundo a classificação de BET, reação típica de superfícies hidrofílicas com formação de monocamada e multicamadas. O fenômeno da histerese foi observado durante todo o intervalo da ISU. Os modelos matemáticos de Brunauer-Emmett-Teller (BET) e Guggenheim-Anderson-de Boer (GAB) aj...
Hygroscopic behavior of lyophilized products can be visualized starting from the construction of ... more Hygroscopic behavior of lyophilized products can be visualized starting from the construction of Moisture Sorption Isotherms (MSI). Such curves show the relationship between the maximum amount of absorbed water for a substance, with the equilibrium vapor pressure or water activity, at a given constant temperature. Aimed to study later the reconstitution and use of biological materials of lyophilized bovine pericardium, it was plot adsorption and desorption curves, at temperatures of 15, 25 and 35°C, on HydrosorbTM 1000 - water vapor sorption analyzer. The results showed MSI type II, according BET classification, typical reaction of hydrophilic surfaces with monolayer and multilayer formation. Histerese phenomenon was observed during the whole MSI interval. The mathematical models of BET and GAB fitted well the experimental data and allowed the water monolayer calculation, estimate the critical level of residual moisture that assures more stability to the product.O comportamento higr...
Chitosan, a chitin-derivative polysaccharide, known for its non-toxicity, biocompatibility and bi... more Chitosan, a chitin-derivative polysaccharide, known for its non-toxicity, biocompatibility and biodegradability, presents limited applications due to its low solubility in neutral or basic pH medium. Quaternization stands out as an alternative to modify this natural polymer, aiming to improve its solubility over a wide pH range and, consequently, expand its range of applications. Quaternization occurs by introducing a quaternary ammonium moiety onto or outside the chitosan backbone, via chemical reactions with primary amino and hydroxyl groups, under vast experimental conditions. The oldest and most common forms of quaternized chitosan involve N,N,N-trimethyl chitosan (TMC) and N-[(2-hydroxy-3-trimethyl ammonium) propyl] chitosan (HTCC) and, more recently, quaternized chitosan by insertion of pyridinium or phosphonium salts. By modifying chitosan through the insertion of a quaternary moiety, permanent cationic charges on the polysaccharide backbone are achieved and properties such a...
The increasing need for point-of-care diagnosis has sparked the development of label-free sensing... more The increasing need for point-of-care diagnosis has sparked the development of label-free sensing platforms, some of which are based on impedance measurements with biological cells. Here, interdigitated electrodes were functionalized with layer-by-layer (LbL) films of hyaluronan (HA) and chitosan (CHI) to detect prostatic tumor cells (PC3 line). The deposition of LbL films was confirmed with atomic force microscopy and polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS), which featured the vibrational modes of the HA top layer capable of interacting specifically with glycoprotein CD44 receptors overexpressed in tumor cells. Though the CHI/HA LbL films cannot be considered as a traditional biosensor due to their limited selectivity, it was possible to distinguish prostate tumor cells in the range from 50 to 600 cells/µL in in vitro experiments with impedance spectroscopy. This was achieved by treating the impedance data with information visualization methods...
Silk fibroin (SF) and konjac glucomannan (KGM) are promising materials in the biomedical field du... more Silk fibroin (SF) and konjac glucomannan (KGM) are promising materials in the biomedical field due to their low toxicity, biocompatibility, biodegradability and low immune response. Beads of these natural polymers are interesting scaffolds for biomedical applications, but their fabrication is a challenge due to their low stability and the necessary adaptation of their chemical and mechanical properties to be successfully applied. In that sense, this study aimed to synthesize a blend of silk fibroin and konjac glucomannan (SF/KGM) in the form of porous beads obtained through dripping into liquid nitrogen, with a post-treatment using ethanol. Intermolecular hydrogen bonds promoted the integration of SF and KGM. Treated beads showed higher porous size, crystallinity, and stability than untreated beads. Characterization analyses by Fourier-transform infrared spectroscopy (FTIR), thermogravimetric (TGA), and X-ray diffraction (XDR) evidenced that ethanol treatment allows a conformational...
Revista dos Trabalhos de Iniciação Científica da UNICAMP, 2019
Este trabalho foi dedicado ao desenvolvimento de filmes finos de ácido hialurônico e quitosana pa... more Este trabalho foi dedicado ao desenvolvimento de filmes finos de ácido hialurônico e quitosana para a captura de células tumorais prostáticas. Os recobrimentos foram feitos com a técnica Layer-by-Layer, por meio da qual são construídas camadas alternadas de polieletrólitos de cargas opostas. Devido à interação dos receptores CD44, superexpressos em células tumorais, com o ácido hialurônico, este configurou a última camada depositada nos filmes. Foram utilizadas condições variadas de pH e número de bicamadas, de forma a investigar tais fatores nas propriedades físico-químicas e no potencial seletivo dos recobrimentos. As caracterizações foram feitas através das técnicas de Perfilometria, Ângulo de Contato,UV-Visível e Microscopia de Força Atômica. Já os testes de adesão foram realizados com células tumorais prostáticas da linhagem PC3.
Langmuir : the ACS journal of surfaces and colloids, Jan 6, 2018
Chitosan-based thin films were assembled using the layer-by-layer technique and the axial composi... more Chitosan-based thin films were assembled using the layer-by-layer technique and the axial composition was accessed using X-ray photoelectron spectroscopy with depth profiling. Chitosan (CHI) samples possessing different degree of acetylation (DA) and molecular weight (Mv) produced via ultrasound assisted deacetylation reaction were used in this study as well as two different polyanions, namely sodium polystyrene sulfonate (SPS) and carboxymethylcellulose (CMC). When chitosan, a positively charged polymer in aqueous acid medium, was combined with a strong polyanion (SPS), the total positive charge of chitosan, directly related to its D), was the key factor affecting the film formation. However, for CMC/CHI films, the pH of the medium and Mv of chitosan strongly affected film structure and composition. Consequently, the structure and the axial composition of chitosan-based films can be finely adjusted by choosing the polyanion and defining the chitosan to be used according to its DA a...
Miscibility is an important issue in biopolymer blends for analysis of the behavior of polymer pa... more Miscibility is an important issue in biopolymer blends for analysis of the behavior of polymer pairs through the detection of phase separation and improvement of the mechanical and physical properties of the blend. This study presents the formulation of a stable and one-phase mixture of collagen and regenerated silk fibroin (RSF), with the highest miscibility ratio between these two macromolecules, through inducing electrostatic interactions, using salt ions. For this aim, a ternary phase diagram was experimentally built for the mixtures, based on observations of phase behavior of blend solutions with various ratios. The miscibility behavior of the blend solutions in the miscible zones of the phase diagram was confirmed quantitatively by viscosimetric measurements. Assessing the effects of biopolymer mixing ratio and salt ions, before and after dialysis of blend solutions, revealed the importance of ion-specific interactions in the formation of coacervate-based materials containing ...
Silk fibroin (SF) and sodium alginate (SA) offer promising properties for application as biomater... more Silk fibroin (SF) and sodium alginate (SA) offer promising properties for application as biomaterials, especially as artificial skin and wound dressing. By blending SF and SA, it is possible to conjugate their properties, producing a material with suitable mechanical properties and good efficiency for wound healing applications. Degree of swelling in water, water contact angle, water vapor transmission, tensile strength and in vitro cytotoxicity tests were performed on blend membranes and in the pure component membranes. The blend membrane presented intermediate values for all tests when compared to pure SF and pure SA. SA membrane presented the highest degree of swelling (310%), while SF presented 59.5% of swelling. The water vapor transmission was also higher for SA membrane. SA presented the lowest water contact angle. It is known that the cellular adhesion and growth is enhanced in hydrophilic surfaces. The tensile strength of SA, blend and SF membranes were 95.70 MPa, 73.00 MPa...
O comportamento higroscópico de produtos desidratados pode ser visualizado a partir da construção... more O comportamento higroscópico de produtos desidratados pode ser visualizado a partir da construção de curvas denominadas Isotermas de Sorção de Umidade (ISU). Esse tipo de curva relaciona a quantidade máxima de água absorvida por uma substância, com a pressão de vapor de equilíbrio ou a atividade de água, numa dada temperatura mantida constante. Com o objetivo de estudar posteriormente a reconstituição, material de embalagem e utilização de implantes feitos a partir de pericárdio bovino liofilizado, foram traçadas curvas de adsorção e dessorção de umidade em um analisador de sorção de vapor de água, HydrosorbTM 1000, nas temperaturas de 15, 25 e 35°C. Os resultados obtidos mostraram ISU tendendo ao tipo II, segundo a classificação de BET, reação típica de superfícies hidrofílicas com formação de monocamada e multicamadas. O fenômeno da histerese foi observado durante todo o intervalo da ISU. Os modelos matemáticos de Brunauer-Emmett-Teller (BET) e Guggenheim-Anderson-de Boer (GAB) aj...
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