Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 8.006
Filtrar
1.
Chemosphere ; 242: 125287, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31896200

RESUMO

A novel electrospun dual-responsive polyethersulfone-poly(dimethyl amino) ethyl methacrylate nanofibrous adsorbent was fabricated via electrospinning for the removal of Cu (II) from aqueous solution. Morphological, chemical, and dual-responsiveness of the composite nanofibrous adsorbent were characterized using scanning electron microscope equipped with energy dispersive x-ray, Fourier transform infrared, and UV-VIS spectrophotometer, respectively. The obtained uniform and bead-free nanofibers were then used for the removal of Cu (II) from aqueous solution. Results showed that the temperature-responsiveness of the nanofibers is dependent on the pH of the solution, as indicated by the decreasing lower critical solution temperature with increasing pH level. Temperature and pH offer a synergistic effect on the adsorption of Cu (II), with maximum adsorption observed at pH 6.5 at 55 °C. Kinetic, thermodynamic, and isotherm studies indicate that the adsorption of copper ions follows chemisorption and is thermodynamically favored at increasing temperature. From the Langmuir isotherm model, the obtained maximum adsorption capacity, qm, was 161.30 mg g-1 at 55 °C. From the desorption studies, results showed that the maximum desorption was observed at pH 3 at 25 °C. In conclusion, PES-PDMAEMA has the capability to adsorb and desorb Cu (II) by adjusting both pH and temperature, hence it can be considered as an efficient and economical adsorbent for heavy metals such Cu (II).


Assuntos
Cobre/análise , Metacrilatos/química , Nanofibras/química , Nylons/química , Polímeros/química , Sulfonas/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Concentração de Íons de Hidrogênio , Íons , Cinética , Propriedades de Superfície , Temperatura Ambiente , Termodinâmica
2.
Drug Dev Ind Pharm ; 46(1): 146-158, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31894720

RESUMO

The aim of this research was to assess the effect of polymer blend and effervescent components on the floating and swelling behaviors of swellable gastro-floating formulation as well as the drug release through a compartmental modeling analysis. Swellable gastro-floating formulation of freely water-soluble drug, metformin HCl as a drug model, was formulated and developed using D-optimal design. Polymer combination between interpolymer complex (IPC) (poly-vinyl acetate-copolymer methacrylate) and hydroxy propyl methyl cellulose (HPMC), and effervescent components were studied and optimized in this work. Several factors affecting the drug release behavior were determined e.g. swelling behavior, erosion behavior, and floating behavior were studied as well as the drug release through compartmental modeling analysis. The results revealed that the hydrophilic polymer was responsible for gas entrapment formed from effervescent reaction, meanwhile IPC contributed on maintaining the swollen matrix integrity through intermolecular polymer interaction. In addition, effervescent components played fundamental role in the formation of porous system as well as inducing burst release effect. Compartmental modeling provided different outlook about the drug release. Presence of IPC at a high proportion (10-15%) of the polymer blend modulated the changes of pattern of the drug release kinetics and mechanism. Finally, compartmental modeling-based approach was more adequate to describe the drug release kinetics and mechanism compared to the monophasic equation model correlating with process understanding of the drug release from swellable gastro-floating formulation.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Metacrilatos/química , Polímeros/química , Estômago/fisiologia , Administração Oral , Liberação Controlada de Fármacos , Derivados da Hipromelose/química , Derivados da Hipromelose/farmacologia , Cinética , Metacrilatos/farmacologia , Comprimidos
3.
Chem Biol Interact ; 315: 108870, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31669216

RESUMO

The toxic effects of poly(HEMA)-based polymeric nanoparticles must be analyzed before their biomedical applications as drug delivery systems. The aim of the study was to characterize and evaluate the toxicity for its biocompatibility of a newly synthesized l-glutamic acid-g-p(HEMA) polymeric nanoparticle The nanoparticle was synthesized with surfactant-free emulsion polymerization and grafting techniques. Grafting efficiency was estimated at 58%. The nanoparticle shape was verified as nearly spherical by scanning electron microscopy. Atomic force microscopy images showed a rough surface topography. The nanoparticle had an average size of ~194.6 nm on zeta analysis, and the zeta potential value was -18 mV. Fourier transformed infrared spectroscopy revealed spectra from 750 to 4000 cm-1 and characteristic peaks of stretching bands. The swelling ratio was 46%. With 24-h exposure, p(HEMA) and l-glutamic acid-g-p(HEMA) did not have cytotoxic effects on a human bronchial epithelial cell line (16HBE) and human monocyte cell line by water-soluble tetrazolium salt 1 (WST-1) assay and lactate dehydrogenase assay (LDH). It did not show genotoxic potential by comet assay and did not have mutagenic effects on Salmonella typhimurium TA98, TA100, TA1535 and TA1537 strains by Ames test. The nanoparticle at 160 µg/ml showed 2% hemolytic activity on erythrocytes. On cell migration assay, the percentage closure difference between exposed and control cells was estimated at 21%. We found no irritation effect on Hen's egg test-chorioallantoic membrane test. We determined that the polymeric nanoparticle l-glutamic acid-g-p(HEMA) was biocompatible and has potential for use in a drug delivery system.


Assuntos
Metacrilatos/química , Metacrilatos/toxicidade , Nanopartículas/química , Nanopartículas/toxicidade , Polímeros/química , Polímeros/toxicidade , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/toxicidade , Linhagem Celular , Galinhas , Sistemas de Liberação de Medicamentos/métodos , Emulsões/química , Emulsões/farmacologia , Emulsões/toxicidade , Eritrócitos/efeitos dos fármacos , Humanos , Monócitos/efeitos dos fármacos , Tamanho da Partícula , Coelhos , Salmonella typhimurium/efeitos dos fármacos , Propriedades de Superfície/efeitos dos fármacos , Tensoativos/química
4.
J Chromatogr A ; 1609: 460455, 2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31443967

RESUMO

In this paper, a novel core-shell structure magnetic microsphere Fe3O4@SiO2-TPM@StVp(Fe3O4@SiO2-3-(trimethoxysilyl)propyl methacrylate@styrene and n-vinylpyrrolidone) was successfully synthesized and used as a magnetic solid-phase extraction adsorbent for extraction of aristolochic acid I (AAI) in traditional Chinese medicine soup. The prepared Fe3O4@SiO2-TPM@StVp was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM) and Fourier-transform infrared spectroscopy (FT-IR). The microspheres have various advantages of excellent hydrophilicity and π-electron system, which is very suitable for determining target analytes followed by high performance liquid chromatography (HPLC). The main factors, including the pH of samples, amount of adsorbent, adsorption time, elution solvent and desorption time, were optimized. Under optimal conditions, the proposed method showed a wide linear range of 0.4-10 µg/mL and a good correlation coefficient (R2 = 0.9918). The pretreatment procedure was achieved within 10 min. The recoveries of aristolochic acid I in real samples range from 80.9% to 89.6% with relative standard deviations less than 4.9%, highlighting the accuracy of this method.


Assuntos
Ácidos Aristolóquicos/análise , Cromatografia Líquida de Alta Pressão/métodos , Fenômenos Magnéticos , Medicina Tradicional Chinesa , Extração em Fase Sólida/métodos , Adsorção , Compostos Férricos/química , Concentração de Íons de Hidrogênio , Metacrilatos/química , Microesferas , Padrões de Referência , Reprodutibilidade dos Testes , Dióxido de Silício/química , Solventes , Espectroscopia de Infravermelho com Transformada de Fourier , Fatores de Tempo
5.
J Chromatogr A ; 1609: 460446, 2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31420178

RESUMO

Two new copolymer-grafted silica stationary phases were prepared and employed in hydrophilic interaction chromatography (HILIC). 2-(Dimethylamino)ethyl methacrylate (DMAEMA) are copolymerized with itaconic acid (IA) and acrylic acid (AA) respectively, via thiol-ene click reaction on silica surface with deep eutectic solvents (DES) as new solvents. The obtained poly(DMAEMA-co-itaconic acid)-grafted silica (Sil-PDM-PIA) and poly(DMAEMA-co-acrylic acid)-grafted silica (Sil-PDM-PAA) were characterized by Fourier transform infrared spectroscopy, elemental analysis and solid-state 13C NMR spectra. Their hydrophilic interaction performances were evaluated by separating nucleosides, nucleobases, saccharides, and amino acids. Compared with previous reported poly(itaconic acid)-grafted silica (Sil-PIA) and poly(acrylic acid)-grafted silica (Sil-PAA) stationary phases, these two new copolymer-grafted silica performed higher selectivity and better separation for polar analytes in HILIC.


Assuntos
Cromatografia/métodos , Química Click/métodos , Interações Hidrofóbicas e Hidrofílicas , Polímeros/química , Dióxido de Silício/química , Solventes/química , Compostos de Sulfidrila/química , Acetonitrilos/química , Aminoácidos/isolamento & purificação , Entropia , Concentração de Íons de Hidrogênio , Espectroscopia de Ressonância Magnética , Metacrilatos/química , Nucleosídeos/isolamento & purificação , Nylons/química , Reprodutibilidade dos Testes , Sais/química , Espectroscopia de Infravermelho com Transformada de Fourier , Succinatos/química , Temperatura Ambiente
6.
Chemosphere ; 239: 124736, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31494326

RESUMO

In this work, a novel process involving the preparation of nanochitosan-grafted flocculants (CPAM-g-NCS) to treat low turbid and salmonella suspensions simultaneously was introduced. Nanotechnology was employed to enhance the adsorption-adhesion and sterilization abilities of dual-functional flocculants. The monomers of chitosan, acrylamide, methacryloyl ethyl trimethyl ammonium chloride, and sodium tripolyphosphate were utilized for flocculants copolymerization. Then, using fourier-transform infrared spectroscopy, nuclear magnetic resonance hydrogen spectrum, and thermogravimetric and differential scanning calorimetry analysis, the successful synthesis of CPAM-g-NCS was verified. Scanning electron microscopy and size analysis suggested that nanostructured flocculants with irregular morphology and nanocolloids of 60.44 nm were formed. CPAM-g-NCS was applied to treat a series of simulated low turbid and salmonella suspensions. The simulation results showed that the minimum residual turbidity of 1.97 NTU and optical density of 0.16 (initial 0.89) can be achieved at dosages of 2.5 and 8.75 mg L-1, respectively, which were superior to conventional organics flocculants. Mechanistic studies suggested that the excellent adsorption property, and large numbers of quaternary ammonium and amino groups of nanoflocculants contributed to the superior flocculation and antibacterial performance of CPAM-g-NCS.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Nanoestruturas/química , Purificação da Água/métodos , Acrilamida/química , Varredura Diferencial de Calorimetria , Quitosana/química , Floculação , Espectroscopia de Ressonância Magnética , Metacrilatos/química , Microscopia Eletrônica de Varredura , Polimerização , Salmonella typhimurium/efeitos dos fármacos , Espectroscopia de Infravermelho com Transformada de Fourier , Suspensões , Termogravimetria , Microbiologia da Água
7.
Chemosphere ; 239: 124732, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31499304

RESUMO

A polar modified post-cross-linked poly (divinylbenzene-co-ethyleneglycol-dimethacrylate) (PCL-PDE) resin was synthesized by suspension polymerization of ethylene glycol dimethacrylate (EGDMA) and divinylbenzene (DVB), and a post-cross-linked reaction. After characterization, the adsorption behaviors of 5-hydroxymethylfurfural (5-HMF) on PCL-PDE resin were determined in comparison with the starting copolymers PDE resin. The equilibrium adsorption capacity of 5-HMF on PCL-PDE resin was much larger than PDE resin and the increase rate was greater than 52.6%. The equilibrium data of 5-HMF onto PCL-PDE resin were found to be better fitted by the Langmuir isotherm model. The kinetic data shows that the adsorption reached equilibrium in a short time (less than 20 min) can be fitted by the pore diffusion model (PDM) at various operating conditions. The effective pore diffusion coefficient was dependent upon adsorption temperature, and were 6.706 × 10-10, 8.958 × 10-10, 1.136 × 10-9 and 1.429 × 10-9 m2 s-1 at 288, 298, 308 and 318 K, respectively. Furthermore, the effects of feed flow rate (Qf = 0.6, 1.5, 3.0 and 6.0 mL min-1) and initial 5-HMF concentration (cf = 0.52, 1.02, 2.00 and 4.96 g L-1) on the adsorption were investigated systematically. Besides, a general rate model (GRM) was used to predict adsorption breakthrough curves of 5-HMF. The simulation results are highly consistent with the experimental data, indicating that the GRM can successfully simulate this process. In the desorption process, the desorption capacity reaches 99.6% of adsorbed capacity, suggesting that the PCL-PDE resin exhibited good reusability. Therefore, it could be suggested that the PCL-PDE resin has a potential application in the separation and purification of 5-HMF.


Assuntos
Resinas Acrílicas/química , Furaldeído/análogos & derivados , Resinas Acrílicas/síntese química , Adsorção , Reagentes para Ligações Cruzadas/química , Difusão , Furaldeído/química , Furaldeído/isolamento & purificação , Cinética , Metacrilatos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura Ambiente , Compostos de Vinila/química
8.
Chemosphere ; 240: 124866, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31546191

RESUMO

Three series of co-graft cationic starch (St)-based flocculants with distinct structural characteristics, namely, charge density (CD), graft-chain length (L), and graft-chain distribution (N), were successfully synthesized through graft copolymerization of [(2-methacryloyloxyethyl) trimethyl ammonium chloride] and acrylamide. These St-based flocculants with different molecular structures were used to flocculate various kaolin suspensions with different initial turbidities and a sodium humate (NaHA) aqueous solution. The experimental results indicated that CD contributed to flocculation evidently, whereas average L and its N were insignificant in experimentally measured ranges. On the basis of phenomenological theory, a second-order polynomial equation was used to further quantitatively analyze the effects of the three structural factors on the flocculation performance of these St-based flocculants, which were fully consistent with the experimental results. Besides, the optimal dose and its corresponding removal rate could be predicted exactly, and the flocculation mechanisms were discussed in detail according to the established models. With the combination of floc properties and zeta potentials, the flocculation mechanisms of these St-based flocculants for flocculation of kaolin suspensions and NaHA aqueous solution were mainly ascribed to charge patching and simple charge neutralization, respectively. These results improve the understanding of the structure-activity relationship of these graft St-based flocculants, which is of significant guidance for the utilization and design of novel flocculants.


Assuntos
Acrilamida/química , Substâncias Húmicas , Metacrilatos/química , Amido/química , Floculação , Caulim/química , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Polímeros , Espectroscopia de Infravermelho com Transformada de Fourier , Relação Estrutura-Atividade , Purificação da Água/métodos
9.
Chem Commun (Camb) ; 56(6): 908-911, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31850411

RESUMO

Poly(glycerol methacrylate) chitosan nanospheres were facilely one-pot synthesized. For the first time, poly(glycerol methacrylate) with a highly flexible density of hydrophilic molecules grafted on the surface of chitosan was applied to highly specific enrichment of glycopeptides.


Assuntos
Quitosana/química , Glicopeptídeos/análise , Metacrilatos/química , Configuração de Carboidratos , Quitosana/síntese química , Interações Hidrofóbicas e Hidrofílicas , Metacrilatos/síntese química , Nanosferas/química , Tamanho da Partícula , Propriedades de Superfície
10.
Chem Commun (Camb) ; 55(96): 14506-14509, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31735949

RESUMO

Polymers are an attractive anchoring platform for the synthesis of radioimmunoconjugates. They enable independent control over the amount of radioisotope loading and antibody attachment, which is pivotal in developing tailorable formulations for personalised medicine. Herein, we report the synthesis of p(HEMA-ran-GMA) for the conjugation of lutetium ions and rituximab as a functional platform for radioimmunotherapy. We demonstrate the suitability of this platform using non-Hodgkin's lymphoma cells.


Assuntos
Imunoconjugados/química , Linfoma não Hodgkin/radioterapia , Radioimunoterapia , Antineoplásicos Imunológicos/química , Antineoplásicos Imunológicos/farmacologia , Antineoplásicos Imunológicos/uso terapêutico , Sobrevivência Celular/efeitos dos fármacos , Química Click , Compostos de Epóxi/química , Humanos , Imunoconjugados/farmacologia , Imunoconjugados/uso terapêutico , Lutécio/química , Metacrilatos/química , Polímeros/química , Rituximab/química , Rituximab/farmacologia , Rituximab/uso terapêutico
11.
Int J Mol Sci ; 20(20)2019 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-31614713

RESUMO

Gelatin methacrylate (GelMA) has been gaining popularity in recent years as a photo-crosslinkable biomaterial widely used in a variety of bioprinting and tissue engineering applications. Several studies have established the effects of process-based and material-based parameters on the physical-mechanical properties and microstructure of GelMA hydrogels. However, the effect of encapsulated cells on the physical-mechanical properties and microstructure of GelMA hydrogels has not been fully understood. In this study, 3T3 fibroblasts were encapsulated at different cell densities within the GelMA hydrogels and incubated over 96 h. The effects of encapsulated cells were investigated in terms of mechanical properties (tensile modulus and strength), physical properties (swelling and degradation), and microstructure (pore size). Cell viability was also evaluated to confirm that most cells were alive during the incubation. It was found that with an increase in cell density, the mechanical properties decreased, while the degradation and the pore size increased.


Assuntos
Gelatina/química , Hidrogéis/química , Metacrilatos/química , Resistência à Tração , Tecidos Suporte/química , Células 3T3 , Animais , Fibroblastos/citologia , Interações Hidrofóbicas e Hidrofílicas , Camundongos , Porosidade , Engenharia Tecidual/métodos
12.
J Appl Oral Sci ; 27: e20180262, 2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31508789

RESUMO

The incorporation of antimicrobials in the composites as an attempt to reduce bacterial adhesion without jeopardizing mechanical properties is a challenge for Dentistry. OBJECTIVE To evaluate the bacterial adhesion and physical properties of a composite containing the methacrylate triclosan- derivative monomer (TM). METHODOLOGY TM was synthesized and added to an experimental composite. Samples were divided into two groups: Control and TM (13.4 wt%). Antibacterial Activity: Three specimens of each material were prepared and placed on bacterial suspensions of Streptococcus mutans for 1, 5 and 10 days. After these periods the counting of the colonies (log10) was performed. Assays was performed in triplicate. Physical Properties: Three-body Abrasion (TBA): Ten specimens of each material were prepared and stored at 37°C/24 h. The surface roughness (Ra) and hardness (KHN) were analyzed. Next, the specimens were submitted to abrasive wear (30,000 cycles) and re-evaluated for Ra and KHN; Sorption/solubility (SS): cylindrical specimens (n=10) were prepared and weighted. The specimens were immersed in deionized water for 7 days at 37°C and then their weight was verified again. SS were calculated using accepted formulas; Diametral tensile strength (DTS): specimens (n=10) underwent test performed in an Instron universal testing machine at a crosshead speed of 1 mm/min. Data were submitted to appropriate statistical tests according to data distribution and assay (p<0.05). RESULTS Bacterial Adhesion: TM showed a significant reduction on biofilm accumulation in the evaluated periods: 1 day (1.537±0.146); 5 days (2.183±0.138) and 10 days (4.469±0.155) when compared with Control: 1 day (4.954±0.249); 5 days (5.498±0.257) and 10 days (6.306±0.287). Physical Properties: For TBA, SS and DTS no significant difference was found between groups Control and TM. The incorporation of methacrylate triclosan-based monomer in the experimental composite reduce bacterial adhesion of S. mutans and did not affect important polymer properties.


Assuntos
Antibacterianos/química , Resinas Compostas/química , Metacrilatos/química , Triclosan/química , Antibacterianos/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Contagem de Colônia Microbiana , Resinas Compostas/farmacologia , Testes de Dureza , Teste de Materiais , Metacrilatos/farmacologia , Valores de Referência , Reprodutibilidade dos Testes , Solubilidade , Streptococcus mutans/efeitos dos fármacos , Propriedades de Superfície , Resistência à Tração , Fatores de Tempo , Escovação Dentária , Triclosan/farmacologia
13.
Artigo em Inglês | MEDLINE | ID: mdl-31525722

RESUMO

Activators regenerated by electron transfer atom transfer radical polymerization (AGET ATRP) were firstly used in suspension polymerization to prepare macroporous microspheres based on a copolymer of glycidyl methacrylate and ethylene glycol dimethacrylate. Compared to conventional radical polymerization (CRP), the microspheres by AGET ATRP showed more homogeneous structure, larger pores, and higher protein binding capacity. The body of microspheres are formed by the large clusters resulted from the aggregated little particles. The size of the particles in microspheres by AGET ATRP was 10-300 nm which was smaller than that (400-800 nm) of the microspheres by CRP. AGET ATRP gave larger pore size (275 ±â€¯5 nm) and surface area (59.3 ±â€¯1 m2/g) than CRP (234 ±â€¯5 nm, 37.5 ±â€¯1 m2/g). The microspheres were modified with polyethylene imine for anion resins that were evaluated in term of its protein binding capacity. The results indicated that the static (69 ±â€¯0.5 mg/mL) and dynamic binding capacity (61 ±â€¯0.5 mg/mL) of proteins on modified microspheres by AGET ATRP were higher than that (34 ±â€¯0.5 mg/mL and 19 ±â€¯0.5 mg/mL) by CRP. Meanwhile, the proteins binding capacity on the microspheres by AGET ATRP decreased only less than 10% when the flow rate increased 10 times. These macroporous media show a large potential in rapid separation of proteins.


Assuntos
Etilenoglicóis/química , Metacrilatos/química , Microesferas , Proteínas/isolamento & purificação , Cromatografia em Gel/métodos , Tamanho da Partícula , Polimerização , Porosidade , Ligação Proteica , Proteínas/química , Proteínas/metabolismo
14.
Eur J Pharm Biopharm ; 144: 174-179, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31541663

RESUMO

Capsules are a widely used oral dosage form due to their simplicity and ease of manufacture. They are equally popular for both pharmaceutical and nutraceutical products and since they do not need extensive formulation development, it is a dosage form of choice for new drugs undergoing animal or clinical trials. In addition to the standard hard-gelatin or cellulose-based vegetarian capsules, functional capsules such as those with built-in gastroresistance would be of great value. In this work, commonly used enteric polymers were investigated for the production of hard-capsules. The polymers used in this study included cellulose derivatives (HPMC AS-LF and HP-55) and acrylic/methacrylic acid derivatives (EUDRAGIT L100 and S100). A range of concentrations of polymers and plasticisers were tested to optimise the formulation for the production of capsule shells with desirable physicochemical and gastroresistance characteristics. Drug release from optimised capsules produced from HPMC AS-LF, HP-55, EUDRAGIT L100 and S100 was shown to be comparable to drug release from corresponding polymer-coated tablets in both compendial and physiological bicarbonate buffer. In summary, herein we report a simple method for producing enteric capsule shells which do not need an additional coating step which, if validated at large scale, can significantly reduce the cost of manufacturing of conventional enteric coated dosage forms. These capsules are also likely to improve the inter-tablet variability in post-gastric drug release inherent in conventional dosage forms due to coating variability.


Assuntos
Cápsulas/química , Polímeros/química , Bicarbonatos/química , Tampões (Química) , Celulose/química , Química Farmacêutica/métodos , Preparações de Ação Retardada/química , Sistemas de Liberação de Medicamentos/métodos , Liberação Controlada de Fármacos/efeitos dos fármacos , Excipientes/química , Gelatina/química , Concentração de Íons de Hidrogênio , Metacrilatos/química , Metilcelulose/análogos & derivados , Metilcelulose/química , Ácidos Polimetacrílicos/química , Solubilidade/efeitos dos fármacos , Comprimidos/química
15.
Biosens Bioelectron ; 143: 111636, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31476596

RESUMO

Ketamine is one of the most widely abused drugs in the world and poses a serious threat to human health and social stability; therefore, the ability to accurately monitor the substance in real-time is necessary. However, several problems still exists towards this goal, such as the generally low concentration of the target molecules disturbed in the complex samples that undergo analysis during criminal investigations. In this work, the sensitive and selective detection of ketamine was accomplished by molecularly imprinted electrochemical sensor. The molecularly imprinted membrane as a biomimetic recognition element was fabricated by the UV-induced polymerization of methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) on a metal-organic framework/graphene nanocomposite (MOFs@G) modified screen-printed electrode. The screen printed electrode (SPE) provided good adhesion for the formation of the imprinted membranes and increased the stability of the sensor. The morphology and performance of the imprinted films were characterized in detail by scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). The experimental results demonstrated that the imprinted sensor had excellent sensitivity, selectivity, and long-term stability. It offered a low detection limit (4.0 × 10-11 mol L-1) and had a dynamic range from 1.0 × 10-10 mol L-1 to 4.0 × 10-5 mol L-1. Furthermore, the established method was successfully applied for the determination of ketamine in urine and saliva samples.


Assuntos
Técnicas Biossensoriais , Grafite/isolamento & purificação , Ketamina/isolamento & purificação , Impressão Molecular , Etilenoglicol/química , Grafite/química , Humanos , Ketamina/química , Estruturas Metalorgânicas/química , Metacrilatos/química , Nanocompostos/química
16.
Nat Commun ; 10(1): 3936, 2019 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-31477728

RESUMO

Janus colloids with one attractive patch on an otherwise repulsive particle surface serve as model systems to explore structure formation of particles with chemically heterogeneous surfaces such as proteins. While there are numerous computer studies, there are few experimental realizations due to a lack of means to produce such colloids with a well-controlled variable Janus balance. Here, we report a simple scalable method to precisely vary the Janus balance over a wide range and selectively functionalize one patch with DNA. We observe, via experiment and simulation, the dynamic formation of diverse superstructures: colloidal micelles, chains, or bilayers, depending on the Janus balance. Flexible dimer chains form through cooperative polymerization while trimer chains form by a two-stage process, first by cooperative polymerization into disordered aggregates followed by condensation into more ordered stiff trimer chains. Introducing substrate binding through depletion catalyzes dimer chains to form nonequilibrium rings that otherwise do not form.


Assuntos
Coloides/química , Micelas , Polímeros/química , Coloides/síntese química , Simulação por Computador , DNA/química , Cinética , Metacrilatos/química , Modelos Químicos , Modelos Moleculares , Compostos de Organossilício/química , Tamanho da Partícula , Polimerização , Polímeros/síntese química , Poliestirenos/química , Propriedades de Superfície
17.
Mater Sci Eng C Mater Biol Appl ; 104: 109894, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499968

RESUMO

This paper describes the fabrication of topologically anisotropic cup shaped polylactide (PLA)/poly[methyl methacrylate­co­2­(2­bromopropionyloxy) ethyl methacrylate] (poly(MMA-co-BEMA)) (75/25) composite particles of ~6 µm size using electrojetting technique. An attempt was made to understand the mechanism of cup shape formation from the miscible blend by electrojetting. Both the solution parameters and the processing conditions affected the particles' shape which can be varied from cup shaped to discoid type. Surface initiated atom transfer radical polymerization (ATRP) of stimuli responsive DMAEMA (2­dimethylamino ethyl methacrylate) was subsequently carried out for 1 h onto the surface of cup shaped particles to observe pH responsiveness of the modified anisotropic particles. Interestingly, morphology of the cup shaped particles was changed to elongated cup which did show significant swelling under acidic pH (swelling ratio:~1.6) and enhanced dye adsorption at specific pH as observed by optical microscope and confocal laser scanning microscope implying that DMAEMA polymerization happened onto the surface of the composite microparticles. The Raman microscopy and FTIR spectra obtained from the particles after polymerization further confirmed the immobilization of pH responsive poly(DMAEMA) brushes onto the cup shaped particles which may potentially function as triggered/targeted drug delivery vehicles. Moreover, the brush modified cup shaped particles were found to be two times more efficient in adsorbing dye compared to disc shaped one indicating a clear advantage of using cup shaped particles over other shapes for immobilizing/adsorbing charged species e.g. sensitive biomolecules.


Assuntos
Polímeros/química , Adsorção , Anisotropia , Concentração de Íons de Hidrogênio , Metacrilatos/química , Polimerização , Propriedades de Superfície
18.
Mater Sci Eng C Mater Biol Appl ; 104: 109952, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499985

RESUMO

The aim of this work is to provide a new kind of polyurethane with improved surface blood compatibility for long-term blood-contacting biomaterials. In the study, an aliphatic poly(ester-urethane) (H-PEU) with uniform-size hard segments was synthesized by one-step chain extension of poly(ε-caprolactone) (PCL) with diurethane diisocyanate (HBH), and biomimetic phosphorylcholine (PC) groups were immobilized onto the film surface with high grafting efficiency by three-step chemical treatments under mild reaction conditions. The H-PEU film was firstly treated with 1,6-hexanediisocyanate (HDI) to introduce -NCO groups on the surface (H-PEU-NCO) through an allophanate reaction; the -NCO groups were then coupled via a condensation reaction with one of -NH2 groups of tris(2-aminoethyl)amine (TAEA) to immobilize -NH2 on the surface (H-PEU-NH2); finally, the double bond of 2-methacryloyloxyethyl phosphorylcholine (MPC) reacted with -NH2 by Michael addition reaction to obtain MPC-grafted H-PEU (H-PEU-MPC). The modified surfaces were characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The results verified that MPC was successfully grafted onto H-PEU surface with high grafting density. The blank and modified films showed similar crystallization behaviors, thermal stabilities and mechanical properties, indicating that the chemical treatments had minimum influence on the physicochemical properties of the substrate. The H-PEU-MPC displaying a much lower water contact angle (~15.2°) than H-PEU (80.3°) meant that the hydrophilic PC functional groups improved the surface hydrophilicity significantly. The surface blood compatibility was examined by bovine serum albumin adsorption and platelet adhesion tests, and the results revealed that H-PEU-MPC had improved resistance to protein adsorption and platelet adhesion capacity. The MPC-grafted H-PEU film possessed outstanding mechanical properties (ultimate stress: 36.1 MPa; strain at break: 883%), low protein adsorption quantity (1.33 µg/cm2) and good anti-platelet adhesion capacity (582 ±â€¯16 per mm2), implying its high potential to be applied as biomaterials for vascular grafts, subcutaneously implanted devices or other blood-contacting devices.


Assuntos
Materiais Biocompatíveis/química , Metacrilatos/química , Fosforilcolina/análogos & derivados , Poliésteres/química , Poliuretanos/química , Adsorção/efeitos dos fármacos , Animais , Caproatos/química , Isocianatos/química , Lactonas/química , Fosforilcolina/química , Adesividade Plaquetária/efeitos dos fármacos , Coelhos , Soroalbumina Bovina/química , Propriedades de Superfície
19.
Anal Bioanal Chem ; 411(25): 6745-6754, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31482291

RESUMO

In the literature, there are reports of the utilization of various hydrogels to create generic platforms for protein microarray applications. Here, a novel strategy was developed to obtain high-performance microarrays. In it, a dextran hydrogel is used to covalently immobilize oligonucleotides and proteins. This method employs aqueous solutions of dextran methacrylate (Dx-MA), which is a biocompatible photopolymerizable monomer. Capture probes are immobilized inside the hydrogel via a light-induced thiol-acrylate coupling reaction at the same time as the dextran polymer is formed. Hydrogel microarrays based on this technique were prepared on different surfaces, such as a Blu-ray Disk and polycarbonate or alkene-functionalized glass slides, and these systems showed high probe-loading capabilities and good biorecognition yields. This methodology presents advantages such as a low cost, a short analysis time, a low limit of detection, and multiplexing capabilities, among others. Confocal fluorescence microscopy analysis demonstrated that in these hydrogel-based microarrays, receptor immobilization and the biorecognition event occurred within the hydrogel and not merely on the surface.


Assuntos
Dextranos/química , Ácidos Nucleicos Imobilizados/química , Metacrilatos/química , Química Click/métodos , Hidrogéis/química , Ácidos Nucleicos/análise , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Cimento de Policarboxilato/química , Compostos de Sulfidrila/química
20.
Int J Pharm ; 570: 118668, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31494237

RESUMO

Tumor cell nucleus is the ultimate target of many first-line chemotherapeutics and therapeutic genes. However, nuclear drug delivery is always hampered by multiple intracellular obstacles especially low efficiency of cellular uptake and insufficient nuclear trafficking. It is urgent to establish novel nuclear drug delivery systems to simultaneously overcome barriers including cell membranes and nuclear envelope. Herein, an N-(2-hydroxypropyl) methacrylamide (HPMA) polymer-based drug delivery system was designed to achieve enhanced intracellular and intranuclear drug delivery. A biomimetic peptide (SVS-1), derived from antimicrobial peptides, which was reported to efficiently penetrate cell membranes and translocate rapidly into nucleus without decreasing cell viability, was conjugated to the HPMA copolymer backbone. The in vitro studies showed that SVS-1 could enhance the uptake and nuclei accumulation of HPMA copolymer by 4.1 and 7.0-fold on human cervical cancer cells (HeLa) separately compared with corresponding non-SVS-1 modified HPMA copolymers (P-DOX). This also transferred to greater DNA damage, more apoptosis and superior cytotoxicity (2.4-fold) of doxorubicin which was chosen as the model drug and attached to SVS-1 modified HPMA copolymer (SVS-1-P-DOX). Furthermore, the in vivo investigation revealed that compared with free doxorubicin, SVS-1-P-DOX not only showed prolonged blood circulation and preferential tumor accumulation, but also suppressed tumor growth more efficiently with tumor growth inhibition of 78.7% in HeLa tumor-bearing BALB/c nude mice without causing noticeable physiological change in major organs. These results demonstrated that the SVS-1 modification was a promising strategy for contemporaneously overcome cell membranes and nuclear envelope, which might provide new opportunities for constructing nucleus-targeted anticancer therapy.


Assuntos
Antineoplásicos/administração & dosagem , Antineoplásicos/química , Peptídeos/química , Animais , Apoptose/efeitos dos fármacos , Biomimética/métodos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Doxorrubicina/administração & dosagem , Doxorrubicina/química , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos/métodos , Células HeLa , Humanos , Metacrilatos/química , Camundongos , Camundongos Endogâmicos BALB C , Polímeros/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA