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1.
Food Chem ; 334: 127563, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32791433

RESUMO

A new magnetic Cu(II) IIP (Fe3O4@IIP-IDC) is synthesized by polymerization of Imidazole-4,5-dicarboxylic acid functionalized Allyl chloride, and significant improvement of its performance has been compared. SPE parameters were optimized using Box-Behnken design to achieve the twin objectives of quantitative determination and removal of Cu(II). FLPSO kinetic model and BS isotherm model fits well with the capacity of 175 mg g-1. Analytical figures of merit includes a linearity range of 10-5,000 µg L-1 (R2 = 0.9986), preconcentration factor of 50 after eluting with 5 mL of 1 M HNO3, LOD of 1.03 µg L-1 and LOQ of 4.5 µg L-1. Accuracy was assessed by analysis of SRM (Standard Reference Material) and recovery experiments after spiking in food samples (Tea, coffee, chocolate, spinach, infant milk substitute) and battery wastewater. Ease of use, reusability (15 cycles), rapid adsorption and high selectivity makes it a promising candidate for efficient and selective removal and trace determination.


Assuntos
Cobre/análise , Análise de Alimentos/métodos , Impressão Molecular/métodos , Polímeros/química , Poluentes Químicos da Água/análise , Adsorção , Compostos Alílicos/química , Cobre/isolamento & purificação , Ácidos Dicarboxílicos/química , Análise de Alimentos/instrumentação , Contaminação de Alimentos/análise , Imidazóis/química , Limite de Detecção , Fenômenos Magnéticos , Águas Residuárias/análise , Poluentes Químicos da Água/isolamento & purificação
2.
Food Chem ; 334: 127345, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32712485

RESUMO

The development of a novel molecularly imprinted solid-phase extraction (MISPE) method for simultaneous preconcentration of imazapyr (IMP), imazapic (IMZ) and imazethapyr (IMT) with determination by HPLC-PAD (High performance liquid chromatography - photodiode-array detector) is proposed. The polymer synthesis was performed using imazethapyr as template molecule and 1-vinylimidazole as functional monomer. The method is based on preconcentration of 100.0 mL of sample through 200.0 mg of molecularly imprinted poly(vinylimidazole-TRIM) (MIP-1VN) at pH 4.0, followed by elution with 2.0 mL of MeOH:CH2Cl2:HAc (34:62:4, v/v). The range of analytical curve (0.29-200.0, 0.21-200.0 and 0.15-200.0 µg L-1), limits of detection (0.09, 0.06 and 0.04 µg L-1) and preconcentration factors (92, 96 and 98) determined for the herbicides, IMP, IMZ and IMT, respectively, were greatly superior when compared with those ones obtained with commercial adsorbents. The analytical method was successfully applied to spiked surface water and rice samples with good results of recovery values (86-107%).


Assuntos
Herbicidas/análise , Impressão Molecular/métodos , Oryza/química , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/análise , Cromatografia Líquida de Alta Pressão/métodos , Contaminação de Alimentos/análise , Imidazóis/análise , Imidazóis/síntese química , Imidazóis/química , Limite de Detecção , Niacina/análogos & derivados , Niacina/análise , Ácidos Nicotínicos/análise , Ácidos Nicotínicos/química , Polivinil/síntese química , Polivinil/química , Sementes/química , Extração em Fase Sólida/instrumentação
3.
Bull Environ Contam Toxicol ; 105(5): 806-812, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33057741

RESUMO

A molecularly imprinted polymer for the selective determination of Di(2-ethylhexyl) phthalate (DEHP) in water was synthesized and evaluated. This was accomplished by the use of sodium methacrylate as the monomer, toluene as a porogen, ethylene glycol dimethacrylate as a crosslinker, azobisisobutyronitrile as initiator and DEHP as a template molecule to generate the selectivity of the polymer for the compound, as well as synthesizing non-imprinted polymers. Three different polymerization approaches were used, emulsion, bulk and co-precipitation, the polymers obtained by emulsion presented a high retention rate reaching 99%. The method was able to pre-concentrate DEHP in water samples up to 250 times. To evaluate the applicability of the method, concentrations in fortified and bottled water were assessed using our polymer and determining DEHP concentrations by gas chromatography with mass spectrometry. Reported concentrations in bottled water were 12.1 µg/L, well above reference values established by the U.S. Environmental Protection Agency.


Assuntos
Dietilexilftalato/análise , Impressão Molecular/métodos , Polímeros , Poluentes Químicos da Água/análise , Água Potável/química , Cromatografia Gasosa-Espectrometria de Massas , Metacrilatos/química , Nitrilos/química , Polímeros/síntese química , Polímeros/química , Extração em Fase Sólida/métodos , Tolueno/química
4.
Biosens Bioelectron ; 169: 112604, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32980805

RESUMO

Virus severely endangers human life and health, and the detection of viruses is essential for the prevention and treatment of associated diseases. Metal-organic framework (MOF), a novel hybrid porous material which is bridged by the metal clusters and organic linkers, has become a promising biosensor platform for virus detection due to its outstanding properties including high surface area, adjustable pore size, easy modification, etc. However, the MOF-based sensing platforms for virus detection are rarely summarized. This review systematically divided the detection platforms into nucleic acid and immunological (antigen and antibody) detection, and the underlying sensing mechanisms were interpreted. The nucleic acid sensing was discussed based on the properties of MOF (such as metal ion, functional group, geometry structure, size, porosity, stability, etc.), revealing the relationship between the sensing performance and properties of MOF. Moreover, antibodies sensing based on the fluorescence detection and antigens sensing based on molecular imprinting or electrochemical immunoassay were highlighted. Furthermore, the remaining challenges and future development of MOF for virus detection were further discussed and proposed. This review will provide valuable references for the construction of sophisticated sensing platform for the detection of viruses, especially the 2019 coronavirus.


Assuntos
Técnicas Biossensoriais/métodos , Estruturas Metalorgânicas/química , Viroses/virologia , Vírus/isolamento & purificação , Animais , Anticorpos Antivirais/análise , Antígenos Virais/análise , Técnicas Biossensoriais/instrumentação , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Humanos , Imunoensaio/instrumentação , Imunoensaio/métodos , Modelos Moleculares , Impressão Molecular/instrumentação , Impressão Molecular/métodos , Ácidos Nucleicos/análise , Espectrometria de Fluorescência/instrumentação , Espectrometria de Fluorescência/métodos , Viroses/diagnóstico
5.
Pharm Res ; 37(10): 193, 2020 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-32914377

RESUMO

PURPOSE: The incidence of breast cancer worldwide has been on the rise since the late 1970s, and it has become a common tumor that threatens women's health. Aminoglutethimide (AG) is a common treatment of breast cancer. However, current treatments require frequent dosing that results in unstable plasma concentration and low bioavailability, risking serious adverse reactions. Our goal was to develop a molecularly imprinted polymer (MIP) based delivery system to control the release of AG and demonstrate the availability of this drug delivery system (DDS), which was doped with carbon nanotube with aid of metal-organic gel. METHODS: Preparation of MIP was optimized by key factors including composition of formula, ratio of monomers and drug loading concentration. RESULTS: By using multi-walled carbon nanotubes (MWCNT) and metal-organic gels (MOGs), MIP doubled the specific surface area, pore volume tripled and the IF was 1.6 times than the reference. Compared with commercial tablets, the relative bioavailability was 143.3% and a more stable release appeared. CONCLUSIONS: The results highlight the influence of MWCNT and MOGs on MIP, which has great potential as a DDS.


Assuntos
Aminoglutetimida/química , Antineoplásicos Hormonais/química , Complexos de Coordenação/química , Sistemas de Liberação de Medicamentos/métodos , Nanotubos de Carbono/química , Aminoglutetimida/administração & dosagem , Aminoglutetimida/farmacocinética , Animais , Antineoplásicos Hormonais/administração & dosagem , Antineoplásicos Hormonais/farmacocinética , Complexos de Coordenação/administração & dosagem , Compostos Férricos/química , Géis/administração & dosagem , Géis/química , Humanos , Células MCF-7 , Masculino , Impressão Molecular/métodos , Ratos , Ácidos Tricarboxílicos/química
6.
J Chromatogr A ; 1623: 461200, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505289

RESUMO

Selectivity and high throughput are important for determination of trace level of various organophosphate flame retardants (OPFRs) in environmental matrices. In this work, three selective monolithic fibers for solid phase microextraction (SPME) were prepared and evaluated. They are graphene oxide (GO)-based surface trimethyl phosphate (TMP) imprinted polymeric fiber (GO/TMP-IPF), GO-based surface tri (2-chloroethyl) phosphate (TCEP) imprinted polymeric fiber (GO/TCEP-IPF) and GO-based surface triphenyl phosphate (TPhP) imprinted polymeric fiber (GO/TPhP-IPF). The imprinting factors of GO/TMP-IPF for TMP, GO/TECP-IPF for TCEP and GO/TPhP-IPF for TPhP were tested as high as 4.3, 4.5, 10.3, respectively. The three fibers were bound to a stainless steel wire to assemble a GO-based surface molecularly imprinted polymeric fiber array (GO/MIP-FA). GO/MIP-FA-SPME device was coupled to gas chromatography-flame photometric detector and carried out simultaneous determination of TMP, TCEP and TPhP in environmental water. Under the optimal conditions, ultralow limits of quantification (1.7 ng L-1-5.0 ng L-1); linearity (>0.99); intra- and inter-day precision expressed as relative standard deviations for an array in the range of 4.9-8.6% and 5.8-8.2%, respectively, and array-to-array reproducibility in the range of 7.2-9.1% were obtained. The GO/MIP-FA-SPME technique was successfully applied for the determination of OPFRs in various environmental water samples, and the relative recoveries were found to be in the range from 72.4 to 112.0%.


Assuntos
Retardadores de Chama/análise , Grafite/química , Impressão Molecular/métodos , Organofosfatos/análise , Polímeros/química , Microextração em Fase Sólida/métodos , Poluentes Químicos da Água/análise , Resíduos Industriais/análise , Cinética , Reprodutibilidade dos Testes , Temperatura
7.
Food Chem ; 329: 127162, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32492599

RESUMO

We report for the first time the use of biochar as a stabilizer for oil-in-water (o/w) Pickering emulsion. The emulsion is subsequently used to prepare tetracycline-imprinted biochar composite microspheres (MIPMs) with tailored sizes and good uniformity. The adsorption properties of tetracycline to the MIPMs were investigated using different adsorption experiments including adsorption kinetic experiment, equilibrium binding experiment, selectivity evaluation and competitive adsorption tests. The MIPMs were used as adsorbent for solid phase extraction (SPE) for the extraction of tetracycline present in drinking water, fish, and chicken samples. Under optimal conditions, the results showed good recovery yield ranging from ~73% to ~95% with a relative standard deviation (RSD) ranging from ~0.3% to ~8.4%, respectively.


Assuntos
Carvão Vegetal/química , Emulsões/química , Contaminação de Alimentos/análise , Extração em Fase Sólida/métodos , Tetraciclina/isolamento & purificação , Adsorção , Antibacterianos/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Análise de Alimentos/instrumentação , Análise de Alimentos/métodos , Microesferas , Impressão Molecular/métodos , Extração em Fase Sólida/instrumentação , Poluentes Químicos da Água/isolamento & purificação
8.
J Chromatogr A ; 1622: 461147, 2020 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-32450989

RESUMO

Molecularly imprinted polymers coated magnetic particles (Fe3O4@MIPs) were prepared and used as adsorbents in solid phase extraction for efficient enantioseparation of racemic tryptophan (Trp) in aqueous medium. The amino-modified magnetic particles (Fe3O4-NH2) were first synthesized by one-pot hydrothermal method. Then the template molecules (L-Trp) were assembled on the surface of Fe3O4-NH2. Finally, Fe3O4@MIPs were prepared via a sol-gel method using L-Trp@Fe3O4-NH2 complex as matrix, 3-aminopropyltriethoxylsilane and n-octyltriethoxysilane as functional monomers. The as-prepared Fe3O4@MIPs were spherical with an average diameter about 149 ± 6.0 nm. The thickness of MIPs layer was approximately 3.5 ± 2.3 nm. The adsorption isotherms data of Fe3O4@MIPs toward L-Trp and D-Trp were well described by the Langmuir model. The maximum adsorption capacities of Fe3O4@MIPs for L-Trp and D-Trp were calculated to be 17.2 ± 0.34 mg/g and 7.2 ± 0.19 mg/g, respectively. The material exhibited good selectivity toward L-Trp with imprinting factor of 5.6. Excitingly, the enantiomeric excess (ee) of Trp in supernatant after adsorption of racemic Trp by Fe3O4@MIPs was as high as 100%. The result suggests that the imprinted caves in Fe3O4@MIPs are highly matched with L-Trp molecule in space structure and spatial arrangement of active functional groups. The work also demonstrates that sol-gel technology has great potential in preparation of MIPs for chiral separation.


Assuntos
Fenômenos Magnéticos , Impressão Molecular/métodos , Polímeros/síntese química , Triptofano/química , Triptofano/isolamento & purificação , Água/química , Adsorção , Compostos Férricos/química , Concentração de Íons de Hidrogênio , Polímeros/química , Reprodutibilidade dos Testes , Extração em Fase Sólida/métodos , Espectroscopia de Infravermelho com Transformada de Fourier , Eletricidade Estática , Estereoisomerismo , Temperatura , Fatores de Tempo
9.
Food Chem ; 326: 126969, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32438229

RESUMO

Biocompatible magnetic molecularly imprinted polymers (BMMIPs) were prepared with Zein for the first time, and were used to enrich tetracycline compounds selectively. Innovative combination of BMMIPs and electrochemistry to obtain lower detection line to satisfy industrial detection demands. Using Zein as the crosslinking agent, the polymers were synthesized on the surface of Fe3O4 particles. The scanning electron microscope, transmission electron microscope and X-ray diffraction technologies were used to characterize BMMIPs. Through optimization, BMMIPs attained large adsorption capacity (236.40 mg/g) with fast kinetics (40 min) and followed the Langmuir isotherm and pseudo-second-order kinetic models. BMMIPs had good recognition ability, the selective factors of oxytetracycline, chlortetracycline, doxycycline were 4.78, 4.23, and 3.39, respectively. Excellent linearity was attained in the range of 0.025-500 µg/mL, with low detection limits and low quantitation limits of 0.025 and 0.083 µg/mL. According to our exploring, BMMIPs was ideal materials for enrichment of tetracycline in complex biological samples.


Assuntos
Materiais Biocompatíveis/química , Contaminação de Alimentos/análise , Leite/química , Impressão Molecular/métodos , Tetraciclinas/análise , Adsorção , Animais , Antibacterianos/análise , Antibacterianos/química , Antibacterianos/isolamento & purificação , Técnicas Eletroquímicas , Análise de Alimentos/métodos , Limite de Detecção , Fenômenos Magnéticos , Nanopartículas de Magnetita/química , Polímeros/química , Tetraciclina/análise , Tetraciclina/química , Tetraciclina/isolamento & purificação , Tetraciclinas/química , Tetraciclinas/isolamento & purificação , Difração de Raios X , Zeína/química
10.
Food Chem ; 321: 126673, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32278983

RESUMO

In this work, a novel method was developed, for isolation of S. aureus from complex (food) samples using molecular imprinting.  Dopamine was used as a functional monomer and fluorescence microscopy was used for detection. Conditions for preparation of molecularly imprinted polymers (MIPs), adsorption performance, adsorption kinetic, and selectivity of the polymeric layers were investigated. The various procedures were combined in a single extraction process, with the imprinted layer on the surface of the magnetic particles (magnetic MIPs). Subsequently, MIPs were used for extraction of S. aureus from milk and rice. Moreover, raw milk from cows with mastitis was tested successfully. Using this novel MIP-based method, it was possible to detect bacteria in milk at 1 × 103CFU·ml-1, which corresponds to the limit set in European Union legislation for microbial control of food.


Assuntos
Leite/microbiologia , Impressão Molecular/métodos , Staphylococcus aureus/isolamento & purificação , Adsorção , Animais , Bovinos , Fenômenos Magnéticos , Magnetismo , Polímeros/química , Extração em Fase Sólida
11.
J Dairy Sci ; 103(6): 4941-4950, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32307169

RESUMO

Dairy cow feed contains, among other ingredients, soybeans, legumes, and clover, plants that are rich in phytoestrogens. Several publications have reported a positive influence of phytoestrogens on human health; however, several unfavorable effects have also been reported. In this work, a simple, selective, and eco-friendly method of phytoestrogen isolation based on the technique of noncovalent molecular imprinting was developed. Genistein was used as a template, and dopamine was chosen as a functional monomer. A layer of molecularly imprinted polymers was created in a microtitration well plate. The binding capability and selective properties of obtained molecularly imprinted polymers were investigated. The imprinted polymers exhibited higher binding affinity toward chosen phytoestrogen than did the nonimprinted polymers. A selectivity factor of 6.94 was calculated, confirming satisfactory selectivity of the polymeric layer. The applicability of the proposed sensing method was tested by isolation of genistein from a real sample of bovine milk and combined with micellar electrokinetic capillary chromatography with UV-visible detection.


Assuntos
Eletroforese Capilar , Leite/química , Impressão Molecular , Fitoestrógenos/análise , Animais , Bovinos , Feminino , Genisteína/análise , Genisteína/química , Impressão Molecular/métodos , Polímeros/química
12.
J Chromatogr A ; 1620: 461013, 2020 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-32201037

RESUMO

Dummy molecularly imprinted microspheres (DMIMs) were synthesized by Pickering emulsion polymerization and used as the matrix solid-phase dispersion extraction (MSPD) sorbent for sample pre-treatment of azole fungicides in fish samples. Alpha-(2,4-Dichlorophenyl)-1H-imidazole-1-ethanol (DCE) was used as the fragment dummy template for the imprinting of climbazole (CBZ), clotrimazole (CMZ) and miconazole (MNZ). The morphology of the microspheres were characterized by scanning electron microscopy (SEM) and nitrogen adsorption measurements, narrow diameter distribution (20-50 µm) with regular spherical shape and high surface area (SBET = 408.91 ± 6.72 m2 g-1) were achieved. Good class-selectivity of the DMIMs was found for CBZ, CMZ and MNZ by static adsorption experiments. The imprinted microspheres as MSPD sorbent was then evaluated for the extraction and purification of CBZ, CMZ and MNZ in fish samples. The extracted azole fungicides were detected by HPLC-DAD analysis at 225 nm. MSPD conditions including elution, mass ratio of sample/sorbent and washing were carefully evaluated. The optimized MSPD method have good recoveries (89.2-101.5%) and reproducibility (RSDs 1.6-4.8%, n = 5) for fish samples spiked at 0.5, 2.5 and 12.5 µg g-1. The limits of detection (LODs) were 0.045, 0.036 and 0.033 µg g-1 for CBZ, CMZ and MNZ, respectively. The results show that this method has a good application prospect for the pretreatment of azole fungicides in fish samples.


Assuntos
Azóis/isolamento & purificação , Emulsões/química , Peixes/metabolismo , Fungicidas Industriais/isolamento & purificação , Microesferas , Impressão Molecular/métodos , Polimerização , Extração em Fase Sólida/métodos , Adsorção , Animais , Limite de Detecção , Tamanho da Partícula , Porosidade , Reprodutibilidade dos Testes , Soluções , Temperatura
13.
Food Chem ; 319: 126575, 2020 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-32172051

RESUMO

A core-shell molecular imprinting fluorescence nanosensor was developed for the ratiometric fluorescence and visual detection of folic acid (FA). The nanosensor was prepared by anchoring imprinting shell on the silica nanoparticles, and embedding the CdTe quantum dots in imprinted shell to provide FA-dependent fluorescence signals. Under the optimum conditions, a favorable linearity relationship between the fluorescence intensities ratio (I449/I619) and the FA concentration over 0.23-113 µM was offered with a detection limit (LOD) of 48 nM. The visual detection for FA was realized by evaluating profuse fluorescence color change from red to pink to purple to final blue. The proposed sensor possessed excellent sensing performances of rapid response, high precision, super sensitivity and selective recognition. Furthermore, endogenous FA was detected in real samples ranging from 37.4 to 265.8 µg/100 g; satisfactory spiked recoveries were obtained within 94.8-104.2%, which conformed to the measurement results by HPLC-UV.


Assuntos
Ácido Fólico/análise , Análise de Alimentos/instrumentação , Análise de Alimentos/métodos , Impressão Molecular/métodos , Compostos de Cádmio/química , Cor , Ácido Fólico/química , Limite de Detecção , Nanopartículas/química , Propilaminas/química , Pontos Quânticos/química , Sensibilidade e Especificidade , Silanos/química , Dióxido de Silício/química , Espectrometria de Fluorescência/instrumentação , Espectrometria de Fluorescência/métodos , Telúrio/química
14.
Soft Matter ; 16(12): 3039-3049, 2020 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-32129364

RESUMO

Glycoproteins are involved in the pathogenesis and development of many diseases and are used as biomarkers for disease diagnosis. It is highly desirable to develop highly sensitive and selective methods for the detection of glycoproteins without the use of antibodies. Imprinting of proteins represents one of the most challenging tasks. Glycoprotein imprinted self-assembled monolayers (SAMs) were created, for the first time, from an oligo(ethylene glycol) (OEG) terminated 1,2-dithiolane derivative linked through an alkyl chain incorporated with two amide groups (DHAP) and combined functional thiols of p-mercaptophenylboronic acid (PMBA) and p-aminothiophenol (PATP) in aqueous media, without the use of polymerization initiators. Combined action of PMBA and PATP was essential for the development of boronate recognition sites for glycoproteins at the physiological pH, attributed to the water molecule-mediated Lewis acid-base interactions between the electron-deficient PMBA and the electron-rich PATP. DHAP played key roles not only in cementation of imprinted cavities by means of double hydrogen bond networks through the amide groups but also in resistance to nonspecific protein binding by terminal OEG moieties, as well as hydrogen bond binding sites from the amide groups exposed to imprinted cavities. The created glycoprotein imprinted SAMs showed excellent recognition selectivity of target glycoproteins. The strategy for tailor-made glycoprotein imprinted SAMs explores a new avenue to the creation of intelligent biomaterials and fabrication of chemosensors.


Assuntos
Ácidos Borônicos/química , Glicoproteínas/análise , Impressão Molecular/métodos , Polímeros/química , Compostos de Sulfidrila/química , Compostos de Anilina/síntese química , Compostos de Anilina/química , Animais , Ácidos Borônicos/síntese química , Bovinos , Cavalos , Humanos , Polímeros/síntese química , Compostos de Sulfidrila/síntese química , Propriedades de Superfície
15.
Biosensors (Basel) ; 10(3)2020 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-32120922

RESUMO

Molecularly imprinted polymers (MIPs) can often bind target molecules with high selectivity and specificity. When used as MIPs, conductive polymers may have unique binding capabilities; they often contain aromatic rings and functional groups, which can undergo π-π and hydrogen bonding interactions with similarly structured target (or template) molecules. In this work, an electrochemical method was used to optimize the synthetic self-assembly of poly(aniline-co-metanilic acid) and testosterone, forming testosterone-imprinted electronically conductive polymers (TIECPs) on sensing electrodes. The linear sensing range for testosterone was from 0.1 to 100 pg/mL, and the limit of detection was as low as ~pM. Random urine samples were collected and diluted 1000-fold to measure testosterone concentration using the above TIECP sensors; results were compared with a commercial ARCHITECT ci 8200 system. The testosterone concentrations in the tested samples were in the range of 0.33 ± 0.09 to 9.13 ± 1.33 ng/mL. The mean accuracy of the TIECP-coated sensors was 90.3 ± 7.0%.


Assuntos
Técnicas Eletroquímicas/métodos , Impressão Molecular/métodos , Polímeros/química , Testosterona/metabolismo , Humanos , Masculino
16.
Biosensors (Basel) ; 10(3)2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32143406

RESUMO

The development of a sensor based on molecularly imprinted polymer nanoparticles (nanoMIPs) and electrochemical impedance spectroscopy (EIS) for the detection of trace levels of cocaine is described in this paper. NanoMIPs for cocaine detection, synthesized using a solid phase, were applied as the sensing element. The nanoMIPs were first characterized by Transmission Electron Microscopy (TEM) and Dynamic Light Scattering and found to be ~148.35 ± 24.69 nm in size, using TEM. The nanoMIPs were then covalently attached to gold screen-printed electrodes and a cocaine direct binding assay was developed and optimized, using EIS as the sensing principle. EIS was recorded at a potential of 0.12 V over the frequency range from 0.1 Hz to 50 kHz, with a modulation voltage of 10 mV. The nanoMIPs sensor was able to detect cocaine in a linear range between 100 pg mL-1 and 50 ng mL-1 (R2 = 0.984; p-value = 0.00001) and with a limit of detection of 0.24 ng mL-1 (0.70 nM). The sensor showed no cross-reactivity toward morphine and a negligible response toward levamisole after optimizing the sensor surface blocking and assay conditions. The developed sensor has the potential to offer a highly sensitive, portable and cost-effective method for cocaine detection.


Assuntos
Técnicas Biossensoriais/métodos , Cocaína/química , Técnicas Eletroquímicas/métodos , Impressão Molecular/métodos , Nanopartículas/química , Cocaína/análise , Humanos
17.
Food Chem ; 317: 126431, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32109657

RESUMO

Novel dummy magnetic molecularly imprinted polymers (dex-MMIPs) were prepared for highly selective recognition and fast enrichment of acrylamide (AA) in potato chips. Propionamide (PA) was used as dummy template molecule and the Fe3O4 nanoparticles modified with carboxymethyl dextran were developed as supports. Methacrylic acid (MAA) and ethyleneglycoldimethacrylate (EGDMA) were chosen as the functional monomer and cross-linker, respectively. Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and transmission electron microscopy (TEM) were used to characterize the synthesized dex-MMIPs. The adsorption of dex-MMIPs reached equilibrium within 20 min, and the maximum adsorption quantity (Qm) was 19.28 mg/g with the dissociation constant (Kd) of 35.7 mg/L. Moreover excellent recognition toward acrylamide was achieved compared to analogs, such as N, N'-methylenebisacrylamide (MBA) and nicotinamide (VPP). The satisfactory recoveries of 83.9-96.8% were achieved for selective separation and enrichment of AA in spiked potato chips by dex-MMIPs.


Assuntos
Acrilamida/análise , Análise de Alimentos/métodos , Nanopartículas de Magnetita/química , Impressão Molecular/métodos , Polímeros/química , Solanum tuberosum , Adsorção , Cromatografia Líquida de Alta Pressão , Culinária , Dextranos/química , Contaminação de Alimentos/análise , Magnetismo , Metacrilatos/química , Microscopia Eletrônica de Transmissão , Niacinamida/análise , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria
18.
Anal Chim Acta ; 1101: 111-119, 2020 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-32029101

RESUMO

We designed a new type of MIP-SERS substrate for specific and label-free detection of patulin (PAT), by combining molecular imprinting polymer (MIP) selectivity and SERS technology sensitivity. Initially, the solid substrate of PDMS/AAO was prepared using poly dimethylsiloxane (PDMS) concreted anodized aluminum oxide (AAO) template. Then moderate Au was sputtered on the surface of PDMS/AAO to obtain Au/PDMS/AAO SERS substrate. Based on the HRP enzyme initiated in situ polymerization on the Au/PDMS/AAO, the MIP-SERS substrate was successfully synthesized with selective polymer and high tense of SERS "hot spots". The new MIP-SERS substrate showed strong SERS enhancement effect and good selectivity for PAT. Besides, the results showed that the method owned a linear range from 5 × 10-10 to 10-6 M with the limit of detection (LOD) of 8.5 × 10-11 M (S/N = 3) for PAT. The proposed method also exhibited acceptable reproducibility (relative standard deviation, RSD = 4.7%),good stability (Raman intensity is above 80% after two weeks) and recoveries from 96.43% to 112.83% with the average RSD of 6.3%. The substrate is easy to use without complex sample pretreatment, which makes it a potential candidate as a rapid and sensitive detection method in food samples.


Assuntos
Dimetilpolisiloxanos/química , Patulina/análise , Óxido de Alumínio/síntese química , Óxido de Alumínio/química , Armoracia/enzimologia , Mirtilos Azuis (Planta) , Citrus paradisi , Citrus sinensis , Dimetilpolisiloxanos/síntese química , Sucos de Frutas e Vegetais/análise , Ouro/química , Peroxidase do Rábano Silvestre/química , Limite de Detecção , Impressão Molecular/métodos , Polimerização , Reprodutibilidade dos Testes , Análise Espectral Raman/métodos
19.
Anal Chim Acta ; 1101: 32-40, 2020 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-32029116

RESUMO

In this paper, molecular imprinting and photonic crystal techniques were combined to construct a four-channel sensor array for the simultaneous identification of various sulfonamides. The assay was composed of four units. Three of these units were prepared using sulfaguanidine, sulfamethazine, or sulfathiazole as template molecules. The fourth unit was prepared without a template molecule. The preparation was optimized to obtain maximum identification with a molar ratio of template, monomer, and cross-linker of 1:50:10. The response time was as short as 10 min. For demonstration, six sulfonamides were selected as analytes. The Bragg diffraction patterns of analytes at different concentrations were measured using the sensor array. Data obtained were analyzed using linear discrimination analysis (LDA) and principal component analysis (PCA). LDA can be applied for SAs discrimination. The message ratios of 87.6%, 94.4%, and 95.8% for six SAs at 10-4 mol L-1, 10-6 mol L-1, and 10-8 mol L-1 were achieved using LDA. The sensor array identified the mixture containing various SAs with an LDA coefficient of 86.1%, thereby indicating that the sensor array had a strong anti-interference ability. The sensor array was used to identify six SAs in fish samples. The measured data in spiked samples were consistent with the fingerprint collected from standard solutions. The accuracy rate reached 90.9%, indicating that the array can be used to identify SAs from food samples.


Assuntos
Polímeros/química , Sulfonamidas/análise , Animais , Análise Discriminante , Peixes , Contaminação de Alimentos/análise , Limite de Detecção , Impressão Molecular/métodos , Análise de Componente Principal , Alimentos Marinhos/análise , Dióxido de Silício/química , Espectrofotometria Ultravioleta/métodos , Sulfonamidas/química
20.
AAPS PharmSciTech ; 21(2): 63, 2020 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-31933030

RESUMO

Bimatoprost is widely used for the management of glaucoma. Currently, it is delivered via eye drop solution, which is highly inefficient due to low bioavailability. To control the release of ocular drugs, contact lenses are used by scientists. However, the conventional soaking method showed high burst release due to absence of any efficient controlling membrane. The objective of the paper was to apply molecular imprinting technology to improve the loading of bimatoprost from the soaking solution and to sustain the release of drug from the contact lens. The bimatoprost was loaded by conventional soaking method (BT-SM) and compared with the molecular imprinted contact lenses (BT-MP). The loading of bimatoprost by molecular imprinting technology affect the swelling of the contact lens; however, the batch BT-MP-10 did not showed significant alterations. The uptake study showed improvement in the bimatoprost loading by molecular imprinting technology in comparison to the conventional soaking technology. The in vitro bimatoprost release data showed improvement in the bimatoprost release rate profiles with BT-MP contact lenses (up to 36-60 h) lenses in comparison to BT-SM contact lenses (up to 24-36 h). The in vivo rabbit tear fluid data with BT-MP batch showed improvement in the bimatoprost retention time in comparison to BT-SM contact lens and eye drop solution. The rabbit model failed to respond bimatoprost; thus, the efficacy studies need to be conducted on canines or human primates. The paper revealed the potential of using molecular imprinting technology to improve the uptake of bimatoprost and to achieve sustain release kinetics without altering the swelling, transmittance and folding endurance properties of the contact lens.


Assuntos
Bimatoprost/administração & dosagem , Lentes de Contato , Glaucoma/tratamento farmacológico , Impressão Molecular/métodos , Animais , Bimatoprost/química , Liberação Controlada de Fármacos , Feminino , Masculino , Coelhos , Silicones
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