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1.
Electron. j. biotechnol ; 44: 60-68, Mar. 2020. tab, graf, ilus
Artigo em Inglês | LILACS | ID: biblio-1087705

RESUMO

Background: Oleaginous yeasts can be grown on different carbon sources, including lignocellulosic hydrolysate containing a mixture of glucose and xylose. However, not all yeast strains can utilize both the sugars for lipogenesis. Therefore, in this study, efforts were made to isolate dual sugar-utilizing oleaginous yeasts from different sources. Results: A total of eleven isolates were obtained, which were screened for their ability to utilize various carbohydrates for lipogenesis. One promising yeast isolate Trichosporon mycotoxinivorans S2 was selected based on its capability to use a mixture of glucose and xylose and produce 44.86 ± 4.03% lipids, as well as its tolerance to fermentation inhibitors. In order to identify an inexpensive source of sugars, nondetoxified paddy straw hydrolysate (saccharified with cellulase), supplemented with 0.05% yeast extract, 0.18% peptone, and 0.04% MgSO4 was used for growth of the yeast, resulting in a yield of 5.17 g L−1 lipids with conversion productivity of 0.06 g L−1 h−1 . Optimization of the levels of yeast extract, peptone, and MgSO4 for maximizing lipid production using Box­Behnken design led to an increase in lipid yield by 41.59%. FAME analysis of single cell oil revealed oleic acid (30.84%), palmitic acid (18.28%), and stearic acid (17.64%) as the major fatty acids. Conclusion: The fatty acid profile illustrates the potential of T. mycotoxinivorans S2 to produce single cell oil as a feedstock for biodiesel. Therefore, the present study also indicated the potential of selected yeast to develop a zero-waste process for the complete valorization of paddy straw hydrolysate without detoxification


Assuntos
Trichosporon/metabolismo , Oryza , Xilose/isolamento & purificação , Trichosporon/química , Óleos/química , Lipogênese , Biocombustíveis , Fermentação , Glucose/isolamento & purificação , Hidrólise , Lignina/metabolismo , Lipídeos/biossíntese
2.
Biosens Bioelectron ; 149: 111845, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31733486

RESUMO

High throughput and high sensitivity are two important aspects in multiple biomarker recognition, drug discovery and relevant biochemical sensing. Here, we integrate mini-pillar microarray with the circuit components toward high-throughput individual electrochemical sensing in microdroplets. On such droplet-microarray-based electrochemical platform, the high adhesion of the mini-pillar can hold a microdroplet (hundreds nanoliter to a few microliter) regardless of rotation and deformation. Each pillar as a unit has a three-electrode to achieve individual electrochemical sensing, and electrodes are integrated on one side to achieve the sequential electrochemical read-out. Qualitative and quantitative electrochemical assessments of multiple glucose concentrations in individual microdroplets are also achieved. Such mini-pillar-based individual electrochemical platform shows great potential in high-throughput and high-sensitive biomolecular recognitions, provides an opportunity to develop miniaturized sensing platform for emerging biological and pathological applications.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Glucose/isolamento & purificação , Análise em Microsséries , Glucose/química
3.
Sensors (Basel) ; 19(22)2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31731703

RESUMO

A simple photoelectrochemical (PEC) sensor based on non-modified nanostructured anodic TiO2 was fabricated and used for a rapid and sensitive detection of glucose. The anodic TiO2 layers were synthesized in an ethylene glycol-based solution containing NH4F (0.38 wt.%) and H2O (1.79 wt.%) via a three-step procedure carried out at the constant voltage of 40 V at 20 °C. At the applied potentials of 0.2, 0.5, and 1 V vs. saturated calomel electrode (SCE), the developed sensor exhibited a photoelectochemical response toward the oxidation of glucose, and two linear ranges in calibration plots were observed. The highest sensitivity of 0.237 µA µmol-1 cm-2 was estimated for the applied bias of 1 V. The lowest limit of detection (LOD) was obtained for the potential of 0.5 V vs. SCE (7.8 mM) with the fastest response at ~3 s. Moreover, the proposed PEC sensor exhibited relatively high sensibility, good reproducibility, and due to its self-cleaning properties, a good long-term stability. Interfering tests showed the selective response of the sensor in the presence of urea and uric acid. Real-life sample analyses were performed using an intravenous glucose solution, which confirmed the possibility of determining the concentration of analyte in such types of samples.


Assuntos
Técnicas Biossensoriais , Eletroquímica/métodos , Glucose/isolamento & purificação , Glucose/química , Humanos , Limite de Detecção , Nanotubos de Carbono/química , Oxirredução , Titânio/química
4.
ACS Appl Mater Interfaces ; 11(50): 47311-47319, 2019 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-31742992

RESUMO

Inspired by blood coagulation and mussel adhesion, we report novel adhesive fibrin-bone@polydopamine (PDA)-shell composite matrix as highly efficient immobilization platform for biomacromolecules and nanomaterials. Fibrin, as a bioglue, and PDA, as a chemical adhesive, are integrated in a one-pot simultaneous polymerization consisting of biopolymerization of fibrinogen and chemical polymerization of dopamine. Fibrin fibers act as adhesive bones to construct scaffold, while PDA coat on the scaffold to form adhesive shell, generating 3D porous composite matrix with unique bone@shell structure. Two types of enzymes (glucose oxidase and acetylcholinesterase) and Au nanoparticles were adopted as respective model biomolecules and nanomaterials to investigate the immobilization capability of the matrix. The bionanocomposites showed high efficiency in capturing nanoparticles and enzymes, as well as significant mass-transfer and biocatalysis efficiencies. Therefore, the bionanocomposites exhibited significant potential in biosensing of glucose and paraoxon with limits of detection down to 5.2 µM and 4 ppt, respectively. The biological-chemical-combined polymerization strategy and composite platform with high immobilization capacity and mass-transfer efficiency open up a novel way for the preparation of high-performance bionanocomposites for various applications, in particular, biosensing.


Assuntos
Técnicas Biossensoriais , Fibrina/química , Glucose/isolamento & purificação , Paraoxon/isolamento & purificação , Adesivos/química , Biocatálise , Dopamina/química , Enzimas Imobilizadas/química , Fibrina/síntese química , Fibrinogênio/química , Glucose/química , Glucose Oxidase/química , Ouro/química , Humanos , Indóis/química , Limite de Detecção , Nanopartículas Metálicas/química , Paraoxon/química , Polimerização , Polímeros/química
5.
Sensors (Basel) ; 19(22)2019 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-31744089

RESUMO

In the last few years, quantum dot (QD) nanoparticles have been employed for bioimaging and sensing due to their excellent optical features. Most studies have used photoluminescence (PL) intensity-based techniques, which have some drawbacks, especially when working with nanoparticles in intracellular media, such as fluctuations in the excitation power, fluorophore concentration dependence, or interference from cell autofluorescence. Some of those limitations can be overcome with the use of time-resolved spectroscopy and fluorescence lifetime imaging microscopy (FLIM) techniques. In this work, CdSe/ZnS QDs with long decay times were modified with aminophenylboronic acid (APBA) to achieve QD-APBA conjugates, which can act as glucose nanosensors. The attachment of the boronic acid moiety on the surface of the nanoparticle quenched the PL average lifetime of the QDs. When glucose bonded to the boronic acid, the PL was recovered and its lifetime was enhanced. The nanosensors were satisfactorily applied to the detection of glucose into MDA-MB-231 cells with FLIM. The long PL lifetimes of the QD nanoparticles made them easily discernible from cell autofluorescence, thereby improving selectivity in their sensing applications. Since the intracellular levels of glucose are related to the metabolic status of cancer cells, the proposed nanosensors could potentially be used in cancer diagnosis.


Assuntos
Técnicas Biossensoriais , Glucose/isolamento & purificação , Neoplasias/diagnóstico , Pontos Quânticos/química , Ácidos Borônicos/química , Compostos de Cádmio/química , Humanos , Microscopia de Fluorescência , Nanopartículas/química , Neoplasias/química , Compostos de Selênio/química , Sulfetos/química , Compostos de Zinco/química
6.
Biosens Bioelectron ; 145: 111704, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31539649

RESUMO

A simple and efficient strategy was developed to fabricate CuO nanoparticles (CuO-NPs) with high surface area by the direct pyrolysis of a metal-organic gel (MOG) precursor for constructing versatile catalytic interfaces. Unexpectedly, the obtained CuO-NPs exhibited excellent electrocatalytic activity for glucose (Glu) oxidation reaction. The linear range of glucose was from 5 µM to 600 with the detection limit of 0.59 µM. Additionally, the CuO-NPs showed distinguished intrinsic peroxidase-mimicking activities, which can be further used as biomimetic nanozymes for sensitively and rapidly detecting cholesterol. A good linearity of cholesterol was performed in the range from 1 µM to 15 µM with the detection limit of 0.43 µM. The as-prepared CuO-NPs could provide a versatile catalytic platform for the application of electrochemical sensors and biomimetic enzyme catalytic systems. This study proved the high potential of MOG-derived nanostructured transition metal oxides (TMOs) with multiple complex functions.


Assuntos
Técnicas Biossensoriais , Colesterol/isolamento & purificação , Cobre/química , Glucose/isolamento & purificação , Biomimética , Catálise , Colesterol/química , Técnicas Eletroquímicas/métodos , Glucose/química , Nanopartículas Metálicas/química , Oxirredução , Peroxidase
7.
Biosens Bioelectron ; 144: 111637, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31494509

RESUMO

The wearable smart detection of body biomolecules and biomarkers is being of significance in the practical fields. Hydrogen peroxide (H2O2) is a product of some enzyme-catalyzed biomolecular reactions. The detection of H2O2 could reflect the concentration information of the enzyme reaction biomolecule substrate such as glucose. A high-performance berlin green (BG) carbon ink for monitoring H2O2 was prepared in this work. And we have successfully developed the wearable smartsensors for detecting H2O2 and glucose based on one-step fabricated BG arrays by screen-printing technology. Comparing with other detection methods, these sensors are wearable, movable, flexible and biocompatible for monitoring biomolecules. As a result, the sensors exhibited good sensitivity, specificity, stability and reproductivity towards H2O2 and glucose. Additionally, there also received stable response after near one hundred times stretching and thousands of bending. Moreover, the wearable sensors could be easily remotely controlled by a smart phone, when integrated with wireless into the device. In prospective studies, the one-step fabricated wearable smartsensors is of great significance in developing a straightforward, highly-efficient and low-cost method for actual detection of biomolecules reflecting body health status, and would potentially be applied in the artificial intelligence (AI) fields.


Assuntos
Biomarcadores/química , Técnicas Biossensoriais , Dispositivos Eletrônicos Vestíveis , Corantes/química , Glucose/química , Glucose/isolamento & purificação , Peróxido de Hidrogênio/química , Impressão Tridimensional , Estudos Prospectivos
8.
Sensors (Basel) ; 19(18)2019 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-31500222

RESUMO

The development of new bioelectronic platforms for direct interactions with oral fluid could open up significant opportunities for healthcare monitoring. A tongue depressor is a widely used medical tool that is inserted into the mouth, where it comes into close contact with saliva. Glucose is a typical salivary biomarker. Herein, we report-for the first time-a tongue depressor-based biosensor for the detection of glucose in both phosphate buffer and real human saliva. Carbon nanotubes (CNTs) are attractive electronic materials, with excellent electrochemical properties. The sensor is constructed by printing CNTs and silver/silver chloride (Ag/AgCl) to form three electrodes in an electrochemical cell: Working, reference, and counter electrodes. The enzyme glucose oxidase (GOD) is immobilized on the working electrode. The glucose detection performance of the sensor is excellent, with a detection range of 7.3 µM to 6 mM. The glucose detection time is about 3 min. The discretion between healthy people's and simulated diabetic patients' salivary samples is clear and easy to tell. We anticipate that the biosensor could open up new opportunities for the monitoring of salivary biomarkers and advance healthcare applications.


Assuntos
Técnicas Biossensoriais , Glucose Oxidase/química , Glucose/isolamento & purificação , Nanotubos de Carbono/química , Eletrodos , Enzimas Imobilizadas/química , Glucose/química , Humanos , Peróxido de Hidrogênio/química
9.
J Agric Food Chem ; 67(35): 9840-9850, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31424924

RESUMO

In the present study, methanolysis of poplar biomass was conducted for the selective transformation of hemicellulose and lignin, which leads to methyl glycosides (mainly C5 glycosides) and lignin fragments in the liquefied products that can be separated according to their difference in hydrophilicity. The distribution of methyl glycosides and delignification was dependent on the presence of acid catalysts and reaction temperatures. The obtained lignin fraction was separated into solid lignin fragments and liquid lignin oil according to their molecular weight distribution. Subsequently, directional conversion of methyl C5 glycosides into methyl levulinate was performed with dimethoxymethane/methanol as the cosolvent. A yield of 12-30% of methyl levulinate yield (based on the methyl glycoside) was achieved under these conditions. The remaining cellulose-rich substrate showed enhanced susceptibility to enzymatic hydrolysis, resulting in a yield of glucose of above 70%. Overall, the described strategy shows practical implications for the effective valorization of biomass.


Assuntos
Fracionamento Químico/métodos , Glucose/isolamento & purificação , Ácidos Levulínicos/isolamento & purificação , Metanol/química , Fenóis/isolamento & purificação , Extratos Vegetais/isolamento & purificação , Populus/química , Madeira/química , Catálise , Celulose/química , Celulose/isolamento & purificação , Glucose/química , Ácidos Levulínicos/química , Lignina/química , Lignina/isolamento & purificação , Fenóis/química , Extratos Vegetais/química
10.
Sensors (Basel) ; 19(13)2019 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-31261919

RESUMO

T-cell resonators have been used lately for non-invasive blood glucose measurements for photoacoustic spectroscopy on skin samples. A resonator has a significant role in determining the strength of the measured signal and the overall sensitivity of the sensor. Here we present results of the measurement of the photoacoustic signal of such a T-cell resonator. The signal is also modelled using the amplitude mode expansion method, which is based on eigenmode expansion and the introduction of losses in the form of loss factors. The measurement reproduced almost all the calculated resonances from the numerical models with fairly good agreement. The cause of the differences between the measured and the simulated resonances are explained. In addition, the amplitude mode expansion simulation model is established as a faster and computationally less demanding photoacoustic simulation alternative to the viscothermal model. The resonance frequencies from the two models differ by less than 1.8%. It is noted that the relative height of the amplitudes from the two models depends on the location of the antinodes within the different parts of the resonator. The amplitude mode expansion model provides a quick simulation tool for the optimization and design of macro resonators.


Assuntos
Técnicas Biossensoriais , Glucose/isolamento & purificação , Técnicas Fotoacústicas , Linfócitos T/metabolismo , Simulação por Computador , Glucose/metabolismo , Humanos , Sistemas de Infusão de Insulina , Linfócitos T/química
11.
Molecules ; 24(14)2019 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-31340590

RESUMO

Honey maturity is an important factor in evaluating the quality of honey. We established a method for the identification of natural mature acacia honey with eighteen physicochemical parameters combined with chemometric analysis. The analysis of variance showed significant differences between mature and immature acacia honey in physicochemical parameters. The principal component analysis explained 82.64% of the variance among samples, and indicated that total phenolic content, total protein content, and total sugar (glucose, fructose, sucrose) were the major variables. The cluster analysis and orthogonal partial least squares-discriminant analysis demonstrated that samples were grouped in relation to the maturity coinciding with the results of the principal component analysis. Meanwhile, the 35 test samples were classified with 100% accuracy with the method of multi-physicochemical parameters combined with chemometric analysis. All the results presented above proved the possibility of identifying mature acacia honey and immature acacia honey according to the chemometric analysis based on the multi-physicochemical parameters.


Assuntos
Acacia/química , Qualidade dos Alimentos , Mel/análise , Pólen/química , Análise de Variância , Animais , Abelhas/fisiologia , China , Cromatografia Líquida de Alta Pressão , Frutose/classificação , Frutose/isolamento & purificação , Glucose/classificação , Glucose/isolamento & purificação , Humanos , Análise dos Mínimos Quadrados , Fenóis/classificação , Fenóis/isolamento & purificação , Análise de Componente Principal , Sacarose/classificação , Sacarose/isolamento & purificação
12.
ACS Appl Mater Interfaces ; 11(30): 27233-27242, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31282641

RESUMO

Hybrid nanoparticles (NPs) have emerged as an important class of nanomaterials owing to their integrated enhanced properties and functionality. In this study, we have developed an effective nanodot templating strategy for the in situ formation of surfactant-free nanohybrids with unique plasmonic-fluorescent properties. A bright photoluminescent biodot synthesized from serine and histamine biomolecular precursors (Ser-Hist dot) was first engineered to have rich functional groups on the nanosurface capable of anchoring Ag+ ions via electrostatic interaction. Upon UV irradiation, free electrons could transfer from the photoexcited Ser-Hist dot to the Ag+ ions, facilitating the in situ growth of AgNPs. The resulting nanohybrid system (Bio@AgNPs) exhibits distinct characteristic surface plasmon resonance absorbance and highly quenched PL intensity due to the inner filter effect. Furthermore, the Bio@AgNP nanohybrid retains its redox capability, enabling hydrogen peroxide sensing via AgNP etching, which in turn empowers a dual colorimetric and fluorescent detection of glucose and cholesterol in complex biological samples (i.e., synthetic urine and human plasma) with high selectivity and sensitivity. This finding reveals a new effective and facile method for the preparation of highly functional hybrid nanomaterials for dual-mode detection of hydrogen peroxide-producing species and/or reactions.


Assuntos
Técnicas Biossensoriais , Colesterol/isolamento & purificação , Glucose/isolamento & purificação , Peróxido de Hidrogênio/isolamento & purificação , Carbono/química , Colesterol/química , Colorimetria , Glucose/química , Glucose Oxidase/química , Ouro , Humanos , Nanopartículas Metálicas/química , Pontos Quânticos/química , Prata , Ressonância de Plasmônio de Superfície
13.
Methods Mol Biol ; 1996: 207-216, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31127559

RESUMO

Cancer stem cells (CSCs) or tumor-initiating cells (TICs) are a population of cells present within tumor that have increased self-renewal, chemoresistance, and aggressiveness, thereby contributing to tumor relapse. Literature shows that CSCs or TICs typically originate within the hypoxic niches of the tumor, making hypoxia one of the driving factors for generation of this population. Hypoxic stress promotes adaptation to low oxygen tension in the tissues by altering metabolic properties of the CSCs. This leads to a number of altered enzymatic activities in the CSC population that further contribute to the survival of the CSCs leading to resistance to standard therapy. Hence, understanding this altered metabolic pathways as well as targeting key nodes in these may pave the way for cancer management.Glucose and glutamine are the major substrates utilized by cancer cells and feed into multiple biosynthetic pathways. Hence, labeling and tracking these compounds may reveal some novel metabolic pathways exploited by cancer stem cells to acquire survival advantage. In these current book chapters, we elaborately summarized the basic steps required for isolation, characterization, and metabolic labeling (13C6 glucose and 13C5 glutamine) of CSC for flux analysis.


Assuntos
Marcação por Isótopo/métodos , Análise do Fluxo Metabólico/métodos , Metabolômica/métodos , Células-Tronco Neoplásicas/metabolismo , Animais , Antineoplásicos/farmacologia , Isótopos de Carbono/química , Isótopos de Carbono/isolamento & purificação , Hipóxia Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Separação Celular/métodos , Modelos Animais de Doenças , Glucose/química , Glucose/isolamento & purificação , Glucose/metabolismo , Glutamina/química , Glutamina/isolamento & purificação , Glutamina/metabolismo , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/antagonistas & inibidores , Redes e Vias Metabólicas/efeitos dos fármacos , Camundongos , Células-Tronco Neoplásicas/efeitos dos fármacos , Neoplasias Pancreáticas/patologia , Análise de Célula Única/métodos
14.
Biosens Bioelectron ; 139: 111323, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31121437

RESUMO

Herein, a novel one step synthesis of multicomponent three dimensional polyacrylic acid (PAA) based conducting hydrogel (CH) incorporated with iron phthalocyanine functionalised graphene nanoplatelets (GPL-FePc) is reported. An amperometric glucose biosensor was fabricated by the immobilization of glucose oxidase (GOx) onto the synthesised PAA-VS-PANI/GPL-FePc-CH (where VS-PANI is vinyl substituted polyaniline). Scanning electron microscopy reveals the presence of three dimensional microporous structure with estimated pore size of 19 µm. The 5-(trifluoromethyl)-2-mercaptopyridine substitution onto FePc enabled the solubility of FePc in water and controls the aggregation of GPL-FePc in the synthesised CH. A sharp peak around 699 nm in UV-visible spectra confirms the presence of incorporated GPL-FePc into CH. Cyclic voltammogram of the synthesised CH biosensor exhibited well defined redox peaks with a ΔEp value of 0.26 V in Fe(CN)63-/4- bench mark solution. The fabricated PAA-VS-PANI/GPL-FePc/GOx-CH amperometric biosensor resulted in remarkable detection sensitivity of 18.11 µA mM-1 cm-2 with an average response time of ∼1 s, linearity from 1 to 20 mM, and low detection limit of 6.4 µM for the determination of glucose.


Assuntos
Técnicas Biossensoriais , Enzimas Imobilizadas/química , Glucose/isolamento & purificação , Grafite/química , Nanotubos de Carbono/química , Glucose/química , Glucose Oxidase/química , Humanos , Hidrogéis/química
15.
Biosens Bioelectron ; 137: 161-170, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31096082

RESUMO

We report on a wearable tear bioelectronic platform, integrating a microfluidic electrochemical detector into an eyeglasses nose-bridge pad, for non-invasive monitoring of key tear biomarkers. The alcohol-oxidase (AOx) biosensing fluidic system allowed real-time tear collection and direct alcohol measurements in stimulated tears, leading to the first wearable platform for tear alcohol monitoring. Placed outside the eye region this fully wearable tear-sensing platform addresses drawbacks of sensor systems involving direct contact with the eye as the contact lenses platform. Integrating the wireless electronic circuitry into the eyeglasses frame thus yielded a fully portable, convenient-to-use fashionable sensing device. The tear alcohol sensing concept was demonstrated for monitoring of alcohol intake in human subjects over multiple drinking courses, displaying good correlation to parallel BAC measurements. We also demonstrate for the first time the ability to monitor tear glucose outside the eye and the utility of wearable devices for monitoring vitamin nutrients in connection to enzymatic flow detector and rapid voltammetric scanning, respectively. These developments pave the way to build an effective eyeglasses system capable of chemical tear analysis.


Assuntos
Técnicas Biossensoriais , Óculos , Monitorização Fisiológica , Lágrimas/química , Álcoois/química , Álcoois/isolamento & purificação , Glucose/química , Glucose/isolamento & purificação , Humanos , Vitaminas/química , Vitaminas/isolamento & purificação , Dispositivos Eletrônicos Vestíveis
16.
Sensors (Basel) ; 19(7)2019 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-30970595

RESUMO

A highly sensitive glucose sensor was prepared by a one-step method using 3-aminophenyl boronic acid as a unit of recognition and a screen-printed carbon electrode (SPCE) as an electrochemical transducer. Scanning Electron Microscopy confirmed the success of the functionalization of the SPCE due to the presence of clusters of boronic acid distributed on the carbon surface. In agreement with the Electrochemical Impedance Spectroscopy (EIS) tests performed before and after the functionalization, Cyclic Voltammetry results indicated that the electroactivity of the electrode decreased 37.9% owing to the presence of the poly phenylboronic acid on the electrode surface. EIS revealed that the sensor was capable to selectively detect glucose at a broad range of concentrations (limit of detection of 8.53 × 10-9 M), not recognizing fructose and sucrose. The device presented a stable impedimetric response when immediately prepared but suffered the influence of the storage time and some interfering species (dopamine, NaCl and animal serum). The response time at optimized conditions was estimated to be equal to 4.0 ± 0.6 s.


Assuntos
Técnicas Biossensoriais , Ácidos Borônicos/química , Técnicas Eletroquímicas , Glucose/isolamento & purificação , Carbono/química , Espectroscopia Dielétrica , Eletrodos , Glucose/química , Ouro/química , Humanos , Limite de Detecção , Microscopia Eletrônica de Varredura , Polímeros/química , Soro/química
17.
Biomed Res Int ; 2019: 7127869, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31032360

RESUMO

Natural enzyme mimics have attracted considerable attention due to leakage of enzymes and their easy denaturation during their storage and immobilization procedure. Here in this study, for the first time, a new iron oxide hydroxide, ferrihydrite - Fe1.44O0.32 (OH) 3.68 magnetic nanoparticles were synthesized by bacterial strain named Comamonas testosteroni. The characterization of the produced magnetic nanoparticles was confirmed by transmission electron microscopy (TEM), Fourier-transform spectroscopy (FTIR), X-ray diffraction (XRD), and magnetization hysteresis loops. Further, these extracted nanoparticles were proven to have biogenic magnetic behavior and to exhibit enhanced peroxidase-like activity. It is capable of catalyzing the oxidation of 3, 3', 5, 5'-Tetramethylbenzidine (TMB) by H2O2 to produce blue color (typical color reactions). Catalysis was examined to follow Michaelis-Menton kinetics and the good affinity to both H2O2 and TMB. The K m value of the Fe1.44O0.32 (OH) 3.68 with H2O2 and TMB as the substrate was 0.0775 and 0.0155 mM, respectively, which were lower than that of the natural enzyme (HRP). Experiments of electron spin resonance (ESR) spectroscopy proved that the BMNPs could catalyze H2O2 to produce hydroxyl radicals. As a new peroxidase mimetic, the BMNPs were exhibited to offer a simple, sensitive, and selective colorimetric method for determination of H2O2 and glucose and efficiently catalyze the detection of glucose in real blood samples.


Assuntos
Comamonas testosteroni/química , Glucose/química , Peróxido de Hidrogênio/química , Peroxidase/química , Benzidinas/química , Biomimética , Técnicas Biossensoriais , Catálise , Espectroscopia de Ressonância de Spin Eletrônica , Compostos Férricos/síntese química , Compostos Férricos/química , Compostos Férricos/farmacologia , Glucose/isolamento & purificação , Peróxido de Hidrogênio/isolamento & purificação , Cinética , Nanopartículas de Magnetita , Microscopia Eletrônica de Transmissão , Oxirredução/efeitos dos fármacos , Peroxidase/síntese química , Peroxidase/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
18.
ACS Appl Mater Interfaces ; 11(10): 10153-10162, 2019 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-30821141

RESUMO

Ultrathin two-dimensional NiS/Ni(OH)2 nanosheets (NiS/Ni(OH)2 NSs) were successfully filled within the hollow interiors of ammonium polyacrylate-functionalized polypyrrole nanotubes (NH4PA/PPyNTs) by a simple solvothermal method. This kind of novel hierarchical nanostructures with typical structural features of a nanoconfined system, denoted by NiS/Ni(OH)2/NH4PA/PPyNTs, were prepared by two main sections: polyacrylic acid (PAA) was first polymerized on PPyNTs containing vinyl groups, and the obtained PAA/PPyNTs exhibited a typical Janus structure, whose external surface was covered with carboxyl groups and the internal surface was still covered with PPy chains; second, Ni2+ ions as a precursor were facilely combined with -NH- segments in PPy chains by the coordination interaction under the solvothermal environment; therefore, NiS/Ni(OH)2 NSs (<1 nm) were well distributed on the internal surface of NH4PA/PPyNTs by the in situ growth. Because of the synergistic effects of ionizable NH4PA, PPy with good conductivity, NiS and Ni(OH)2 with electrocatalytical activity, as well as the nanoconfinement effect, the obtained NiS/Ni(OH)2@NH4PA/PPyNTs exhibited excellent electrocatalytic performance for detecting glucose. Sufficiently thin shells composed of ionizable NH4PA and good conductive PPyNTs can not only promote the electronic transmission effectively during the electrochemical detection of glucose but also hardly limit the transport of glucose and products. In addition, ultrathin NiS/Ni(OH)2 NSs may further enhance the electrocatalytic performance for glucose because of the more exposed active sites with the large surface area. Therefore, NiS/Ni(OH)2@NH4PA/PPyNTs can be applied as a good electrode material with stability and sensitivity for building a nonenzymatic glucose sensor.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Glucose/isolamento & purificação , Nanotubos/química , Resinas Acrílicas/química , Compostos de Amônio/química , Glucose/química , Humanos , Nanocompostos/química , Níquel/química , Polímeros/química , Pirróis/química
19.
ACS Appl Mater Interfaces ; 11(10): 9724-9729, 2019 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-30816047

RESUMO

We have recently demonstrated that Enokitake mushroom-like gold with nanoparticles as the "head" and nanowires as the "tail" could grow directly on elastomeric substrates, which are extremely stretchable electrodes that can be used as wearable sensors for detecting strain and pressure. In this work, we show that such electrodes can also be used as intrinsically stretchable glucose biosensors. By modifying the vertical gold nanowire electrodes with glucose oxidase and Prussian blue nanoparticles, a limit of detection of 10 µM, sensitivity of 23.72 µA·mM-1·cm-2, and high selectivity can be achieved. The as-obtained glucose biosensors were able to maintain a high sensing performance under various mechanical deformations. Even for 30% strain, a sensitivity of 4.55 µA·mM-1·cm-2 toward glucose detection in the artificial sweat was possible. Furthermore, it was found that strains could be simultaneously detected with a gauge factor of 2.30 (strain 0-10%) and 22.64 (strain 10-20%), demonstrating the potential of such bimodal sensors to allow simultaneous monitoring of physical and biological signals.


Assuntos
Técnicas Biossensoriais , Flammulina/química , Glucose Oxidase/química , Glucose/isolamento & purificação , Agaricales/química , Glucose/química , Ouro/química , Humanos , Nanofios/química , Dispositivos Eletrônicos Vestíveis
20.
Biosensors (Basel) ; 9(1)2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30832254

RESUMO

Performance of a sensing device is dependent on its construction material, especially for components that are directly involved in transporting and translating signals across the device. Understanding the morphology and characteristics of the material components is therefore crucial in the development of any sensing device. This work examines the morphological and electrochemical characteristics of reduced graphene oxide interspersed with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (rGO-PEDOT:PSS) used as a transducer material deposited on a commercially available screen-printed carbon electrode (SPCE). Electron microscopy shows that PEDOT:PSS is interspersed between rGO layers. Raman and XRD analyses suggest that the graphene crystallinity in GO-PEDOT:PSS and rGO-PEDOT:PSS remains intact. Instead, PEDOT:PSS undergoes a change in structure to allow PEDOT to blend into the graphene structure and partake in the π-π interaction with the surface of the rGO layers. Incorporation of PEDOT:PSS also appears to improve the electrochemical behavior of the composite, leading to a higher peak current of 1.184 mA, as measured by cyclic voltammetry, compared to 0.522 mA when rGO is used alone. The rGO-PEDOT:PSS transducing material blended with glucose oxidase was tested for glucose detection. The sensitivity of glucose detection was shown to be 57.3 µA/(mM·cm²) with a detection limit of 86.8 µM.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Glucose Oxidase/química , Glucose/isolamento & purificação , Glucose/química , Grafite/química , Humanos , Microscopia Eletrônica , Nanocompostos , Poliestirenos/química , Tiofenos/química
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