Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 22
Filtrar
1.
ACS Sens ; 9(4): 1831-1841, 2024 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-38489767

RESUMO

Detection of pathogenic viruses for point-of-care applications has attracted great attention since the COVID-19 pandemic. Current virus diagnostic tools are laborious and expensive, while requiring medically trained staff. Although user-friendly and cost-effective biosensors are utilized for virus detection, many of them rely on recognition elements that suffer major drawbacks. Herein, computationally designed epitope-imprinted polymers (eIPs) are conjugated with a portable piezoelectric sensing platform to establish a sensitive and robust biosensor for the human pathogenic adenovirus (HAdV). The template epitope is selected from the knob part of the HAdV capsid, ensuring surface accessibility. Computational simulations are performed to evaluate the conformational stability of the selected epitope. Further, molecular dynamics simulations are executed to investigate the interactions between the epitope and the different functional monomers for the smart design of eIPs. The HAdV epitope is imprinted via the solid-phase synthesis method to produce eIPs using in silico-selected ingredients. The synthetic receptors show a remarkable detection sensitivity (LOD: 102 pfu mL-1) and affinity (dissociation constant (Kd): 6.48 × 10-12 M) for HAdV. Moreover, the computational eIPs lead to around twofold improved binding behavior than the eIPs synthesized with a well-established conventional recipe. The proposed computational strategy holds enormous potential for the intelligent design of ultrasensitive imprinted polymer binders.


Assuntos
Adenovírus Humanos , Epitopos , Humanos , Adenovírus Humanos/imunologia , Adenovírus Humanos/química , Epitopos/imunologia , Epitopos/química , Técnicas Biossensoriais/métodos , Polímeros/química , Simulação de Dinâmica Molecular , Polímeros Molecularmente Impressos/química , Impressão Molecular/métodos , Limite de Detecção , SARS-CoV-2/imunologia , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/química
2.
Micromachines (Basel) ; 14(5)2023 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-37241709

RESUMO

Simple, fast, selective, and reliable detection of human epidermal growth factor receptor 2 (HER2) is of utmost importance in the early diagnosis of breast cancer to prevent its high prevalence and mortality. Molecularly imprinted polymers (MIPs), also known as artificial antibodies, have recently been used as a specific tool in cancer diagnosis and therapy. In this study, a miniaturized surface plasmon resonance (SPR)-based sensor was developed using epitope-mediated HER2-nanoMIPs. The nanoMIP receptors were characterized using dynamic light scattering (DLS), zeta potential, Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and fluorescent microscopy. The average size of the nanoMIPs was determined to be 67.5 ± 12.5 nm. The proposed novel SPR sensor provided superior selectivity to HER2 with a detection limit (LOD) of 11.6 pg mL-1 in human serum. The high specificity of the sensor was confirmed by cross-reactivity studies using P53, human serum albumin (HSA), transferrin, and glucose. The sensor preparation steps were successfully characterized by employing cyclic and square wave voltammetry. The nanoMIP-SPR sensor demonstrates great potential for use in the early diagnosis of breast cancer as a robust tool with high sensitivity, selectivity, and specificity.

3.
Food Chem ; 408: 135209, 2023 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-36563624

RESUMO

Insect oil is one of the most sustainable lipid sources with remarkable health effects. Herein, the type of organic solvents (i.e., n-hexane, ethanol, and isopropanol) and their binary mixtures was evaluated based on the quantity (e.g., yield extraction) and quality (e.g., bioactive compounds, thermal stability, DPPH scavenging rate, fatty acid profile, and nutritional indices) of lesser mealworm oils. The oils extracted by ethanol/isopropanol and ethanol/n-hexane significantly showed the highest extraction yield and efficiency, lightness, accelerated thermal stability, phenolics, tocopherols, vitamin D, campesterol, ß-sitosterol, phosphatidylinositol and phosphatic acid, linoleic acid, and hypocholesterolemic/hypercholesterolemic ratio, while these organic mixtures meaningfully extracted lipids with the lowest peroxide value, free fatty acid, and atherogenicity and thrombogenicity indices. These solvents compared to pure ones could dissolve membrane and internal lipids with the complete disintegration of external structures. The ethanol/isopropanol mixture would be a promising solvent for n-hexane substitution to extract this oil on an industrial scale.


Assuntos
Antioxidantes , Tenebrio , Animais , Ácidos Graxos , Óleos de Plantas/química , Larva , 2-Propanol , Solventes/química , Etanol
4.
Membranes (Basel) ; 12(11)2022 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-36363672

RESUMO

Waterborne viruses are a public health concern due to relatively small infection doses. Particularly, adenoviruses (AdVs) are more resistant than RNA viruses to water purification treatments in terms of ultraviolet (UV) irradiation, pH, and chlorination tolerance. Moreover, AdVs are one of the most predominant waterborne viruses. Membrane separations have proven superior removal capabilities of waterborne pathogens over other separation methods. However, virus removal at ultratrace levels is still a significant challenge for current membrane technology. This study successfully addressed this challenge by developing a bioselective polyethersulfone (PES) membrane by a joint strategy involving chitosan hydrophilic surface modification and the immobilization of adenovirus-specific molecularly imprinted nanoparticles (nanoMIPs). The topological and chemical changes taking place on the membrane surface were characterized by using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Furthermore, hydrophilicity and membrane performance were investigated in terms of swelling behavior, permeation flux, and surface fouling studies. The membrane efficacy was evaluated by filtration experiments, where the virus concentration of the loading solution before filtration and the permeates after filtration was quantified. The novel bioselective membrane showed excellent virus removal capabilities by separating 99.99% of the viruses from the water samples.

5.
Antioxidants (Basel) ; 11(10)2022 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-36290666

RESUMO

The ultrasound-assisted extraction (UAE) of oil from lesser mealworm (Alphitobius diaperinus L.) larvae powders (LMLPs) using ethanol/isopropanol as the superior solvent was optimized. The evaluation of time (9.89−35.11 min), solvent-to-LMLPs (2.39−27.61 v/w), and temperature (16.36−83.64 °C) showed that the highest extraction efficiency (EE, 88.08%) and in vitro antioxidant activity (IVAA) of reducing power (0.651), and DPPH free-radical scavenging capacity (70.79%) were achieved at 22.5 v/w solvent-to-LMLPs and 70 °C for 22.64 min. Optimal ultrasound conditions significantly improved the EE than n-hexane extraction (60.09%) by reducing the electric energy consumption by ~18.5 times from 0.637 to 0.035 kWh/g. The oil diffusivity in ethanol-isopropanol during the UAE (0.97 × 10−9 m2/s) was much better than that of n-hexane (5.07 × 10−11 m2/s). The microstructural images confirmed the high efficiency of ethanol-isopropanol in the presence of ultrasounds to remove oil flakes from the internal and external surfaces of LMLPs. The improved IVAA was significantly associated with the total phenolic (4.306 mg GAE/g, r = 0.991) and carotenoid (0.778 mg/g, r = 0.937) contents (p < 0.01). Although there was no significant difference in the fatty acid profile between the two extracted oils, ethanol-isopropanol under sonication acceptably improved oxidative stability with lower peroxides, conjugated dienes and trienes, and free fatty acids.

6.
Gels ; 8(9)2022 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-36135262

RESUMO

There is a high demand for designing healthy-functional dairy gels with a newly structured protein network in the food industry. Non-fat yogurt gels enriched with stable tarragon essential oil-nanoemulsions (TEO-NEs) using crosslinking of microbial transglutaminase (MTGase) were developed. The gas chromatography-mass spectrometry analysis showed that methyl chavicol (85.66%) was the major component in TEO extracted by the hydrodistillation process. The storage-dependent droplet size and physicochemical stability data of samples at room temperature for 30 days revealed that the TEO-NE containing 0.5% tween-80 and 1:2 TEO/sunflower oil had the lowest peroxide value and droplet growth ratio. The response surface methodology-based formulation optimization of free-fat yogurt gels using MTGase (0.15-0.85 U/g) and the best TEO-NE (0.5-3.02%) using the fitted second-order polynomial models proved that the combination of 0.87% TEO-NE and 0.70 U/g MTGase led to the desired pH (4.569) and acidity (88.3% lactic acid), minimum syneresis (27.03 mL/100 g), and maximum viscosity (6.93 Pa s) and firmness (0.207 N) responses. Scanning electron microscopy images visualized that the MTGase-induced crosslinks improved the gel structure to increase the firmness and viscosity with a reduction in the syneresis rate. The optimal yogurt gel as a nutritious diet not only provided the highest organoleptic scores but also maintained its storage-related quality with the lowest mold/yeast growth and free-radical oxidation changes.

7.
Biosensors (Basel) ; 12(5)2022 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-35624658

RESUMO

Tea, after water, is the most frequently consumed beverage in the world. The fermentation of tea leaves has a pivotal role in its quality and is usually monitored using the laboratory analytical instruments and olfactory perception of tea tasters. Developing electronic sensing platforms (ESPs), in terms of an electronic nose (e-nose), electronic tongue (e-tongue), and electronic eye (e-eye) equipped with progressive data processing algorithms, not only can accurately accelerate the consumer-based sensory quality assessment of tea, but also can define new standards for this bioactive product, to meet worldwide market demand. Using the complex data sets from electronic signals integrated with multivariate statistics can, thus, contribute to quality prediction and discrimination. The latest achievements and available solutions, to solve future problems and for easy and accurate real-time analysis of the sensory-chemical properties of tea and its products, are reviewed using bio-mimicking ESPs. These advanced sensing technologies, which measure the aroma, taste, and color profiles and input the data into mathematical classification algorithms, can discriminate different teas based on their price, geographical origins, harvest, fermentation, storage times, quality grades, and adulteration ratio. Although voltammetric and fluorescent sensor arrays are emerging for designing e-tongue systems, potentiometric electrodes are more often employed to monitor the taste profiles of tea. The use of a feature-level fusion strategy can significantly improve the efficiency and accuracy of prediction models, accompanied by the pattern recognition associations between the sensory properties and biochemical profiles of tea.


Assuntos
Nariz Eletrônico , Chá , Eletrônica , Controle de Qualidade , Paladar , Chá/química
8.
Int J Biol Macromol ; 202: 494-507, 2022 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-35045346

RESUMO

This overview highlighted the in vitro and in vivo antitumor effects of polysaccharides extracted by ultrasound- and microwave-assisted solvent extraction methods. The polysaccharide fragments with stronger antiproliferation, antitumoral, and anticarcinoma effects can be identified through purification, fractionation, and bio-analytical assessments. Most of the extracted glucan-based polysaccharides in a dose-dependent manner inhibited the growth of human cancer cell types with cell death-associated morphological changes. Glucans, glucogalactans, and pectins without any cytotoxicity on normal cells showed the antitumor potential by the apoptosis induction and the inhibition of their tumorigenesis, metastasis, and transformation. There is a significantly high association among antiproliferative activities, structural features (e.g., molecular weight, monosaccharide compositions, and contents of sulfate, selenium, and uronic acid), and other bio-functionalities (e.g., antiradical and antioxidant) of isolated polysaccharides. The evaluation of structure-activity relationships of antitumor polysaccharides is an intriguing step forward to develop highly potent anticancer pharmaceuticals and foods without any side effects.


Assuntos
Micro-Ondas , Polissacarídeos , Antioxidantes/química , Fracionamento Químico/métodos , Humanos , Monossacarídeos , Polissacarídeos/química
9.
Biosens Bioelectron ; 166: 112464, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32771854

RESUMO

The determination of disease-associated molecules at trace amounts is a key factor for early and efficient diagnosis from human body fluids. Herein, an ultrasensitive electrochemical sensor based on hybrid epitope imprinting and nanomaterial amplification was developed. The hybrid epitope imprinting was achieved by electropolymerization in the presence of two computationally selected and cysteine modified epitopes of neuron specific enolase (NSE), as-synthesized gold nanoparticles (AuNPs), and functional monomer. The AuNPs decorated epitope-mediated hybrid MIPs, as well as the standard hybrid MIPs, were utilized for the preparation of electrochemical sensors to demonstrate the impact of nanomaterial's modification in the polymer network for biomarker sensing. The fabrication process of both sensor types was investigated by employing cyclic voltammetry, square wave voltammetry, atomic force microscopy, and scanning electron microscopy. The biomarker assay using the standard hybrid MIPs resulted in 2.5-fold higher sensitivity compared to single epitope imprints, whereas the AuNP-hybrid MIPs enhanced the sensitivity level to a great extent and allowed the recognition of NSE in human serum in a concentration range of 25-4000 pg/mL. Comparative selectivity studies with non-imprinted polymer resulted in an imprinting factor of 4.2, confirming the high target selectivity of AuNP-MIP cavities. Cross-reaction of the sensor with four reference molecules (dopamine, bovine serum albumin, glucose and elongated peptide) was negligible. As compared to current strategies for epitope imprinting which rely on single epitopes for the formation of molecular cavities, the hybrid epitope-MIPs, particularly with the inclusion of AuNPs have provided more desirable sensing platforms with high sensitivity, affinity and specificity.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Impressão Molecular , Neoplasias , Biomarcadores Tumorais , Técnicas Eletroquímicas , Epitopos , Ouro , Humanos , Limite de Detecção
10.
Carbohydr Polym ; 240: 116301, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32475574

RESUMO

The process optimization and biological characterization of marshmallow root polysaccharides (MRPs) obtained from the microwave-assisted extraction (MAE) were studied. The highest MAE-yield (14.47%) was optimized at 457.32 W and 75 °C for 26 min. The extracted crude polysaccharides were purified using ion-exchange and gel-filtration chromatographies and eluted a single symmetrical narrow peak, showing a homogenous fraction (MRP-P1) with a molecular weight of 4.87 × 104 Da. The surface morphology of polysaccharides and functional groups of MRP-P1 were determined by employing scanning electron microscopy and Fourier-transform infrared spectroscopy, respectively. The major monosaccharide composition of MRPs were the three monomers of rhamnose, galactose, and glucose. The antioxidant, antimicrobial, and antitumor activities were increased in a concentration-dependent manner (1.0-10.0 mg/mL). MRP-P1 exhibited a strong in vitro antiproliferative activity against lung (A549), liver (HepG2), and breast (MCF-7) cancer cells. The anticancer activity of polysaccharides extracted under optimal MAE conditions was highly associated with their antioxidant and antibacterial functions.


Assuntos
Althaea , Antibacterianos , Antineoplásicos , Antioxidantes , Polissacarídeos , Células A549 , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Antioxidantes/química , Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Compostos de Bifenilo/química , Sobrevivência Celular/efeitos dos fármacos , Células Hep G2 , Humanos , Radical Hidroxila/química , Células MCF-7 , Micro-Ondas , Peso Molecular , Picratos/química , Raízes de Plantas , Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Polissacarídeos/farmacologia
11.
Anal Chem ; 92(7): 4798-4806, 2020 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-32167737

RESUMO

The research in biomedicine, cell signaling, diagnostics, and biocatalysis rely on selective protein binders that specifically capture a protein in a complex medium for either preparative or analytical use. These molecules are generally of biological origin and exposed to instability, denaturation, high cost, and inherently low binding capability. Imprinted polymers, serving as the artificial protein binders, demonstrate good potential to overcome these drawbacks. In this study, a novel epitope imprinting strategy is reported by employing double-cysteine-modified peptides as the templates and adsorbing the templates on a gold surface by means of forming self-assembled monolayer bridges, followed by electropolymerization to create a polymer network. The imprinted surface was initially designed to demonstrate specific affinity toward a short peptide (i.e., the epitope) or a target protein (i.e., neuron specific enolase) in buffer. This surface was subsequently used to measure the cancer biomarker in human serum that allows detecting 12 times lower concentration than threshold level of the biomarker. The molecular receptors exhibited a Kd < 65 pM for their respective target protein and low cross-reactivity with four nonspecific molecules. As compared to current strategies for the epitope imprinting, for example, through traditional, vertically adsorbed, or histidine-modified peptides, such a molecularly tunable system based on a surface-imprinting process may provide more efficient sensing systems with desirable affinity, sensitivity, and specificity in diagnostics applications.


Assuntos
Biomarcadores Tumorais/sangue , Epitopos/química , Neoplasias Pulmonares/sangue , Impressão Molecular , Oligopeptídeos/sangue , Carcinoma de Pequenas Células do Pulmão/sangue , Técnicas Biossensoriais , Técnicas Eletroquímicas , Eletrodos , Humanos , Modelos Moleculares , Conformação Molecular , Tamanho da Partícula , Propriedades de Superfície
12.
Sensors (Basel) ; 20(4)2020 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-32079119

RESUMO

Due to the proliferative cancer rates, cardiovascular diseases, neurodegenerative disorders, autoimmune diseases and a plethora of infections across the globe, it is essential to introduce strategies that can rapidly and specifically detect the ultralow concentrations of relevant biomarkers, pathogens, toxins and pharmaceuticals in biological matrices. Considering these pathophysiologies, various research works have become necessary to fabricate biosensors for their early diagnosis and treatment, using nanomaterials like quantum dots (QDs). These nanomaterials effectively ameliorate the sensor performance with respect to their reproducibility, selectivity as well as sensitivity. In particular, graphene quantum dots (GQDs), which are ideally graphene fragments of nanometer size, constitute discrete features such as acting as attractive fluorophores and excellent electro-catalysts owing to their photo-stability, water-solubility, biocompatibility, non-toxicity and lucrativeness that make them favorable candidates for a wide range of novel biomedical applications. Herein, we reviewed about 300 biomedical studies reported over the last five years which entail the state of art as well as some pioneering ideas with respect to the prominent role of GQDs, especially in the development of optical, electrochemical and photoelectrochemical biosensors. Additionally, we outline the ideal properties of GQDs, their eclectic methods of synthesis, and the general principle behind several biosensing techniques.


Assuntos
Biomarcadores/química , Técnicas Biossensoriais , Grafite/química , Pontos Quânticos/química , Humanos , Nanoestruturas/química
13.
Food Chem ; 302: 125347, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31430631

RESUMO

This work aims to prolong the storage stability of polyphenols, obtained from grape pomace, using a spray drying-based microencapsulation technique. The microcapsules obtained under optimal conditions were stored at two different relative humidities (33% and 52%) during 75 days. The analyses of total phenolic content, antioxidant activity, and individual phenolic compounds were carried out every 15 days, and the most stable microcapsules were achieved with maltodextrin DE4-7 prepared by adding gum Arabic to the wall material at a ratio of 8:2. The phenolic content loss rate was found to be in a range of 0.93-5.42 % depending on phenolic compound. The decrease in the content of rutin, chlorogenic acid, epicatechin, caffeic acid, gallic acid, caftaric acid and catechin was only 0.93, 2.09, 2.13, 2.27, 2.41, 3.40 and 5.42%, respectively. These results indicate more efficient storage conditions than those of previously reported studies.


Assuntos
Cápsulas/química , Armazenamento de Alimentos , Polifenóis/química , Vitis/química , Antioxidantes/análise , Antioxidantes/química , Catequina/análise , Catequina/química , Ácido Clorogênico/análise , Ácido Clorogênico/química , Composição de Medicamentos/métodos , Goma Arábica/química , Umidade , Fenóis/análise , Fenóis/química , Extratos Vegetais/química , Polifenóis/análise , Polissacarídeos/química , Rutina/análise , Rutina/química
14.
Materials (Basel) ; 13(1)2019 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-31878102

RESUMO

In the area of biomedicine, research for designing electrochemical sensors has evolved over the past decade, since it is crucial to selectively quantify biomarkers or pathogens in clinical samples for the efficacious diagnosis and/or treatment of various diseases. To fulfil the demand of rapid, specific, economic, and easy detection of such biomolecules in ultralow amounts, numerous nanomaterials have been explored to effectively enhance the sensitivity, selectivity, and reproducibility of immunosensors. Graphene quantum dots (GQDs) have garnered tremendous attention in immunosensor development, owing to their special attributes such as large surface area, excellent biocompatibility, quantum confinement, edge effects, and abundant sites for chemical modification. Besides these distinct features, GQDs acquire peroxidase (POD)-mimicking electro-catalytic activity, and hence, they can replace horseradish peroxidase (HRP)-based systems to conduct facile, quick, and inexpensive label-free immunoassays. The chief motive of this review article is to summarize and focus on the recent advances in GQD-based electrochemical immunosensors for the early and rapid detection of cancer, cardiovascular disorders, and pathogenic diseases. Moreover, the underlying principles of electrochemical immunosensing techniques are also highlighted. These GQD immunosensors are ubiquitous in biomedical diagnosis and conducive for miniaturization, encouraging low-cost disease diagnostics in developing nations using point-of-care testing (POCT) and similar allusive techniques.

15.
Sensors (Basel) ; 19(23)2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31810313

RESUMO

In recent years, an increasing number of nanomaterials have been explored for their applications in biomedical diagnostics, making their applications in healthcare biosensing a rapidly evolving field. Nanomaterials introduce versatility to the sensing platforms and may even allow mobility between different detection mechanisms. The prospect of a combination of different nanomaterials allows an exploitation of their synergistic additive and novel properties for sensor development. This paper covers more than 290 research works since 2015, elaborating the diverse roles played by various nanomaterials in the biosensing field. Hence, we provide a comprehensive review of the healthcare sensing applications of nanomaterials, covering carbon allotrope-based, inorganic, and organic nanomaterials. These sensing systems are able to detect a wide variety of clinically relevant molecules, like nucleic acids, viruses, bacteria, cancer antigens, pharmaceuticals and narcotic drugs, toxins, contaminants, as well as entire cells in various sensing media, ranging from buffers to more complex environments such as urine, blood or sputum. Thus, the latest advancements reviewed in this paper hold tremendous potential for the application of nanomaterials in the early screening of diseases and point-of-care testing.


Assuntos
Técnicas Biossensoriais/métodos , Nanoestruturas/química , Humanos
16.
Biosens Bioelectron ; 123: 260-268, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30243846

RESUMO

This research aims to engineer molecularly imprinted polymer (MIP)-based synthetic receptors for the molecular recognition of neuron specific enolase (NSE) biomarker. The synthetic peptide derived from the NSE was synthesized along with its cysteine and histidine modified versions. The modified peptides were utilized as templates for molecular imprinting, which was achieved by combination of epitope- and electrochemical surface imprinting strategy. The subsequently generated imprinted cavities were used for the detection of the NSE derived peptide and NSE. The imprints created with cysteine (CME) and histidine modified epitopes (HME) could detect the peptide in a concentration range of 2-128 µM and 15.6 nM to 128 µM, respectively. The recognition of NSE was achieved by the same imprints in a linear range of 1-64 ng mL-1 (CME) and 0.25-64 ng mL-1 (HME), respectively. The target molecules bound to the control polymer very weakly, confirming the high selectivity of the MIP cavities. Selectivity studies resulted in imprinting factors of 8.8 and 11 for the CME and HME imprints, respectively. The affinity analyses provided dissociation constants of 2.3 × 10-10 M and 3 × 10-11 M for NSE recognition using the corresponding epitope imprints. Cross-reactivity studies with non-specific molecules proved high specificity of the artificial receptors for the targets.


Assuntos
Biomarcadores/química , Técnicas Biossensoriais , Epitopos/isolamento & purificação , Fosfopiruvato Hidratase/isolamento & purificação , Materiais Biomiméticos/química , Cisteína/química , Epitopos/química , Histidina/química , Impressão Molecular , Peptídeos/química , Fosfopiruvato Hidratase/química , Polímeros/química
17.
J Biotechnol ; 239: 23-33, 2016 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-27720817

RESUMO

Phenolic compounds obtained from fruits have recently gained a great attention due to their bioactive roles. However, they are sensitive and they can be easily affected by physicochemical factors that create a great challenge to incorporate them into the food products. Hence, this work aimed to investigate microencapsulation of these compounds to provide a solution for this problem by improving their stability and protecting them against oxidation, light, moisture and temperature. A lab scale spray-dryer was chosen to produce microcapsules of polyphenols using different dextrose equivalents of maltodextrin and gum arabic as a coating material. Two different core: coating material ratios (1:1 and 1:2), three different maltodextrin: gum arabic ratios (10:0, 8:2 and 6:4), and four different inlet temperatures (120, 140, 160, 180°C) were investigated. When all parameters (yields, hygroscopicity, total and surface phenolic contents, antioxidant activity, individual phenolic compounds and particle morphology) were evaluated; the most efficient microcapsules were obtained with an 8:2 ratio of maltodextrin: gum arabic at 140°C inlet temperature. Microcapsules were also comprehensively studied and characterized using scanning electron microscopy (SEM) and high performance liquid chromatography (HPLC).


Assuntos
Composição de Medicamentos/métodos , Goma Arábica/química , Extratos Vegetais/química , Polifenóis/química , Polissacarídeos/química , Vitis/química , Cromatografia Líquida de Alta Pressão , Microscopia Eletrônica de Varredura
18.
Biosens Bioelectron ; 74: 996-1004, 2015 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26264266

RESUMO

Comparative and comprehensive investigations for adenovirus recognition and detection were conducted using plastic and natural antibodies to compare three different strategies. The implementation of molecularly imprinted polymer (MIP) technology for specific and sensitive recognition of viruses with the combination of biosensors was reported. Plastic antibodies (MIPs nanoparticles) were produced for adenovirus by employing a novel solid phase synthesis method. MIP receptors were then characterised using dynamic light scattering (DLS) and transmission electron microscopy (TEM) techniques prior to immobilisation on a surface plasmon resonance (SPR) sensor as affinity receptor for adenovirus detection. Two different templates were also imprinted as control MIPs (vancomycin-MIP and MS2-MIP). The specific recognition of adenovirus was investigated in the concentration range of 0.01-20 pM and the limit of detection was achieved as 0.02 pM. As an alternative to MIP receptors, direct and sandwich assays were developed for adenovirus quantification using natural antibodies. The detection limit of direct and sandwich assays were found as 0.3 pM and 0.008 pM, respectively. The kinetic data analyses were performed for three different adenovirus recognition methods and cross-reactivity studies were also conducted using MS2 phage as control virus and an excellent specificity was achieved with all assays types. This work confirmed the suitability of the MIPs SPR sensor for the detection of viruses.


Assuntos
Adenoviridae/imunologia , Adenoviridae/isolamento & purificação , Anticorpos Antivirais/imunologia , Imunoensaio/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação , Carga Viral/instrumentação , Técnicas Biossensoriais/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Células HEK293 , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
19.
Talanta ; 118: 270-6, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24274298

RESUMO

The detection and quantification of cancer biomarkers in human blood is crucial to diagnose patients in the early stage of a disease. The recent advances in biosensor technology can improve detection by reducing the application time and cost without an invasive approach. In this study, a highly sensitive, novel nanoparticle-modified capacitive sensor was developed for the detection of cancer markers. The current work mainly focused on developing a surface modification protocol for achieving higher sensitivity using Au-NPs. An interdigitated electrode (IDE) transducer was modified using gold nanoparticles (Au-NPs) for signal enhancement, the platform was initially optimized with a small size IL-6 protein and the methodology was then applied for multiple marker detection with the aim of precise disease diagnostics. Carcinoembryonic antigen (CEA) and epidermal growth factor receptor (hEGFR) could be successfully detected in the concentration range of 20-1000 pg mL(-1) while cancer antigen 15-3 (CA15-3) was detected in the range of 10-200 U mL(-1). These results show an increase of sensitivity by five-fold with respect to those not modified, demonstrating a highly sensitive and specific capacitive immunoassay that has a great potential for the use of early diagnosis of cancer disease.


Assuntos
Biomarcadores Tumorais/sangue , Técnicas Biossensoriais/métodos , Eletrodos , Ouro/química , Imunoensaio/métodos , Neoplasias Pulmonares/diagnóstico , Nanopartículas Metálicas/química , Antígeno Carcinoembrionário/sangue , Receptores ErbB/sangue , Humanos , Neoplasias Pulmonares/sangue , Mucina-1/sangue
20.
Toxins (Basel) ; 5(6): 1202-18, 2013 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-23793075

RESUMO

In this paper, we describe a peptide library designed by computational modelling and the selection of two peptide sequences showing affinity towards the mycotoxin, ochratoxin A (OTA). A virtual library of 20 natural amino acids was used as building blocks to design a short peptide library against ochratoxin A template using the de novo design program, LeapFrog, and the dynamic modelling software, FlexiDock. Peptide sequences were ranked according to calculated binding scores in their capacity to bind to ochratoxin A. Two high scoring peptides with the sequences N'-Cys-Ser-Ile-Val-Glu-Asp-Gly-Lys-C' (octapeptide) and N'-Gly-Pro-Ala-Gly-Ile-Asp-Gly-Pro-Ala-Gly-Ile-Arg-Cys-C' (13-mer) were selected for synthesis from the resulting database. These synthesized peptides were characterized using a microtitre plate-based binding assay and a surface plasmon resonance biosensor (Biacore 3000). The binding assay confirmed that both de novo designed peptides did bind to ochratoxin A in vitro. SPR analysis confirmed that the peptides bind to ochratoxin A, with calculated K(D) values of ~15.7 µM (13-mer) and ~11.8 µM (octamer). The affinity of the peptides corresponds well with the molecular modelling results, as the 13-mer peptide affinity is about 1.3-times weaker than the octapeptide; this is in accordance with the binding energy values modelled by FlexiDock. This work illustrates the potential of using computational modelling to design a peptide sequence that exhibits in vitro binding affinity for a small molecular weight toxin.


Assuntos
Modelos Químicos , Ocratoxinas/química , Biblioteca de Peptídeos , Peptídeos/química , Aminoácidos/química , Aminoácidos/metabolismo , Ligantes , Ocratoxinas/metabolismo , Peptídeos/metabolismo , Ligação Proteica , Análise de Sequência de Proteína
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA