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1.
Food Chem ; 399: 133983, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36030731

RESUMO

A simple aptasensor is embedded in the internal surface of a micropipette tip as the aptasensor substrate for the label-free monitoring of acrylamide. The aptasensor is based on the formation of the triple-helix molecular switch (THMS) structure of the DNA strands that induces the salt-enforced aggregation of gold nanoparticles (AuNPs). A smartphone imaging readout-based strategy is applied to quantify acrylamide. The developed aptasensor is novel for the naked-eye monitoring of the target through the color change of the solution inside the micropipette tip. The colorimetric aptasensor detects acrylamide in the concentration range of 0.05-200 nmol L-1 and at the trace level of 0.038 nmol L-1 with the comparable selectivity. The aptasensor can successfully quantify acrylamide in the chips, coffee, and bread samples with recoveries range from 92 to 102 %. The designed aptasensor paves an efficient device for the portable, on-site, facile, and real-time target sensing, superior for food safety control.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Nanopartículas Metálicas , Acrilamida , Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Colorimetria/métodos , Ouro , Limite de Detecção , Nanopartículas Metálicas/química , Smartphone
2.
Food Chem ; 398: 133907, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-35973298

RESUMO

A multi-channel colorimetric device was developed for the low-cost and simultaneous determination of three important parameters in wine safety and quality- total iron (Fe), methanol (MeOH), and total phenols. The detection was performed by assembling light-dependent resistors and light-emitting diodes in a 3D printed chamber, which measured colorimetric signals horizontally transmitting through the microwells of an 8-well strip. This device demonstrated linear relationships (R2 greater than 0.99) for all analytes with detection limits of 0.04 mg/L, 2.26 mg/L, and 3.40 mg/L for Fe, MeOH, and total phenols, respectively. Wine sample measurements showed that the multi-channel device was as accurate as the professional spectrophotometer and could simultaneously provide the three target concentrations to facilitate the analysis. With the merits of low fabrication cost and ease of use, this device could be used as a general platform for multiple-target detection, demonstrating great potential for application in food analysis.


Assuntos
Vinho , Colorimetria , Análise de Alimentos , Metanol/análise , Fenóis/análise , Vinho/análise
3.
Food Chem ; 400: 134037, 2023 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-36055146

RESUMO

2-tert-butyl-1,4-benzoquinone (TBBQ) is the major oxidative product of tert-butylhydroquinone which is a widely used antioxidant in edible oils. The biotoxicity of TBBQ is a risk to human health, that the rapid and accurate monitoring of TBBQ is needed. Herein, a specific chromogenic reaction between TBBQ and polyethyleneimine (PEI) could generate adducts with maximum absorption at 478 nm. Amine groups of PEI are prone to link with TBBQ through Michael addition to form colored adducts. A colorimetric method for detecting TBBQ in edible oils was developed based on the aforesaid chromogenic reaction. The linear range for TBBQ was from 3.0 to 100.0 µg g-1, having a limit of detection of 1.8 µg g-1. Recoveries results ranged from 88.4 % to 93.1 %, which had a good agreement with that of high-performance liquid chromatography. Our study provides a rapid and simple strategy for the sensitive detection of TBBQ using commercial chemicals.


Assuntos
Antioxidantes , Colorimetria , Aminas , Antioxidantes/análise , Benzoquinonas , Cromatografia Líquida de Alta Pressão , Humanos , Óleos Vegetais/química , Polietilenoimina
4.
Biotechnol Bioeng ; 119(3): 994-1003, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34953069

RESUMO

Transition of rapid, ready-to-use, and low-cost nucleic acid-based detection technologies from laboratories to points of sample collection has drastically accelerated. However, most of these approaches are still incapable of diagnosis starting from sampling through nucleic acid isolation and detection in the field. Here we developed a simple, portable, low-cost, colorimetric, and remotely controllable platform for reliable, high-throughput, and rapid diagnosis using loop-mediated isothermal amplification (LAMP) assays. It consists of a thermally isolated cup, low-cost electronic components, a polydimethylsiloxane sample well, and a fast prototyped case that covers electronic components. The steady-state temperature error of the system is <1%. We performed LAMP, Colony-LAMP, and Colony polymerase chain reactions (PCRs) using the yaiO2 primer set for Escherichia coli and Pseudomonas aeruginosa samples at 65°C and 30 min. We detected the end-point colorimetric readouts by the naked eye under day light. We confirmed the specificity and sensitivity of our approach using pure genomic DNA and crude bacterial colonies. We benchmarked our Colony-LAMP detection against Colony PCR. The number of samples tested can easily be modified for higher throughput in our system. We strongly believe that our platform can greatly contribute rapid and reliable diagnosis in versatile operational environments.


Assuntos
Colorimetria , Técnicas de Amplificação de Ácido Nucleico , Escherichia coli/genética , Reação em Cadeia da Polimerase , Pseudomonas aeruginosa/genética , Sensibilidade e Especificidade
5.
Mikrochim Acta ; 189(10): 369, 2022 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-36063228

RESUMO

Ag nanoparticle-decorated Ti3C2 nanosheets (AgNPs@Ti3C2 NSs) were facilely synthesized via a self-reduction approach, in which Ti3C2 NSs acted as both reductant and supporter. The AgNPs@Ti3C2 NS nanocomposite exhibited excellent peroxidase-like activity with o-phenylenediamine (OPD) and H2O2 as substrates. The catalytic behavior followed the typical Michaelis-Menten kinetics; Michaelis constant (Km) and maximum initial velocity (Vmax) for OPD were 0.263 mM and 43.2 × 10-8 M-1 s, indicating high affinity and high catalytic efficiency towards OPD. The catalytic mechanism was revealed to be an accelerated electron transfer process. Based on the inhibition effect on the peroxidase-like activity of AgNPs@Ti3C2 NSs, a simple, fast, and sensitive colorimetric method for detection of low-weight biothiols (cysteine (Cys), homocysteine (Hcy), and glutathione (GSH)) was developed by measuring the absorbance at 425 nm. The colorimetric method displayed wide linear range (50 nM to 50 µM for Cys, 10 nM to 250 µM for Hcy, 10 nM to 50 µM for GSH), low limit of detection (48.5 nM for Cys, 5.5 nM for Hcy, 7.0 nM for GSH), and good selectivity and short assay time (3 min). Moreover, the feasibility of this colorimetric sensor was demonstrated by accurately determining Cys in diluted human serum samples; good recovery (95.9-101.0%) and low relative standard deviations (2.8-4.9%) were obtained, showing great promise for point-of-care test in clinical samples.


Assuntos
Colorimetria , Nanopartículas Metálicas , Colorimetria/métodos , Cisteína , Glutationa , Humanos , Peróxido de Hidrogênio , Oxirredutases , Peroxidase , Peroxidases , Prata , Titânio
6.
Mikrochim Acta ; 189(10): 372, 2022 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-36066687

RESUMO

A dual-channel probe was developed, based on a novel composite metal organic frameworks (ZnMOF-74@Al-MOF) for glyphosate determination through ratio fluorescence and colorimetric methods. The prepared probe can not only recognize and combine glyphosate by introducing copper ion into the MOF, but also possess peroxidase-like catalytic activity. The recognition of target glyphosate brought about changes relative to its concentration on fluorescence intensity and ultraviolet absorption. And, the high specific surface area and porosity of porphyrin MOF provides the developed probe with more response opportunities to afford a better detection performance for glyphosate. Under optimum conditions, the copper ion-mediated method exhibited good detection performance for glyphosate with low detection limits (0.070 and 0.092 µg mL-1 for fluorescence and colorimetric techniques, respectively). Furthermore, the possible mechanisms of the fluorescence quenching and the peroxidase-like catalytic of the probe were also explored. This dual-channel method was applied to monitor glyphosate degradation in environmental samples and satisfactory results were obtained.


Assuntos
Estruturas Metalorgânicas , Colorimetria/métodos , Cobre/análise , Glicina/análogos & derivados , Limite de Detecção , Peroxidase , Peroxidases , Solo , Água
7.
Anal Chim Acta ; 1226: 340286, 2022 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-36068068

RESUMO

This study aims to use a paper-based sensor array for point-of-care detection of COVID-19 diseases. Various chemical compounds such as nanoparticles, organic dyes and metal ion complexes were employed as sensing elements in the array fabrication, capturing the metabolites of human serum samples. The viral infection caused the type and concentration of serum compositions to change, resulting in different color responses for the infected and control samples. For this purpose, 118 serum samples of COVID-19 patients and non-COVID controls both men and women with the age range of 14-88 years were collected. The serum samples were initially subjected to the sensor, followed by monitoring the variation in the color of sensing elements for 5 min using a scanner. By taking into consideration the statistical information, this method was capable of discriminating COVID-19 patients and control samples with 83.0% accuracy. The variation of age did not influence the colorimetric patterns. The desirable correlation was observed between the sensor responses and viral load values calculated by the PCR test, proposing a rapid and facile way to estimate the disease severity. Compared to other rapid detection methods, the developed assay is cost-effective and user-friendly, allowing for screening COVID-19 diseases reliably.


Assuntos
COVID-19 , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , COVID-19/diagnóstico , Teste para COVID-19 , Colorimetria/métodos , Nariz Eletrônico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Técnicas de Amplificação de Ácido Nucleico , Sistemas Automatizados de Assistência Junto ao Leito , Adulto Jovem
8.
Mikrochim Acta ; 189(10): 373, 2022 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-36068359

RESUMO

Peroxidase mimicking Fe3O4@Chitosan (Fe3O4@Chi) nanozyme was synthesized and used for high-sensitive enzyme-free colorimetric detection of H2O2. The nanozyme was characterized in comparison with  Fe3O4 nanoparticles (NPs) using X-ray diffraction, Fourier-transform infrared spectroscopy, dynamic light scattering, and thermogravimetric analysis. The catalytic performance of Fe3O4@Chi nanozyme was first evaluated by UV-Vis spectroscopy using 3,3',5,5'-tetramethylbenzidine. Unlike Fe3O4NPs, Fe3O4@Chi nanozyme exhibited an intrinsic peroxidase activity with a detection limit of 69 nM. Next, the nanozyme was applied to a microfluidic paper-based analytical device (µPAD) and colorimetric analysis was performed at varying concentrations of H2O2 using a machine learning-based smartphone app called "Hi-perox Sens++ ." The app with machine learning classifiers made the system user-friendly as well as more robust and adaptive against variation in illumination and camera optics. In order to train various machine learning classifiers, the images of the µPADs were taken at 30 s and 10 min by four smartphone brands under seven different illuminations. According to the results, linear discriminant analysis exhibited the highest classification accuracy (98.7%) with phone-independent repeatability at t = 30 s and the accuracy was preserved for 10 min. The proposed system also showed excellent selectivity in the presence of various interfering molecules and good detection performance in tap water.


Assuntos
Colorimetria , Peróxido de Hidrogênio , Inteligência Artificial , Colorimetria/métodos , Peróxido de Hidrogênio/análise , Peroxidase/química , Peroxidases
9.
Mikrochim Acta ; 189(10): 375, 2022 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-36074197

RESUMO

A simple and sensitive colorimetric assay for detecting organophosphorus pesticides (OPs) was developed based on 3,3',5,5'-tetramethylbenzidine (TMB)/hydrogen peroxide (H2O2)/dodecyl trimethylammonium bromide (DTAB)-tetramethyl zinc (4-pyridinyl) porphyrin (ZnTPyP). In this system, based on the peroxidase-like activity of DTAB-ZnTPyP, H2O2 decomposes to produce hydroxyl radicals, which oxidize TMB, resulting in blue oxidation products. The OPs (trichlorfon, dichlorvos, and thimet) were first combined with DTAB-ZnTPyP through electrostatic interactions. The OPs caused a decrease in the peroxidase-like activity of DTAB-ZnTPyP due to spatial site blocking. At the same time, π-interactions occurred between them, and these interactions also inhibited the oxidation of TMB (652 nm), thus making the detection of OPs possible. The limits of detection for trichlorfon, dichlorvos, and thimet were 0.25, 1.02, and 0.66 µg/L, respectively, and the corresponding linear ranges were 1-35, 5-45, and 1-40 µg/L, respectively. Moreover, the assay was successfully used to determine OPs in cabbage, apple, soil, and traditional Chinese medicine samples (the recovery ratios were 91.8-109.8%), showing a great promising potential for detecting OPs also in other complex samples.


Assuntos
Praguicidas , Porfirinas , Brometos , Colorimetria/métodos , Diclorvós , Peróxido de Hidrogênio , Metaloporfirinas , Compostos Organofosforados , Peroxidases , Praguicidas/análise , Triclorfon , Zinco , Compostos de Zinco
10.
Artigo em Inglês | MEDLINE | ID: mdl-36078284

RESUMO

Water- and food-related health issues have received a lot of attention recently because food-poisoning bacteria, in particular, are becoming serious threats to human health. Currently, techniques used to detect these bacteria are time-consuming and laborious. To overcome these challenges, the colorimetric strategy is attractive because it provides simple, rapid and accurate sensing for the detection of Salmonella spp. bacteria. The aim of this study is to review the progress regarding the colorimetric method of nucleic acid for Salmonella detection. A literature search was conducted using three databases (PubMed, Scopus and ScienceDirect). Of the 88 studies identified in our search, 15 were included for further analysis. Salmonella bacteria from different species, such as S. Typhimurium, S. Enteritidis, S. Typhi and S. Paratyphi A, were identified using the colorimetric method. The limit of detection (LoD) was evaluated in two types of concentrations, which were colony-forming unit (CFU) and CFU per mL. The majority of the studies used spiked samples (53%) rather than real samples (33%) to determine the LoDs. More research is needed to assess the sensitivity and specificity of colorimetric nucleic acid in bacterial detection, as well as its potential use in routine diagnosis.


Assuntos
Colorimetria , Ácidos Nucleicos , Humanos , Limite de Detecção , Salmonella/genética , Sensibilidade e Especificidade
11.
Med Oncol ; 39(12): 198, 2022 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-36071299

RESUMO

Cancer has become the silent killer in less-developed countries and the most significant cause of morbidity worldwide. The accessible and frequently used treatments include surgery, radiotherapy, chemotherapy, and immunotherapy. Chemotherapeutic drugs traditionally involve using plant-based medications either in the form of isolated compounds or as scaffolds for synthetic drugs. To launch a drug in the market, it has to pass through several intricate steps. The multidrug resistance in cancers calls for novel drug discovery and development. Every year anticancer potential of several plant-based compounds and extracts is reported but only a few advances to clinical trials. The false-positive or negative results impact the progress of the cell-based anticancer assays. There are several cell-based assays but the widely used include MTT, MTS, and XTT. In this article, we have discussed various pitfalls and workable solutions.


Assuntos
Colorimetria , Neoplasias , Artefatos , Desenvolvimento de Medicamentos , Descoberta de Drogas , Humanos , Neoplasias/tratamento farmacológico
12.
Annu Int Conf IEEE Eng Med Biol Soc ; 2022: 4716-4722, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36085740

RESUMO

Changes in skin appearance are among the most recognizable symptoms of a number of medical conditions. The interpretation of such changes, however, may be inadvertently biased by normal physiological processes affecting skin optical properties. In this paper, we assess the impact of one of the most common of these processes, tanning, on variations in skin chromatic attributes elicited by two ubiquitous and serious medical conditions, anemia and hyperbilirubinemia. We employ a first-principles investigation approach centered on the use of predictive computer simulations of light and skin interactions, and on well-established colorimetry methods. In our in silico experiments, we considered skin chromatic attributes resulting from distinct anemia severity levels and hyperbilirubinemia tox-icity stages. Our findings highlight qualitative and quantitative aspects that need to be considered in the visual screening and monitoring of these conditions, notably when they occur with the concomitant presence of tanning-induced changes in the cutaneous tissues' melanin pigmentation and thickness.


Assuntos
Anemia , Pigmentação da Pele , Colorimetria , Humanos , Hiperbilirrubinemia , Pele
13.
Anal Chem ; 94(37): 12699-12705, 2022 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-36054755

RESUMO

Reporting the activity of a specific viral protease remains an acute need for rapid point-of-care detection strategies that can distinguish active infection from a resolved infection. In this work, we present a simple colorimetric approach for reporting the activity of a specific viral protease through direct color conversion on a cotton swab, which has the potential to be extended to detect the corresponding virus. We use SARS-CoV-2 viral protease as a proof-of-concept model system. We use 4-aminomalachite green (4-AMG) as the base chromophore structure to design a CoV2-AMG reporter, which is selective toward the SARS-CoV-2 Mpro but does not produce any observable color change in the presence of other viral proteases. The color change is observable by the naked eye, as well as smartphone imaging, which affords a lower limit of detection. The simplicity and generalizability of the method could be instrumental in combating future viral outbreaks.


Assuntos
COVID-19 , SARS-CoV-2 , COVID-19/diagnóstico , Colorimetria/métodos , Humanos , Peptídeo Hidrolases , Proteases Virais
14.
Biosens Bioelectron ; 216: 114653, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36067719

RESUMO

An hourglass-mimicking biosensor was developed to detect target bacteria in 15 mL centrifugal tube using immune magnetic nanobeads to isolate the target from large-volume sample, gold@platinum nanozymes to label the target for amplification of biological signals, and a microplate reader/colorimetric card for determination of the target. First, a centrifugal tube with an iron ball framework was first coaxially assembled in the center of a Halbach ring magnet. After immune magnetic nanobeads, gold@platinum nanozymes and bacterial sample were mixed by repeated bottom-up of the tube using a stepper motor, nanobead-bacteria-nanozyme complexes were formed. Then, colorless H2O2-TMB was catalyzed by the nanozymes to produce blue TMBox. The color change was finally analyzed using the microplate reader or colorimetric card to determine bacterial concentration. This hourglass-mimicking biosensor could separate ∼95% targets from 10 mL bacteria sample and detect targets from 1.6 × 101 to 1.6 × 106 CFU/mL in 1.0 h with low detection limit of 16 CFU/mL.


Assuntos
Técnicas Biossensoriais , Bactérias , Colorimetria , Ouro , Peróxido de Hidrogênio , Ferro , Platina
15.
Org Biomol Chem ; 20(36): 7302-7315, 2022 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-36069360

RESUMO

A regioselective synthetic strategy for 6-aryl-8,9-dihydrobenzo[c]phenanthridine-10(7H)-ones (4) is accomplished using a one-pot four-component reaction by fine-tuning the reaction temperature. DMSO is excellently used as a reactant-cum-solvent to introduce a carbonyl functionality regioselectively at the C-10 position of the benzophenanthridine backbone, via an MCR, which is unknown yet. The elegant features of this strategy are the formation of two CC, one CN, and one CO bonds in a single step, without using a base and an activator for the oxygenation process. Then, a few compounds (4) are easily aromatised to achieve 6-arylbenzo[c]phenanthridin-10-ol derivatives (7) using I2/DMSO at 100 °C. Nay, a dangling hydroxyl group in 4s, 4u, 4x, and 4z helped them to be employed as promising 'naked eye' colorimetric chemosensors for fluoride with limits of detection of 0.65, 0.60, 0.34, and 2.2 ppm, respectively. Moreover, the reversibility of the chemosensors makes them suitable for combinatorial INHIBIT logic gate formulation. The compounds have also been employed for solid-state F- detection via the spot TLC test.


Assuntos
Dimetil Sulfóxido , Fluoretos , Benzofenantridinas , Colorimetria , Dimetil Sulfóxido/química , Fluoretos/química , Solventes
16.
ACS Appl Mater Interfaces ; 14(37): 41800-41808, 2022 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-36083615

RESUMO

Metal-organic frameworks (MOFs) have many attractive features, including tunable composition, rigid structure, controllable pore size, and large specific surface area, and thus are highly applicable in molecular analysis. Depending on the MOF structure, a high number of unsaturated metal sites can be exposed to catalyze chemical reactions. In the present work, we report that using both Co(II) and Fe(III) to prepare the MIL-88(NH2) MOF, we can produce the bimetallic MOF that can catalyze the conversion of 3,3',5,5″-tetramethylbenzidine (TMB) to a color product through a reaction with H2O2 at a higher reaction rate than the monometallic Fe-MIL-88(NH2). The Michaelis constants (Km) of the catalytic reaction for TMB and H2O2 are 3-5 times smaller, and the catalytic constants (kcat) are 5-10 times higher than those of the horseradish peroxidase (HRP), supporting ultrahigh peroxidase-like activity. These values are also much more superior to those of the HRP-mimicking MOFs reported previously. Interestingly, the bimetallic MOF can be coupled with glucose oxidase (GOx) to trigger the cascade enzymatic reaction for highly sensitive detection of extracellular vesicles (EVs), a family of important biomarkers. Through conjugation to the aptamer that recognizes the marker protein on EV surface, the MOF can help isolate the EVs from biological matrices, which are subsequently labeled by GOx via antibody recognition. The cascade enzymatic reaction between MOF and GOx enables the detection of EVs at a concentration as low as 7.8 × 104 particles/mL. The assay can be applied to monitor EV secretion by cultured cells and also can successfully detect the different EV quantities in the sera samples collected from cancer patients and healthy controls. Overall, we prove that the bimetallic Fe/Co-MIL-88(NH2) MOF, with its high peroxidase activity and high biocompatibility, is a valuable tool deployable in clinical assays to facilitate disease diagnosis and prognosis.


Assuntos
Vesículas Extracelulares , Estruturas Metalorgânicas , Benzidinas , Colorimetria , Corantes/química , Vesículas Extracelulares/química , Compostos Férricos , Glucose Oxidase/metabolismo , Peroxidase do Rábano Silvestre , Peróxido de Hidrogênio/química , Dietilamida do Ácido Lisérgico/análogos & derivados , Estruturas Metalorgânicas/química , Peroxidase/química , Peroxidases/química
17.
Biosens Bioelectron ; 216: 114681, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36087402

RESUMO

L-lysine is a crucial nutrient for both humans and animals, and its main commercial use is as a supplement in animal feed to promote chicken and other animal growth. Fluorescence biosensors based on the transcriptional regulator have been developed for high-throughput screening of L-lysine producers. However, due to its inability to specifically detect lysine, this fluorescent biosensor cannot be employed to screen high-yielding strains. Here, we present a novel technique for observing L-lysine concentrations within individual Corynebacterium glutamicum cells. The transcriptional regulator LysG and its binding site, as well as the phytoene desaturase that catalyzes the synthesis of the red pigment, make up the functional core of the biosensor. The lysine-sensitive mutant LysG(E123Y, E125A), which improved the sensitivity of biosensors, was generated by site-directed saturation mutagenesis. In addition, we increased the lysine-induced chromogenic biosensor response to 320 mM by optimizing the L-lysine export mechanism and the pathway for the synthesis of lycopene precursors. The direct identification of producers with elevated L-lysine accumulation is thus made straightforward by colorimetric screening. Lys-8, a lysine producer with a maximum lysine titer of 316.2 mM, was sorted out based on the biosensor. The enzymatic colorimetric biosensor constructed here is a simple tool with great potential for the development of high-level lysine-producing C. glutamicum.


Assuntos
Técnicas Biossensoriais , Corynebacterium glutamicum , Técnicas Biossensoriais/métodos , Colorimetria , Corynebacterium glutamicum/metabolismo , Humanos , Licopeno/metabolismo , Lisina/metabolismo
18.
Anal Biochem ; 656: 114886, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36087767

RESUMO

In the present investigation, a colorimetric method has been demonstrated for detection of oxytocin using Cysteamine functionalized gold nanoparticles (Cys-AuNP). The analyte oxytocin which finds its use in medical field is purposefully injected in fruits and vegetables for their faster growth. Also, it is used in the milk letdown in cattles. The complexity of segregating oxytocin induced fruit and vegetables from naturally grown ones led to development of the method. The choice of spherical gold nanoparticles for development of sensor was influenced from its unique optical properties. Moreover, functionalization with cysteamine increased its sensitivity towards oxytocin detection. The method was coupled with RGB colorimetric technique which exhibited excellent linear correlation between Oxytocin concentration and RGB color values (R2 = 0.96). The RGB method used measured the intensity of color and a relation was established between measured RGB values and concentration of analyte (Oxytocin) present in the sample. This formed the basis for generation of simple colorimetric card that can be used to relate the color with amount present in the sample. More significantly, the Cys-AuNP shows excellent selectivity towards other coexisting substances present in the sample. This method with good precision (RSD>15%) offers suitability for onsite application without need for complex instrumentation.


Assuntos
Ouro , Nanopartículas Metálicas , Animais , Bovinos , Colorimetria/métodos , Cisteamina , Ocitocina
19.
Biosens Bioelectron ; 216: 114652, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36095977

RESUMO

Accurate on-site analysis of food quality, environmental pollutants, and disease biomarkers is of great significance for safeguarding public health. In this work, based on the novel nanozymes, MnCo oxides@carbon yolk-shell nanocages (MnCo@C NCs), a portable colorimetric sensor with smartphone platform has been developed for rapid, on-site and quantitative analysis of total antioxidant capacity (TAC) and phenolic compounds. The MnCo@C NCs are synthesized via one-step calcination of polydopamine-coated MnCo Prussian blue analogs (MnCo-PBA@PDA). The PDA-derived carbon shell is found to be able to protect the nanocages from collapsing, thus increasing their specific surface areas and porosity. Benefiting from the unique structure and multivalent MnCo bimetallic oxides, the MnCo@C NCs perform outstanding catalytic performance and multiple enzyme-mimicking activities including oxidase, laccase and catalase. Hence, a multifunctional application platform integrated smartphone has been constructed for rapid and sensitive colorimetric detection of three model analytes (i.e., ascorbic acid (AA), 2,4-dichlorophenol (2,4-DP), and epinephrine) with extremely low detection limits of 0.29 µM, 0.76 µM, and 0.70 µM, respectively. This sensor device is successfully applied in TAC analysis in vegetables, fruits, and beverages, as well as epinephrine determination in human serum samples. This work provides new insights into designing multifunctional nanozymes to advance the instant detection technology in the field of food supervision, environment monitoring, and human health.


Assuntos
Técnicas Biossensoriais , Poluentes Ambientais , Antioxidantes , Ácido Ascórbico , Biomarcadores , Carbono/química , Catalase , Colorimetria , Epinefrina , Humanos , Lacase , Óxidos , Smartphone
20.
Biosens Bioelectron ; 216: 114656, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36095978

RESUMO

Paper-based point-of-care (POC) devices exhibit the advantages of simplicity, rapidity, trim sizes, and low cost, which are of particular importance for food safety, biological analysis, and medical diagnosis. However, the materials utilized to make paper-based POC rarely produce multiple signals, hampering further applications in diverse situations. Herein, we present an appealing approach, namely Colorimetric-Temperature Dual-Signal Output Sensor (CTDSS), and construct a CTDSS based on coordinative self-assembly biomimetic nanozymes Fe-GMP-L-His CPNs as a proof of concept. These CPNs mimic the structure of horseradish peroxidase (HRP), in which Fe (II) is the center, nucleotide GMP and histidine are chosen as ligands to simulate metal coordination of the pyrrole ring and protein function in HRP, respectively. This strategy allows CPNs to show an excellent peroxidase-like activity, efficiently converting H2O2 into •OH and oxidizing TMB to generate colorimetric-temperature dual-signal. As a proof-of-concept application, we exploited cholesterol as the target and successfully applied this CTDSS to detect cholesterol, displaying extraordinary features of rapidity, dramatic specificity, and high sensitivity. By utilizing the colorimetric test strip and temperature discoloration sticker, the paper-based POC tools were constructed to visualize the target. Meanwhile, two proposed test strip POC devices generating different signal outputs exhibited remarkable feasibility and were further employed to detect cholesterol in human serum. We anticipate that this CTDSS platform will inspire innovative concepts for future portable detection tools.


Assuntos
Técnicas Biossensoriais , Peróxido de Hidrogênio , Biomarcadores , Biomimética , Colesterol , Colorimetria , Histidina , Peroxidase do Rábano Silvestre , Humanos , Peróxido de Hidrogênio/química , Ligantes , Nucleotídeos , Peroxidases , Sistemas Automatizados de Assistência Junto ao Leito , Pirróis
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