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1.
Analyst ; 147(20): 4570-4577, 2022 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-36106835

RESUMO

The analysis of chiral α-amino acids is of great significance in asymmetric synthesis, nutrition, food science, and microbiology. However, the ability of chiral recognition is difficult to achieve. Due to the demand for expensive equipment and skilled operators, traditional methods such as high-performance liquid chromatography are limited. The previously reported methods based on chemical sensor arrays usually cannot carry out the chiral analysis. Here, we developed a novel biosensor array based on the interaction between a suite of host-based luminescent bacteria and amino acids and used linear discriminant analysis to reflect their luminescence response patterns. This biosensor array could effectively discriminate chiral amino acids, including 19 L-amino acids, their corresponding D-enantiomers, and the achiral glycine. In addition, the determination of enantiomeric purity and quantitative ability has been proved. The successful identification of a complex system containing multiple chiral amino acids further demonstrates the superiority of the bioluminescent sensor array. Moreover, this sensor array could efficiently monitor the dynamic composition of free amino acids in the process of milk fermentation. Finally, the bioluminescence response mechanism of the luminescent bacteria for the recognition of chirality was clarified. This approach possessed the advantages of facile construction, high throughput, easy operation, high accuracy and fast response.


Assuntos
Aminoácidos , Luminescência , Aminas , Aminoácidos/química , Fermentação , Glicina , Estereoisomerismo , Iogurte/análise
2.
Med Sci Monit ; 27: e929408, 2021 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-33819211

RESUMO

BACKGROUND The aim of this study was to assess the interaction between thyroid malignancies and thyroid anterior capsule by ultrasound quantification to determine extra-capsular invasion. MATERIAL AND METHODS A total of 145 patients preoperatively diagnosed with malignant nodules under the thyroid anterior capsule were selected and routinely examined by ultrasound. The length of the nodules (from the junction of the nodule capsule to the deepest point of the nodule, vertical diameter, V) and the distance between the nodule protruding from thyroid capsule and the highest protruding (ledge length, L) nodule were used to obtain the L/V ratio. These parameters where then used to compare the efficacy of predicting extra-thyroid extension (ETE) between L/V, the aspect ratio of the tumor, and manual judgment. RESULTS Out of 145 nodules, there were 63 ETEs and 82 non-ETEs determined by ultrasound. Extra-capsular invasion was associated with L//V ratio, but there was no significant correlation between capsular invasion and AR (aspect ratio), age, location, or presence of clustered calcification. The ability of the ratio of L/V to predict extra-capsular invasion was superior to the predictive ability of the AR ratio. With a Youden index of 0.593, the L/V ratio was 0.2325. The use of the L/V ratio to determine the presence of ETE was superior to subjective visual judgment. CONCLUSIONS The calculation of L/V ratio by ultrasound could more precisely predict the ETE compared with manual judgment, which indirectly reflects the interaction between thyroid capsule and malignant nodules. The above conclusions need to be confirmed by a range of cases.


Assuntos
Carcinoma Papilar/diagnóstico , Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/diagnóstico , Ultrassonografia/métodos , Adulto , Carcinoma Papilar/patologia , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Estudos Retrospectivos , Neoplasias da Glândula Tireoide/patologia
3.
Anal Bioanal Chem ; 412(29): 8127-8134, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32918558

RESUMO

Although luminescent bacteria-based bioluminescence inhibition assay has been widely used in the toxicity assessment of environmental pollutants, the response of a luminescent bacterium usually lacks specificity to a target analyte. Recently, some specific analyte inductive promoters were fused to the lux genes for the purpose of selective bioluminescent sensing, and suits of specific promoters were fused to lux genes to compose a bioluminescent array sensor for simultaneous identification of multiple analytes. However, specific promoter-based methods still suffer from drawbacks including limited selectivity, slow responding time, expensive to construct different promoters involved plasmids, and laborious to find new promoters. Herein, we proposed a novel strategy to construct a lux reporter array sensor by directly transforming the natural lux genes in different bacterial hosts without the involvement of any specific promoters. Due to the distinct pathways of signal production, the responding time of the current different bacterial host (DBH)-based lux reporter array has nearly an order of magnitude faster than with specific promoter-based methods. The DBH-based lux reporter array was successfully used for simultaneous identification, quantification, and toxicity/bioactivity assessment of multiple metal ions. Obviously, all the chemical synthetic material-based metal ion sensing methods cannot simultaneously achieve analysis and toxicity evaluation. This approach possessed additional advantages of facile construction, easy operation, high selectivity, fast response, and strong adaptability to other analytes. A different bacterial host-based lux reporter array was established for simultaneous analysis and toxicity assessment of multiple metal ions.


Assuntos
Bactérias/efeitos dos fármacos , Genes Reporter , Metais/análise , Metais/toxicidade , Bactérias/genética , Genes Bacterianos , Limite de Detecção , Regiões Promotoras Genéticas , Espectrometria de Fluorescência/métodos
4.
Anal Chem ; 91(20): 13174-13182, 2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31545590

RESUMO

The monitoring of alkaline phosphatase (ALP) activity in different tissues is significant for disease diagnosis and therapy. However, the time-resolved in vivo sensing of ALP activity remained unresolved. Herein, a novel red-near-infrared fluorescent ALP probe (Cl2-BDCM-ALP) based on a dichloro-substituted dicyanomethylene-4H-chromene derivative was designed and synthesized with high fluorescence efficiency and stability under biological pH range. By using Cl2-BDCM-ALP, ALP activity under an acidic microenvironment such as a tumor site can be sensitively imaged, which cannot be achieved by some previously reported ALP probes. By further loading the Cl2-BDCM-ALP into a near-infrared (NIR) light-responsive nanocontainer, time-resolved long-term imaging of ALP activity was facilely achieved with noninvasive NIR light remote control. Time-resolved variation of ALP activity of the drug-induced acute liver injury mice was successfully monitored in vivo for the first time. This strategy holds great promise in the in situ ALP detection under a broad pH range with temporal resolution.


Assuntos
Fosfatase Alcalina/análise , Benzopiranos/química , Corantes Fluorescentes/química , Nanopartículas Metálicas/química , Acetaminofen/toxicidade , Animais , Benzopiranos/síntese química , Linhagem Celular Tumoral , Doença Hepática Induzida por Substâncias e Drogas/enzimologia , Feminino , Corantes Fluorescentes/síntese química , Humanos , Camundongos Endogâmicos BALB C , Neoplasias/enzimologia , Imagem Óptica/métodos , Túlio/química , Itérbio/química , Ítrio/química
5.
Nanotechnology ; 30(6): 065502, 2019 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-30523802

RESUMO

Fatty acids (FAs) are important dietary sources of fuel for animals and structural components for cells. The number, position and configuration of olefins in the alkyl chains play important roles in the impacts of FAs on human health. Currently, structural profiling of FAs in edible oils and fats is an important issue in nutrition industries and food safety. Due to the lack of distinct functional groups, it is extremely difficult to discriminate FAs with structural differences by facile and in situ sensing methods. A few chemosensors have been developed for shape selective sensing of FAs, but their capability and performance were still limited. Herein, for the first time, we proposed a multichannel Au nanosensor for visual and pattern-generating inspection of FAs based on the highly selective binding ability of Ag+ to olefinic bonds and Ag+ regulable color variation of Au nanoparticles. As a result, the nanosensor showed good selectivity for five FAs with subtle structural difference as low as 5 nM. By further deriving three channel signals in respect of color and color depth, a signature-like signal pattern could be generated by principal component analysis for each FA and even different FA mixtures such as edible oils. Hence, structural variation of FAs in edible hot pot oils with heat treatment was successfully monitored by this Au nanosensor over time. This sensor holds great promise in point-of-care inspection of edible oils and fats.


Assuntos
Ácidos Graxos/análise , Ouro/química , Nanopartículas/química , Reconhecimento Automatizado de Padrão , Colorimetria , Oxirredução , Óleos de Plantas/análise , Prata
6.
Proc Natl Acad Sci U S A ; 113(40): 11208-11213, 2016 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-27663743

RESUMO

In this work, we constructed a Collagen I-Matrigel composite extracellular matrix (ECM). The composite ECM was used to determine the influence of the local collagen fiber orientation on the collective intravasation ability of tumor cells. We found that the local fiber alignment enhanced cell-ECM interactions. Specifically, metastatic MDA-MB-231 breast cancer cells followed the local fiber alignment direction during the intravasation into rigid Matrigel (∼10 mg/mL protein concentration).


Assuntos
Colágeno/química , Metástase Neoplásica/patologia , Neoplasias/patologia , Biópsia , Linhagem Celular Tumoral , Proliferação de Células , Progressão da Doença , Matriz Extracelular/metabolismo , Feminino , Humanos , Imagem com Lapso de Tempo
7.
Mikrochim Acta ; 185(4): 239, 2018 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-29594715

RESUMO

A dual-channel ratiometric nanoprobe is described for detection and imaging of microRNA. It was prepared from MoS2 quantum dots (QDs; with blue emission and excitation/emission peaks at 310/398 nm) which acts as both the gene carrier and as a donor in fluorescence resonance energy transfer (FRET). Molecular beacons containing loops for molecular recognition of microRNA and labeled with carboxyfluorescein (FAM) were covalently attached to the MoS2 QDs and serve as the FRET acceptor. In the absence of microRNA, the nanoprobe exhibits low FRET efficiency due to the close distance between the FAM tag and the QDs. Hybridization with microRNA enlarges the distance between QD and beacon. This results in an enhancement of the FRET efficiency of the nanoprobe. The ratio of green and blue fluorescence (I520/I398) increases linearly in the 5 to 150 nM microRNA concentration range in both aqueous solution and diluted artificial cerebrospinal fluid. The limit of detection (LOD) is as low as 0.38 nM and 0.52 nM, respectively. Other features of this nanoprobe include (a) excellent resistance to nuclease-induced false positive signals and (b) the option to use it for distinguishing different cell lines by in-situ imaging of intracellular microRNAs. Graphical abstract Schematic of a dual-channel photoluminescence nanoprobe for the determination of microRNA-21 (miR-21) by monitoring the microRNA-triggered enhancement of the fluorescence resonance energy transfer (FRET) efficiency between MoS2 QDs and carboxyfluorescein-labeled molecular beacons.


Assuntos
Dissulfetos/química , Transferência Ressonante de Energia de Fluorescência/métodos , Corantes Fluorescentes/química , MicroRNAs/metabolismo , Molibdênio/química , Sondas de Oligonucleotídeos/química , Imagem Óptica/métodos , Pontos Quânticos/química , Células HeLa , Células Hep G2 , Humanos , MicroRNAs/química , Modelos Moleculares , Conformação Molecular
8.
Mikrochim Acta ; 185(11): 512, 2018 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-30343484

RESUMO

A fluorescent array based on the use of saccharide-functionalized multicolored quantum dots (s-QDs) and of 4-mercaptophenylboronic acid-functionalized MoS2 nanosheets (PBA-MoS2) was constructed for multiple identification and quantitation of lectins and bacteria. In this array, the fluorescence of the s-QDs is quenched by the PBA-MoS2 nanosheets. In the presence of multiple lectins, s-QDs differentially detach from the surface of PBA-MoS2 nanosheets, producing distinct fluorescence response patterns due to both quenching and enhancement of fluorescence. By analyzing the fluorescence responses with linear discriminant analysis, multiple lectins and bacteria were accurately identified with 100% accuracy. The limits of detection of Concanavalin A, Pisum sativum agglutinin, Peanut agglutinin, and Ricius communis I agglutinin are as low as 3.7, 8.3, 4.2 and 3.9 nM, respectively. The array has further been evidenced to be potent for distinguishing and quantifying different bacterial species by recognizing their surface lectins. The detection limits of Escherichia coli and Enterococcus faecium are 87 and 66 cfu mL-1, respectively. Graphical abstract Schematic of a fluorometric array based on the use of saccharides-functionalized quantum dots (s-QDs) and 4-mercaptophenylboronic acid-functionalized MoS2 (PBA- MoS2) nanosheets. This array was successfully applied to simultaneously analysis of lectins, bacteria in real samples with high sensitivity and accuracy.


Assuntos
Dissulfetos/química , Enterococcus faecium/isolamento & purificação , Escherichia coli/isolamento & purificação , Fluorometria/instrumentação , Molibdênio/química , Nanoestruturas/química , Lectinas de Plantas/análise , Pontos Quânticos/química , Ácidos Borônicos/química , Glicosilação , Limite de Detecção , Modelos Moleculares , Conformação Molecular , Compostos de Sulfidrila/química
9.
Sensors (Basel) ; 18(10)2018 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-30262762

RESUMO

Fatty acids (FAs) are of interest to the areas of food science and medicine because they are important dietary sources of fuel for animals and play important roles in many biological processes. The health effects of FAs are different due to the diversity of olefinic bonds in the alkyl chains including number, position and configuration. However, the discrimination of FAs is difficult from a chemical sensing perspective due to the lack of diversity in terms of functional groups. Until now, only a few chemosensors have been developed for selective sensing of FAs based on their overall shape, however they are still limited in discrimination of FAs with subtle structural differences, moreover, they cannot be used for rapid and in situ inspections. Herein, for the first time, we designed a test paper for in situ colorimetric inspection for FAs based on the combination of the highly selective binding of Ag⁺ to olefinic bonds and Ag⁺ mediated color variation of 3,3',5,5',-tetramethylbenzidine. As a result, the sensor exhibited high sensitivity and good selectivity for five FAs with subtle structural differences. Furthermore, our method described herein was successfully applied to monitor the structural variations of FAs and quality changes in mixture edible hot pot oils with heat treatment in time course. Hence, the test paper presented herein holds great potential in the inspection of fats and edible oils in food industries.

10.
Angew Chem Int Ed Engl ; 56(46): 14596-14601, 2017 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-28960798

RESUMO

The profiling of oxidase-catalyzed biomarkers is an essential procedure for the diagnosis and precise treatment of metabolic diseases. Inspired by the metabolism of H2 O2 in peroxisomes, a novel chemiluminescent silica nanodevice (CSN) was designed for the sensitive and selective sensing of intracellular oxidase-catalyzed biomarkers. Oxidases catalyzed the oxidation of biomarkers followed by the production of H2 O2 , and then the generated H2 O2 was employed to trigger chemiluminescence of the CSN. Utilizing this nanodevice, we not only accurately quantified intracellular glucose but also developed its further application for facile insulin sensitizer screening. Furthermore, sensitive and multiparametric analysis of oxidase-catalyzed biomarkers like lactic acid, uric acid, and ethanol was demonstrated. Thus, this peroxisome-inspired CSN holds great promise for the general diagnosis of metabolic diseases and in drug discovery.


Assuntos
Insulina/metabolismo , Peroxissomos/metabolismo , Dióxido de Silício/química , Animais , Biomarcadores/metabolismo , Etanol/metabolismo , Glucose/metabolismo , Células Hep G2 , Humanos , Ácido Láctico/metabolismo , Luminescência , Medições Luminescentes/métodos , Camundongos , Microscopia Eletrônica de Transmissão , Ácido Úrico/metabolismo
11.
Nanotechnology ; 27(27): 275101, 2016 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-27242334

RESUMO

Recently, the newly emerged two-dimensional nanomaterials, layered transition metal dichalcogenide (e.g. MoS2) nanosheets, have drawn tremendous attentions due to their extraordinary electronic and optical properties, and MoS2 quantum dots (MoS2 QDs) with lateral sizes less than 10 nm have been found to be highly luminescent. In the present study, a facile approach for large-scale preparation of MoS2 QDs by Na intercalation reaction without using any toxic organic reagents is proposed. MoS2 QDs were carefully characterized by various techniques including transmission electron microscopy, atomic force microscopy, dynamic light scattering, spectroscopy, in vitro cytotoxicology, and capillary electrophoresis. The as-prepared MoS2 QDs were strongly fluorescent, highly photo-stable, low in cytotoxicity, and readily reactive to thiols. These inherent properties of MoS2 QDs make them excellent fluorescent probes for long-term live cell tracing. The results of live cells imaging indicated that MoS2 QD stained cells remained highly fluorescent after long-term culture, and could be easily traced from other co-cultured cell lines.


Assuntos
Pontos Quânticos , Sobrevivência Celular , Corantes Fluorescentes , Luminescência , Microscopia de Força Atômica , Microscopia Eletrônica de Transmissão
12.
Chemistry ; 19(40): 13362-8, 2013 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-23939943

RESUMO

Herein, we report a new kind of highly fluorescent probe for Cu(2+) sensing generated by hydrothermal treatment of graphene quantum dots (GQDs). After hydrothermal treatment in ammonia, the greenish-yellow fluorescent GQDs (gGQDs) with a low quantum yield (QY, 2.5%) are converted to amino-functionalized GQDs (afGQDs) with a high QY (16.4%). Due to the fact that Cu(2+) ions have a higher binding affinity and faster chelating kinetics with N and O on the surface of afGQDs than other transition-metal ions, the selectivity of afGQDs for Cu(2+) is much higher than that of gGQDs. Furthermore, afGQDs are biocompatible and eco-friendly, and the afGQDs with a positive charge can be easily taken up by cells, which makes it possible to sense Cu(2+) in living cells. The strategy presented here is simple in design, economical, and offers a "mix-and-detect" protocol without dye-modified oligonucleotides or complex chemical modification.


Assuntos
Cobre/química , Grafite/química , Íons/química , Pontos Quânticos/química , Elementos de Transição/química , Luminescência , Espectrofotometria Ultravioleta
13.
Chemosphere ; 313: 137470, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36493886

RESUMO

Accurate ecotoxicity assessment of contaminated soil is critical to public health, and the luminescent bacteria (Vibrio fischeri) method is the most commonly used. Hydrophobic compounds such as polycyclic aromatic hydrocarbons (PAHs) in soil cannot be in contact with luminescent bacteria due to their low water solubility so that the luminescence inhibitory effect cannot be observed. The underestimated biological toxicity makes the test unreliable and en-dangers public health and safety. The commonly adopted improved method of adding cosolvents has limited effect, it was only effective for low-hydrophobicity chemicals and could not be used for ecotoxicity evaluation of high-hydrophobicity chemicals. Therefore, we constructed Pickering emulsions using luminescent bacteria modified with n-dodecanol in which PAHs were dissolved in the oil phase, n-tetradecane. Then the luminescent bacteria could tightly adhere to the oil-water interface and contact PAHs. As a result, their bioluminescence was suppressed to varying degrees depending on the chemical species and concentrations. With no solubility limitation, highly hydrophobic PAHs could even completely inhibit bacterial bioluminescence, hence the toxicity information was accurately displayed and the median effect concentration (EC50) values could be calculated. This Pickering emulsion-based method was successfully applied for the accurate ecotoxicity evaluation of highly hydrophobic PAHs and soil samples contaminated with them, which all previous methods could not achieve. This method overcomes the problem of ecotoxicity evaluation of hydrophobic compounds, and has great potential for practical application, whether it is pure chemicals or various real samples from the ecological environment.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Poluentes do Solo , Aliivibrio fischeri , Hidrocarbonetos Policíclicos Aromáticos/química , Emulsões/farmacologia , Solo , Água/farmacologia , Poluentes do Solo/toxicidade
14.
J Chromatogr A ; 1705: 464142, 2023 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-37329652

RESUMO

Surface-assisted laser desorption/ionization time-of-flight mass spectrometry (SALDI-TOF MS) is an effective method for detecting of low-mass molecules. In this study, two-dimensional boron nanosheets (2DBs) were fabricated through thermal oxidation etching and coupling liquid exfoliation technologies, and applied as a matrix and selective sorbent for detecting cis-diol compounds by SALDI-TOF MS. The outstanding nanostructure and boric acid active sites of 2DBs endow them with sensitivity for cis-diol compound detection, excellent selectivity, and low background interference for complex samples. The specific in-situ enrichment faculty of the 2DBs as a matrix was investigated by SALDI-TOF MS using glucose, arabinose, and lactose as model analytes. In the presence of 100 -fold more interfering substances, the 2DBs showed high selectivity against cis-diol compounds, and exhibited a better sensitivity and a reduced limit of detection through enrichment treatment than graphene oxide matrices. The linearity, limit of detection (LOD), reproducibility, and accuracy of the method were evaluated under optimized conditions. The results showed that the linear relationships of six saccharides remained in the range of 0.05-0.6 mM with a correlation coefficient r ≥0.98. The LODs of six saccharides were 1 nM (glucose, lactose, mannose, fructose) and 10 nM (galactose, arabinose). Sample-to-sample (n = 6) with relative standard deviations (RSDs) of 3.2% to 8.1% were observed. Recoveries (n = 5) of 87.9-104.6% were obtained at three spiked levels in the milk samples. The proposed strategy promoted the development of a matrix for use with SALDI-TOF MS detection, in which the UV absorption properties and enrichment capabilities of 2DBs were combined.


Assuntos
Arabinose , Boro , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Lactose , Reprodutibilidade dos Testes , Glucose , Lasers
15.
Talanta ; 259: 124496, 2023 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-37031543

RESUMO

Chiral transition metal oxides with tunable structures and multiple physicochemical features have been increasingly applied for chiral sensing and detection. In this work, chiral zinc oxide (ZnO) was first applied as selector to construct quartz crystal microbalance (QCM) sensor for enantioselective recognition of amino acids. The chiral ZnO was prepared by a methionine-induced self-assembly strategy and its high topological chirality was confirmed by several techniques such as circular dichroism spectrum. The chiral discrimination factors were calculated by frequency shifts in response to aspartic acid, phenylalanine, lysine and arginine on L-ZnO surface, achieving 1.89 ± 0.04, 1.76 ± 0.11, 1.66 ± 0.07 and 1.54 ± 0.09, respectively. Notably, L-enantiomers preferred stronger absorptions on L-ZnO surface as compared to D-forms. It was further found that this sensor was appropriate for quantitative analysis and enantiomer excess analysis and adsorption kinetics study. Furthermore, molecular docking revealed the recognition mechanism, where chiral distinction was caused by the different steric interactions between enantiomers and chiral ZnO. This method enjoyed merits of high enantioselectivity, simple preparation and low cost, offering newly chiral sensing method for other molecules.


Assuntos
Aminoácidos , Óxido de Zinco , Estereoisomerismo , Técnicas de Microbalança de Cristal de Quartzo/métodos , Simulação de Acoplamento Molecular
16.
Small ; 8(14): 2138-51, 2012 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-22674906

RESUMO

Graphene has attracted much attention in recent years due to its extraordinary electronic, optical, magnetic, thermal, and mechanical properties. Despite continuing theoretical and experimental success, the unique physical properties of graphene remain underused and underappreciated. The key challenge in harnessing of the unique properties of graphene is the difficulty of reliable manipulation of well-dispersed graphene. Chemical and physical functionalization of graphene has become a focus of especial interest, because they can not only stabilize, but also induce new properties of graphene. This review summarizes the intriguing physical properties of chemically oxidized and noncovalently modified graphene, and graphene-based nanocomposites with polymer matrices or nanoparticles. Along with introducing the physical properties of functionalized graphene, their potential applications in diverse research areas are discussed.

17.
Analyst ; 137(23): 5483-6, 2012 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-23050264

RESUMO

Carbon nanodots (C-Dots) have attracted growing interest in recent years due to their low cost, ready scalability, excellent chemical stability, biocompatibility, colloidal stability, and resilience of photoluminescence. They have been employed as novel, ideal fluorescent probes for bio-imaging and smart sensing. In addition, taking advantage of their low-cytotoxicity, C-Dots have potential applications in biochemical and cell biological fields. Herein, we present the first assay with aptamer-functionalized C-Dots as a sensory platform for protein detection. The presence of thrombin can induce the aptamer-modified fluorescent C-Dots to form a sandwich structure with aptamer-functionalized silica nanoparticles through specific protein/aptamer interaction. The assay shows high specificity toward thrombin. A detection limit of 1 nM is obtained, which is significantly improved as compared to that of many previously reported fluorescence-based thrombin detection assays. Using other modified aptamers and antibodies instead of thrombin binding aptamers, this strategy may offer a suitable approach for detection of other proteins in biological, pharmaceutical and nano-mechanical applications.


Assuntos
Aptâmeros de Nucleotídeos/análise , Nanopartículas , Proteínas/análise , Carbono/química , Corantes Fluorescentes/química , Limite de Detecção
18.
Anal Methods ; 13(16): 1905-1910, 2021 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-33913945

RESUMO

The chirality of amino acids plays an important role in biological and medical sciences. The development of achiral small-molecule probes that can simultaneously determine the absolute configuration, enantiomeric excess, and total concentration of amino acids is significant. We reported the currently available achiral coumarin aldehyde probe that could form Schiff bases with free amino acids at room temperature to induce CD signals and change UV-vis signals. The red-shifted UV-vis signals were independent of the substrate's chirality and could be used to determine the total concentration. Conversely, the enantioselective CD signals could be used to determine the absolute configuration and enantiomeric excess. The usefulness and practicability of this sensing method were demonstrated by analyzing 6 non-racemic phenylalanine samples with different enantiomeric compositions and concentrations.


Assuntos
Aminas , Aminoácidos , Aldeídos , Cumarínicos , Estereoisomerismo
19.
Int J Gen Med ; 14: 2321-2328, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34113162

RESUMO

PURPOSE: Ultrasonography as the first choice for thyroid nodules is still difficult to distinguish between solid follicular thyroid neoplasm (FTN) and solid nodular goiter (NG). We tried to investigate the value of relative size (M/S, M: the maximum diameter of target nodule, S: the maximum diameter of the largest of the remaining nodules) that may help to differentiate FTN from NG. METHODS: T test and chi-square test were used to retrospectively analyze the differences of the clinical and ultrasonographic characteristics between FTN and NG in 422 cases in our hospital. T test was used to analyze the difference of M/S value in the two kinds of nodules. ROC was used to evaluate the accuracy of M/S value in distinguishing the two. RESULTS: There were statistically significant differences in age, echogenicity, calcification, peripheral halo and blood supply between the two. The M/S value is not only significantly different in the two kinds of nodules but also can be used as a quantitative indicator to guide ultrasound diagnosis. ROC analysis showed that the cutoff point and AUC of M/S value were 1.94 and 0.709, respectively. CONCLUSION: In the ultrasound diagnosis of multiple thyroid nodules, the M/S value can better distinguish FTN and NG. We need to be aware of FTN when the M/S value of the nodule is greater than 2.

20.
Int J Gen Med ; 14: 5069-5078, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34511989

RESUMO

BACKGROUND: High-resolution ultrasound is the first choice for the diagnosis of thyroid nodules, but it is still difficult to distinguish between follicular thyroid carcinoma (FTC) and follicular adenoma (FA). Our research aimed to develop and validate an ultrasonic diagnostic model for differentiating FTC from FA. METHODS: This study retrospectively analyzed 196 patients who were diagnosed as FTC (n=83) and FA (n=113). LASSO regression analysis was used to screen clinical and ultrasonic features. Multivariate logistic regression analysis was used to establish the ultrasonic diagnostic model of FTC. Nomogram was used for the visualization of diagnostic models. C-index, ROC, and calibration curves analysis were used to evaluate the accuracy of the diagnostic model. Decision curve analysis (DCA) was used to evaluate the net benefits of the ultrasonic diagnostic model for FTC diagnosis under different threshold probabilities. The bootstrap method was used to verify the ultrasonic diagnostic model. RESULTS: After Lasso regression analysis, 10 clinical and ultrasonic features were used to construct the ultrasonic diagnostic model of FTC. The C-index and AUC of the model were 0.868 and 0.860, respectively. DCA showed that the ultrasonic model had good clinical application value. The C-index in the validation group was 0.818, which was close to the C-index in the model. CONCLUSION: Ultrasonic diagnostic model constructed with 10 clinical and ultrasonic features can better distinguish FTC from FA.

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