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1.
Talanta ; 258: 124433, 2023 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-36996585

RESUMO

Norovirus (NoV) is a major foodborne pathogen responsible for acute gastroenteritis epidemics, and establishing a robust detection method for the timely identification and monitoring of NoV contamination is of great significance. In this study, a peptide-target-aptamer sandwich electrochemical biosensor for NoV was fabricated using Au@BP@Ti3C2-MXene and magnetic Au@ZnFe2O4@COF nanocomposites. The response currents of the electrochemical biosensor were proportional to the NoV concentrations ranging from 0.01-105 copies/mL with a detection limit (LOD) of 0.003 copies/mL (S/N = 3). To our best knowledge, this LOD was the lowest among published assays to date, due to the specific recognition of the affinity peptide and aptamer for NoV and the outstanding catalytic activity of nanomaterials. Furthermore, the biosensor showed excellent selectivity, anti-interference performance, and satisfactory stability. The NoV concentrations in simulative food matrixes were successfully detected using the constructed biosensor. Meanwhile, NoV in stool samples was also successfully quantified without complex pretreatment. The designed biosensor had the potential to detect NoV (even at a low level) in foods, clinical samples, and environmental samples, providing a new method for NoV detection in food safety and diagnosing foodborne pathogens.


Assuntos
Técnicas Biossensoriais , Estruturas Metalorgânicas , Nanocompostos , Norovirus , Peptídeos/química , Oligonucleotídeos/química , Limite de Detecção , Titânio/química , Fósforo/química
2.
Talanta ; 237: 122896, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34736712

RESUMO

Noroviruses are the leading cause of acute gastroenteritis and food-borne diseases worldwide. Thus, a rapid, accurate, and easy-to-implement detection method for controlling infection and monitoring progression is urgently needed. In this study, we constructed a novel sandwich-type electrochemical biosensor integrated with two specific recognition elements (aptamer and peptide) for human norovirus (HuNoV). The electrochemical biosensor was fabricated using magnetic covalent organic framework/pillararene heterosupramolecular nanocomposites (MB@Apt@WP5A@Au@COF@Fe3O4) as the signal probes. The sensor showed high accuracy and selectivity. The detection method does not need the extraction and amplification of virus nucleic acid and has a short turn-around time. Intriguingly, the proposed biosensor had a limit of detection of 0.84 copy mL-1 for HuNoV, which was the highest sensitivity among published assays. The proposed biosensor showed higher sensitivity and accuracy compared with immunochromatographic assay in the detection of 98 clinical specimens. The biosensor was capable of determining the predominant infection strain of GII.4 and also GII.3 and achieved 74% selectivity for HuNoV GII group. This study provides a potential method for point-of-care testing and highlights the integrated utilization of Apt and peptide in sensor construction.


Assuntos
Técnicas Biossensoriais , Estruturas Metalorgânicas , Nanocompostos , Norovirus , Humanos , Imunoensaio
3.
Talanta ; 233: 122520, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34215135

RESUMO

This work describes a novel affinity peptide-antibody sandwich electrochemical strategy for the ultrasensitive detection of prostate-specific antigen (PSA). Herein, polydopamine-coated boron-doped carbon nitride (Au@PDA@BCN) was synthesized and used as a sensing platform to anchor gold nanoparticles and immobilize primary antibody. Meanwhile, AuPt metallic nanoparticle and manganese dioxide (MnO2)-functionalized covalent organic frameworks (AuPt@MnO2@COF) was facilely synthesized to serve as a nanocatalyst and ordered nanopore for the enrichment and amplification of signal molecules (methylene blue, MB). PSA affinity peptide was bound to AuPt@MnO2@COF to form Pep/MB/AuPt@MnO2@COF nanocomposites (probe). The peptide-PSA-antibody sandwich biosensor was constructed, and the redox signal of MB was measured with the existence of PSA. The fabricated sensor exhibited a linear response (0.00005-10 ng mL-1) with a low detection limit of 16.7 fg mL-1 under the optimum condition. Additionally, the sensor showed an excellent selectivity, ideal repeatability, and good stability for PSA detection in real samples. Furthermore, the porous structure of COF can enrich more MB molecules and increase the sensitivity of the biosensor. This study provides an efficient and ultrasensitive strategy for PSA detection and broadens the use of organic/inorganic porous nanocomposite in biosensing.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Estruturas Metalorgânicas , Técnicas Eletroquímicas , Ouro , Humanos , Imunoensaio , Limite de Detecção , Masculino , Compostos de Manganês , Óxidos , Peptídeos , Antígeno Prostático Específico
4.
Nanotechnology ; 32(37)2021 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-34044381

RESUMO

Fingerprints formed by the raised papillary ridges are one of the most important markers for individual identification. However, the current visualization methods for latent fingerprints (LFPs) suffer from poor resolution, low contrast, and high toxicity. In this work, the CsPbBr3/Cs4PbBr6nanostructured composite crystal (CsPbBr3/Cs4PbBr6NCC) were synthesized via a simple chemical solvent-assisted method. Compared with conventional perovskites, the as-prepared CsPbBr3/Cs4PbBr6NCC present an outstanding long-term environmental and water stability with 42% and 80% photoluminescence intensity remaining after 28 d under water and air conditions, respectively. Moreover, a special response to biomolecules from fingerprints was observed due to the hydrophobic interactions between the CsPbBr3/Cs4PbBr6NCC surface hydrophobic ligands (oleyl amine and oleic acid) and the hydrophobic groups in the biomolecules from the human fingers. Clear LFPs images were visualized in a bright environment illuminating the prepared CsPbBr3/Cs4PbBr6NCC powder under UV light of wavelength 365 nm. The images were also obtained on porous and non-porous surfaces such as metal, plastic, wood, glass, and paper products. These perovskite nanocrystals are expected a stable and bright luminescent labeling agent for LFPs visualization and have potential application in crime scene and personal identifications.

5.
J Dairy Sci ; 104(3): 2511-2519, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33455776

RESUMO

Chymosin is a predominant enzyme in rennet and is used in cheese production because of its excellent milk-clotting activity. Herein, we proposed a facile and label-free electrochemical method for determining chymosin activity based on a peptide-based enzyme substrate. The synthesized substrate peptide for chymosin was assembled onto the surface of the Au-deposited grassy carbon electrode. The current was proportional to chymosin activity, and thus chymosin activity could be determined. The detection ranges of chymosin activity were 2.5 to 25 U mL-1. The detection limit of chymosin activity was 0.8 U mL-1. The sensing platform was used to quantify chymosin activity in commercial rennet with high selectivity, excellent stability, and satisfactory reproducibility. We developed a facile, fast, and effective electrochemical assay for detecting chymosin activity, which has potential applications in cheesemaking.


Assuntos
Queijo , Quimosina , Animais , Leite , Peptídeos , Reprodutibilidade dos Testes
6.
Sens Actuators B Chem ; 327: 128899, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32952300

RESUMO

The recent pandemic outbreak of COVID-19 caused by a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), poses a threat to public health globally. Thus, developing a rapid, accurate, and easy-to-implement diagnostic system for SARS-CoV-2 is crucial for controlling infection sources and monitoring illness progression. Here, we reported an ultrasensitive electrochemical detection technology using calixarene functionalized graphene oxide for targeting RNA of SARS-CoV-2. Based on a supersandwich-type recognition strategy, the technology was confirmed to practicably detect the RNA of SARS-CoV-2 without nucleic acid amplification and reverse-transcription by using a portable electrochemical smartphone. The biosensor showed high specificity and selectivity during in silico analysis and actual testing. A total of 88 RNA extracts from 25 SARS-CoV-2-confirmed patients and eight recovery patients were detected using the biosensor. The detectable ratios (85.5 % and 46.2 %) were higher than those obtained using RT-qPCR (56.5 % and 7.7 %). The limit of detection (LOD) of the clinical specimen was 200 copies/mL, which is the lowest LOD among the published RNA measurement of SARS-CoV-2 to date. Additionally, only two copies (10 µL) of SARS-CoV-2 were required for per assay. Therefore, we developed an ultrasensitive, accurate, and convenient assay for SARS-CoV-2 detection, providing a potential method for point-of-care testing.

7.
Int J Mol Sci ; 21(14)2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32679647

RESUMO

We reported for the first time that cationic pillar[6]arene (cPA6) could tightly bind to peptide polymer (MW~20-50 kDa), an artificial substrate for tyrosine (Tyr) phosphorylation, and efficiently inhibit Tyr protein phosphorylation through host-guest recognition. We synthesized a nanocomposite of black phosphorus nanosheets loaded with cPA6 (BPNS@cPA6) to explore the effect of cPA6 on cells. BPNS@cPA6 was able to enter HepG2 cells, induced apoptosis, and inhibited cell proliferation by reducing the level of Tyr phosphorylation. Furthermore, BPNS@cPA6 showed a stronger ability of inhibiting cell proliferation in tumor cells than in normal cells. Our results revealed the supramolecular modulation of enzymatic Tyr phosphorylation by the host-guest recognition of cPA6.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , Compostos de Amônio Quaternário/farmacologia , Antineoplásicos/administração & dosagem , Cátions/administração & dosagem , Cátions/farmacologia , Portadores de Fármacos/química , Células Hep G2 , Humanos , Nanoestruturas/química , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Fósforo/química , Compostos de Amônio Quaternário/administração & dosagem , Tirosina/metabolismo
8.
Biosens Bioelectron ; 144: 111691, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31520964

RESUMO

Magnetic covalent organic frameworks (COFs) are useful mesoporous materials for the enrichment and separation of analytes, and are utilized in the pretreatment of samples. However, the use of magnetic COFs in electrochemical immunosensors has rarely reported. Herein, a novel electrochemical assay for the determination of prostate specific antigen (PSA) was developed using black phosphorene (BPene) as a platform and magnetic COFs for signal amplification. BPene was prepared via water-phase exfoliation. BPene nanocomposite (Au@BPene) was prepared by depositing Au nanoparticles (Au NPs) onto BPene. This nanocomposite was utilized as an immunsensing platform to bind primary antibodies and improve electron transfer. Subsequently, an Au NP-loaded magnetic COF was used to immobilize the secondary antibodies and abundant electronic signals of methylene blue (MB). The fabricated sensor exhibited linearity ranging from 0.0001 ng mL-1 to 10 ng mL-1 with the detection limit of 30 fg mL-1. The sensor could determine the PSA in a real sample with excellent specificity, good stability, and desirable reproducibility. The effective signal amplification of the proposed sensor is attributed to the good electron transfer of Au@BPene, excellent enrichment capacity of signal molecules (MB) of the COF, and efficient catalytic activity of Fe3O4. This work not only provides an effective electrochemical assay to detect PSA in real sample, but also broadens the utilization scope of magnetic COFs in immunosensing.


Assuntos
Anticorpos Imobilizados/química , Técnicas Biossensoriais , Imunoensaio , Antígeno Prostático Específico/isolamento & purificação , Anticorpos Imobilizados/imunologia , Técnicas Eletroquímicas , Ouro/química , Humanos , Nanopartículas Metálicas/química , Antígeno Prostático Específico/química
9.
Food Chem ; 283: 191-198, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30722861

RESUMO

A label-free fluorescence assay for resveratrol determination is presented for the first time. The approach was based on fluorescence resonance energy transfer (FRET), via competitive supramolecular recognition, between p-sulfonated calix[6]arene (CX6)-modified reduced graphene oxide (CX6@RGO) and a probe-resveratrol complex. The probe molecule (Rhodamine B or rhodamine 123) had a strong fluorescence signal, and its fluorescence was quenched by CX6@RGO, based on FRET. When the target molecule was added to CX6@RGO, the probe molecule was displaced by resveratrol, and a host-guest complex, CX6@RGO-resveratrol formed, turning-on the fluorescence signal. Fluorescence intensity of the CX6@RGO-probe complex increased linearly with increased resveratrol concentrations (2.0-40.0 µM). The proposed approach was used to determine resveratrol in red wine with satisfactory detection limits and recoveries. Compared with traditional determination methods, our procedure is advantageous because it saves time, is easy to operate, and does not require sample pretreatment.


Assuntos
Transferência Ressonante de Energia de Fluorescência/métodos , Resveratrol/análise , Vinho/análise , Fluorescência , Grafite , Limite de Detecção , Óxidos
10.
Talanta ; 197: 130-137, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30771914

RESUMO

Competitive host-guest recognition has been utilized to determine small molecules using macrocyclic supramolecular host, while less studies focused on the specific recognition and sensing of protein. In the present work, we are the first time to report a label-free fluorescent assay for insulin determination based on the supramolecular recognition between cationic pillar[6]arene (CP6) and insulin. The approach is based on fluorescence resonance energy transfer (FRET) through competitive recognition between CP6 functionalized reduced graphene oxide (CP6@rGO) and probe/insulin molecules. Probe molecule (RhB) has strong fluorescent signal, and its fluorescent is quenched by rGO based on FRET. When target protein molecule (insulin) is added to CP6@rGO, the probe is displaced by insulin and a host-guest complex CP6@rGO/insulin is formed, resulting in a "turn-on" fluorescence signal. The fluorescence intensity of complex increased linearly with the increase of insulin concentration ranging 0.01-0.50 and 1.0-16.0 µM, respectively with a detection limit of 3 nM. The sensor was successfully utilized to determine insulin in artificial serum. The molecular docking result showed that the N-terminal Phe of insulin's B chain was included in the CP6 cavity through electrostatic interaction and formed a stable host-guest complex.


Assuntos
Transferência Ressonante de Energia de Fluorescência , Fluorescência , Insulina/análise , Compostos de Amônio Quaternário/química , Cátions/química , Estrutura Molecular
11.
RSC Adv ; 8(2): 775-784, 2018 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-35538938

RESUMO

In the present study, thiol ß-cyclodextrin (SH-CD) and ethylenediamine ß-cyclodextrin (NH2-ß-CD) were simultaneously grafted on the same interface of an Au NP deposited carboxyl SiC (Au@CSiC) nanocomposite. An electrochemical sensor for the simultaneous determination of nitrophenol isomers (o-nitrophenol, o-NP; p-nitrophenol, p-NP) using SH-CD and NH2-ß-CD functionalized Au@SiC (Au@CSiC-SH/NH2-CD) nanocomposite was successfully constructed. Differential pulse voltammetry was used to quantify o-NP and p-NP within the concentration range of 0.01-150 µM under the optimal conditions. The detection limit (S/N = 3) of the sensor was 0.019 and 0.023 µM for o-NP and p-NP, respectively, indicating a low detection limit. Interference study results demonstrated that the sensor was not affected in the presence of similar aromatic compounds during the determination of NP isomers, showing high selectivity. The proposed electrochemical sensing platform was successfully used to determine NP isomers in tap water. The low detection limit and high selectivity of the proposed electrochemical sensor were caused by the high surface area, the excellent conductivity, and the more recognized (enriched) NP isomer molecules by SH-ß-CD and NH2-ß-CD of the Au@CSiC-SH/NH2-CD nanocomposite.

12.
Nanoscale ; 9(12): 4272-4282, 2017 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-28294236

RESUMO

Alternative cleavage and polyadenylation (APA) is involved in several important biological processes in animals, e.g. cell growth and development, and cancer progression. The increasing data show that cancer cells are inclined to produce mRNA isoforms with a shortened 3'UTR undergoing APA. For example, the Dicer1 isoform with a shorter 3'untranslated region (3'UTR) was found to be overexpressed in some cancer cells, which may be used as a potential novel prognostic biomarker for cancer. In the present work, a novel electrochemical biosensor for ultrasensitive determination of Dicer1 was designed by using gold nanoparticles and p-sulfonated calix[6]arene functionalized reduced graphene oxide (Au@SCX6-rGO) as nanocarriers. The results showed that the expressions of the shorter 3'UTR (Dicer1-S) both in BT474 and SKBR3 were obviously higher than those of the longer Dicer1 (Dicer1-L) by the constructed biosensor, which agreed well with the result analyzed by the RT-qPCR method. The detection ranges of Dicer1-S and Dicer1-L were 10-14-10-9 M and 10-15-10-10 M. The LODs were 3.5 and 0.53 fM. The specificity of the proposed biosensor was also very high. For the first time, the expressional analysis of different 3'UTRs caused by APA was studied by an electrochemical method. Moreover, the use of a macrocyclic host for constructing an electrochemical/biosensing platform has rarely been reported. The proposed electrochemical sensing strategy is thus expected to provide a new method for determination of novel biomarkers and a novel method for fast and cheap analysis of APA.


Assuntos
Regiões 3' não Traduzidas , Técnicas Biossensoriais , RNA Helicases DEAD-box/análise , Ouro , Nanopartículas Metálicas , Ribonuclease III/análise , Animais , Linhagem Celular Tumoral , Técnicas Eletroquímicas , Humanos , Poliadenilação
13.
Biosens Bioelectron ; 91: 863-869, 2017 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-28160654

RESUMO

A sensitive and selective fluorescence approach based on a competitive host-guest interaction between amphiphilic pillar[5]arene (amPA5) and signal probe (acridine orange, AO)/target molecule (acetaminophen, AP) was developed by using amPA5 functionalized reduced graphene oxide (amPA5-RGO) as a receptor. Due to the host-guest interaction, AO and AP molecules both can enter into the hydrophobic inner cavity of amPA5 that could form a complex of 1:1 guest-host with amPA5 according to the size of molecules and the cavity of amPA5, but the AP interacts more strongly with amPA5 than with AO, so it can detect AP by the host-guest competition. The low detection limit of 0.05µM (S/N=3) and a linear response range of 0.1-4.0µM and 4.0-32µM for AP was obtained by using this method. It had lower detection limit and wider linear range than other methods, therefore, it was successfully utilized to detect AP in serum samples, and exhibited a promising application in practice. The molecular docking studies indicated that the major driving forces for the formation of the inclusion complex of AP and amPA5 are hydrogen bonding, π-π interactions, and hydrophobic interactions.


Assuntos
Acetaminofen/sangue , Analgésicos não Narcóticos/sangue , Grafite/química , Compostos de Amônio Quaternário/química , Espectrometria de Fluorescência/métodos , Tensoativos/química , Calixarenos , Humanos , Limite de Detecção , Simulação de Acoplamento Molecular , Oxirredução , Óxidos/química
14.
Biosens Bioelectron ; 89(Pt 1): 361-369, 2017 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-27436432

RESUMO

The present work described the comparison of ß-cyclodextrin (ß-CD) and p-sulfonated calix[6]arene (SCX6) functionalized reduced graphene oxide (RGO) for recognition of tadalafil. In this study, tadalafil and two macrocycles (ß-CD and SCX6) were selected as the guest and host molecules, respectively. The inclusion complexes of ß-CD/tadalafil and SCX6/tadalafil were studied by UV spectroscopy and molecular simulation calculations, proving the higher supermolecular recognition capability of SCX6 than ß-CD towards tadalafil. The ß-CD@RGO and SCX6@RGO composites were prepared by a wet-chemical route. The obtained composites were characterized by Fourier transform infrared spectrometry, thermogravimetric analysis, atomic force microscopy, and zeta potential. The SCX6@RGO showed a higher electrochemical response than ß-CD@RGO, which was caused by the higher recognition capability of SCX6 than ß-CD. By combining the merits of SCX6 and the RGO, a sensitive electrochemical sensing platform was developed based on the SCX6@RGO nanohybrids. A linear response range of 0.1-50 µM and 50-1000 µM for tadalafil with a low detection limit of 0.045 µM (S/N=3) was obtained by using this method. The constructed sensing platform was successfully used to determine tadalafil in herbal sexual health products and spiked human serum samples, suggesting its promising analytical applications for the trace level determination of tadalafil.


Assuntos
Calixarenos/química , Técnicas Eletroquímicas/métodos , Grafite/química , Fenóis/química , Tadalafila/sangue , Vasodilatadores/sangue , beta-Ciclodextrinas/química , Técnicas Biossensoriais/métodos , Humanos , Limite de Detecção , Modelos Moleculares , Simulação de Acoplamento Molecular , Oxirredução , Óxidos/química , Plantas Medicinais/química , Sulfonas/química , Tadalafila/análise , Vasodilatadores/análise
15.
Biosens Bioelectron ; 87: 737-744, 2017 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-27649329

RESUMO

In this work, the molecular recognition of dimethomorph by disulfide bridged ß-cyclodextrin (SS-ß-CD) was studied by UV spectroscopy, 2D NMR, and molecular modeling. The results indicated that the SS-ß-CD/dimethomorph was more stable than ß-CD/dimethomorph, which is ascribed to the fact that the disulfide chain plays an important role in stabilizing the appropriate dual-CD conformation and also promoting the inclusion of the host and guest. In addition, a robust fluorescence method for dimethomorph sensing has been developed based on competitive host-guest interaction by selecting safranine T (ST) as optical indicator and SS-ß-CD functionalized reduced graphene oxide (SS-ß-CD-RGO) as the receptor. Upon the presence of dimethomorph to the pre-formed SS-ß-CD-RGO·ST complex, the ST molecule is displaced by dimethomorph, leading to a "switch-on" fluorescence response. That is due to the fact that the binding constant of the dimethomorph/SS-ß-CD complex was more than 5 times greater than that of ST/SS-ß-CD. The fluorescence intensity of SS-ß-CD-RGO·ST complex increased linearly with increasing concentration of dimethomorph ranging from 0.50 to 20.0µM. The proposed method showed a detection limit of 0.11µM for dimethomorph, and was successfully applied for the determination of dimethomorph residues in vegetables (cabbage, spinach) and environmental samples (water, soil) with good precision and recoveries from 96.5% to 104%.


Assuntos
Dissulfetos/química , Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Transferência Ressonante de Energia de Fluorescência/métodos , Morfolinas/análise , beta-Ciclodextrinas/química , Corantes/química , Água Doce/análise , Limite de Detecção , Modelos Moleculares , Fenazinas/química , Solo/química , Verduras/química
16.
Biosens Bioelectron ; 83: 347-52, 2016 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-27135940

RESUMO

A dual-signalling electrochemical approach has been developed towards aconitine based on competitive host-guest interaction by selecting methylene blue (MB) and p-sulfonated calix[8]arene functionalized single-walled carbon nanohorns (SCX8-SWCNHs) as the "reporter pair". Upon the presence of aconitine to the performed SCX8-SWCNHs·MB complex, the MB molecules are displaced by aconitine. This results in a decreased oxidation peak current of MB and the appearance of an oxidation peak of aconitine, and the changes of these signals correlate linearly with the concentration of aconitine. A linear response range of 1.00-10.00µM for aconitine with a low detection limit of 0.18µM (S/N=3) was obtained by using the proposed method. This method could be successfully utilized to detect aconitine in serum samples. This dual-signalling sensor can provide more sensitive target recognition and will have important applications in the sensitive and selective electrochemical detection of aconitine.


Assuntos
Aconitina/sangue , Adjuvantes Imunológicos/sangue , Calixarenos/química , Técnicas Eletroquímicas/métodos , Nanotubos de Carbono/química , Humanos , Limite de Detecção , Nanotubos de Carbono/ultraestrutura
17.
Biosens Bioelectron ; 82: 146-54, 2016 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-27085945

RESUMO

This work reports a novel method for the determination of aconitine through the competitive host-guest interaction between p-sulfonated calix[8]arene (SCX8) and signal probe/target molecules by using SCX8 functionalized reduced graphene oxide (SCX8-RGO) as a receptor. Three dyes (ST, RhB, BRB) and aconitine were selected as the probe and target molecules, respectively. The formation of SCX8-RGO·ST, SCX8-RGO·RhB, and SCX8-RGO·BRB complexes greatly decreases the fluorescence emission of ST, RhB, and BRB. The aconitine/SCX8 complex possesses a higher binding constant than ST/SCX8, RhB/SCX8, and BRB/SCX8 complexes, thus the dye in the SCX8 cavity can be replaced by aconitine to revert the fluorescence emission of SCX8-RGO·dye, leading to a "switch-on" fluorescence response. The fluorescence intensity of SCX8-RGO·ST, SCX8-RGO·RhB, and SCX8-RGO·BRB complexes increased linearly with increasing concentration of aconitine ranging from 1.0 to 14.0µM, 2.0-16.0µM, and 1.0-16.0µM, respectively. Based on the competitive host-guest interaction, the proposed detection method for aconitine showed detection limits of 0.28µM, 0.60µM, and 0.37µM, respectively, and was successfully applied for the determination of aconitine in human serum samples with good recoveries from 95.1% to 104.8%. The proposed method showed high selectivity for aconitine beyond competitive binding analytes. In addition, the inclusion complex of the SCX8/aconitine was studied by the molecular docking and molecular dynamics simulation, which indicated that the phenyl ester group of the aconitine molecule was included into the SCX8 cavity.


Assuntos
Aconitina/análise , Adjuvantes Imunológicos/análise , Calixarenos/química , Corantes Fluorescentes/química , Grafite/química , Espectrometria de Fluorescência/métodos , Aconitina/sangue , Aconitum/química , Adjuvantes Imunológicos/sangue , Medicamentos de Ervas Chinesas/análise , Medicamentos de Ervas Chinesas/farmacocinética , Humanos , Limite de Detecção , Simulação de Dinâmica Molecular , Sulfonas/química
18.
Analyst ; 141(1): 270-8, 2016 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-26626104

RESUMO

A novel electrochemical method has been developed towards cholesterol detection based on competitive host-guest interaction by selecting methylene blue (MB) and calix[6]arene functionalized graphene (CX6-Gra) as the "reporter pair". In the presence of cholesterol, the MB molecules are displaced by cholesterol in the CX6-Gra.MB complex, leading to a "switch off" electrochemical response. A linear response range of 0.50 to 50.00 µM for cholesterol with a low detection limit of 0.20 µM (S/N = 3) was obtained by using the proposed method. This method could be successfully utilized to detect cholesterol in serum samples, and may be expanded to the analysis of other non-electroactive species. Besides, the host-guest interaction between cholesterol and CX6 was studied by molecular modeling calculations, which revealed that the complexation could reduce the energy of the system and the complex of a 1 : 1 host-guest stoichiometry had the lowest binding free energy of -8.01 kcal mol(-1). In addition, the constructed electrochemical sensing platform is important as it does not use any enzyme or antibody for the detection of cholesterol efficiently and selectively over common interfering species.


Assuntos
Calixarenos/química , Colesterol/análise , Eletroquímica/instrumentação , Grafite/química , Fenóis/química , Colesterol/química , Eletrodos , Estudos de Viabilidade , Limite de Detecção , Azul de Metileno/química , Modelos Moleculares , Conformação Molecular , Oxirredução , Espectrometria de Fluorescência
19.
ACS Appl Mater Interfaces ; 7(48): 26557-65, 2015 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-26571350

RESUMO

A competitive fluorescence method toward tadalafil detection has been developed based on host-guest recognition by selecting rhodamine B (RhB) and p-sulfonated calix[6]arene functionalized graphene (CX6-Gra) as the "reporter pair". Upon the presence of tadalafil to the performed CX6-Gra-RhB complex, the RhB molecules are displaced by tadalafil, leading to a "switch-on" fluorescence signal. The observed fluorescence signal can be used for quantitative detection of tadalafil ranging from 1.00 to 50.00 µM with a detection limit of 0.32 µM (S/N = 3). The inclusion complex of tadalafil and CX6 was studied by molecular docking and the results indicated that a 1:1 host-guest stoichiometry had the lowest ΔG value of -7.18 kcal/mol. The docking studies demonstrated that the main forces including π-π interactions, electrostatic interactions, and hydrophobic interactions should be responsible for the formation of this inclusion compound. The mechanism of the competitive host-guest interaction was clarified. The binding constant (K) of the tadalafil/CX6 complex was more than 5 times greater than that of RhB/CX6.

20.
Anal Chim Acta ; 892: 85-94, 2015 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-26388478

RESUMO

The application of macrocyclic hosts for construction of different electrochemical devices and separation matrices has attracted much attentions due to their benign biocompatibility and simplicity of synthesis. Myricetin and rutin are considered two of the most bioactive flavonoids, which have been proved to exhibit various physiological functions. This work reports a simple and facile approach for the synthesis of ß-cyclodextrin-gold@3, 4, 9, 10-perylene tetracarboxylic acid functionalized single-walled carbon nanohorns (ß-CD-Au@PTCA-SWCNHs) nanohybrids. The simultaneous electrochemical determination of myricetin and rutin using a ß-CD-Au@PTCA-SWCNHs-modified glassy carbon electrode was established. The results show that the ß-CD-Au@PTCA-SWCNHs-modified electrode displayed electrochemical signal superior to those of Au@PTCA-;SWCNHs and SWCNHs towards myricetin and rutin. The proposed modified electrode has a linear response range of 0.01-10.00 µM both for myricetin and rutin with relatively low detection limits of 0.0038 µM for myricetin and 0.0044 µM (S/N = 3) for rutin, respectively. The excellent performance of the sensing platform is considered to be the synergic effects of the SWCNHs (e.g. their good electrochemical properties and large surface area) and ß-CD (e.g. a hydrophilic external surface, a high supramolecular recognition, and a good enrichment capability).


Assuntos
Técnicas Eletroquímicas/métodos , Flavonoides/análise , Nanotubos de Carbono/química , Perileno/análogos & derivados , Rutina/análise , Técnicas Eletroquímicas/instrumentação , Eletrodos , Flavonoides/sangue , Ouro/química , Humanos , Concentração de Íons de Hidrogênio , Perileno/química , Rutina/sangue , beta-Ciclodextrinas/química
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