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A high-throughput plasmonic tongue using an aggregation assay and nonspecific interactions: classification of taste profiles in maple syrup
摘要： A simple colorimetric test detects off-flavour profiles of maple syrups in minutes, which are detectable by the naked eye. As flavour profiles are due to complex mixtures of molecules, the test uses nonspecific interactions for analysing the aggregation and color change of Au nanoparticles (AuNPs) induced by the different organic molecules contained in off-flavour maple syrup. The test was optimal with 13 nm citrate-capped AuNPs reacting 1 : 1 with pure maple syrup diluted 10 times. Under these conditions, normal flavour maple syrups did not react and the solution remained red, while off-flavoured maple syrups aggregated the AuNPs and the solution turned blue. Different classes of molecules were then tested to evaluate the types of compounds typically found in maple syrups reacting in the test, showing that sulfur- and amine-containing amino acids and aromatic amines caused aggregation of the AuNPs. The test was validated with 1818 maple syrup samples from the 2018 harvest in Quebec and 98% of the off-flavoured maple syrups were positively identified against the standard taste test. Preliminary tests were performed on site in maple sugar shacks to validate the applicability of the test on the production site.
关键词： colorimetric test,Au nanoparticles,maple syrup,off-flavour,nonspecific interactions
更新于2025-09-23 15:21:01
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A Colorimetric/Fluorescence Dual-channel Probe for Highly Discriminating Detection of Cysteine
摘要： In this work, a novel fluorescence (FL) probe for selective and sensitive detection of Cys with colorimetric and FL dual signal changes was reported. The probe was synthesized by two step of sulfonamide reaction coupling between a sulfonyl benzoxadiazole (SBD) dye and dansyl chloride linked with rigid piperazine group. The probe showed a specific off-on response to Cys in aqueous solution with nanomolar LOD, and without interference by a range of amino acids and several competing analytes. Upon addition of Cys, the probe will undergo sequential substitution and intramolecular rearrangement reactions, yielding a 4-amino SBD derivative, which results in generation of strong yellow fluorescence emission at 575 nm accompanied by a two-step red shift in the absorption spectral. Moreover, it can be used for imaging of endogenous Cys in living cells.
关键词： Fluorescence probe,Image analysis,Biothiols,Colorimetric
更新于2025-09-23 15:21:01
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Optical properties and colorimetric evaluation of resin cements formulated with thio-urethane oligomers
摘要： Objective: The aim of this study was to evaluate the color parameters and optical properties of resin cements (RCs) formulated with thio-urethanes (TUs). Materials and methods: Six TUs were synthesized by combining thiols (pentaerythritol tetra-3-mercaptopropionate [PETMP] or trimethylol-tris-3-mercaptopropionate [TMP]) with di-functional isocyanates (1,6-Hexanediol-diissocyante [HDDI] [aliphatic-AL] or 1,3-bis(1-isocyanato-1-methylethyl) benzene [BDI] [aromatic-AR] or Dicyclohexylmethane 4,40-Diisocyanate [HMDI] [cyclic-CC]). TUs (20 wt%) were added to a BisGMA/UDMA/TEGDMA matrix. Filler was introduced at 60 wt%. Fluorescence was evaluated through an UV-light emitting equipment. Coordinates L*, a*, and b* were obtained in the black and white reflectance to evaluate the contrast ratio (CR) and translucency parameter (TP00). The coordinates obtained from transmittance were used to evaluate lightness (L*), chroma (C*), color difference (ΔE00) after 6 month, and whiteness index for Dentistry (WID). Results: RCs formulated with TUs presented significantly higher CR, and fluorescence (with T_AR). Significantly lower C*, L*, and TP00 (except for P_AR and T_AL) were also observed in RCs containing TUs. ΔE00 were not significant among the materials. WID was not influenced. Conclusion: RCs composed by TU oligomers present higher CR and lower translucency. The material also present higher fluorescence depending on the oligomer used. Clinical Significance: The use of thio-urethanes to formulate resin cements can ensure a luting material with improved potential to mask colored substrates due to the higher contrast ratio and lower translucency obtained. A final higher fluorescence of restoration is also expected with the use of specific oligomer.
关键词： colorimetric evaluation,resin cements,thio-urethane oligomers,optical properties
更新于2025-09-23 15:21:01
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Recent advances of plasmonic nanoparticle-based optical analysis in homogeneous solution and at the single-nanoparticle level
摘要： Plasmonic nanoparticles with special localized surface plasmon resonance (LSPR) characters have been widely applied for optical sensing of various targets. With the combination of single nanoparticle imaging techniques, dynamic information of reactions and biological processes is obtained, facilitating the deep understanding of their principle and design of outstanding nanomaterials. In this review, we summarize the recently adopted optical analysis of diverse analytes based on plasmonic nanoparticles in both homogeneous solution and single-nanoparticle level. A brief introduction of LSPR is first discussed. Colorimetric and fluorimetric homogeneous detection examples by using different sensing mechanisms and strategies are provided. Single plasmonic nanoparticle-based analysis is concluded in two aspects: visualization of chemical reactions and understanding of biological processes. The basic sensing mechanisms and performances of these systems are introduced. Finally, this review highlights the challenges and future trend of plasmonic nanoparticle-based optical analysis system.
关键词： Plasmonic nanoparticles,Single-nanoparticle level,Fluorimetric assays,Chemical reactions,Localized surface plasmon resonance (LSPR),Optical analysis,Homogeneous solution,Colorimetric assays,Biological processes
更新于2025-09-23 15:21:01
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Design, synthesis, crystal structure and cytotoxicity studies of colorimetric fluorescent “OFF-ON” probes for rapid detection of hydrogen sulfide based on Cu(II) complex
摘要： Four colorimetric fluorescent probes based on copper(II) complexes were synthesized and the molecular structures were characterized by X-ray diffraction, ESI-HRMS and elemental analysis. When exposed to HS–, the synthesized probes showed significant color changes from yellow to red and remarkable increase of fluorescence intensity (over 80-fold). What’s more, the interaction of host-guest could be completed in 2 minutes. However, no clear color and fluorescence intensity changes were observed in the presence of other anions (AcO–, H2PO4–, F–, Cl–, Br–, I–, SO42-, SO32-, CO32-, Cys and GSH). The synthesized colorimetric fluorescent probes could detect HS– rapidly and conveniently. Cytotoxicity studies indicated that the synthesized fluorescent probes were low cytotoxicity in Hela cells and may be used to detect H2S level in vivo.
关键词： hydrogen sulfide,copper complex crystal,fluorescent probe,colorimetric detection,cytotoxicity
更新于2025-09-23 15:21:01
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Dual responsive enzyme mimicking of ternary polyaniline-MnO2-Pd nanowires and its application in colorimetric biosensing
摘要： In recent years, a significant challenge in material science is to fabricate novel functional nanomaterials to mimic the function of natural enzymatic systems. Herein, ternary polyaniline (PANi)-MnO2-Pd nanowires (NWs) are synthesized through a two-step redox reaction process. The prepared PANi-MnO2-Pd NWs were explored to exhibit dual responsive enzyme-like efficiencies, e.g. peroxidase and oxidase-like activities. With the assistance of H2O2, the obtained ternary PANi-MnO2-Pd NWs were able to oxidize the typical peroxidase substrate of 3,3’,5,5’-tetramethylbenzidine (TMB) to yield the oxidized TMB with a blue color, exhibiting a much better peroxidase-like activity than the synthesized PANi-MnO2 NWs alone and Pd nanoparticles owing to the interfacial electron transfer effect among the components. In addition, in the absence of H2O2, the prepared PANi-MnO2-Pd NWs could also oxidize TMB to display an excellent oxidase-like activity. Based on the dual responsive enzyme-like characteristic of the obtained ternary PANi-MnO2-Pd NWs, a rapid and applicative colorimetric way to sensitively determine L-cysteine and ascorbic acid (AA) has been developed. The limits of detection based on the two systems were estimated to be as low as 118 and 34 nM, respectively. We believe that the prepared ternary PANi-MnO2-Pd NWs with both peroxidase and oxidase-like activities will show broad potential applications in bioscience and bioengineering.
关键词： palladium,colorimetric biosensing,enzyme-mimicking,manganese dioxide,polyaniline
更新于2025-09-23 15:21:01
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A luminescent probe for highly selective Cu2+ sensing using a lanthanide-doped metal organic framework with large pores
摘要： Metal-organic frameworks (MOFs) are a class of porous coordination polymer. Recently, some studies have been focused on the detection of various analytes using luminescent MOFs. In this study, an MOF, Eu@1, is synthesized using ([Zn3(TAPB)2(CH3OH)2]) (1) as a precursor to encapsulate Eu3+. It has large pores and excellent luminescent properties, and the quantum yield is up to 30.2%, which can be used as a luminescent probe for highly selective Cu2+ sensing. It is simple and intuitive to use a lanthanide-doped MOF for highly sensitive sensing of Cu2+ by the change of emitting color (from red to blue). The inductively coupled plasma (ICP) and X-ray photoelectron spectroscopy (XPS) data indicate that Cu2+ can easily be exchanged with Eu3+ in 1D channels and replace a portion of the central ions. The good luminescent properties and visible color detectable to the naked eye demonstrate the potential application of this probe in colorimetric detection.
关键词： ions exchange,metal organic framework,large pores materials,luminescence,colorimetric sensor
更新于2025-09-23 15:21:01
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Black phosphorus quantum dots are useful oxidase mimics for colorimetric determination of biothiols
摘要： Black phosphorus quantum dots (BP QDs) with small size are synthesized using an easy to operate thermal method. It was found that BP QDs possess oxidase-mimicking activity. They can catalyze the oxidation of the substrate 3,3′,5,5′-tetramethylbenzidine to produce a blue-colored product even in the absence of hydrogen peroxide. Active oxygen species are proved to be involved in the reaction through the experiments of radical scavenging and electron spin resonance. Biothiols including reduced glutathione and cysteine inactivate the oxidase-mimicking activity of BP QDs, concomitant to the fading of the blue solution. This provides the base for a colorimetric method for the determination of glutathione and cysteine. The decreased absorbance at 652 nm displays linear response to the concentrations of glutathione ranging from 0.1 to 5.0 μmol L?1, and cysteine from 0.1 to 10.0 μmol L?1. The detection limits are 0.02 μmol L?1 and 0.03 μmol L?1 for glutathione and cysteine, respectively. Successive determinations of 1.0 μmol L?1 glutathione and 5.0 μmol L?1 cysteine solution give relative standard deviations of 0.8% and 1.7% (n = 11), respectively. As a preliminary application, the practicability of the method was evaluated by the determination of glutathione in pharmaceutical preparations. This work not only discovers a useful oxidase mimics but also sets up a reliable platform based on BP QDs in colorimetric detection.
关键词： Cysteine,Pharmaceutical,Nanoprobe,Reactive oxygen species,Black phosphorous quantum dots,Oxidase-mimicking activity,Glutathione,Biothiols,Colorimetric method
更新于2025-09-23 15:19:57
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Metallic nanoparticles enabled sensing of drug-of-abuse, an attempt to forensic application
摘要： Gamma-hydroxybutyric acid (GHB) functions as depressant on the central nerve systems and serves as pharmaceutical agent in the treatment of narcolepsy and alcohol withdraw. In recent year, GHB has been misused as recreational drug due to its ability to induce euphoric feelings. Moreover, it has gained increasing attentions as a popular drug of abuse which is frequently related to drug-facilitated sexual assaults. By now, chromatography exhibit detection methods based on extraordinary sensitivity for GHB sensing. However, such techniques require complicated sample treatment prior to analysis. Optical sensors provide an alternative approach for rapid and simple analysis of GHB samples. Unfortunately, currently reported probes are mostly based on hydrogen bonding to recognize GHB, which may raise concern such as lack of specificity. In this work, we reported a bioinspired strategy for selective sensing of GHB. Such method is based on specific enzyme recognition to allow highly selective detection of GHB with minimum interference even in complex sample matrix (e.g. simulated urine). In addition, the result can be obtained by either quantitative spectroscopy analysis as well as colormetric change observed by naked-eye demonstrating the potential application in drug screening and forensic analysis.
关键词： drug sensing,Au NPs,colorimetric detection
更新于2025-09-23 15:19:57
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Luminescent Sulfur Quantum Dots for Colorimetric Discrimination of Multiple Metal Ions.
摘要： The classical chemistry of sodium thiosulphate was applied to synthesize luminescent Sdots where elemental sulfur produced in situ was etched with NaOH. This method notably reduces the synthesis time of Sdots in comparison to the previously reported etching technique of bulk sulfur. The as-synthesized Sdots exhibited excitation dependent photoluminescence with a QY of 2.5 %, photostabality under UV light irradiation, excellent dispersibility in aqueous medium and also the stability even after several weeks. Notably, no emission was observed due to the oxidation of PEG-400 during the course of reaction. The Sdots was then employed as a dual function probe for the sensing of metal ions. Using fluorimetric method, Sdots showed preferential selectivity towards the Co2+ metal ions. However, a single probe Sdots can colorimetrically distinguish multiple metal ions such as Co2+, Cr6+ and Pb2+ by displaying color change on the immediate addition of analytes. Furthermore, the color change of Sdots is demonstrated with the help of hue images and hue spectra (or histogram) that will help in the development of Sdots based portable device. The present study contributes to the further advancement of this emerging field as a promising single-element nanomaterial an alternative to luminescent metallic nanomaterials.
关键词： Colorimetric Discrimination,Photoluminescence,Hue,Sodium Thiosulphate,Sdots,Metal Ions
更新于2025-09-23 15:19:57