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- 实验方案
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Phenanthroline-Derivative Functionalized Carbon Dots for Highly Selective and Sensitive Detection of Cu2+ and S2? and Imaging inside Live Cells
摘要： Developing effective methods for the instant detection of Cu2+ and S2? is highly desired in the biological and environmental fields. Herein, a novel fluorescent nanoprobe was elaborately designed and synthesized by grafting a phenanthroline derivative onto the surface of carbon dots (CDs). The obtained functionalized CDs (FCDs) exhibited blue fluorescence (FL) with excellent photostability and possessed a mean diameter around 4 nm. Cu2+ can be selectively captured by the phenanthroline group of FCDs to generate an absorptive complex in situ, leading to obvious quenching of the FCDs’ FL signal through an inner filter effect. Furthermore, the FL of the FCD–Cu2+ can be effectively recovered by S2? anions due to the release of FCDs from the FCD–Cu2+ complex owing to the formation of stable CuS (Ksp = 1.27 × 10?36) between S2? and Cu2+. The detection limits of the FCDs were determined to be 40.1 nM and 88.9 nM for Cu2+ and S2?, respectively. Moreover, this nanoprobe can also be used for the imaging of intracellular Cu2+ and S2?, which shows strong application prospects in the field of biology.
关键词： carbon dots,fluorescent nanoprobe,(2,3-f)-pyrazino(1,10)phenanthroline-2,3-dicarboxylic acid,Cu2+,S2?
更新于2025-09-23 15:23:52
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A Nanoprobe for Diagnosing and Mapping Lymphatic Metastasis of Tumor Using 3D Multispectral Optoacoustic Tomography Owing to Aggregation/Deaggregation Induced Spectral Change
摘要： Lymphatic metastasis of tumor is one of leading causes of cancer-related death, and diagnosing lymphatic metastasis is of significance in terms of optimal disease management and possible better outcomes for patients. Herein a turn-on optoacoustic nanoprobe is reported for noninvasively diagnosing and locating lymphatic metastasis in vivo. A positively charged tricyanofuran-containing polyene chromophore (TCHM) with high extinction coefficient is designed, synthesized, and allowed to form the nanoprobe with a negatively charged hyaluronan. The TCHMs take an aggregated state within the nanoprobe and exhibit weak absorption at 882 nm, the overexpressed hyaluronidase in cancer cells specifically degrades hyaluronan into small fragments and disaggregates TCHMs, thereby greatly enhancing the absorption at 882 nm and generating prominent optoacoustic signals. For multispectral optoacoustic tomography (MSOT) imaging in vivo, mice models with subcutaneous tumor and orthotopic bladder tumor are imaged first to demonstrate the nanoprobe’s capability for detecting HAase-overexpressing tumors. A mouse model of lymphatic metastasis of tumor is then established and the lymphatic metastasis is successfully imaged and tracked optoacoustically. The imaging results were verified using multiple biochemical assays. Moreover, 3D MSOT renderings are obtained for precisely locating and tracking the metastasis of tumor in lymphatic system in a spatiotemporal manner.
关键词： lymphatic metastasis,imaging,multispectral,nanoprobe,3D,optoacoustic tomography,aggregation
更新于2025-09-23 15:23:52
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White-light emissive upconversion nanoparticles for visual and colorimetric determination of the pesticide thiram
摘要： The authors describe the use of white-light emitting upconversion nanoparticles (WL-UCNPs) for visual detection of the pesticide thiram. The method is demonstrated to undergo a better discernable color change upon target binding. The WL-UCNPs are modified with the lead(II)-dithizone complex which acts as the energy acceptor and recognition unit. This leads to quenching of the blue (475 nm) and green (545 nm) emissions of the WL-UCNPs, while the red emission (650 nm) remains unaffected. Upon addition of thiram, the quenched emissions are recovered, with a linear signal increase in the range from 2 nM to 20 nM of thiram and a limit of detection of 0.26 nM. The nanoprobe was further integrated into a test paper for visual detection. The concentration-dependent color change that varies from red to cyan and bluish violet and then to white can be visually distinguished.
关键词： Lead-dithizone complex,Color-differentiation,Upconversional nanoprobe,Test paper,Energy transfer
更新于2025-09-23 15:22:29
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Molecular imaging of telomerase and the enzyme activity-triggered drug release by using a conformation-switchable nanoprobe in cancerous cells
摘要： So far, the development of a unique strategy for specific biomolecules activity monitoring and precise drugs release in cancerous cells is still challenging. Here, we designed a conformation-switchable smart nanoprobe to monitor telomerase activity and to enable activity-triggered drug release in cancerous cells. The straightforward nanoprobe contained a gold nanoparticle (AuNP) core and a dense layer of 5-carboxyfluorescein (FAM)-labeled hairpin DNA shell. The 3′ region of hairpin DNA sequence could function as the telomerase primer to be elongated in the presence of telomerase, resulting in the conformational switch of hairpin DNA. As a result, the FAM fluorescence was activated and the anticancer drug doxorubicin (Dox) molecules which intercalated into the stem region of the hairpin DNA sequence were released into cancerous cells simultaneously. The smart method could specifically distinguish cancerous cells from normal cells based on telomerase activity. It also showed a good performance for monitoring telomerase activity in the cytoplasm by molecular imaging and precise release of Dox triggered by telomerase activity in cancerous cells. These advantages may offer a great potential of this method for monitoring telomerase activity in cancer progression and estimating therapeutic effect.
关键词： drug release,molecular imaging,nanoprobe,telomerase,cancerous cells
更新于2025-09-23 15:21:21
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Preparation and comparison of molecularly imprinted polymer fluorimetric nanoprobe based on polymer dots and carbon quantum dots for determination of acetamiprid using response surface method
摘要： In this study molecularly imprinted polymers (MIP) based on carbon quantum dots (CQDs) and polymer dots (PDs) are developed for selective determination of acetamiprid using fluorometry. The measurement is based on the fluorescence quenching of CQDs and PDs in the presence of acetamiprid. PDs were prepared using a one-step aqueous synthesis method from ascorbic acid and diethylenetriamine at room temperature. CQDs were prepared from the same materials using the hydrothermal method at 180 °C. These particles were characterized using field emission scanning electron microscopy (FE-SEM), FTIR, dynamic light scattering (DLS), X-ray diffraction (XRD), UV–Vis, and fluorescence. The quantum yield was 47% for PDs and 8% for CQDs. Then, molecularly imprinted polymers (MIP) were prepared based on PDs and CQDs using reverse microemulsion method. The fluorescence quenching of CQD@MIPs and PD@MIPs was investigated at an excitation wavelength of 350 nm and emission wavelength of 440 nm in the presence of a template. Other variables affecting the fluorescence peaking were optimized using design expert software. The results illustrate that the use of PD@MIPs had a wide dynamic range 0.08–109 nmol L?1, good accuracy and detection limit of 0.02 nmol L?1, while using CQD@MIPs led to a lower dynamic range 0.36–64 nmol L?1, and detection limit of only 0.11 nmol L?1. The responses of the optical nanoprobe for acetamiprid in water (recovery 92–102%) and apple (recovery 92–103%) were also investigated.
关键词： Molecularly imprinted polymers,Fluorescence quencing,Carbon dots,Polymer dots,Optical nanoprobe,Acetamiprid
更新于2025-09-23 15:21:01
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Near-infrared light controlled fluorogenic labeling of glycoengineered sialic acids <i>in vivo</i> with upconverting photoclick nanoprobe
摘要： Near-infrared light controlled fluorogenic labeling of glycoengineered sialic acids in vivo with upconverting photoclick nanoprobe. Sialic acid serves as an important determinant for profiling cell activities in diverse biological and pathological processes. The precise control of sialic acid labeling to visualize its biological pathways under endogenous conditions is significant but still challenging due to the lack of reliable methods. Herein, we developed an effective strategy to spatiotemporally label the sialic acids with a near-infrared (NIR) light activated upconverting nanoprobe (Tz-UCNP). With this photoclickable nanoprobe and a stable N-alkene-D-mannosamine (Ac4ManNIPFA), metabolically synthesized alkene sialic acids on the cell surface were labeled and imaged in real time through fluorogenic cycloaddition. More importantly, we achieved spatially selective visualization of sialic acids in specific tumor tissues of the mice under NIR light activation in a spatially controlled manner. This in situ controllable labeling strategy thus enables the metabolic labeling of specific sialic acids in complex biological systems.
关键词： fluorogenic labeling,sialic acids,Near-infrared light,upconverting nanoprobe,photoclick chemistry
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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Highly Rectifying Heterojunctions Formed by Annealed ZnO Nanorods on GaN Substrates
摘要： We study the effect of thermal annealing on the electrical properties of the nanoscale p-n heterojunctions based on single n-type ZnO nanorods on p-type GaN substrates. The ZnO nanorods are prepared by chemical bath deposition on both plain GaN substrates and on the substrates locally patterned by focused ion beam lithography. Electrical properties of single nanorod heterojunctions are measured with a nanoprobe in the vacuum chamber of a scanning electron microscope. The focused ion beam lithography provides a uniform nucleation of ZnO, which results in a uniform growth of ZnO nanorods. The specific configuration of the interface between the ZnO nanorods and GaN substrate created by the focused ion beam suppresses the surface leakage current and improves the current-voltage characteristics. Further improvement of the electrical characteristics is achieved by annealing of the structures in nitrogen, which limits the defect-mediated leakage current and increases the carrier injection efficiency.
关键词： chemical bath deposition,nanoscale heterojunctions,ZnO nanorods,nanoprobe in the scanning electron microscope,current-voltage characteristics,annealing,focused ion beam patterning
更新于2025-09-23 15:19:57
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DNA enzyme mediated ratiometric fluorescence assay for Pb(II) ion using magnetic nanosphere-loaded gold nanoparticles and CdSe/ZnS quantum dots
摘要： Based on the inner filter effect mechanism of quantum dots, a ratiometric fluorescence nanoprobe was constructed for the determination of Pb(II) ion. Green emitting quantum dots conjugated with DNA substrate (DNA2) acted as donors providing green fluorescence, while gold nanoparticles coupled with DNA enzyme (DNA1) as acceptors quench the green fluorescence. Meanwhile, Fe3O4 nanosphere served as magnetic substrates to facilitate separation process and red fluorescence as an “inner rule” to eliminate the background signal. In the presence of Pb(II) ion, the DNA1 specifically recognize and capture Pb(II) ion with enhanced catalytic activity, which can cleave DNA2 and “turn on” the green fluorescence (I540), while the red fluorescence (I630) remained unchanged. In this way, the ratio of I540/I630 reflects the Pb(II) ion in the system, enabling the quantitative and selective determination of Pb(II) ion over nine different metal ions. Under optimal conditions, the ratiometric fluorescence assay showed good linearity (R2 = 0.98) within the range 10 to 100 ng mL?1. The limit of detection (LOD) was calculated to be 1.79 pg mL?1 (S/N = 3, n = 3, ±3.8%). The proposed fluorescence nanoprobe provides better sensitivity and accuracy than non-ratiometric signal evaluation for Pb(II) ion determination.
关键词： Fluorescence nanoprobe,Inner rule,Magnetic separation,Tea sample,Metal ions,Inner filter effect
更新于2025-09-23 15:19:57
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Dual-emission CdTe/AgInS2 photoluminescence probe coupled to neural network data processing for the simultaneous determination of folic acid and iron (II)
摘要： This work focused on the combination of CdTe and AgInS2 quantum dots in a dual-emission nanoprobe for the simultaneous determination of folic acid and Fe(II) in pharmaceutical formulations. The surface chemistry of the used QDs was amended with suitable capping ligands to obtain appropriate reactivity in terms of selectivity and sensitivity towards the target analytes. The implementation of PL-based sensing schemes combining multiple QDs of different nature, excited at the same wavelength and emitting at different ones, allowed to obtain a specific analyte-response profile. The first-order fluorescence data obtained from the whole emission spectra of the CdTe/AgInS2 combined nanoprobe upon interaction with folic acid and Fe(II) were processed by using chemometric tools, namely partial least-squares (PLS) and artificial neural network (ANN). This enabled to circumvent the selectivity issues commonly associated with the use of QDs prone to indiscriminate interaction with multiple species, which impair reliable and accurate quantification in complex matrices samples. ANN demonstrated to be the most efficient chemometric model for the simultaneous determination of both analytes in binary mixtures and pharmaceutical formulations due to the non-linear relationship between analyte concentration and fluorescence data that it could handle. The R2P and SEP% obtained for both analytes quantification in pharmaceutical formulations through ANN modelling ranged from 0.92 to 0.99 and 5.7e9.1%, respectively. The obtained results revealed that the developed approach is able to quantify, with high reliability and accuracy, more than one analyte in complex mixtures and real samples with pharmaceutical interest.
关键词： CdTe/AgInS2 combined nanoprobe,Artificial neural network,Iron,Partial least-squares,Folic acid
更新于2025-09-23 15:19:57