- 标题
- 摘要
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- 实验方案
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Rational design of nanoptodes architecture – Towards multifunctional sensors
摘要： Liposome type nano-optodes are reported. Probe architecture allows tailored – yet spontaneous – positioning of the reporter dye with chromophore group facing the sample solution. As a result the emission signal – related to competition between analyte cations and hydrogen ions, ultimately leading to deprotonation of chromoionophore and emission increase – can be read instantly after contact of the sensor with sample but also allows observation of optical signal in unique for these sensors days’ time scale, without loss of intensity. Possibility of optode signal observation in days’ time scale allows exploration of solvatochromic properties of applied chromoionophore group and estimation of sensor sample contact time as minute change in the position of chromophore group emission maximum.
关键词： Liposome,Fluorimetry,Optode,Time,Nanosensor,Concentration
更新于2025-09-19 17:15:36
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ZnTe-coated ZnO nanorods: Hydrogen sulfide nano-sensor purely controlled by pn junction
摘要： In this study, the double hydrothermal method is proposed as a facile approach to the synthesis of ZnTe/ZnO core–shell nanorods. The coating thickness of the p-type ZnTe is varied to adjust the junction depth in the n-type ZnO nanorods, and the conductance measurements reveal the change in the conduction path in the heterojunction structures. Structural and chemical investigations conducted using X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy confirm the hetero-nanostructure formation of ZnTe/ZnO. The role of ZnTe in H2S-gas sensing by the ZnO nanorods is discussed. The enhanced sensing performance observed with a thin ZnTe coating confirms the importance of the base resistance of the nano-transducer in achieving high response characteristics. The composite structure also demonstrates a superior sensing performance of good repeatability, stability, linearity, and gas selectivity at temperatures greater than 200 °C.
关键词： p-n junction,ZnO gas sensor,H2S gas sensor,nanosensor
更新于2025-09-19 17:13:59
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Plasmonic nanosensor based on multiple independently tunable Fano resonances
摘要： A novel refractive index nanosensor with compound structures is proposed in this paper. It consists of three different kinds of resonators and two stubs which are side-coupled to a metal–dielectric–metal (MDM) waveguide. By utilizing numerical investigation with the finite element method (FEM), the simulation results show that the transmission spectrum of the nanosensor has as many as five sharp Fano resonance peaks. Due to their different resonance mechanisms, each resonance peak can be independently tuned by adjusting the corresponding parameters of the structure. In addition, the sensitivity of the nanosensor is found to be up to 1900 nm/RIU. For practical application, a legitimate combination of various different components, such as T-shaped, ring, and split-ring cavities, has been proposed which dramatically reduces the nanosensor dimensions without sacrificing performance. These design concepts pave the way for the construction of compact on-chip plasmonic structures, which can be widely applied to nanosensors, optical splitters, filters, optical switches, nonlinear photonic and slow-light devices.
关键词： metal–dielectric–metal (MDM) waveguide,nanosensor,on-chip plasmonic structures,Fano resonance,surface plasmon polaritons (SPPs)
更新于2025-09-16 10:30:52
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Construction of single quantum dot nanosensor with the capability of sensing methylcytosine sites for sensitive quantification of methyltransferase
摘要： The CpG island methylation plays an important role in diverse biological processes including the regulation of imprinted genes, X chromosome inactivation, and tumor suppressor gene silencing in human cancer. Due to the dependence of DNA methylation upon DNA methyltransferase (MTase) activity, DNA MTases have become the potential targets in anticancer therapy. Herein we demonstrate for the first time the construction of a single quantum dot (QD) nanosensor with the capability of sensing methylcytosine sites for sensitive quantification of M.SssI CpG methyltransferase (M.SssI MTase). We design a biotin-/phosphate-modified double-stranded DNA (dsDNA) substrate with a 5’-G-C-G-mC-3’/3’-mC-G-mC-G-5’ site for sensing M.SssI MTase. In the presence of M.SssI MTase, the methylation-responsive sequence of dsDNA substrate is methylated and cleaved by GlaI endonuclease, producing two dsDNA fragments with free 3’-OH terminus. In the presence of terminal deoxynucleotidyl transferase (TdT), multiple Cy5-dATPs can be sequentially added to the free 3’-OH terminus of dsDNA fragments to obtain the biotin-/multiple Cy5-labeled dsDNAs. The resultant biotin-/multiple Cy5-labeled dsDNAs can assemble on the surface of the streptavidin-coated QD to obtain a QD-dsDNA-Cy5 nanostructure in which the fluorescence resonance energy transfer (FRET) from the QD to Cy5 can occur. The emission of Cy5 can be simply quantified by single-molecule detection. By the integration of sensing methylcytosine sites and enzymatic polymerization, the sensitivity of this nanosensor have been significantly enhanced. This nanosensor can detect as low as 2.1 × 10-7 U/μL M.SssI MTase with good selectivity against other cytosine MTases, and it can be further applied for the screening of MTase inhibitors and complex biological sample analysis, holding great potential in clinic diagnosis and drug discovery.
关键词： methyltransferase,quantum dot,methylcytosine,nanosensor,single-molecule detection
更新于2025-09-16 10:30:52
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Key Roles of Plasmonics in Wireless THz Nanocommunicationsa??A Survey
摘要： Wireless data traffic has experienced an unprecedented boost in past years, and according to data traffic forecasts, within a decade, it is expected to compete sufficiently with wired broadband infrastructure. Therefore, the use of even higher carrier frequency bands in the THz range, via adoption of new technologies to equip future THz band wireless communication systems at the nanoscale is required, in order to accommodate a variety of applications, that would satisfy the ever increasing user demands of higher data rates. Certain wireless applications such as 5G and beyond communications, network on chip system architectures, and nanosensor networks, will no longer satisfy speed and latency demands with existing technologies and system architectures. Apart from conventional CMOS technology, and the already tested, still promising though, photonic technology, other technologies and materials such as plasmonics with graphene respectively, may offer a viable infrastructure solution on existing THz technology challenges. This survey paper is a thorough investigation on the current and beyond state of the art plasmonic system implementation for THz communications, by providing in-depth reference material, highlighting the fundamental aspects of plasmonic technology roles in future THz band wireless communication and THz wireless applications, that will define future demands coping with users’ needs.
关键词： surface plasmon polariton (SPP),wireless NoC (WiNoC),graphennas,multiple-input-multiple-output (MIMO),wireless nanosensor networks (WNSNs),GFET,THz transceiver,graphene based WiNoCs (GWiNoCs)
更新于2025-09-16 10:30:52
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Modified CdS quantum dots as selective turn-on fluorescent nanosensor for detection and determination of methamphetamine
摘要： Surface modification of cadmium sulfide quantum dots (CdS-QDs) with anti-methamphetamine (anti-METH) antibody produced a new turn-on fluorescent nanosensor, anti-METH-CdS-QDs, for detection of methamphetamine. The anti-METH-CdS-QDs nanosensor was obtained readily via the covalent conjugation of mercaptoacetic acid capped CdS-QDs with anti-METH in the presence of N-ethyl-N′-(3-dimethylaminopropyl carbodiimide) (EDC) and Sulfo-N-hydroxysuccinimide (Sulfo-NHS) as coupling agents. The results of FT-IR and energy dispersive X-ray (EDX) spectroscopies confirmed the functionalization of CdS-QDs with anti-METH species. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses revealed the crystal phase and microstructure of CdS-QDs in the anti-METH-CdS-QDs. The obtained anti-METH-CdS-QDs exhibited fluorescence enhancement upon addition of methamphetamine molecules which allowed the highly sensitive and selective determination of methamphetamine with detection limit of 0.006 mg/L. Further studies disclosed that this nanosensor has little interaction with other drugs such as codeine and ibuprofen. Hence, it can be utilized as simple, inexpensive, and selective nanosensor for determination of methamphetamine in low concentrations.
关键词： FRET mechanism,Methamphetamine,Anti-METH antibody,Fluorescent nanosensor,CdS quantum dots
更新于2025-09-12 10:27:22
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CdTe Quantum Dots Modified with Cysteamine: A New Efficient Nanosensor for the Determination of Folic Acid
摘要： In this paper, we report the synthesis, characterization, and application of a new fluorescent nanosensor based on water-soluble CdTe quantum dots (QDs) coated with cysteamine (CA) for the determination of folic acid (FA). CdTe/CA QDs were characterized by high-resolution transmission electron microscopy, the zeta potential, and Fourier-transform infrared (FT-IR), UV-visible, and fluorescence spectroscopy. CdTe QDs coated with mercaptopropionic acid (MPA) and glutathione (GSH) were prepared for comparison purposes. The effect of FA on the photoluminescence intensity of the three thiol-capped QDs at pH 8 was studied. Only CdTe/CA QDs showed a notable fluorescence quenching in the presence of FA. Then, a nanosensor based on the fluorescence quenching of the CdTe QDs at pH 8 was explored. Under optimum conditions, the calibration curve showed a linear fluorescence quenching response in a concentration range of FA from 0.16 to 16.4 μM (R2 = 0.9944), with a detection limit of 0.048 μM. A probable mechanism of fluorescence quenching was proposed. The nanosensor showed good selectivity over other possible interferences. This method has been applied for FA quantification in orange beverage samples with excellent results (recoveries from 98.3 to 103.9%). The good selectivity, sensitivity, low cost, and rapidity make CdTe /CA QDs a suitable nanosensor for FA determination.
关键词： electron transfer,folic acid nanosensor,positive quantum dots,fluorescence quenching
更新于2025-09-12 10:27:22
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A Single Fluorophore Ratiometric Nanosensor Based on Dual-Emission DNA-templated Silver Nanoclusters for Ultrasensitive and Selective Pb2+ Detection
摘要： Lead ion (Pb2+) is known as a major non-degradable environmental pollutant and is quite harmful to human health. In our investigation, a novel ratiometric fluorescent nanosensor with DNA-AgNCs as single fluorophore has been successfully constructed for ultrasensitive and specific detection of Pb2+. The single-strand DNA templated silver nanoclusters present green emission, which can be converted into red emission after approaching a specific DNA segment by forming duplex with its complementary DNA strands (ds-DNA-AgNCs). The ds-DNA-AgNCs contains rA cleavage site of Pb2+-dependent DNAzyme configuration. In the presence of Pb2+, the specific DNA segment would be released from the ds-DNA-AgNCs, resulting in discoloration of DNA-AgNCs from red to green. Since Pb2+ can successively cleave the rA site, the signal change from red to green emission is amplified. Thus, benefiting from the Pb2+-dependent DNAzyme and the charming properties of DNA-AgNCs, the proposed platform exhibits a good linear relationship from 0.001 nM to 10 nM with a detection limit of 1.0 pM for Pb2+ determination, which is lower than most of the reported Pb2+ biosensors. Moreover, this sensitive ratiometric fluorescent probe exhibits excellent selectivity toward Pb2+ detection in real samples, such as lake water, tap water, and human serum samples, illustrating the huge potential applications for complicated samples in the future.
关键词： Pb2+ detection,Ratiometric fluorescent nanosensor,DNA-templated silver nanoclusters,Single fluorophore
更新于2025-09-10 09:29:36
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The effect of morphology and functionalization on UV detection properties of ZnO networked tetrapods and single nanowires
摘要： Rapid detection and fast response of nanoelectronic devices based on semiconducting oxides is nowadays a modern and stringent subject of research. Device performances depend mainly on the morphologies of the metal oxide nanostructures. In the scope of this work, the influence of the structural morphology of three-dimensional (3-D) ZnO nano- and microstructured networks on the room temperature UV detection properties is studied in detail. We show that the formation of multiple potential barriers between the nanostructures, as well as the diameter of the nanostructures, which is in the same order of magnitude as the Debye length, strongly influence the UV sensing properties. Consequently, 3-D ZnO networks consisting of interconnected ultra-long wire-like tips (up to 10 μm) and with small wire diameters of 50–150 nm, demonstrated the highest UV sensing performances (UV response ratio of ～3100 at 5 V applied bias voltage). Furthermore, we demonstrate the possibility of substantially increasing the UV sensing performances of individual ZnO nanowire (NW) (diameter of ～50 nm) by surface functionalization with carbon nanotubes (CNTs), showing high response ratio (～60–50 mW/cm2), as well as fast response (～1 s) and recovery (～1 s) times. The obtained results thus provide a platform with respect to the next generation of portable UV radiation detectors based on semiconducting oxide networks.
关键词： CNT,UV photodetector,ZnO,Device,Individual nanostructures,Nanosensor
更新于2025-09-10 09:29:36
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β-Cyclodextrin protected gold nanoparticle based cotton swabs as an effective candidate for specific sensing of trace levels of cyanide
摘要： In recent work, we demonstrate a rapid colorimetric and easy visual determination of cyanide ions (CNˉ ions) in water based on gold nanoparticles stabilized with β-cyclodextrin (β-CD). Optical detection of CNˉ ions were carried out using β-CD-AuNPs by tracking the changes in the SPR band and colorimetric nature of the β-CD AuNPs. This colorimetric nanosensor capably and ultra sensitively distinguishes the CNˉ ions owing to the capacity of etching the β-CD AuNPs surface and form a stable water soluble Au-CN complex. Under investigational conditions, the colorimetric assay demonstrated a steady response for CNˉ ions over a concentration arrays from 4.50 × 10-6 to 99.00 × 10-6 mol dm-3 with R = 0.994. Lowest limit of detection of this economical, naked eye visual approach is 93.00 × 10-9 mol dm-3, which is under the tolerant limit value (1.90 × 10-6 mol dm-3) described by the World health organization in drinking water. Specificity of β-CD-AuNPs based optical platform for the detection of CNˉ ions is superb evaluated with the various potential interfering anions. Furthermore, the proposed β-CD-AuNPs nanoprobe is effectively applied to quantify the CNˉ ions in tap and drinking water samples. For convenient use, we have designed a very stable β-CD-AuNPs containing cotton swab and it revealed good sensitivity against CNˉ ions in the environment with only bare eye.
关键词： cotton swab,Colorimetric analysis,drinking water samples,cyanide ions,nanosensor
更新于2025-09-10 09:29:36