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- 2018
- metal object detection (MOD)
- wireless power transfer (WPT)
- auxiliary detection coil
- Chest X-ray (CXR)
- Computer-aided Diagnosis (CADx)
- Early detection of tuberculosis
- Electrical Engineering and Automation
- Optoelectronic Information Science and Engineering
- Shanghai Jiao Tong University
- Bandung Institute of Technology (ITB)
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Ultrathin and Isotropic Metal Sulfide Wrapping on Plasmonic Metal Nanoparticles for SERS-based Detection of Trace Heavy Metal Ions.
摘要： A facile and general strategy is presented for homogenous and ultrathin metal sulfide-wrapping on plasmonic metal (PM) nanoparticles (NPs) based on a thiourea-induced isotropic shell growth. This strategy is typically implemented just via adding the thiourea into pre-formed PM colloidal solutions containing target metal ions. The validity of this strategy is demonstrated by taking the wrapped NPs with Au core and CuS shell or Au@CuS NPs as an example. They are successfully fabricated via adding the thiourea and Cu2+ solutions into pre-formed Au NP colloidal solution. The CuS shell layer is highly homogenous (<10% in relative standard deviation of shell thickness), regardless of the NPs’ shape or curvature. The shell thickness can be controlled from tens down to 0.5 nm just by the addition amounts of the shell precursors. The formation of the shell layer on the Au NPs can be attributed to the alternative deposition of Cu2+ and S2- ions on the thiourea-modified surface of Au NPs in the solution, which induces the isotropic shell growth. Further, this strategy is of good universality. Many other sulfide-wrapped PM NPs, such as Ag@CuS, Au@PtS2, Au@HgS, Ag@Ag2S NPs and Ag@CuS nanorods have been successfully obtained with homogeneous and ultrathin shells. Importantly, such ultrathin sulfide-wrapped PM NPs can be used for SERS-based detection of trace heavy metal ions with strong anti-interference via ion exchange process between the metal sulfide shell and heavy metal ions. This study provides a simple and controllable route for wrapping the homogenous and ultrathin sulfide layers on the PM NPs, and such wrapped NPs have good practical applications in the SERS-based detection of trace heavy metal ions.
关键词： Plasmonic metal nanoparticles,Trace heavy metal ions,Ultrathin sulfide wrapping,Thiourea-induced isotropic shell growth,SERS-based detection
更新于2025-11-14 17:04:02
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A novel photoelectrochemical biosensor for the sensitive detection of dual microRNAs using molybdenum carbide nanotubes as nanocarriers and energy transfer between CQDs and AuNPs
摘要： Herein, a novel photoelectrochemical (PEC) biosensor was developed for the ultrasensitive detection of dual microRNAs (miRNAs), with the detection being based on energy transfer (ET) between carbon quantum dots (CQDs) and gold nanoparticles (AuNPs). The PEC platform consisted of a CQDs@Mo2C nanotube modified ITO electrode. Two hairpin probes (H1 and H2) carrying the Au NPs were used “switch off” and “switch on” the PEC signal of the CQDs, with a close approach of the tagged AuNPs to the CQDs quenching the PEC signal. The introduction of different miRNAs (miRNA-159b and miRNA-166a) altered the interparticle distance between the AuNPs and CQDs, thereby affecting the intensity of the PEC response. This approach allowed the highly sensitive detection of both miRNA-159b and miRNA-166a. The linear range of the biosensor for miRNA-159b and miRNA-166a detection were 0.5–5000 fM, with low detection limits of 0.15 fM and 0.21 fM, respectively. To our knowledge, this is the first reported CQDs-based ET biosensor for the PEC detection of dual miRNAs. Results suggest that this approach offers a promising platform for the ultrasensitive detection of multiple miRNAs.
关键词： MicroRNA detection,AuNPs,Photoelectrochemistry,Energy transfer,CQDs@Mo2C
更新于2025-11-14 17:03:37
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2,4,6-Trinitrophenol detection by a new portable sensing gadget using carbon dots as a fluorescent probe
摘要： An optical sensing gadget using fluorescence of carbon dots (CDs) was developed to realize the in-field detection of 2,4,6-trinitrophenol (TNP) in tap water and lake water samples. Fluorescent CDs were prepared through a one-step hydrothermal synthetic route. The fluorescence spectra demonstrated that the CDs could specifically discriminate TNP from other nitroaromatic explosives in an aqueous medium. The fluorescence of the CDs was quenched linearly with the concentration of TNP in the range from 1 to 100 μM, with a detection limit of 0.48 μM (3σ/k). The detection mechanism was ascribed to the synergistic effect of the inner filter effect and electron transfer. In addition, a portable sensing gadget based on a high-precision RGB color sensor and a micro control unit was developed. With use of the sensing gadget and the CDs, TNP detection in tap water and lake water samples was realized. Importantly, the portable sensing gadget combined with highly stable, low-toxicity, and sensitive CDs might have great potential for application in extensive in-field sensing situations.
关键词： 2,4,6-Trinitrophenol detection,Portable sensing gadget,Carbon dots,Fluorescence analysis
更新于2025-11-14 17:03:37
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Sensitive surface-enhanced Raman scattering detection of atrazine based on aggregation of silver nanoparticles modified carbon dots
摘要： The development of precise detection methods with simply operation for pesticides in various environmental samples is a particular challenge. Here a highly sensitive surface-enhanced Raman scattering (SERS) approach for the selective detection of trace atrazine was proposed with R6G as a Raman reporter, which was adsorbed on silver nanoparticles modified carbon dots. The latter were prepared by the reduction of Ag+ by carbon dots. In the presence of atrazine, the aggregation of the modified carbon dots due to the interaction between silver nanoparticles and atrazine led to great enhancement of the SERS signal of R6G. Under optimal assay conditions, the limit of quantification was estimated to be 10 nM, which matched with the standard for drinking water quality of China and WHO defined limit. A good linear response to atrazine was found in the concentration range of 10-1000 nM with the relative standard deviations between 1.8% and 5.6%. The determination of atrazine in real water samples was also carried out to confirm the practicability of the proposed method, which showed the recoveries from 95% to 117.5%. The target induced aggregation for enhancing the signal offered great potential for sensitive on-site detection of atrazine in environments.
关键词： Silver nanoparticles,Pesticides,SERS detection,Target induced aggregation,Atrazine,Carbon dots
更新于2025-11-14 17:03:37
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Highly Selective Optical Detection of Fe <sup>3+</sup> Ions in Aqueous Solution Using Label-Free Silicon Nanocrystals
摘要： Highly brightness amine-terminated silicon nanocrystals (Si NCs) have been utilized in a simple and rapid assay for the highly selective and sensitive detection of Fe3+ via quenching of their strong blue luminescence, without the need for analyte-specific labeling groups. Sensitive detection of Fe3+ is successfully demonstrated, with a linear relationship observed between luminescence quenching and Fe3+ concentration from 5 × 10?6 to 900 × 10?6 m and a limit of detection of 1.3 × 10?6 m. The Si NCs show excellent selectivity toward Fe3+ ions, with no quenching of the luminescence signal induced by the presence of Fe2+ ions, allowing for solution phase discrimination between the ionic species in different charge states.
关键词： nanocrystal,sensor,iron,optical detection
更新于2025-11-14 15:32:45
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N-arylated bisferrocene pyrazole for dual-mode detection of hydrogen peroxide: AIE-active fluorescent “turn on/off” and electrochemical non-enzymatic sensor
摘要： A series of new N?arylated bisferrocene pyrazole (D-π-A-π-D) chromophores have been synthesized by the Chan?Lam cross-coupling (1, 2) and Buchwald–Hartwig amination (3, 4) reactions. The compounds 1-4 were characterized with the aid of analytical and spectroscopic methods. The solvatochromism behaviour of compounds (1, 3) showed positive solvatochromism and later (2, 4) exhibited negative solvatochromism. The compounds 1-4 interestingly showcased high-enhanced fluorescent intensity in their aggregate state while in the solution state they exhibited low fluorescent intensity behaviour. The origin of enhanced emission in the aggregated state is due to a restriction of intramolecular rotation, especially in the ratio of mixture 40:60 (CH3CN/H2O). The aggregation-induced emission(AIE) properties were utilized to detect the H2O2 which show quick response in a linear range of 10-50 μM with a detection limit of 38.8 nM (1) and 15.9 nM (3). Furthermore, the electrochemical reduction of hydrogen peroxide in the same linear range as above showed and a limit of detection (3σ) of 14.4 mM (1) and 11.6 mM (3).
关键词： Dual-mode detection of H2O2,Electrochemical non?enzymatic sensor,AIE-active luminogens
更新于2025-11-14 15:29:11
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A colorimetric, ultraviolet absorption and fluorescence three-signal probe based on bis-carbazole for Al3+ detection and the application in cell imaging
摘要： A novel Schiff-base, [9-(2-Chloro-ethyl)-9H-carbazol-3-yl-methylene]-(9-ethyl-9H-carbazol-3-yl)-amine (CECA) was designed and synthesized, which was highly selective and sensitive for the detection of Al3+ by colorimetric, ultraviolet absorption and fluorescence three-signal methods. The detection limit was evaluated to be as low as 74 nmol/L for the ultraviolet absorption method and 19 nmol/L for fluorometric method. These three methods could determine qualitatively and quantitatively the concentrations of Al3+ and been used in different conditions. The mechanism was explored that the double bond (C=N) of CECA was broken to form the carbazole aldehyde and carbazole amine complex accompanied by fluorescence enhancement by the Job's plot, 1H NMR, the electrospray ionization mass spectra (EI-MS) and fluorescence methods. More significantly, the fluorescence imaging showed that CECA could detect Al3+ in living cells.
关键词： Schiff base,Al3+,Detection,Imaging,Three-signal
更新于2025-11-14 15:29:11
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Luminescence Tuning of Layered Rare-Earth Hydroxides (LRHs, R = Tb, Y) Composites with 3-Hydroxy-2-naphthoic Acid and Application to the Fluorescent Detection of Al <sup>3+</sup>
摘要： Tunable luminescence (quenching or blue shift) of HNA/OS-LRH composites (HNA is 3-hydroxy-2-naphthoic acid; OS is the anionic surfactant of 1-octanesulfonic acid sodium; LRHs are layered rare-earth hydroxides, R = Tb3+, Y3+) in the solid state and delaminated state is reported, which is utilized as an effective fluorescent probe for detecting metal ions. HNA/OS species are intercalated into LRH layers to generate composites of HNAxOS1?x-LTbH (x = 0.10, 0.15, 0.20 , 0.25) and HNAyOS1?y-LYH (y = 0.05, 0.10, 0.15, 0.20, 0.25, 0.30). In the solid state, LYH composites exhibit green emissions (from 493 to 504 nm) with a large blue shift in comparison to the 542 nm emission of free HNA? anions, while in the delaminated state in formamide (FM), the composites display blue emission (480 nm) relative to the green emission (512 nm) of an HNA soltuion in FM. However, LTbH composites display coquenched luminescence in both the solid state and delaminated state. Also, HNA0.25OS0.75-1:1-LYH, HNA0.25OS0.75-1:2-LYH, and HNA0.05OS0.95-1:1-LYH (1:1 and 1:2 are HNA:NaOH molar ratios) show significantly elongated fluorescence lifetimes of 15.35, 14.37, and 12.72 ns, respectively, in comparison with free HNA-Na (6.44 ns), and their quantum yields of 23.40%, 21.97%, and 22.31%, respectively, are much larger than that of free HNA-Na (4.86%). The LTbH composite (HNA0.25OS0.75-1:1-LTbH) has also a relatively higher quantum yield of 12.46%. The HNA0.25OS0.75-1:1-LYH colloid exhibits excellent recognition selectivity for Al3+ over other metal ions (Mg2+, Co2+, Ni2+, Cu2+, Zn2+, Pb2+, Cd2+, and Hg2+) with distinct fluorescence sensitization. It shows an intense change in its fluorescence emission when it is bound to Al3+ ions, giving a lower detection limit of 6.32 × 10?6 M. This is novel research on the fluorescence chemosensing of LRH composites.
关键词： Layered rare-earth hydroxides,Fluorescent detection,Chemosensing,Luminescence tuning,Al3+ ions
更新于2025-11-14 15:28:36
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Systematic Truncating Aptamers to Create High Performance Graphene Oxide (GO)-based Aptasensors for Multiplex Detection of Mycotoxins
摘要： Graphene Oxide (GO)-based aptasensor is currently one of the most popular sensing platforms for simple and rapid detection of various targets. Unfortunately, the GO-based aptasensors with long aptamer strands typically show unsatisfactory performance resulted from insignificant structural transformations upon target bindings. We report herein the utilization of an aptamer truncating strategy to combat such a challenge. Taking a pre-selected anti-aflatoxin B1 (AFB1) aptamer (P-AFB1-50) as a trial system, we sequentially remove the extraneous nucleotides within the aptamer by means of circular dichroism (CD) spectroscopy and binding affinity analysis. Particularly, the ratio of the quenching constants between the GO sheets and the truncated aptamers (labelled with fluorophores) in the absence and presence of target was determined for each of the truncated aptamers to evaluate the optimal sequence. As a result, the truncated aptamer comprising 40 nucleotides was confirmed to show the highest FL output and best detection limit upon conjugation with GO sheets. More importantly, we demonstrated that this truncating strategy is versatile, i.e., it can be easily extended to other aptamer systems (anti-ochratoxin A (OTA) aptamer, P-OTA-61, as an example) for extraneous nucleotide identification. Impressively, the two optimal truncated aptamers can work together on GO sheets to achieve a simultaneous detection of two different mycotoxins (i.e., AFB1 and OTA) in one single testing. Essentially, this research opens a new avenue for the design and testing of aptamer/GO based-sensing platforms for rapid, low-cost and multiplex quantification of analytical targets of interest.
关键词： DNA/GO-based biosensors,AFB1,OTA,long-chain aptamer,multiplex detection,extraneous nucleotide truncation
更新于2025-11-14 15:28:36
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Rapid preparation of homogeneous carbon dots with yellow fluorescence and formation mechanistic investigation
摘要： In this study, homogeneous carbon dots with yellow fluorescence and high absolute fluorescence quantum yields (78.6%) were firstly prepared through a one-step solvothermal method without complicated process of separation, in which sodium citrate, carbamide, and anhydrous calcium chloride were adopted as precursors, while toluene was selected as solvent. The as-prepared carbon dots with an average size of 5.9 nm have a high degree of crystallinity. According to the discussion of the formation mechanism carbon dots, it is found that the toluene guarantee the formation of crystalline core and Ca2+ promotes the formation of carbonaceous core with high crystallinity, which is responsible for the ultrahigh quantum yield. Furthermore, the fluorescent properties of carbon dots are excellent in organic solvents and could be quenched by water, making them a promising material used without any modification in the detection of water in organic solvents, which has a great influence on organic chemical reaction, and may even determine the resultant, yield, and selectivity of organic reaction.
关键词： Detection of water content,Ultrahigh quantum yield,Yellow fluorescence,Carbon dots,Quantum dot
更新于2025-11-14 15:28:36