Interactions between surface plasmons (SP) of metallic surfaces and photoluminescence (PL) of semiconductor nanocrystal (S-NC) surfaces have been extensively investigated, and SP-induced PL ...enhancement has been used as a sensitive analytical technique. However, this SP induced electrochemiluminescence (ECL) enhancement is rarely studied. In this work, we report greatly enhanced ECL of CdS thin films by gold nanoparticles (Au NPs) for ultrasensitive detection of thrombin. The system was composed of a CdS NC film on glassy carbon electrode (GCE) as ECL emitter attached an aptamer of thrombin. Then, ssDNA–AuNP conjugates hybridized with the aptamer to form a separation length of ca. 12 nm between CdS NCs and Au NPs. The system showed 5-fold enhancement of ECL intensity as compared to that without Au NPs, which might be attributed to the long-distance interaction between the S-NCs and SPR field of noble metal nanoparticles (MNPs).We also found that the enhanced ECL could be influenced by the involving factors such as the separation distance, spectral overlap, and magnetic field. Such enhancement in combination with smart recognition of aptamer and target protein allowed us to construct an ultrasensitive aptasensor for attomolar detection of thrombin. The presence of target protein was reflected by the ECL signal decrease caused by the target-induced removal of ssDNA–AuNP conjugates. The decrease of ECL signal was logarithmically linear with the concentration of thrombin in a wide range from 100 aM to 100 fM. The principle described in this work could be also applied to many other bioassays.
DNA/RNA strand displacement is one of the most fundamental reactions in DNA and RNA circuits and nanomachines. In this work, we reported an exploration of the dynamic process of the toehold-mediated ...strand displacement via core–satellite plasmon rulers at the single-molecule level. Applying plasmon rulers with unlimited lifetime, single-strand displacement triggered by the invader that resulted in stepwise leaving of satellite from the core was continuously monitored by changes of scattering signal for hours. The kinetics of strand displacement in vitro with three different toehold lengths have been investigated. Also, the study revealed the difference in the kinetics of strand displacement between DNA/RNA and DNA/DNA duplexes. For the kinetics study in vivo, influence from the surrounding medium has been evaluated using both phosphate buffer and cell lysate. Applying core–satellite plasmon rulers with high signal/noise ratio, kinetics study in living cells proceeded for the first time, which was not possible by conventional methods with a fluorescent reporter. The plasmon rulers, which are flexible, easily constructed, and robust, have proven to be effective tools in exploring the dynamical behaviors of biochemical reactions in vivo.
We have established a new protocol for detecting severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) using a peptidomimetic to covalently detect a viral marker protease.
A one-step, ...reagent-free, low-cost, high-stability assay for the detection of SARS-CoV-2.
Though significant advances are made in the arena of single‐cell electroanalysis, quantification of intracellular amino acids of human cells remains unsolved. Exemplified by l‐histidine (l‐His), this ...issue is addressed by a practical electrochemical nanotool synergizing the highly accessible nanopipette with commercially available synthetic DNAzyme. The fabricated nanotools are screened before operation of a single‐use manner, and the l‐His‐provoked cleavage of the DNA molecules can be sensibly transduced by the ionic current rectification response, the intrinsic property of nanopipette governed by its interior surface charges. Regional distribution of cytosolic l‐His level in human cells is electrochemically quantified for the first time, and time‐dependent drug treatment effects are further revealed. This work unveils the possibility of electrochemistry for quantification of cytosolic amino acids of a spatial‐ and time‐based manner and ultimately enables a better understanding of amino acid‐involved events in living cells.
The solution‐to‐electrochemical single‐cell analysis of intracellular amino acids is achieved by integrating nanopipette with specific DNAzyme and exemplified by targeting l‐histidine. It allowed minimally invasive detection with high sensitivity and selectivity. Drug treatment is also probed of a spatial‐ and time‐based manner.
This work proposes the concept of single‐cell microRNA (miR) therapy and proof‐of‐concept by engineering a nanopipette for high‐precision miR‐21‐targeted therapy in a single HeLa cell with sensitive ...photoelectrochemical (PEC) feedback. Targeting the representative oncogenic miR‐21, the as‐functionalized nanopipette permits direct intracellular drug administration with precisely controllable dosages, and the corresponding therapeutic effects can be sensitively transduced by a PEC sensing interface that selectively responds to the indicator level of cytosolic caspase‐3. The experimental results reveal that injection of ca. 4.4 × 10−20 mol miR‐21 inhibitor, i.e., 26488 copies, can cause the obvious therapeutic action in the targeted cell. This work features a solution to obtain the accurate knowledge of how a certain miR‐drug with specific dosages treats the cells and thus provides an insight into futuristic high‐precision clinical miR therapy using personalized medicine, provided that the prerequisite single‐cell experiments are courses of personalized customization.
The concept of high‐precision single‐cell microRNA therapy is proposed and devised by a functional nanopipette, which allows precise miR‐21 inhibitor delivery to induce cell apoptosis and responds selectively to caspase‐3 of a sensitive photoelectrochemical feedback. It can reveal what the precise drug amount can cause the effective therapeutic action.
The transport behavior of ions in the nanopores has an important impact on the performance of the electrochemical devices. Although the classical Transmission‐Line (TL) model has long been used to ...describe ion transport in pores, the boundary conditions for the applicability of the TL model remain controversial. Here, we investigated the transport kinetics of different ions, within nanochannels of different lengths, by using transient single‐particle imaging with temporal resolution up to microseconds. We found that the ion transport kinetics within short nanochannels may deviate significantly from the TL model. The reason is that the ion transport under nanoconfinement is composed of multi basic stages, and the kinetics differ much under different stage domination. With the shortening of nanochannels, the electrical double layer (EDL) formation would become the “rate‐determining step” and dominate the apparent ion kinetics. Our results imply that using the TL model directly and treating the in‐pore mobility as an unchanged parameter to estimate the ion transport kinetics in short nanopores/nanochannels may lead to orders of magnitude bias. These findings may advance the understanding of the nanoconfined ion transport and promote the related applications.
In situ tracking of ion transport kinetics under nanoconfinement was achieved by transient single‐particle imaging method. The results implied that the ion transport kinetics in long nanochannels is dominated by the in‐pore diffusion, while in short nanopores/nanochannels is governed by electrical double layer (EDL) formation. The local ion accumulation within EDL changes the ion mobility and then affects the apparent ion transport kinetics.
The quenching of electrochemiluminescence (ECL) from a CdS:Mn nanocrystal film by proximal Au nanoparticles was observed as a result of Förster energy transfer, while an enhancement of ECL takes ...place after hybridization with target DNA due to the energy transfer of ECL excited surface plasmon resonances in AuNPs to the CdS:Mn NCs at large separation, based on which an ultrasensitive and specific DNA biosensor was constructed.
Cuproptosis, a kind of newly recognized cell death modality, shows enormous prospect in cancer treatment. The inducer of cuproptosis has more advantages in tumor therapy, especially that can trigger ...cuproptosis and chemodynamic therapy (CDT) simultaneously. However, cuproptosis is restricted to the deficiency of intracellular copper ions and the nonspecific delivery of copper-based ionophores. Therefore, high level delivery, responsive release, and utilizing synergistic-function of inducer become the key on cuproptosis-based oncotherapy. In this work, a cascade nanosystem is constructed for enhanced cuproptosis and CDT. In the weak acidic environment of tumor cells, DNA, zinc ions, and Cu
can release from the nanosystem. Since Cu
having superior performance in mediating both Fenton-like reaction and cuproptosis, the released Cu
induces cuproptosis and CDT efficiently, accompanied by Cu
generation. Then Cu
can be converted into Cu
partially by glutathione (GSH) to from a Cu
supply loop and ensure the synergistic action. Meanwhile, the consumption of GSH also contributes to cuproptosis and CDT in return. Finally, DNA and Zn
form DNAzyme to shear catalase-related RNA, resulting in the accumulation of hydrogen peroxide and further enhancing combination therapy. These results provide a promising nanotherapeutic platform and may inspire the design for potential cancer treatment based on cuproptosis.
Abstract
Construction of white‐light emitters is of great importance in practical applications but is challenging for metal nanoclusters. Herein, arginine (Arg)‐mediated copper nanoclusters (Cu NCs) ...assemblies with white‐light emission (WLE) are reported for the first time. The multidentate ligand, Arg, not only effectively tailors the high stability and locally‐excited emission (LES) of aqueous phase Cu NCs, but also bridges 1‐naphthalenol methylcarbamate (NMC) to generate a blue emitter via through‐space interactions (TSIs), resulting in a stable mixed light. Density functional theory calculation and mass spectrum further confirm that Arg can allow for the formation of strong hydrogen‐bonds with the ligand 2,4‐diaminotoluene of Cu NCs, and formation of TSIs‐based complexes with NMC. More importantly, pure white‐light emission (WLE) with Commission Internationale de L’Eclairagecoordination (0.30, 0.31) is observed by regulating the ratio between Arg and the interfacial ligand of NMC. The findings not only provide a new perspective for the construction of WLE emitters via interface modification chemistry but also open a window to gain insight into the mechanism of interface engineering.
Plasmonic photocatalysts have opened up a new direction in utilization of visible light and promoting photocatalytic efficiency. An electrochemical deposition method is reported to synthesise ...metal@semiconductor (M@SC) core-shell nanocrystals. Due to the strong affinity of Au atoms to S
2−
and Se
2−
reduced at negative potential, CdS, CdSe and ZnS were selectively deposited on the surface of the Au core to form a uniform shell with a clear metal/semiconductor interface, which conquered the barrier caused by the large lattice mismatch between the two components. Plasmonic effects increased the photocatalytic performance, as well as provided a chance to
in situ
monitor the surface nucleation and growth. The structure formation process could be observed under dark-field microscopy (DFM) in real-time and precisely controlled
via
the scattering color, intensity and wavelength. The proof-of-concept strategy combines the electrochemical deposition and plasmonic imaging, which provides a universal approach in controllable synthesis of core-shell heterostructures, and leads to the improvement of plasmonic photocatalysts.
Plasmonic photocatalysts with a core-shell heterostructure were synthesized
via
electrochemical deposition guided by single particle plasmonic imaging.
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