Monitoring
and characterization methods that provide performance
tracking of hydrogen evolution reaction (HER) at the single-nanoparticle
level can greatly advance our understanding of catalysts’ structure
and activity relationships. Electrochemiluminescence (ECL) microscopy
is implemented for the first time to identify HER activities of single
nanocatalysts and to provide a direction for further optimization.
Here, we develop a novel ECL blinking technique at the single-nanoparticle
level to directly monitor H2 nanobubbles generated from
hollow carbon nitride nanospheres (HCNSs). The ECL ON and OFF mechanisms
are identified being closely related to the generation, growth, and
collapse of H2 nanobubbles. The power-law distributed durations
of ON and OFF states demonstrate multiple catalytic sites with stochastic
activities on a single HCNS. The power-law coefficients of ECL blinking
increase with improved HER activities from modified HCNSs with other
active HER catalysts. Besides, ECL blinking phenomenon provides an
explanation for the low cathodic ECL efficiency of semiconductor nanomaterials.
Catalytic route electrochemiluminescence microscopy enables us to image upper cell membranes with a vertical resolution mode by using nitrogen-doped carbon dots as nano-coreactants and labels.
Classic electrochemiluminescence (ECL) assays relying on the change in luminescence intensity face a challenge in the quantitative analysis of complex samples. Here, we report the design and implementation of a new sensing strategy, using the maximum luminescence wavelength (λ) shift as the readout to achieve quantitative detection. This approach includes an ECL luminophore (RuSiO@GO) and a HS-sensitive inner filter absorber (CouMC). The absorbance of CouMC illustrates a dependence on the HS concentration, which induces a change in the maximum luminescence wavelength (Δλ) of the ECL luminophore. Both experimental and simulated results suggest that the spectral shift of ECL effectively avoids the interference of the total luminescence intensity fluctuations, enabling a highly reliable quantitative analysis. This spectral shift-based ECL assay strategy offers a wide application potential by extending types of ECL luminophores and absorptive chemodosimeters, based on an inner filter effect.
Electrospinning, as a novel nontextile filament technology, is an important method to prepare continuous nanofibers and has shown its remarkable advantages, such as a broadly applicable material system, controllable fiber size and structure, and simple process. Electrospun nanofiber membranes prepared by electrospinning have shown promising applications in many fields, such as supercapacitors, lithium-ion batteries, and sodium-ion batteries, owing to their large specific surface area and adjustable network pore structure. The principle of electrospinning and key points relevant to its usage in the preparation of high-performance electrochemical energy storage materials are reviewed herein based on recent publications, particularly focusing on research progress of relative materials. Also, this review describes a distinctive conclusion and perspective on the future challenges and opportunities in electrospun nanomaterials.
The primary principle for new molecular evolution is from nature, mimicking nature, and beyond nature, since it is extremely important for the artificial molecules to keep their structure and function in the natural system. It is especially true for the self-assembled supramolecular construction in situ in complicated living bodies. Herein, we put forward a directed evolution strategy consisting of high-content screening from the living system and artificial modification in order to find "totipotential peptides" in a precise way. Progressive dimension reduction of the capability and precise anchoring of the target were realized. Through the living system evolution, we obtain a glioma-targeting and living system-induced self-assembled leading compound CCP. Through the artificial evolution, CCP was further stapled and was hydrophobically modified as N SCCP 2 , which demonstrated stability and NIR-II emission characteristics. N SCCP 2 could realize highresolution molecular imaging and therapy simultaneously. We envision that the strategy and its applications provide a new method for molecular discovery and improve the performance of peptide nano-self-assemblies for diagnostics and therapy.
Measurement of electron transfer at single-molecule level is normally restricted by the detection limit of faraday current, currently in a picoampere to nanoampere range. Here we demonstrate a unique graphene-based electrochemical microscopy technique to make an advance in the detection limit. The optical signal of electron transfer arises from the Fermi level-tuned Rayleigh scattering of graphene, which is further enhanced by immobilized gold nanostars. Owing to the specific response to surface charged carriers, graphene-based electrochemical microscopy enables an attoampere-scale detection limit of faraday current at multiple individual gold nanoelectrodes simultaneously. Using the graphene-based electrochemical microscopy, we show the capability to quantitatively measure the attocoulomb-scale electron transfer in cytochrome c adsorbed at a single nanoelectrode. We anticipate the graphene-based electrochemical microscopy to be a potential electrochemical tool for in situ study of biological electron transfer process in organelles, for example the mitochondrial electron transfer, in consideration of the anti-interference ability to chemicals and organisms.
Small-molecular targeting peptides
possess features of biocompatibility,
affinity, and specificity, which is widely applied in molecular recognition
and detection. Moreover, peptides can be developed into highly ordered
supramolecular assemblies with boosting binding affinities, diverse
functions, and enhanced stabilities suitable for biosensors construction.
In this Review, we summarize recent progress of peptide-based biosensors
for precise detection, especially on tumor-related analysis, as well
as further provide a brief overview of the progress in tumor immune-related
detection. Also, we are looking forward to the prospective future
of peptide-based biosensors.
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