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Cationic porphyrins with large side arm substituents as resonance light scattering ratiometric probes for specific recognition of nucleic acid G-quadruplexes
摘要： Specific G-quadruplex-probing is crucial for both biological sciences and biosensing applications. Most reported probes are focused on fluorescent or colorimetric recognition of G-quadruplexes. Herein, for the first time, we reported a new specific G-quadruplex-probing technique—resonance light scattering (RLS)-based ratiometric recognition. To achieve the RLS probing of G-quadruplexes in the important physiological pH range of 7.4-6.0, four water soluble cationic porphyrin derivatives, including an unreported octa-cationic porphyrin, with large side arm substituents were synthesized and developed as RLS probes. These RLS probes were demonstrated to work well for ratiometric recognition of G-quadruplexes with high specificity against single- and double-stranded DNAs, including long double-stranded ones. The working mechanism was speculated to be based on the RLS signal changes caused by porphyrin protonation that was promoted by the end-stacking of porphyrins on G-quadruplexes. This work adds an important member in G-quadruplex probe family, thus providing a useful tool for studies on G-quadruplex-related events concerning G-quadruplex formation, destruction and changes in size, shape and aggregation. As a proof-of-concept example of applications, the RLS probes were demonstrated to work well for label-free and sequence-specific sensing of microRNA. This work also provides a simple and useful way for the preparation of cationic porphyrins with high charges.
关键词： G-quadruplex,ratiometric recognition,microRNA sensing,resonance light scattering,cationic porphyrin
更新于2025-11-19 16:56:35
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LSPR Biosensing Approach for the Detection of Microtubule Nucleation
摘要： Microtubules are dynamic protein ?laments that are involved in a number of cellular processes. Here, we report the development of a novel localized surface plasmon resonance (LSPR) biosensing approach for investigating one aspect of microtubule dynamics that is not well understood, namely, nucleation. Using a modi?ed Mie theory with radially variable refractive index, we construct a theoretical model to describe the optical response of gold nanoparticles when microtubules form around them. The model predicts that the extinction maximum wavelength is sensitive to a change in the local refractive index induced by microtubule nucleation within a few tens of nanometers from the nanoparticle surface, but insensitive to a change in the refractive index outside this region caused by microtubule elongation. As a proof of concept to demonstrate that LSPR can be used for detecting microtubule nucleation experimentally, we induce spontaneous microtubule formation around gold nanoparticles by immobilizing tubulin subunits on the nanoparticles. We ?nd that, consistent with the theoretical model, there is a redshift in the extinction maximum wavelength upon the formation of short microtubules around the nanoparticles, but no signi?cant change in maximum wavelength when the microtubules are elongated. We also perform kinetic experiments and demonstrate that the maximum wavelength is sensitive to the microtubule nuclei assembly even when microtubules are too small to be detected from an optical density measurement.
关键词： localized surface plasmon resonance,optical biosensors,gold nanoparticles,microtubule nucleation
更新于2025-11-19 16:56:35
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Broad-Spectrum Tunable Photoluminescent Material Based on Cascade Fluorescence Resonance Energy Transfer between Three Fluorophores Encapsulated within the Self-Assembled Surfactant Systems
摘要： A broad spectrum tunable photoluminescent material with dual encryption based on a two-step Fluorescence Resonance Energy Transfer (FRET) between Pyrene (Py), Coumarin480 (Cou480) and Rhodamine6G (R6G) in micelles of SDS and bmimDS is presented. The phenomenon is achievable due to the encapsulation of the fluorophores within these micelles. The transfer of energy as FRET between the pair Py and Cou480 showed ON at 336 nm and OFF at 402 nm in contrast to the FRET observed between the pair Cou480 and R6G that showed ON at 402nm and OFF at 336 nm. However, the transfer of energy as FRET occurs from Py to R6G in the presence of Cou480 when excited at 336 nm, thereby making it a chain of three fluorophores with Cou480 acting as a relay fluorophore receiving energy from Py and transferring it to R6G. The different FRET scenarios between the three fluorophores in micelles provide a window for the generation of a matrix of colors, which occupies a significant 2D area in the chromaticity diagram, having potential applications in security printing. The different fluorophoric ratios generate different colors based on their individual photonic emissions and the FRET processes taking place between them. Writing tests were carried out using varied ratios of the fluorophores in the micellar systems producing different colored outputs under the UV light with insignificant visibility under the white light. We envision that this as-discovered three fluorophoric FRET system could form the basis for the future development of multi-FRET light-harvesting devices and anti-counterfeiting security inks based on much simpler non-covalent interaction aided encapsulation of the fluorophores within the self-assembled soft systems.
关键词： micelles,security printing,Rhodamine6G (R6G),SDS,Pyrene (Py),Coumarin480 (Cou480),bmimDS,Fluorescence Resonance Energy Transfer (FRET),photoluminescent material
更新于2025-11-19 16:46:39
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Free-label dual-signal responsive optical sensor by combining resonance Rayleigh scattering and colorimetry for sensitive detection of glutathione based on ultrathin MnO2 nanoflakes
摘要： Glutathione (GSH) plays a critical role in the living system and its abnormalities are closely associated with numerous clinical diseases. Thus, monitoring and detecting the content of GSH in the living system is still of great importance. Herein, a novel dual-signal responsive optical sensor is developed by using resonance Rayleigh scattering (RRS) and colorimetry for sensitive detection of GSH. In this sensor, MnO2 nanoflakes are used as both GSH recognizer and signal transducer of RRS and colorimetry. The solution of MnO2 nanoflakes shows strong RRS and absorption signals because MnO2 nanoflakes possess a large surface area and high molar extinction coefficient. However, MnO2 can be reduced to Mn2+ and MnO2 nanoflakes can be etched to small nanoparticles by GSH, causing both the RRS and absorption signals to decrease. Based on the change of RRS signal and absorbance of MnO2 nanoflakes, a novel dual-signal responsive optical sensor is successfully constructed to detect the content of GSH. The as-developed optical sensor toward GSH presents a favorable sensitivity with a detection limit of 0.033 and 0.67 μM for RRS and colorimetry, respectively. Furthermore, the as-developed approach is straightforward, quickly responsive, free-label, and cost-effective. More significantly, this method combines the advantages of RRS and colorimetry for the detection of GSH. Beyond this, the proposed RRS method has also been successfully utilized to detect the content of GSH in glutathione injection samples.
关键词： Glutathione,Resonance Rayleigh scattering,MnO2 nanoflakes,Colorimetry,Dual-signal
更新于2025-11-14 17:04:02
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Electrochemiluminescence sensing platform for ultrasensitive DNA analysis based on resonance energy transfer between graphitic carbon nitride quantum dots and gold nanoparticles
摘要： Electrogenerated chemiluminescence (ECL) of semiconductor quantum dots (QDs) is considered as a powerful technique in the fabrication of biosensor, however, the inherent toxicity of the heavy metal ion containing in QDs limits their further applications. Thus, searching for environment-friendly luminescent nanomaterials with high electrochemiluminescence (ECL) e?ciency is an urgent goal. In this work, a solid-state method under low temperature was adopted to prepare graphitic carbon nitride quantum dots (g-CNQDs). By using coreactant K2S2O8, a strong cathodic ECL signal of g-CNQDs could be observed in phosphate bu?er. A novel ECL resonance energy transfer procedure was constructed between g-CNQDs (emitter) and gold nanoparticles (acceptor). A signal probe was formed by connecting gold nanoparticles at the hairpin DNA (Hai-DNA) terminal. When the signal probe was anchored on g-CNQDs, ECL resonance energy transfer occurred due to the ECL quenching of gold nanoparticles to g-CNQDs. This phenomenon decreased the ECL signal. In the presence of target DNA (T-DNA), the looped structure of Hai-DNA could be destroyed by T-DNA, and gold nanoparticles were separated from g-CNQDs. Accordingly, the ECL resonance energy transfer procedure was hindered, and the ECL signal was recovered again. The ECL intensities exhibited linear correlation with the logarithm of T-DNA concentration from 0.02 fM to 0.1 pM, and the limit of detection was 0.01 fM (3σ). With the developed ECL resonance energy transfer system, good selectivity and high sensitivity were achieved in T-DNA detection.
关键词： Graphitic carbon nitride quantum dots,Electrochemiluminescence,DNA,Resonance energy transfer,Biosensor
更新于2025-11-14 17:04:02
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A magnetofluorescent boron-doped carbon dots as a metal-free bimodal probe
摘要： High-resolution observation of biological process is vital for biological researches and diagnosing diseases, which requires accurate diagnosis that involves coordinating imaging technologies such as fluorescence and magnetic resonance (MR). Nowadays, metal-based labels have been used for dual modality imaging. However, heavy metal ions are not environment-and organism-friendly. Therefore, it is a desirable to fabricate a metal-free label with fluorescence and MR properties. Herein, we synthesized boron–doped carbon dots (B–CDs) with dual modal properties through a one-pot solvothermal process. Compared with boron-free CDs, B–CDs exhibited apparent red-shift, higher fluorescence intensity, and higher longitudinal relaxivity (r1 = 5.13 mM-1 s-1). It demonstrated that boron doping can enhance the fluorescence intensity of CDs, and maybe lead to form paramagnetic centers. The fluorescence and MR imaging of B–CDs make them a prospective label for clinical applications as a result of their oversimplified synthesis process, low cost, good biocompatibility and low toxicity. It will open a new window for building novel imaging labels.
关键词： Boron,Magnetic resonance,Fluorescence,Carbon dots
更新于2025-11-14 17:03:37
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Preparation of Ag-doped Bi5O7I composites with enhanced visible-light-induced photocatalytic performance
摘要： A novel heterostructure photocatalysts, Ag-doped Bi5O7I composites (Ag/Bi5O7I), were synthesized by a simple hydrothermal method. Compared with Bi5O7I, Ag/Bi5O7I composites had a stronger light absorption in the visible and near-infrared region and the light absorption edge of Ag/Bi5O7I composites had a slight red shift. Moreover, Ag/Bi5O7I composites possessed a higher photocatalytic activity than Bi5O7I on the degradation of rhodamine B (RhB) and methyl orange (MO) under visible-light irradiation (λ ≥ 420 nm). When the content of Ag was 1%, the degradation efficiency of the Ag/Bi5O7I composites toward RhB and MO reached the maximum value, which was about 20.2 and 7.6 times higher than that of Bi5O7I, respectively. The trapping experiments shown that superoxide radicals and holes were the main active species in the photodegradation process. The excellent photocatalytic performance could be attributed to Ag/Bi5O7I heterojunction and surface plasma resonance effect of Ag, which could increase absorption of visible light and cause the efficient separation and migration of carriers.
关键词： Ag-doped Bi5O7I,Visible-light,Surface plasma resonance,Heterostructure photocatalysts
更新于2025-11-14 17:03:37
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Deep-ultraviolet plasmon resonances in Al-Al <sub/>2</sub> O <sub/>3</sub> @C core-shell nanoparticles prepared via laser ablation in liquid
摘要： We developed a convenient, facile, low cost and ‘‘green” method to synthesize nanoparticles(NPs) with deep-ultraviolet localized surface plasmon resonances (LSPR) based on laser ablation of aluminum target in liquid. The nanoparticles had an Al-Al2O3@C core-shell structure, and the LSPR peak ranged from 240nm to 250nm with the increasing of laser radiation time. It is found that the LSPR peak of the NPs is related to the presence of Al2O3 based on experimental characterization and theoretical simulation. The carbon shell can reduce the oxidation of Al nanoparticles and enhance the stability, which is significant important to achieve the deep-ultraviolet LSPR. Moreover, we demonstrated the enhancement of the blue fluorescence intensity from CsPbBr3-xClx by the Al-Al2O3@C NPs, due to the stronger excitations for CsPbBr3-xClx by the enhancement of localized electromagnetic field from LSPR.
关键词： PL enhancement,plasmonics,localized surface plasmon resonance,Al nanoparticle,deep-ultraviolet
更新于2025-11-14 15:32:45
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Highly Sensitive and Selective Nanogap-Enhanced SERS Sensing Platform
摘要： This paper reports a highly sensitive and selective surface-enhanced Raman spectroscopy (SERS) sensing platform. We used a simple fabrication method to generate plasmonic hotspots through a direct maskless plasma etching of a polymer surface and the surface tension-driven assembly of high aspect ratio Ag/polymer nanopillars. These collapsed plasmonic nanopillars produced an enhanced near-field interaction via coupled localized surface plasmon resonance. The high density of the small nanogaps yielded a high plasmonic detection performance, with an average SERS enhancement factor of 1.5 × 107. More importantly, we demonstrated that the encapsulation of plasmonic nanostructures within nanofiltration membranes allowed the selective filtration of small molecules based on the degree of membrane swelling in organic solvents and molecular size. Nanofiltration membrane-encapsulated SERS substrates do not require pretreatments. Therefore, they provide a simple and fast detection of toxic molecules using portable Raman spectroscopy.
关键词： hotspots,sensors,molecular filtration,surface-enhanced Raman spectroscopy,localized surface plasmon resonance
更新于2025-11-14 15:30:11
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Promoting Photoreduction Properties via Synergetic Utilization between Plasmonic Effect and Highly Active Facet of BiOCl
摘要： Exploring highly efficient photocatalysts is an urgent task for achieving efficient solar-to-chemical conversion. Plasmonic effect is widely used in improving the photocatalytic properties via reducing the activation barrier for chemical reactions, enhancing the absorption of the photocatalysts or injecting the hot carriers into the photocatalysts from the plasmon metals. In this work, we design BiOCl-Ag-E with Ag loaded on the edge side of BiOCl. This hybrid structure takes the advantages of highly photocatalytic active (001) facet of BiOCl and the plasmonic effect. The plasmon metal is proposed to provide the (001) facets with more photogenerated charge carriers driving by the internal electric field, which is convinced by the photocurrent response and the detection of active species. Due to the accumulation of more negative charge carriers on (001) facet, BiOCl-Ag-E presents outstanding waste-water cleaning and CO2 photoreduction properties. The methodology of material design in this work paves the way for future design of efficient photocatalysts.
关键词： photocatalyst,synergy effect,surface plasmon resonance,CO2 photoreduction,selective growth
更新于2025-11-14 15:27:09