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Highly Erbium-Doped Nanoplatform with Enhanced Red Emission for Dual-Modal Optical-Imaging-Guided Photodynamic Therapy
摘要： Generally, luminescence quenching at high doping concentrations typically limits the concentration of doped ions in the lanthanide material to less than 0.05?20 mol %, and this is still a major hindrance in designing nanoplatforms with improved brightness. In this research, a nanoplatform capable of dual-modal imaging and synergetic antitumor cells therapy was designed. NaYF4:x%Er@NaXF4 (x = 5, 25, 50, and 100; X = Lu and Y) core@shell nanoparticles with Er3+ ion concentration up to 100 mol % were synthesized, and the luminescence properties under near-infrared (NIR) excitation were detected. The results show the strong coupled of surface and concentration quenching effects in upconversion nanoparticles (UCNP). Upconversion luminescence (UCL) and NIR-II emission intensity increased with negligible concentration quenching effect under 980 and 800 nm NIR lasers because of the growth of epitaxial shells. Therefore, the enhanced red luminescence transfers energy to photosensitizer ZnPc as the photodynamic therapy (PDT) agent for tumor inhibition efficacy.
关键词： photodynamic therapy,upconversion nanoparticles,luminescence quenching,nanoplatform,synergetic antitumor cells therapy,NaYF4:x%Er@NaXF4,dual-modal imaging
更新于2025-09-10 09:29:36
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Photoacoustic and fluorescent effects in multilayer plasmon-dye interfaces
摘要： Progress in understanding the cell biology and progression of disease depends on advanced imaging and labeling techniques. Here, we address this demand by exploring novel multilayered nanocomposites (MNCs) with plasmonic nanoparticles and adsorbing dyes in thin nonabsorbing shells as supercontrast multimodal photoacoustic (PA) and fluorescent agents in the near-infrared range. The proof of concept was performed with gold nanorods (GNRs) and indocyanine green (ICG) dispersed in a matrix of biodegradable polymers. We demonstrated synergetic PA effects in MNCs with the gold–ICG interface that could not be achieved with ICG and GNRs alone. We also observed ultrasharp PA and emission peaks that could be associated with nonlinear PA and spaser effects, respectively. Low-toxicity multimodal MNCs with unique plasmonic, thermal, and acoustic properties have the potential to make a breakthrough in PA flow cytometry and near-infrared spasers in vivo by using the synergetic interaction of plasmonic modes with a nearby absorbing medium.
关键词： gold nanorods,fluorescence,in vivo flow cytometry,biocompatible polymers,photoacoustic effect,indocyanine green,multilayer composite,fluorescence quenching
更新于2025-09-10 09:29:36
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Facile Construction and In Silico Study of Quinoline-Attached Resorcinarene Fluorescent Sensor for the Recognition of Insensitive Munition Compounds
摘要： N-methyl-4-nitroaniline (MNA), an insensitive munition is selectively and sensitively recognized by a new resorcinarene bearing quinoline moiety, i.e, Tetra-Methoxy Resorcinarene Tetra-Quinoline Acetamide (TMRTQA). A simple and efficient spectrofluorimetric technique demonstrates the quenching of the fluorescence intensity of TMRTQA upon addition of MNA within concentration limits of 2 nM to 1 μM. Binding constant and quantum yield have been determined in this study. Molecular docking studies have been performed to predict the best binding affinity and the possible interactions for the formation of complex between TMRTQA and MNA supporting the 1:1 stoichiometry. Density functional theory calculation also support the excitation wavelength and geometry optimization. MNA being a hazardous environmental pollutant has been successfully detected from the water sample by standard addition method.
关键词： N-methyl-4-nitroaniline (MNA),Resorcinarene,Quenching,Insensitive munitions,Chemoinformatics,Fluorescent analysis
更新于2025-09-10 09:29:36
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A Spectroscopic Study of the Interaction between Cyanine Dyes with Different Skeleton Structures and Transferrin
摘要： Human serum transferrin (hTf) has been exploited as a bio-carrier for targeted drugs to cancer cells where transferrin receptors are expressed at high levels. In this study, cyanine dyes DMSA and DMSB with a similar main core structure were selected to evaluate the effects of heterocycle on binding with hTf by spectroscopic methods. Fluorescence spectral results have shown that DMSB, which contains a selenazole ring, had a strong affinity binding with transferrin, up to 104-fold higher than DMSA, which contains a thiazole ring. This difference may be attributed to the larger molecular volume of selenazole compared with DMSA. Binding distance between cyanine dyes and hTf demonstrated that the non-radioactive energy transfer mechanism was also involved in the fluorescence quenching of protein. Furthermore, DMSB-binding gave rise to a greater decrease of the α-helix content of hTf than DMSA suggesting that hTf, which shows a looser structure binding with DMSB, increased polarity around the tryptophan residues of hTf, which was confirmed by circular dichroism and synchronous fluorescence spectroscopy. The study provides a certain theoretical basis for the design of cyanine dyes as biomolecular probe to target drugs for hTf.
关键词： Human serum transferrin,Fluorescence quenching,Conformational changes,Cyanine dyes
更新于2025-09-10 09:29:36
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Changes in the photosynthesis properties and photoprotection capacity in rice (Oryza sativa) grown under red, blue, or white light
摘要： Non-photochemical quenching (NPQ) of the excited state of chlorophyll a is a major photoprotective mechanism plants utilize to survive under high light. Here, we report the impact of long-term light quality treatment on photosynthetic properties, especially NPQ in rice. We used three LED-based light regimes, i.e., red (648–672 nm), blue (438–460 nm), and “warm” white light (529–624 nm), with the incident photon flux density of 300 μmol photons m?2 s?1, the difference in the absorbed photon flux densities by leaves grown under different light quality being less than 7%. Our results show that blue light, as compared to white light, induced a significant decrease in Fv/Fm, a decreased rate of reduction of P700+ after P700 was completely oxidized; furthermore, blue light also induced higher NPQ with an increased initial speed of NPQ induction, which corresponds to the qE component of NPQ, and a lower maximum quantum yield of PSII, i.e., Y(II). In contrast, rice grown under long-term red light showed decreased Y(II) and increased NPQ, but with no change in Fv/Fm. Furthermore, we found that rice grown under either blue or red light showed decreased transcript abundance of both catalase and ascorbate peroxidase, together with an increased H2O2 content, as compared to rice grown under white light. All these data suggest that even under a moderate incident light level, rice grown under blue or red light led to compromised antioxidant system, which contributed to decreased quantum yield of photosystem II and increased NPQ.
关键词： Non-photochemical quenching of the excited state of chlorophyll a,Effective quantum yield of PSII,Light quality,Quantum yield of regulated energy dissipation in PSII,Oryza sativa,Antioxidant system
更新于2025-09-10 09:29:36
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Advancing Terrestrial Ecosystem Science with a Novel Automated Measurement System for Sun-Induced Chlorophyll Fluorescence for Integration with Eddy Covariance Flux Networks
摘要： Sun-induced chlorophyll fluorescence (SIF) provides critical information on the dynamics of gross primary productivity, a unique role not readily achievable using other methods. Long-term continuous SIF observations have the potential to advance terrestrial ecosystem science. Realizing this potential, however, requires synergistic implementation of SIF measurements within eddy covariance (EC) flux networks. There is a need for SIF systems that can integrate seamlessly with EC instrumentation to maximize synergistic use of obtained data. Here, we introduce the Fluorescence Auto-Measurement Equipment (FAME) and protocol that fulfill such a purpose. FAME is designed specifically for plug-and-play integration with existing EC data acquisition systems. Its innovative hardware and software designs provide versatility, extensibility, autonomous operation, and ease of maintenance for acquiring SIF data of high quality and quantity. A major novel feature of FAME is its synchronized sampling of spectral irradiance and environmental variables, allowing for more precise interpretation of the SIF signal. FAME has been deployed since September 2016 at the Missouri Ozark AmeriFlux site, providing high-quality measurements even when air temperatures approached 40?C. Results reveal that canopy SIF saturated or even slightly decreased at high light, similar to leaf-level photosynthesis. Clear diurnal hysteresis was observed: for the same light, morning SIF was higher than afternoon. Dynamic energy dissipation processes and stress-induced movements of chloroplasts and leaves may explain the observed pattern. The technology and measurement protocol introduced here advances the coordinated observation of SIF and EC fluxes and represents a step change in observational ecosystem and carbon cycle science research.
关键词： canopy photosynthesis,non-photochemical quenching,ecosystem carbon cycle,Instrument design and measurement protocol,gross primary production
更新于2025-09-10 09:29:36
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Two new luminescent ternary Cd(II)-MOFs by regulation of aromatic dicarboxylate ligands used as efficient dual-responsive sensors for toxic metal ions in water
摘要： Two new Cd(II) metal-organic frameworks (MOFs) formulated as [Cd(L)(atpa)]n (1) and [Cd(L)(tbta)(H2O)]n (2) [H2atpa = 2-aminoterephthalic acid, H2tbta = tetrabromoterephthalic acid, L = 1,4-bis(benzimidazol-1-yl)-2-butene] were hydrothermally synthesized. 1-2 were characterized by IR spectroscopy, elemental analysis, and single-crystal X-ray diffraction. 1 displays a 3D framework with five-fold interpenetrating dia topology. 2 holds a 2D corrugated sql layer. Both MOFs were confirmed to be dual-responsive luminescent sensors (Cu2+ and Cr2O7 2- for 1, Hg2+ and Cr2O7 2- for 2) in water through the luminescence quenching experiments. The detection limits for these species were 1.2 μM (Cu2+) and 0.29 μM (Cr2O7 2-) of 1, 0.043 μM (Hg2+) and 0.13 μM (Cr2O7 2-) of 2, respectively. The luminescence quenching mechanism was investigated.
关键词： Hydrothermal synthesis,Luminescence quenching,Semi-rigidity bis(benzimidazole),Crystal structure,Cadmium(II) MOF
更新于2025-09-10 09:29:36
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Two Highly Stable Luminescent Lead Phosphonates Based on Mixed Ligands: Highly Selective and Sensitive Sensing for Thymine Molecule and VO <sub/>3</sub><sup>–</sup> Anion
摘要： Two luminescent lead phosphonates with two-dimensional (2D) layer and three-dimensional (3D) framework structure, namely, Pb3[(L1)2(Hssc)(H2O)2] (1) and [Pb2(L2)0.5(bts)(H2O)2]·H2O (2) (H2L1 = O(CH2CH2)2NCH2PO3H2, H4L2 = H2PO3CH2NH(C2H4)2NHCH2PO3H2, H3ssc = 5-sulfosalicylic acid, NaH2bts = 5-sulfoisophthalic acid sodium) have been prepared via hydrothermal techniques. The two compounds not only show excellent thermal stability but also remain intact in aqueous solution within an extensive pH range. Moreover, the atomic absorption spectroscopy analysis experiment indicates that there does not exist the leaching of Pb2+ ions from the lead phosphonates, which show they are nontoxic in aqueous solution. In compound 1, the Pb(1)O4, Pb(2)O7, Pb(3)O4, and CPO3 polyhedra are interlinked into a one-dimensional chain, which is further connected to adjacent chain by sharing the Hssc2? to form a 2D layer. Interestingly, compound 1 as a highly selective and sensitive luminescent material can be used to detect the thymine molecule with a very low detection limit of 8.26 × 10?7 M. In compound 2, the Pb(1)O6 and Pb(2)O5 polyhedra are interlinked into a dimer via edge sharing, which is further connected to adjacent dimer to form a tetramer via corner sharing, and such a tetramer is then interlinked into a 2D layer through bts3? ligands; the adjacent 2D layers are finally constructed to a 3D structure by sharing the L24? ligand. Compound 2 can be applied as an excellent luminescent sensor for sensing of VO3? anion. Furthermore, the probable fluorescent quenching mechanisms of the two compounds have also been studied.
关键词： chemical stability,luminescent lead phosphonates,VO3? anion,thermal stability,hydrothermal techniques,fluorescent quenching mechanisms,thymine molecule
更新于2025-09-10 09:29:36
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Improvement of Superconducting Properties by Optimized Post-Heat Treatment for Nb3Al Wires Fabricated by RHQ
摘要： With extremely high critical current density (Jc) and excellent strain tolerance, Nb3Al superconductor is considered as an alternative to Nb3Sn for application of high-filed magnets. However, complexity in the phase formation of Nb3Al hinders the Nb3Al superconducting wires to satisfy the requirement of engineering applications at present. Here, we have reported the improved performance of simple-structured 18-filamnet jelly-roll Nb3Al precursor long wires fabricated with rapid heating and quenching (RHQ) process. After processed with RHQ heat-treatment under various heating conditions, the Nb3Al wire were post-heat treated at a temperature between 700 oC to 1100 oC. The phase formation and the superconducting properties of the wires were investigated. It has been found that even if the RHQ process deviates from the optimum processing state, the superconducting properties of the wire can be improved by appropriately selecting post-heat treatment conditions.
关键词： critical current density,Nb3Al wires,rapid heating and quenching process,superconductivity
更新于2025-09-10 09:29:36
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Quenched Stochastic Optical Reconstruction Microscopy (qSTORM) with Graphene Oxide
摘要： Quenched Stochastic Optical Reconstruction Microscopy (qSTORM) was demonstrated with graphene oxide sheets, peptides and bacteria; a method of contrast enhancement with super-resolution fluorescence microscopy. Individual sheets of graphene oxide (GO) were imaged with a resolution of 16 nm using the quenching of fluorescence emission by GO via its large Resonant Energy Transfer (RET) efficiency. The method was then extended to image self-assembled peptide aggregates (resolution 19 nm) and live bacterial cells (resolution 55 nm, the capsular structure of E. coli from urinary tract infections) with extremely low backgrounds and high contrasts (between one and two orders of magnitude contrast factor improvements that depended on the thickness of the graphene oxide layer used). Graphene oxide films combined with STORM imaging thus provide an extremely convenient method to image samples with large backgrounds due to non-specifically bound fluorophores (either due to excess labelling or autofluorescent molecules), which is a common occurrence in studies of both biological cells and soft-condensed matter. The GO quenches the fluorescence across a thin layer at distances of less than 15 nm. Graphene oxide films coated with thin layers (≤15 nm) of polystyrene, polymethylmethacrylate and polylysine are shown to be effective in producing high contrast qSTORM images, providing a convenient modulation of sample/substrate interactions. The GO coatings can also provide an increased image resolution and a factor of 2.3 improvement was observed with the peptide fibres using a feature of interest metric,when there was a large non-specifically bound background.
关键词： Quenched Stochastic Optical Reconstruction Microscopy,contrast enhancement,peptide aggregates,qSTORM,fluorescence quenching,RET,bacterial cells,Resonant Energy Transfer,graphene oxide,super-resolution fluorescence microscopy
更新于2025-09-10 09:29:36