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Turbidimetric inhibition immunoassay revisited to enhance its sensitivity via an optofluidic laser
摘要： Turbidimetric inhibition immunoassay (TIIA) is a classic immunodiagnostic method that has been extensively used for biomarker detection. However, the low sensitivity of this technique hinders its applications in the early diagnosis of diseases. Here, a new concept, optofluidic laser TIIA (OFL-TIIA), is proposed and demonstrated for sensitive protein detection. In contrast to the immunoreaction in traditional TIIA, in which the single-pass laser loss is detected, the immunoreaction in the OFL-TIIA method takes place in a laser cavity, which considerably increases the loss induced by antigen-antibody complexes (AACs) via the amplification effect of the laser. A commercial IgG TIIA kit was selected as a demonstrative model to characterize the performance of OFL-TIIA. A wide dynamic range of five orders of magnitude with an exceptional limit of detection (LOD) (1.8×10-10 g/L) was achieved. OFL-TIIA is a fast, sensitive, and low-cost immunoassay with a simple homogeneous and wash-free process and low-volume sample consumption, thus providing a new detection platform for disease diagnostics.
关键词： Biomarker detection,Optofluidic laser,Turbidimetric inhibition immunoassay,Antigen-antibody complexes,Laser dye
更新于2025-11-25 10:30:42
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Coordination geometry-induced optical imaging of <scp>l</scp> -cysteine in cancer cells using imidazopyridine-based copper( <scp>ii</scp> ) complexes
摘要： Overexpression of cysteine cathepsins proteases has been documented in a wide variety of cancers, and enhances the L-cysteine concentration in tumor cells. We report the synthesis and characterization of copper(II) complexes [Cu(L1)2(H2O)](SO3CF3)2, 1, L1 = 3-phenyl-1-(pyridin-2-yl)imidazo[1,5-a]pyridine, [Cu(L2)2(SO3CF3)]SO3CF3, 2, L2 = 3-(4-methoxyphenyl)-1-pyridin-2-yl-imidazo[1,5-a]pyridine, [Cu(L3)2(H2O)](SO3CF3)2, 3, L3 = 3-(3,4-dimethoxy-phenyl)-1-pyridin-2-yl-imidazo[1,5-a]pyridine and [Cu(L4)2(H2O)](SO3CF3)2, 4, L4 = dimethyl-[4-(1-pyridin-2-yl-imidazo[1,5-a]pyridin-3-yl)phenyl]amine as 'turn-on' optical imaging probes for L-cysteine in cancer cells. The molecular structure of complexes adopted distorted trigonal pyramidal geometry (τ, 0.68–0.87). Cu–Npy bonds (1.964–1.989 ?) were shorter than Cu–Nimi bonds (2.024–2.074 ?) for all complexes. Geometrical distortion was strongly revealed in EPR spectra, showing gk (2.26–2.28) and Ak values (139–163 × 10?4 cm?1) at 70 K. The d–d transitions appeared around 680–741 and 882–932 nm in HEPES, which supported the existence of five-coordinate geometry in solution. The Cu(II)/Cu(I) redox potential of 1 (0.221 V vs. NHE) was almost identical to that of 2 and 3 but lower than that of 4 (0.525 V vs. NHE) in HEPES buffer. The complexes were almost non-emissive in nature, but became emissive by the interaction of L-cysteine in 100% HEPES at pH 7.34 via reduction of Cu(II) to Cu(I). Among the probes, probe 2 showed selective and efficient turn-on fluorescence behavior towards L-cysteine over natural amino acids with a limit of detection of 9.9 × 10?8 M and binding constant of 2.3 × 105 M?1. The selectivity of 2 may have originated from a nearly perfect trigonal plane adopted around a copper(II) center (～120.70°), which required minimum structural change during the reduction of Cu(II) to Cu(I) while imaging Cys. The other complexes, with their distorted trigonal planes, required more reorganizational energy, which resulted in poor selectivity. Probe 2 was employed for optical imaging of L-cysteine in HeLa cells and macrophages. It exhibited brighter fluorescent images by visualizing Cys at pH 7.34 and 37 °C. It showed relatively less toxicity for these cell lines as ascertained by the MTT assay.
关键词： optical imaging,cancer cells,turn-on fluorescence,imidazopyridine,L-cysteine,Copper(II) complexes
更新于2025-11-21 11:08:12
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Utilization of Ternary Europium Complex for Organic Electroluminescent Devices and as a Sensitizer to Improve Electroluminescence of Red-Emitting Iridium Complex
摘要： Two new lanthanide complexes [Ln(hfaa)3(Py-Im)] [hfaa = hexafluoroacetylacetone, Py-Im = 2-(2-pyridyl)benzimidazole and Ln = Eu(III) (1) and Tb(III) (2)] were synthesized and characterized. An X-ray crystal structure determination confirms that complex 1 is eight-coordinate with a distorted trigonal dodecahedral geometry. It shows typical vivid red Eu(III) emission in the solid state, in solution, and in a polymer matrix. The observed lifetime (τobs) of complex 1 in the solid state, in dichloromethane (DCM) solution, and in thin films is 833.01, 837.95, and 626.16?715.69 μs, respectively, with a photoluminescence quantum yield QEuL ≈ 33% in DCM solution. Complex 2 displays a yellowish-green emission in the solid state (τobs ≈ 36.99 μs), while a near white-light emission in solution (x; 0.2574: y; 0.3371) and in thin films. Therefore, it is a potential candidate for generating single-component white light-emitting materials for solid-state lighting applications. The kinetic scheme for modeling energy-transfer processes shows that the main donor state for 1 is the ligand triplet state (T1) and that energy transfer occurs to both the 5D1 (56.55%) and 5D0 (40.58%) levels. We fabricated a series of single- and double-layer organic light-emitting devices using complex 1. The luminance of the optimized double-layer electroluminescence (EL) device was 373 cd/m2 with very low turn-on voltage of ～4.2 V. Complex 1 was further utilized as a sensitizer to improve the EL of a red-emitting iridium complex PQ2Ir(dpm) (PQ = phenylquinoly-N,C2′, dpm = dipivaloylmethane). The codoped device achieved a maximum brightness and maximum current efficiency (ηc) of 93 224 cd/m2 and 36.38 cd/A, respectively.
关键词： electroluminescence,organic light-emitting devices,photoluminescence,energy transfer,lanthanide complexes
更新于2025-11-20 15:33:11
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Magnesium tetrapyrazinoporphyrazines: tuning of the pKa of red-fluorescent pH indicators
摘要： Magnesium (II) tetrapyrazinoporphyrazines (TPyzPzs) are excellent red fluorophores (λF ~ 663 nm, ΦF ~ 0.53 in THF). In this work, a series of magnesium (II) complexes of unsymmetrical TPyzPzs bearing one or two phenol substituents was prepared. Suitable substitutions on the phenolic moiety tuned its pKa in the range of 5.5 to 13. Deprotonation of the phenolic group at higher pH induced a strong donor (phenolate) in the macrocycle that led to pH-dependent quenching of the red fluorescence of these indicators. pH sensing was proven in water solutions after incorporation of TPyzPs into two delivery systems – microemulsions and liposomes. The latter also serves as a simple model of biomembranes. Finally, a wavelength-ratiometric probe was constructed by incorporation of a TPyzPz indicator and lipophilic pH-nonsensitive BODIPY dye into liposomes. Synthetic precursors for TPyzPzs, substituted pyrazine-2,3-dicarbonitriles, also represent donor-acceptor system and the pH-dependent changes in absorption spectra may be easily visible to the naked eye.
关键词： pH indicators,microemulsions,fluorescence,BODIPY,wavelength-ratiometric probe,liposomes,tetrapyrazinoporphyrazines,magnesium complexes
更新于2025-11-20 15:33:11
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Strategies towards rational design of gold(iii) complexes for high-performance organic light-emitting devices
摘要： Gold(iii) complexes are attractive candidates as phosphorescent dopants in organic light-emitting devices for high-luminance full-colour displays. However, no data on the stability of such devices have been reported to date. Through rational molecular design and synthesis, we have successfully generated a new class of cyclometalated gold(iii) C^C^N complexes with tunable emission colours spanning from sky-blue to red. These complexes exhibit high photoluminescence quantum yields of up to 80% in solid-state thin films, excellent solubility and high thermal stability. Solution-processable and vacuum-deposited organic light-emitting devices based on these complexes operate with external quantum efficiencies of up to 11.9% and 21.6%, respectively, and operational half-lifetimes of up to 83,000 h at 100 cd m?2.
关键词： operational stability,phosphorescent dopants,organic light-emitting devices,cyclometalated,gold(iii) complexes,C^C^N complexes
更新于2025-11-19 16:56:35
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Control of Excited-State Supramolecular Assembly Leading to Halide Photorelease
摘要： Ground- and excited-state control of halide supramolecular assembly was achieved through the preparation of a series of ester- and amide-functionalized ruthenium polypyridyl complexes in CH2Cl2. Hydrogen-bonding amide and alcohol groups on the receptor ligand were found to direct interactions with halide, while halide association with the ethyl ester groups was not observed. The various functional groups on the receptor ligands tuned the ground-state equilibrium constants over 2 orders of magnitude (1 × 10^5 to 1 × 10^7 M^?1), and the fractional contribution of each hydrogen-bond donor to the total equilibrium constant was determined. Pulsed-laser excitation of the complexes resulted in excited-state localization on the ester- or amide-functionalized ligands. In the case where the excited state was oriented toward an associated halide ion (the amide complexes), an 80 ± 10 meV Coulombic repulsion was induced that lowered the excited-state equilibrium constant (K*_eq) and resulted in halide photorelease. The rate constants for excited-state halide release (k*_21) were determined, and the values varied based on the functional groups present in the receptor ligand. Complexes with more hydrogen-bonding donors had smaller rate constants for halide photorelease. In a complex without a specific receptor ligand, the excited-state dipole was not oriented toward the associated halide, and the excited state was therefore found to have a larger equilibrium constant for halide association than the ground state.
关键词： halide supramolecular assembly,excited-state equilibrium,photorelease,hydrogen-bonding,ruthenium polypyridyl complexes
更新于2025-11-19 16:56:35
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Electrical and optical properties of organic light-emitting diodes with rhenium(I) complexes using DC and AC methods
摘要： Four rhenium(I) tricarbonyl complexes with 1,10-phenanthroline and derivative bearing electron-donating CH3 and OCH3 substituents were doped into host material poly (9-vinylcarbazole) (PVK) with a mass ratio of 8% as the emissive layer in organic light-emitting diodes (OLEDs). All complexes showed photoluminescence in the solution and embedded into a PVK matrix (λmax～520–550 nm). The comparison with the bare PVK emission and the compound/PVK ?lm shows that the emission of the polymer was quenched through an energy transfer process from PVK to the dopant. The electrical properties of the devices with FTO/PEDOT:PSS/Complex:PVK/Al architecture were investigated using the DC method by curves of current density-voltage and the AC method as admittance spectroscopy, which showed that the behavior of the devices is controlled by charge carrier injection rather than bulk transport.
关键词： Energy transfer,Re(I) complexes,Charge injection,Admittance spectroscopy,Emission,OLEDs
更新于2025-11-14 17:28:48
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Synthesis and spectral luminescent properties of 4,4′,4′′,4′′′-tetra(tert-butyl)-5,5′,5′′,5′′′-tetrakis(phenylsulfanyl)phthalocyanines and their sulfo acids
摘要： Magnesium and zinc complexes of 4,4′,4′′,4′′′-tetra(tert-butyl)-5,5′,5′′,5′′′-tetrakis(phenylsulfanyl)phthalocyanine were synthesized. The corresponding sulfo acids were prepared by sulfochlorination and further hydrolysis. Spectral luminescent properties of the synthesized phthalocyanine derivatives were studied. Introduction of sulfo groups resulted in a bathochromic shift of Q-band in the spectra recorded in DMF and pyridine regardless of the metal nature as well as in a hypsochromic shift in sulfuric acid.
关键词： metal complexes,phthalocyanines,sulfo acids,luminescence
更新于2025-11-14 15:32:45
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Mechanofluorochromism based on BOPIM complexes: The effect of substituents and regulation of the direction of the emission color changes
摘要： Novel boron 2-(2′-pyridyl)imidazole (BOPIM) complexes T1, T2 and T3 with different substituents (including bromo, tert-butyl and methoxyl) on the benzene ring of BOPIM dyes have been designed and synthesized, and their optical properties in both solution and the solid state were investigated and compared. The three compounds exhibited typical intramolecular charge transfer (ICT) characteristics. Solvent-dependent UV-vis absorption, fluorescence emission spectra and quantum chemical calculation indicated a molecular push-pull electronic structure. Their ICT degrees increased with the sequence of T1 < T2 < T3. The analysis of the X-ray crystal structure revealed the twisted molecular conformation of BOPIM dyes. Furthermore, they showed remarkable reversible mechanofluorochromic (MFC) features under mechanical force. It was found that the MFC activities could be tuned easily by changing the substituents on the BOPIM dyes. T1 exhibited emission color change from bright green to yellowish green with a spectral red-shift of only 22 nm under mechanical stimuli, whereas T2 and T3 gave the large spectral red-shifts of 36 and 30 nm. Electronic and steric effects of the substitutes were proved playing significant roles in regulating the ICT effect and intermolecular interactions. More importantly, the remarkable effect of substituents on the MFC behaviors of BOPIM dyes will provide an effective way to obtain novel high-contrast MFC dyes.
关键词： Mechanofluorochromism,Substituent effect,Intramolecular charge transfer,Solid-state fluorescence,BOPIM complexes
更新于2025-11-14 15:26:12
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Blue-green-emitting cationic iridium complexes with oxadiazole-type counter-anions and their use for highly efficient solution-processed organic light-emitting diodes
摘要： Cationic iridium complexes are promising phosphorescent dopants for solution-processed organic light-emitting diodes (OLEDs) and counter-anion control has emerged as a facile approach to tailor their properties for high-performance devices. A series of oxadiazole-type anions, 3-(5-phenyl-1,3,4-oxadiazol-2-yl)benzenesulfonate (OXD-SO3?), 3-(5-(4-(tert-butyl)phenyl)-1,3,4-oxadiazol-2-yl)benzenesulfonate (tBuOXD-SO3?) and (3-(5-(4-(tert-butyl)phenyl)-1,3,4-oxadiazol-2-yl)phenyl)trifluoroborate (tBuOXD-BF3?), have been prepared as counter-anions for blue-green-emitting cationic iridium complexes. The photophysical and electrochemical properties of the anions and the complexes have been comprehensively characterized. The anions do not affect the emission properties of the phosphorescent cation and efficiently transfer their energy to the cations in films. Solution-processed, double-layer OLEDs using the complexes as dopants have shown much higher (～1.4) efficiencies than the device using the reference complex with a PF6? counter-anion, owing to the improvement of carrier transport/recombination balance by the electron-trapping effect of oxadiazole-type anions. In particular, the blue-green device using the complex with the OXD-SO3? counter-anion affords a peak current efficiency of 37.6 cd A?1 and a peak external quantum efficiency (EQE) of 15.2%, which is the highest for solution-processed OLEDs based on cationic iridium complexes reported so far.
关键词： solution-processed OLEDs,oxadiazole-type counter-anions,phosphorescent dopants,cationic iridium complexes,high-performance devices
更新于2025-11-14 15:23:50