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Modulating the cellular uptake of fluorescently tagged substrates of prostate-specific antigen before and after enzymatic activation
摘要： A series of peptides based on the prostate-specific antigen (PSA) specific sequence histidine-serine-serine-lysine-leucine-glutamine were functionalised with an anthraquinone fluorophore at the C-terminal residue side chain using the copper(I) catalyzed azide-alkyne cycloaddition reaction. The effect of incorporating a negatively charged N-terminal tetra-glutamic acid group to the substrate and the effect of masking the negatively charged C-terminal carboxylic acid functionality of the substrate was investigated using confocal fluorescence microscopy in two cell lines (DLD-1 and LnCaP). The addition of a tetra-glutamic acid group to the N-terminus of the intact sequence was shown to reduce cellular uptake of the intact substrate prior to activation by PSA. In contrast, masking the C-terminal carboxylic acid group of the substrate as a methyl ester was shown to improve cellular uptake of the peptide fragment after activation by PSA. The synthesized C-terminal methyl ester substrates with the anthraquinone attached to the side chain were confirmed to be cleaved by PSA in LC-MS analysis, and the cytotoxicity of the substrates was shown to increase in the presence of PSA, consistent with cleavage and uptake of the C-terminal fragment. The results indicate that C- and N- terminal functionalisation of peptide substrates targeting PSA can be used to modulate the cellular uptake of peptides before and after enzymatic activation, and may thus be an important consideration in the design of tumour activated prodrugs.
关键词： peptide substrates,cellular uptake,tumour activated prodrugs,prostate-specific antigen,anthraquinone fluorophore
更新于2025-09-04 15:30:14
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Experimental Evidence for “Hot Exciton” Thermally Activated Delayed Fluorescence Emitters
摘要： Contradiction between no effective photophysical experiments and high device results causes the “hot exciton” thermally activated delayed fluorescence (TADF) mechanism to be still a controversial question. Here, the steady and transient photophysical characterization combined with theoretical calculation based on 4,7-bis(9,9-dimethyl-9H-fluoren-2-yl)-5,6-difluorobenzo[c][1,2,5]thiadiazole (2F-BTH-DMF), 4,7-bis(9,9-dimethyl-9H-fluoren-2-yl)benzo[c][1,2,5]thiadiazole (BTH-DMF), and 5,6-bis(9,9-dimethyl-9H-fluoren-2-yl)benzo[c][1,2,5] thiadiazole (o-BTH-DMF) demonstrate that all the emitters exhibit TADF via reverse intersystem crossing (RISC) from “hot exciton” triplet excited state. The fast RISC process “hot exciton” mechanism affords a very short delayed lifetime (1 μs). Organic light-emitting diodes (OLEDs) based on these emitters exhibit high exciton utilization over 25% and the best device shows a maximum current efficiency of 31.02 cd A?1, maximum power efficiency of 27.85 lm W?1, and external quantum efficiency of 9.13%, which are the highest performances for reported OLEDs with “hot exciton” mechanism. The experimental evidence for fast RISC process via “hot exciton” triplet state and short delayed lifetime highlights the TADF emitters with “hot exciton” mechanism for high-performance OLEDs with very low efficiency roll-off.
关键词： hot excitons,reverse intersystem crossing,thermally activated delayed fluorescence,organic light-emitting devices
更新于2025-09-04 15:30:14
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Effect of Zn Content on the physicochemical Characteristics and Photoactivity of ZnO supported Activated Carbon
摘要： In the present work, synthesis of ZnO dispersed onto activated carbon (ZnO/AC) is reported. Synthesis was conducted by using impregnation method by zinc acetate as precursor at varied Zn content. A systematic characterization of ZnO/C materials was performed using XRD, SEM, gas sorption analyzer and diffuse reflectance UV-Visible spectrophotometer. Photoactivity of the materials was studied in phenol removal via photooxidation mechanism. From the study it is confirmed that ZnO dispersion give acceleration of phenol removal refer to surface area contribution. It is no linear correlation of each physical character to the photocatalytic activity.
关键词： ZnO,Activated Carbon,Photocatalyst,Photooxidation
更新于2025-09-04 15:30:14