Synergetic Modulation of Steric Hindrance and Excited State for Anti-Quenching and Fast Spin-Flip Multi-Resonance Thermally Activated Delayed Fluorophore.

Multi-resonance thermally activated delayed fluorescence (MR-TADF) materials hold great promise for advanced high-resolution organic light-emitting diode (OLED) displays. However, persistent challenges, such as severe aggregation-caused quenching (ACQ) and slow spin-flip, hinder their optimal performance. We propose a synergetic steric-hindrance and excited-state modulation strategy for MR-TADF emitters, which is demonstrated by two blue MR-TADF emitters, IDAD-BNCz and TIDAD-BNCz, bearing sterically demanding 8,8-diphenyl-8H-indolo[3,2,1-de]acridine (IDAD) and 3,6-di-tert-butyl-8,8-diphenyl-8H-indolo[3,2,1-de]acridine (TIDAD), respectively. These rigid and bulky IDAD/TIDAD moieties, with appropriate electron-donating capabilities, not only effectively mitigate ACQ, ensuring efficient luminescence across a broad range of dopant concentrations, but also induce high-lying charge-transfer excited states that facilitate triplet-to-singlet spin-flip without causing undesired emission redshift or spectral broadening. Consequently, implementation of a high doping level of IDAD-BNCz resulted in highly efficient narrowband electroluminescence, featuring a remarkable full-width at half-maximum of 34 nm and record-setting external quantum efficiencies of 34.3 % and 31.8 % at maximum and 100 cd m-2, respectively. The combined steric and electronic effects arising from the steric-hindered donor introduction offer a compelling molecular design strategy to overcome critical challenges in MR-TADF emitters.

[Microsatellite alterations of circulating DNA in the plasma of patients with hepatocellular carcinoma].

OBJECTIVE: To explore the features of microsatellite alterations of circulating DNA in the plasma of patients with hepatocellular carcinoma (HCC) and whether they are in concordance with those in the carcinoma tissues. METHODS: Peripheral blood samples were collected from 62 HCC patients and the corresponding tumor tissues were obtained during operation. Three high-polymorphic microsatellite markers located at chromosome 8p, D8S277, D8S298, and D8S1771, were selected to be used to detect the loss heterozygosity (LOH) and microsatellite instability (MSI) by PCR and sequencing. RESULTS: Joint detection showed that 39 out of the 62 tissue samples showed LOH at all the 3 loci, and the same alterations at the same loci were seen in 33 matched plasma samples with a concordance rate of 84.6%. Nineteen tissue samples showed MSI at all 3 loci, and the same alterations were shown in 14 matched plasma samples with a concordance rate of 73.3%. The rate of LOH for at least one locus in the plasma DNA was 58.1% (36/62), significantly higher than the rate of MSI at at least one locus in the plasma samples (29.0%, 18/62, P < 0.01). The MSI positive rate in the loci D8S277 of the plasma DNA was 22.6%, significantly higher than those of the other 2 loci (4.8% and 4.8% respectively, both P < 0.05). The MSI positive rate at the loci D8S277 of the cancer tissue was 46.8%, significantly higher than those of the other 2 loci (38.7% for D8S298 and 37.1% for D8S1771, both P < 0.05). CONCLUSION: Microsatellite alterations show a high concordant pattern between the tissue and plasma DNA in HCC, which indicates that the microsatellite alterations of tumor tissue are reflected by plasma DNA, LOH may play an important role in hepatocarcinogenesis whereas MSI may also contribute to this progress in a less significant way, and D8S277 is a sensitive locus to MSI in HCC.