Shandong Normal University

Intracellular redox homeostasis is indispensable for the physiological processes of organisms and represents a pivotal mechanism underlying drug therapy for tumors. Among the various redox conjugates, superoxide anion (O₂^•-) and glutathione (GSH) play crucial roles in reflecting the redox state of living cells. Given the significance of the redox pair between O₂^•- and GSH in living organisms, herein, we report a near-infrared (NIR) fluorescent probe, BDPos, that enables real-time visualization of propranolol-induced redox imbalance during vascular tumor therapy by monitoring the dynamics alterations of O₂^•- and GSH. During the process of selective oxidation by O₂^•- and subsequent reduction recovery by GSH, BDPos exhibits a pronounced absorption shift between 708 nm and 620 nm, demonstrating its reversible responsiveness and the ability to visualize the redox status. Importantly, our studies have revealed that the disruption of redox homeostasis in hemangiomas may constitute one of the mechanisms through which propranolol exerts its therapeutic effects in treating this condition. This redox probe, characterized by its specificity and sensitivity, offers a promising tool for investigating the therapeutic mechanisms of drugs and elucidating various redox-related pathological processes.

Circularly polarized thermally activated delayed fluorescence (CP-TADF) organic light-emitting diodes (OLEDs) have emerged as promising optoelectronic devices due to their high exciton utilization efficiency and simplified device architecture, demonstrating broad application prospects in 3D displays, quantum computing, and information storage. However, the inherent trade-off between luminescent efficiency and luminescent dissymmetry factor (g_lum) has significantly limited the diversity of high-performance CP-TADF materials. In this study, we systematically investigated the luminescent mechanism of a reported thermally activated delayed fluorescence molecule QAO using density functional theory (DFT) and time-dependent DFT (TD-DFT) methods coupled with the thermal vibration correlation function (TVCF) approach. Through calculations of intersystem crossing rates, reverse intersystem crossing rates, radiative decay rates, and non-radiative decay rates, we confirmed the TADF characteristics of QAO. Moreover, the evaluation of electronic circular dichroism (ECD) spectrum and g_lum values (1.92 × 10^-3) confirmed the circularly polarized luminescent (CPL) feature. Furthermore, based on these findings, two strategies (introducing chiral unit and extending the acceptor unit) were proposed to enhanced the CPL and TADF properties, and two new efficient CP-TADF molecules (QAO-Cz and QAO-CzNCF) were constructed. Results indicate that the g_lum values of QAO-Cz (4.06 × 10^-3) and QAO-CzNCF (4.46 × 10^-3) were largely improved compared with that of initial QAO with decreased electric transition dipole moment (|μ|) and magnetic transition dipole moment (|m|) of the molecules. Compared to |m| (0.723 × 10^-20 erg·G^-1, 0.474 × 10^-20 erg·G^-1, 0.349 × 10^-20 erg·G^-1), |μ| (3.885 × 10^-18 esu·cm, 1.242 × 10^-18 esu·cm, 0.786 × 10^-18 esu·cm) exhibits a greater degree of reduction, leading to an enhancement in |m|/|μ| and g_lum values and further improving the CPL performance. Meanwhile, the energy gap of the molecules QAO-Cz (0.03 eV) and QAO-CzNCF (0.05 eV) are significantly reduced compared to QAO (0.14 eV), while the spin-orbit coupling values are remarkably increased, ensuring the excellent TADF properties of these molecules. Thus, the fundamental structure-property relationship is revealed and inner luminescent mechanism is illustrated. Wise strategy for designing CP-TADF molecules is proposed, and both designed CP-TADF molecules successfully achieve synergistic optimization of CPL and TADF properties, this work provides new insights for developing high-performance CP-TADF emitters.

Metal-organic frameworks (MOFs), known for their high porosity and tunable properties, have attracted significant interest in enhancing the sensitivity and functionality of plasmonic optoelectronic devices. However, their application in surface plasmon resonance (SPR) fiber-optic sensors remains challenging due to difficulties in the preparation and transfer of large-area two-dimensional (2D) MOFs. Here, a large-area continuous ultrathin MOF film was successfully fabricated using an interfacial synthesis strategy and seamlessly adhered to the tilted fiber Bragg gratings (TFBG). The resulting 2D MOF film not only exhibited excellent optoelectronic properties, thereby enhancing the plasmonic response in the sensing region, but also due to its exceptionally high specific surface area, facilitated molecular enrichment within the effective sensing region. Subsequently, gold nanoparticles (AuNPs) were uniformly grown in situ on the 2D MOF films, leveraging the localized surface plasmon resonance (LSPR) effect of AuNPs to amplify the sensing signal, which significantly improved the sensor's performance for trace analysis. Concurrently, the AuNPs and the MOF-constructed nanozymes facilitated ultrasensitive glucose detection through a cascade catalytic reaction, obviating the need for additional receptors. The prepared sensor demonstrates excellent detection capabilities for glucose and DNA molecules in complex biological samples, such as serum. It exhibits strong performance in stability, reproducibility, and scalability, and holds potential for transformation in industrial testing applications. This design fully leverages the synergistic effects among diverse materials, enhancing the sensor's detection capabilities and providing valuable insights for the development of next-generation sensors.