Latest ArticlesBenzotriazole (BTA)-based A2-A1-D-A1-A2 type wide-bandgap (WBG) non-fullerene acceptors (NFAs) have shown promising potential in indoor photovoltaic, and in-depth investigation of their structure-property relationship is of great significance. Herein, we explored the chlorination effect of the side chain on the terminals. We introduced Cl atoms into the benzyl side chains in parent BTA5 to synthesize two NFAs, BTA5-Cl with mono-chlorinated benzyl groups and BTA5-2Cl containing bi-chlorinated benzyl groups. We chose D18-Cl with deep-energy levels and strong crystallinity to pair with these three acceptors, affording high photovoltage and photocurrent. With the stepwise chlorination, the open-circuit voltage (VOC) values decrease from 1.28, 1.22, to 1.20 V, while the corresponding power conversion efficiencies (PCEs) improve from 5.07%, 9.15%, to 10.96%. Compared with BTA5-based OSCs, introducing Cl atoms downshifts the energy levels and slightly increases the non-radiative energy loss (0.14 < 0.17 < 0.19 eV), resulting in a sequential decrease in VOC. However, more chlorine atom replacements produce more effective exciton dissociation, higher charge transfer, and balanced carrier mobility in the blend films, ultimately achieving better PCEs. This work indicates that chlorination of the benzyl group on the terminals can improve the device's performance, implying good application potential in indoor photovoltaics.
Diradicaloid polycyclic hydrocarbons (PHs) own unique open-shell electronic structures and exhibit potential utility in the fields of organic electronics and spintronics. Herein, we disclose precise fusion of B/O-heterocycles onto PHs for control over their electronic structures and diradical properties. We designed and synthesized four B/O-containing diradicaloid isomers that feature the fluoreno[3,2-b]fluorene and fluoreno[2,1-a]fluorene π-skeletons, respectively. The precise B/O-heterocycle fusion modes along with the changed conjugation patterns lead to their modulated electronic structures and properties, such as diradical and aromatic structures, energy levels and band gaps, as well as magnetic, electrochemical and photophysical properties. Notably, the mode A may decrease the open-shell extent, whereas the mode B can enhance the diradical nature, leading to their well-tuned diradical characters in the range of 0.46‒0.70. Moreover, the mode A stabilizes the LUMOs and the mode B obviously increases the HOMO levels, which are remarkably contributed by the B and O atoms, respectively, further giving rise to the decreased band gaps and redshifted absorptions. This study clearly illustrates the electronic effects of B/O-heterocycle fusion on PHs and gains insight into B/O-type organic diradicaloids. These findings will provide an important guideline for the design of more fascinating heteroatom-containing diradicaloids.
An N-heterocyclic carbene (NHC) catalyzed enantioselective cyclisation and trifluoromethylation of olefins with cinnamaldehydes via radical relay cross-coupling in the presence of Togni reagent is reported and δ-lactones tolerated with stereogenic centers at β- and γ-positions are obtained in moderate to high yields and with high enantioselectivities. Further computational studies explain that the radical cross-coupling step is the key to determining the enantioselectivity. Energy analysis of key transition states and intermediates also provides a reasonable explanation for the difficulty of diastereoselective control. DFT calculations also reveal that the hydrogen-bonding interaction plays a vital role in the promotion of this chemistry.
Intracellular redox homeostasis is of indispensable importance in pathophysiology. In order to maintain the balance of the redox state within the cell, reactive oxygen species (ROS) and reactive sulfur species (RSS) react and transform with each other, and their levels also directly reflect the degree of oxidative stress and disease. Hypochlorous acid (HClO) and cysteine (Cys) usually co-exist in organisms, interacting with each other in many important physiological processes and synergistically maintaining the dynamic redox balance in the body. To understand the relevance and pathophysiological effects of these two signaling molecules in oxidative stress, unique fluorescence imaging tools are required. Herein, we designed and developed a dual-channel fluorescent probe HP, for the individual and continuous detection of HClO and Cys. This probe could simultaneously monitor the changes in the concentrations of HClO and Cys in cells, and was characterized by a fast response, high sensitivity and high selectivity, especially compared with glutathione (GSH) and homocysteine (Hcy), the probe had a good specificity for Cys. Importantly, probe HP successfully observed dynamic changes in HClO- and Cys-mediated redox status in the oxygen-glucose deprivation/reperfusion (OGD/R) model of HeLa cells and dynamically monitored fluctuations in endogenous HClO levels in lipopolysaccharides (LPS)-induced peritonitis mice.
Immunotherapy offers significant potential but is often hampered by the immunosuppressive environment in oral squamous cell carcinoma (OSCC). To address this, we propose an enhanced immunotherapeutic strategy that revitalizes the tumor immune microenvironment (TIME) in OSCC by integrating upconversion-based photodynamic therapy (PDT) with chemotherapy. Using a red blood cell membrane-inspired biomimetic nanoplatform, our approach concurrently delivers chlorin e6@upconversion nanoparticles (Ce6@UCNP) and doxorubicin (DOX). By leveraging fluorescence resonance energy transfer (FRET) for 980 nm to 660 nm upconversion excitation, we address challenges such as limited tissue penetration and tissue damage, as well as nanoplatform issues including immunogenicity and targeting inaccuracy Our integrated approach enhances PDT and chemotherapy with the goal of transforming immunologically "cold" tumors into "hot" ones through a cascaded therapy, thereby revitalizing the tumor immune microenvironment in OSCC.
The demand for enhanced optical properties in advanced fluorescence technologies has driven research into the structure-property relationship of fluorophores. In this paper, we use naphthalene fluorophores NaDC-Aze and PhDO-Aze as a case study to emphasize the pivotal role of cross conjugation in tuning the optical structure-property relationship. NaDC-Aze and PhDO-Aze, formed by hybridizing two distinct conjugated systems in a single naphthalene molecule, exhibit spectral characteristics from both conjugated systems. Experimental data and theoretical calculations demonstrate the coexistence of two electron-delocalization systems in a cross-conjugation manner in both NaDC-Aze and PhDO-Aze. The cross-conjugation fluorophores exhibit high brightness, large Stokes shift, and a broad absorption wavelength range by combining distinct spectral properties from its parent fluorophores. These spectral properties will be advantageous for certain applications (i.e., panchromatic absorption in organic solar cells, and fluorophores compatible with a wide range of excitation wavelengths).
The treatment of skin wounds, especially chronic wounds, remains a critical clinical challenge and places a heavy burden on patients and healthcare systems. In recent years, the engineering strategy of using biomaterial-assisted exosomes has emerged as a powerful tool for skin repair. Compared to treatments such as debridement and regular dressing changes, the design of biomaterial-assisted exosomes not only maintains the bioactivity of exosomes at the wound site but also provides an appropriate microenvironment for the repair of complex tissues, thereby accelerating wound healing. This review systematically introduces the general characteristics of exosomes and their functions in skin wound healing, highlights recent advances in classification of natural exosomes and engineering methods which enriching their functions in intercellular communication. Then, various emerging and innovative approaches based on biomaterials delivery of exosomes are comprehensively discussed. The review seeks to bring an in-depth understanding of bioactive dressings based on exosomes therapeutic strategies, aiming to facilitate new clinical application value.
A transition-metal- and oxidant-free amination/cyclization reaction to access 1,2,4-triazolo[1,5-a]pyridines was realized in water by using amino diphenylphosphinate as amino source. A broad array of readily accessible N-(pyridyl)amides could be converted into the products featuring a diverse set of functional groups. The sustainable methodology was successfully applied to the late-stage functionalization of natural products and drugs.
Herein, we report the dynamic kinetic resolution asymmetric acylation of γ-hydroxy-γ-perfluoroalkyl butenolides/phthalides catalyzed by amino acid-derived bifunctional organocatalysts, and a series of ketals were obtained in high yields (up to 95%) and excellent enantioselectivities (up to 99%). In terms of synthetic utility, the reaction can be performed on a gram scale, and the product can be converted into potential biological nucleoside analog.
Aflatoxins B1 (AFB1) contamination in agro-food holds great threaten to human and animal health. Conventional test strips for rapid AFB1 visualized monitoring remains challenged by improvement of sensitivity and matrix interference resistance. In this case, we developed a portable electrochemiluminescence (ECL) imaging test strip with dual-signal outputs for AFB1 quantification in corn samples. Ru-PEI@SiO2@Au nanospheres were synthesized for bonding with anti-AFB1 antibody and then colorimetrical signal-reported on test line through the capillary flow at strips. Meanwhile, ECL imaging signal of the constructed carbon-ink-based working electrode on polyvinyl chloride substrate of strips was exported under an applied potential of 1.25 V. The whole ECL test strips not only endowed convenient colorimetric responses but guaranteed quick-witted ECL image distinguishment even at extremely low AFB1 content. The detection limit of this ECL imaging-integrated mode was 10-fold lower than that of only colorimetric mode. Furthermore, satisfactory selectivity, reliability and practicability of the as-proposed ECL test strips were demonstrated. This work offered a promising platform for on-site, accurate and sensitive detection of pollutants in foods.
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