Asymmetric <i>tris</i>-Heteroleptic Iridium^III Complexes Containing a 9‑Phenyl-9-phosphafluorene Oxide Moiety with Enhanced Charge Carrier Injection/Transporting Properties for Highly Efficient Solution-Processed Organic Light-Emitting Diodes

A cyclometalating ligand containing a 9-phenyl-9-phosphafluorene oxide (PhFlPO) moiety has been synthesized and used to construct asymmetric <i>tris</i>-heteroleptic cyclometalating Ir^III complexes in combination with other ppy-type (Hppy = 2-phenylpyridine) ligands containing a functional group with a different charge carrier injection/transporting character. Their photophysical properties, electrochemical behaviors, and electroluminescent (EL) performances have been characterized in detail. Time-dependent density functional theory (TD-DFT) and natural transition orbital (NTO) calculation were carried out to gain insight into the photophysical properties of these complexes. The NTO results show that the characters of the lowest triplet excited states (T₁) can be delicately manipulated through the combination of different cyclometalating ligands. In addition, the strong electron injection/transporting (EI/ET) ability associated with the PhFlPO moiety can confer EI/ET properties to the asymmetric <i>tris</i>-heteroleptic cyclometalating Ir^III complexes. Consequently, the solution-processed organic light-emitting diodes/devices (OLEDs) based on these asymmetric <i>tris</i>-heteroleptic Ir^III phosphorescent complexes can exhibit outstanding electroluminescent (EL) performances with the maximum external quantum efficiency (η_ext) of 19.3%, current efficiency (η_L) of 82.5 cd A^–1, and power efficiency (η_P) of 57.3 lm W^–1 for the yellow-emitting device. These results show the great potential of a PhFlPO moiety in developing phosphorescent emitters and functional materials with excellent EI/ET properties

Pyrimidine-Based Mononuclear and Dinuclear Iridium(III) Complexes for High Performance Organic Light-Emitting Diodes

Containing two nitrogen atoms, the electron-deficient pyrimidine ring has excellent coordinating capability with transition metal ions. However, compared with the widely used pyridine ring, applications of the pyrimidine ring in phosphorescent Ir­(III) complexes are rare. In this research, two highly emissive pyrimidine-based mononuclear Ir­(III) complexes and their corresponding dinuclear Ir­(III) complexes were prepared with a simple one-pot reaction. The incorporation of the second Ir­(III) center can lead to dramatic differences of both photophysical and electrochemical properties between the mono- and dinuclear complexes. Besides, these properties can also be fine-tuned with different substituents. Theoretical calculations have also been performed to understand their photophysical behaviors. The electroluminescent investigations demonstrate that the pyrimidine-based mono- and dinuclear Ir­(III) complexes could show impressive device performance. The vacuum-deposited organic light-emitting diode (OLED) based on the mononuclear Ir­(III) complex exhibited an external quantum efficiency (EQE) of 16.1% with almost no efficiency roll-off even at 10 000 cd m^–2. More encouragingly, the solution-processed OLED based on the dinuclear Ir­(III) complex achieved the outstanding EQE, current efficiency (CE), and power efficiency (PE) of 17.9%, 52.5 cd A^–1, and 51.2 lm W^–1, respectively, representing the highest efficiencies ever achieved by OLEDs based on dinuclear Ir­(III) complexes

A novel intramural TGF β 1 hydrogel delivery method to decrease murine abdominal aortic aneurysm and rat aortic pseudoaneurysm formation and progression

Objectives: Aneurysms are generally the result of dilation of all 3 layers of the vessel wall, and pseudoaneurysms are the result of localized extravasation of blood that is contained by surrounding tissue. Since there is still no recommended protocol to decrease aneurysm formation and progression, we hypothesised that intramural delivery of TGF β1 hydrogel can decrease aneurysm and pseudoaneurysm formation and progression. Materials: Male C57BL/6 J mice (12–14 wk), SD rats (200 g) and pig abdominal aortas were used, and hydrogels were fabricated by the interaction of sodium alginate (SA), hyaluronic acid (HA) and CaCO3. Methods: A CaCl2 adventitial incubation model in mice and a decellularized human great saphenous vein patch angioplasty model in rats were used. TGF β1 hydrogel was intramurally delivered after CaCl2 incubation in mice; at day 7, the abdomen in some mice was reopened, and TGF β1 hydrogel was injected intramurally into the aorta. In rats, TGF β1 hydrogel was delivered intramurally after patch angioplasty completion. Tissues were harvested at day 14 and analysed by histology and immunohistochemistry staining. The pig aorta was also intramurally injected with hydrogel. Results: In mice, rhodamine hydrogel was still found between the medium and adventitia at day 14. In the mouse aneurysm model, there was a thicker wall and smaller amount of elastin breaks in the TGF β1 hydrogel-delivered groups both at day 0 and day 7 after CaCl2 incubation, and there were larger numbers of p-smad2- and TAK1-positive cells in the TGF β1 hydrogel-injected groups. In the rat decellularized human saphenous vein patch pseudoaneurysm model, there was a higher incidence of pseudoaneurysm formation when the patch was decellularized using 3% SDS, and delivery of TGF β1 hydrogel could effectively decrease the formation of pseudoaneurysm formation and increase p-smad2 and TAK1 expression. In pig aortas, hydrogels can be delivered between the medium and adventitia easily and successfully. Conclusions: Intramural delivery of TGF β1 hydrogel can effectively decease aneurysm and pseudoaneurysm formation and progression in both mice and rats, and pig aortas can also be successfully intramurally injected with hydrogel. This technique may be a promising drug delivery method and therapeutic choice to decrease aneurysm and pseudoaneurysm formation and progression in the clinic

High Triplet Energy Level Achieved by Tuning the Arrangement of Building Blocks in Phosphorescent Polymer Backbones for Furnishing High Electroluminescent Performances in Both Blue and White Organic Light-Emitting Devices

A high triplet energy level (<i>E</i>_T) of ca. 2.83 eV has been achieved in a novel polymer backbone through tuning the arrangement of two kinds of building blocks, showing enhanced hole injection/transporting capacity. Based on this new polymer backbone with high <i>E</i>_T, both blue and white phosphorescent polymers were successfully developed with a trade-off between high <i>E</i>_T and enhanced charge-carrier transporting ability. In addition, their photophysical features, electrochemical behaviors, and electroluminescent (EL) properties have been characterized in detail. Benefitting from the advantages associated with the novel polymer backbone, the blue phosphorescent polymers show top-ranking EL performances with a maximum luminance efficiency (η_L) of 15.22 cd A^–1, corresponding to a power efficiency (η_P) of 12.64 lm W^–1, and external quantum efficiency (η_ext) of 6.22% and the stable Commission Internationale de L’Eclairage (CIE) coordinates of (0.19, 0.38). Furthermore, blue–orange (B–O) complementary-colored white phosphorescent polymers based on this novel polymer backbone were also obtained showing encouraging EL efficiencies of 12.34 cd A^–1, 9.59 lm W^–1, and 4.10% in the optimized WOLED together with exceptionally stable CIE coordinates of (Δ<i>x</i> = 0.014, Δ<i>y</i> = 0.010) in a wide driving voltage range from 4 to 16 V. All of these attractive EL results achieved by these novel phosphorescent polymers show the great potential of this new polymer backbone in developing highly efficient phosphorescent polymers

Deciphering the causal relationship between blood pressure and regional white matter integrity: A two-sample Mendelian randomization study

Elevated arterial blood pressure (BP) is a common risk factor for cerebrovascular and cardiovascular diseases, but no causal relationship has been established between BP and cerebral white matter (WM) integrity. In this study, we performed a two-sample Mendelian randomization (MR) analysis with individual-level data by defining two nonoverlapping sets of European ancestry individuals (genetics–exposure set: N = 203,111; mean age = 56.71 years, genetics–outcome set: N = 16,156; mean age = 54.61 years) from UK Biobank to evaluate the causal effects of BP on regional WM integrity, measured by fractional anisotropy of diffusion tensor imaging. Two BP traits: systolic and diastolic blood pressure were used as exposures. Genetic variant was carefully selected as instrumental variable (IV) under the MR analysis assumptions. We existing large-scale genome-wide association study summary data for validation. The main method used was a generalized version of inverse-variance weight method while other MR methods were also applied for consistent findings. Two additional MR analyses were performed to exclude the possibility of reverse causality. We found significantly negative causal effects (FDR-adjusted p < .05; every 10 mmHg increase in BP leads to a decrease in FA value by .4% ~ 2%) of BP traits on a union set of 17 WM tracts, including brain regions related to cognitive function and memory. Our study extended the previous findings of association to causation for regional WM integrity, providing insights into the pathological processes of elevated BP that might chronically alter the brain microstructure in different regions.https://doi.org/10.1002/jnr.2520

Direct Visualization of Vesicle Disassembly and Reassembly Using Photocleavable Dendrimers Elucidates Cargo Release Mechanisms

Release of cargo molecules from cell-like nanocarriers can be achieved by chemical perturbations, including changes to pH and redox state and optical modulation of membrane properties. However, little is known about the kinetics or products of vesicle breakdown due to limitations in real-time imaging at nanometer length scales. Using a library of 12 single-single type photocleavable amphiphilic Janus dendrimers, we developed a self-assembling light-responsive dendrimersome vesicle platform. A photocleavable -nitrobenzyl inserted between the hydrophobic and hydrophilic dendrons of amphiphilic Janus dendrimers allowed for photocleavage and disassembly of their supramolecular assemblies. Distinct methods used to self-assemble amphiphilic Janus dendrimers produced either nanometer size small unilamellar vesicles or micron size giant multilamellar and onion-like dendrimersomes. observation of giant photosensitive dendrimersomes confocal microscopy elucidated rapid morphological transitions that accompany vesicle breakdown upon 405 nm laser illumination. Giant dendrimersomes displayed light-induced cleavage, disassembling and reassembling into much smaller vesicles at millisecond time scales. Additionally, photocleavable vesicles demonstrated rapid release of molecular and macromolecular cargos. These results guided our design of multilamellar particles to photorelease surface-attached proteins, photoinduce cargo recruitment, and photoconvert vesicle morphology. Real-time characterization of the breakdown and reassembly of lamellar structures provides insights on partial cargo retention and informs the design of versatile, optically regulated carriers for applications in nanoscience and synthetic biology