Self-Assembly of Hybrid Oxidant POM@Cu-BTC for Enhanced Efficiency and Long-Term Stability of Perovskite Solar Cells.

The controllable oxidation of spiro-OMeTAD and improving the stability of hole-transport materials (HTMs) layer are crucial for good performance and stability of perovskite solar cells (PSCs). Herein, we report an efficient hybrid polyoxometalate@metal-organic framework (POM@MOF) material, [Cu2 (BTC)4/3 (H2 O)2 ]6 [H3 PMo12 O40 ]2 or POM@Cu-BTC, for the oxidation of spiro-OMeTAD with Li-TFSI and TBP. When POM@Cu-BTC is introduced to the HTM layer as a dopant, the PSCs achieve a superior fill factor of 0.80 and enhanced power conversion efficiency 21.44 %, as well as improved long-term stability in an ambient atmosphere without encapsulation. The enhanced performance is attributed to the oxidation activity of POM anions and solid-state nanoparticles. Therefore, this research presents a facile way by using hybrid porous materials to accelerate oxidation of spiro-OMeTAD, further improving the efficiency and stability of PSCs.

CRISPR/Cas9-mediated gene knockout for DNA methyltransferase Dnmt3a in CHO cells displays enhanced transgenic expression and long-term stability.

CHO cells are the preferred host for the production of complex pharmaceutical proteins in the biopharmaceutical industry, and genome engineering of CHO cells would benefit product yield and stability. Here, we demonstrated the efficacy of a Dnmt3a-deficient CHO cell line created by CRISPR/Cas9 genome editing technology through gene disruptions in Dnmt3a, which encode the proteins involved in DNA methyltransferases. The transgenes, which were driven by the 2 commonly used CMV and EF1α promoters, were evaluated for their expression level and stability. The methylation levels of CpG sites in the promoter regions and the global DNA were compared in the transfected cells. The Dnmt3a-deficent CHO cell line based on Dnmt3a KO displayed an enhanced long-term stability of transgene expression under the control of the CMV promoter in transfected cells in over 60 passages. Under the CMV promoter, the Dnmt3a-deficent cell line with a high transgene expression displayed a low methylation rate in the promoter region and global DNA. Under the EF1α promoter, the Dnmt3a-deficient and normal cell lines with low transgene expression exhibited high DNA methylation rates. These findings provide insight into cell line modification and design for improved recombinant protein production in CHO and other mammalian cells.

Proteomic analysis of halotolerant proteins under high and low salt stress in Dunaliella salina using two-dimensional differential in-gel electrophoresis.

Dunaliella salina, a single-celled marine alga with extreme salt tolerance, is an important model organism for studying fundamental extremophile survival mechanisms and their potential practical applications. In this study, two-dimensional differential in-gel electrophoresis (2D-DIGE) was used to investigate the expression of halotolerant proteins under high (3 M NaCl) and low (0.75 M NaCl) salt concentrations. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS) and bioinformatics were used to identify and characterize the differences among proteins. 2D-DIGE analysis revealed 141 protein spots that were significantly differentially expressed between the two salinities. Twenty-four differentially expressed protein spots were successfully identified by MALDI-TOF/TOF MS, including proteins in the following important categories: molecular chaperones, proteins involved in photosynthesis, proteins involved in respiration and proteins involved in amino acid synthesis. Expression levels of these proteins changed in response to the stress conditions, which suggests that they may be involved in the maintenance of intracellular osmotic pressure, cellular stress responses, physiological changes in metabolism, continuation of photosynthetic activity and other aspects of salt stress. The findings of this study enhance our understanding of the function and mechanisms of various proteins in salt stress.

Overexpression of YTHDF3 increases the specific productivity of the recombinant protein in CHO cells by promoting the translation process.

Due to their high-quality characteristics, Chinese hamster ovary (CHO) cells have become the most widely used and reliable host cells for the production of recombinant therapeutic proteins in the biomedical field. Previous studies have shown that the m6A reader YTHDF3, which contains the YTH domain, can affect a variety of biological processes by regulating the translation and stability of target mRNAs. This study investigates the effect of YTHDF3 on transgenic CHO cells. The results indicate that stable overexpression of YTHDF3 significantly enhances recombinant protein expression without affecting host cell growth. Transcriptome sequencing indicated that several genes, including translation initiation factor, translation extension factor, and ribosome assembly factor, were upregulated in CHO cells overexpressing YTHDF3. In addition, cycloheximide experiments confirmed that YTHDF3 enhanced transgene expression by promoting translation in CHO cells. In conclusion, the findings in this study provide a novel approach for mammalian cell engineering to increase protein productivity by regulating m6A.

Apilimod enhances specific productivity in recombinant CHO cells through cell cycle arrest and mediation of autophagy.

Chinese hamster ovary (CHO) cells are expected to acquire the ability to produce higher recombinant therapeutic protein levels using various strategies. Genetic engineering targeting the cell cycle and autophagy pathways in the regulation of cell death in CHO cell cultures has received attention for enhancing the production of therapeutic proteins. In this study, we examined the small-molecule compound apilimod, which was found to have a positive influence on recombinant protein expression in CHO cells. This was confirmed by selective blocking of the cell cycle at the G0/G1 phase. Apilimod treatment resulted in decreased expression of cyclin-dependent kinase 3 (CDK3) and Cyclin C and increased expression of cyclin-dependent kinase suppressor p27Kip1, which are critical regulators of G1 cell cycle progression and important targets controlling cell proliferation. Furthermore, total transcription factor EB (TFEB) was lower in apilimod-treated CHO cells than in control cells, resulting in decreased lysosome biogenesis and autophagy with apilimod treatment. These multiple effects demonstrate the potential of apilimod for development as a novel enhancer for the production of recombinant proteins in CHO cell engineering.

Chemical doping engineering by utilizing trilacunary Keggin polyoxometalates as a dopant for high performance perovskite solar cells.

Chemical doping engineering is an effective strategy to modify the hole transport layer (HTL) and achieve high-efficiency perovskite solar cells (PSCs). In this work, we synthesize an infrequent trilacunary Keggin type polyoxometalate Na10[Zn2(H2O)6(WO2)2(BiW9O33)2] (BiW9-Zn) and apply it as an additive to enhance the hole mobility and electrical conductivity of Spiro-OMeTAD based HTLs. Thanks to the strong electron-accepting properties of polyoxometalate molecules, the as-synthesized BiW9-Zn can directly oxidize Spiro-OMeTAD under an inert atmosphere and avoid the tedious long-term oxidation process. Therefore, the power conversion efficiency (PCE) of optimal PSCs with BiW9-Zn doping is enhanced from 17.58% (without doping) to 19.56% with a significantly improved fill factor and open-circuit voltage. In addition, the assembly repeatability and long-term stability of PSCs are also improved. This work demonstrates the potential of using polyoxometalates (POMs) as low-cost, efficient and highly flexible chemical dopants for HTLs, and more importantly paves a new route to enhance the performance of PSCs.

New Insight into the Lewis Basic Sites in Metal-Organic Framework-Doped Hole Transport Materials for Efficient and Stable Perovskite Solar Cells.

Currently, Spiro-OMeTAD is the most widely used hole transport material (HTM) in the best-performing perovskite solar cells (PSCs), resulting from its suitable energy level and facile processing. However, the intrinsic properties of organic molecules, such as low conductivity and a nonpolar contact interface, will limit the power conversion efficiency (PCE) and stability of Spiro-OMeTAD-based PSCs. Chemical doping could be an effective strategy to ameliorate the performance of Spiro-OMeTAD, and most of the dopants are designed for controllably oxidizing Spiro-OMeTAD. In this work, a highly stable metal-organic framework {[Zn(Hcbob)]·(solvent)}n (Zn-CBOB) with rod topology and Lewis basic sites is assembled and employed as a dopant for the hole transport layer. It is found that Zn-CBOB not only controllably oxidizes Spiro-OMeTAD and improves the conductivity of the HTM but also passivates the surface traps of the perovskite film by coordinating with Pb2+. The Zn-CBOB-doped PSCs achieved a remarkable PCE of 20.64%. In addition, the hydrophobicity of Zn-CBOB can prevent water from destroying the perovskite layer, which helps elevate the stability of PSCs.

Heterojunction Incorporating Perovskite and Microporous Metal-Organic Framework Nanocrystals for Efficient and Stable Solar Cells.

In this paper, we present a facile approach to enhance the efficiency and stability of perovskite solar cells (PSCs) by incorporating perovskite with microporous indium-based metal-organic framework [In12O(OH)16(H2O)5(btc)6]n (In-BTC) nanocrystals and forming heterojunction light-harvesting layer. The interconnected micropores and terminal oxygen sites of In-BTC allow the preferential crystallization of perovskite inside the regular cavities, endowing the derived films with improved morphology/crystallinity and reduced grain boundaries/defects. Consequently, the In-BTC-modified PSC yields enhanced fill factor of 0.79 and power conversion efficiency (PCE) of 20.87%, surpassing the pristine device (0.76 and 19.52%, respectively). More importantly, over 80% of the original PCE is retained after 12 days of exposure to ambient environment (25 °C and relative humidity of ~ 65%) without encapsulation, while only about 35% is left to the pristine device.

Insights into the Mechanism of Solid-State Metal Organic Complexes as Controllable and Stable p-Type Dopants in Efficient Planar Perovskite Solar Cells.

Perovskite solar cells (PSCs) based on spiro-OMeTAD have achieved efficiencies greater than 20% in recent years; however, poorly designed dopants and ambiguous working mechanisms are still obstacles that restrict the process of commercialization. Various dopants have been introduced to modulate the electrical properties of spiro-OMeTAD, often accompanying some negative problems, such as complex synthetic routes and accelerated degradation of perovskite. Here, two novel metal organic complexes (Cu-2Cl and Cu-4Cl) with similar molecular fragments are designed and synthesized to investigate the effects on the chemical p-doping of spiro-OMeTAD. The unique coordination environment of copper ions and harmless oxidation byproducts make Cu-2Cl superior for oxidation of spiro-OMeTAD, and the possible synergetic mechanism of the heterogeneous reactions with Li-TFSI is also proposed. Utilizing Cu-2Cl-doped hole transport materials to fabricate PSCs will facilitate hole transport, reduce interfacial charge recombination, and passivate the trap states of perovskite, resulting in a champion efficiency of 20.97%. In addition, the intrinsic solid-state hydrophobic characteristics of Cu-2Cl nanoparticles well dispersed in the hole transport layer successfully suppress the invasion of water vapor, and the corresponding device retains 84% of its original efficiency after being stored for 720 h in ambient air condition.

A Copper Coordination Polymer with Matching Energy Level for Modifying Hole Transport Layers to Improve the Performance of Perovskite Solar Cells.

Spiro-OMeTAD is currently the most widely used hole transport material for the preparation of high-performance perovskite solar cells (PSCs), usually requiring the addition of additives to achieve the desired electronic conductivity. However, the quality of the film is degraded owing to the addition of additives. Holes and defects can be observed, and the dispersion of the additives are uneven inside. Here, a copper coordination polymer, Cu-bix, with matching energy level and fluorescent properties was screened for use as an additional additive to dope Spiro-OMeTAD. The doping of Cu-bix effectively improved the dispersion state of the additives in the hole transport layers and alleviated the aggregation of LiTFSI (lithium bis(trifluoromethanesulfonyl)imide) or/and lithium salt complexes in the film. Owing to better dispersion of the additives, Spiro-OMeTAD was more fully and uniformly oxidized whereas the possibility of charge recombination was reduced in the devices. Furthermore, the flat and tightly bonded film layer obtained by optimization of the doping amount can efficiently transfer holes from the perovskite layers to the hole transport layers. Possible interaction mechanisms between additives and the copper coordination polymer are proposed and discussed. The resulting power conversion efficiency (PCE) for Cu-bix-doped PSCs was improved from 16.52 % to 18.47 % compared to the pristine devices, and this type of PSCs also showed a long stability in air owing to the increased hydrophobicity of the Cu-bix-based hole transport layers.

Effects and mechanism of Xin Mai Jia in a rabbit model of atherosclerosis.

The aim of this study was to investigate the protective effects of Xin Mai Jia (XMJ) on atherosclerosis (AS) in rabbits and to explore the underlying mechanisms in order to provide experimental evidence for the clinical application of XMJ. An intraperitoneal injection of vitamin D3, combined with a high-fat diet and sacculus injury, was utilized to establish the AS rabbit model. Following the oral administration of lovastatin, Zhibituo and different dosages of XMJ, respectively, blood was drawn from each rabbit for the detection of blood rheological indicators, such as serum lipids. The pathological changes in the right common carotid artery were observed. Vascular function experiments and the expression detection of common carotid artery-related proteins by immunohistochemistry were conducted. XMJ was observed to decrease the blood lipid levels of the AS rabbits; increase the concentration of high-density lipoprotein and apolipoprotein A; decrease blood viscosity, erythrocyte sedimentation rate and hematocrit; elevate the levels of endothelial nitric oxide synthase (eNOS) and Na+/H+ exchanger 1 in vascular tissues and decrease the levels of angiotensin II receptor, type 1 (AT-1) and endothelin-1 (ET-1). In conclusion, XMJ was shown to lower the blood lipid levels of the experimental AS rabbits, improve the abnormal changes in hemorheology, increase the eNOS content in the vascular tissue, decrease the AT-1 and ET-1 levels and increase the endothelium-dependent vasodilation reaction. XMJ therefore has an anti-AS effect.