Squaramide Formation for DNA-Encoded Library Synthesis.

DNA-encoded libraries (DELs) can be considered as one of the most powerful tools for the discovery of small molecules of biological interest. However, the ability to access large DELs is contingent upon having chemical transformations that work in aqueous phase and generate minimal DNA alterations and the availability of building blocks compatible with on-DNA chemistry. In addition, accessing scaffolds of interest to medicinal chemists can be challenging in a DEL setting because of inherent limitations of DNA-supported chemistry. In this context, a squaramide formation reaction was developed by using a two-step process. The mild and high-yielding reaction tolerates a wide array of functional groups and was shown to be safe for DNA, thereby making this methodology ideal for DELs.

Coaxial Nanowire Electrodes Enable Exceptional Fuel Cell Durability.

Polymer-electrolyte-membrane fuel cells (PEMFCs) hold great promise for applications in clean energy conversion, but cost and durability continue to limit commercialization. This work presents a new class of catalyst/electrode architecture that does not rely on Pt particles or carbon supports, eliminating the primary degradation mechanisms in conventional electrodes, and thereby enabling transformative durability improvements. The coaxial nanowire electrode (CANE) architecture consists of an array of vertically aligned nanowires, each comprising an ionomer core encapsulated by a nanoscale Pt film. This unique design eliminates the triple-phase boundary and replaces it with two double-phase boundaries, increasing Pt utilization. It also eliminates the need for carbon support and ionomer binder, enabling improved durability and faster mass transport. Fuel cell membrane electrode assemblies based on CANEs demonstrate extraordinary durability in accelerated stress tests (ASTs), with only 2% and 5% loss in performance after 5000 support AST cycles and 30000 catalysts AST cycles, respectively. The high power density and extremely high durability provided by CANEs can enable a paradigm shift from random electrodes based on unstable platinum nanoparticles dispersed on carbon to ordered electrodes based on durable Pt nanofilms, facilitating rapid deployment of fuel cells in transportation and other clean energy applications.

Robust Copper-Based Nanosponge Architecture Decorated by Ruthenium with Enhanced Electrocatalytic Performance for Ambient Nitrogen Reduction to Ammonia.

Electrochemical conversion of nitrogen to green ammonia is an attractive alternative to the Haber-Bosch process. However, it is currently bottlenecked by the lack of highly efficient electrocatalysts to drive the sluggish nitrogen reduction reaction (N2RR). Herein, we strategically design a cost-effective bimetallic Ru-Cu mixture catalyst in a nanosponge (NS) architecture via a rapid and facile method. The porous NS mixture catalysts exhibit a large electrochemical active surface area and enhanced specific activity arising from the charge redistribution for improved activation and adsorption of the activated nitrogen species. Benefiting from the synergistic effect of the Cu constituent on morphology decoration and thermodynamic suppression of the competing hydrogen evolution reaction, the optimized Ru0.15Cu0.85 NS catalyst presents an impressive N2RR performance with an ammonia yield rate of 26.25 µg h-1 mgcat.-1 (corresponding to 10.5 µg h-1 cm-2) and Faradic efficiency of 4.39% as well as superior stability in alkaline medium, which was superior to that of monometallic Ru and Cu nanostructures. Additionally, this work develops a new bimetallic combination of Ru and Cu, which promotes the strategy to design efficient electrocatalysts for electrochemical ammonia production under ambient conditions.

Large scale controlled Fab exchange GMP process to prepare bispecific antibodies.

Objective: Bispecific antibodies (BsAbs) have demonstrated significant therapeutic impacts for the treatment of a broad spectrum of diseases that include oncology, auto-immune, and infectious diseases. However, the large-scale production of clinical batches of bispecific antibodies still has many challenges that include having low yield, poor stability, and laborious downstream purification processes. To address such challenges, we describe the optimization of the controlled Fab arm exchange (cFAE) process for the efficient generation of BsAbs. Methods: The process optimization of a large-scale good manufacturing practice (GMP) cFAE strategy to prepare BsAbs was based on screening the parameters of temperature, reduction, oxidation, and buffer exchange. We include critical quality standards for the reducing agent cysteamine hydrochloride. Results: This large-scale production protocol enabled the generation of bispecific antibodies with >90% exchange yield and at >95% purity. The subsequent downstream processing could use typical mAb procedures. Furthermore, we demonstrated that the bispecific generation protocol can be scaled up to ∼60 L reaction scale using parental monoclonal antibodies that were expressed in a 200 L bioreactor. Conclusion: We presented a robust development strategy for the cFAE process that can be used for a larger scale GMP BsAb production.

Physical exercise/sports ameliorate the internet addiction from college students during the pandemic of COVID-19 in China.

The rapid advancement of modern technology has significantly driven progress in various IT-related activities, resulting in a substantial increase in internet penetration rates, particularly among college students. The utilization of the internet has become one of the most essential tools in our modern society. However, internet addiction (IA) has emerged as a serious concern, particularly among college students, adversely affecting academic performance and having significant psychological and psychiatric implications. The aim of the current study was to determine the impact of physical exercise, gender and academic year on IA among college students. In the present study, we investigated internet usage, engagement in sports activities, and academic performance among college students from Western, Middle, and Eastern regions of Chinese universities. It's noteworthy that most of the respondents were freshmen. Our findings indicate that freshmen students were more susceptible to experiencing IA. Approximately 75% of students engaged in leisure sports activities, revealing an inverse correlation between sports activity and IA. This correlation aligns with the level of sports involvement, emphasizing the potential benefits of physical activity in mitigating IA. However, our study did not uncover any correlation between geographic location and the occurrence of IA, nor did it find differences between medical and non-medical students. Furthermore, our study revealed no significant variations in IA among students from different ethnic backgrounds. The underlying mechanism of IA is being currently determined. Our data suggest that physical exercise, gender, and academic year have a significant impact on IA among college students.

Drifts in N-Linked Glycosylation Result in ADCC Potency Variation of Perjeta® from August 2020 to October 2021 in China.

The proposed biosimilar candidate needs to demonstrate biosimilarity with reference products, and the quality target product profile and biosimilarity assessment criteria are prerequisite, which should be based on extensive characterization of the reference products. In this study, 13 lots of China-sourced pertuzumab (trademark: Perjeta®), with an expiration date from 2020 to 2021, were comprehensively characterized. Despite the consistency of purity, drifts in N-glycan profile were observed, which resulted in the variation of antibody-dependent cellular cytotoxicity (ADCC) activity. In detail, four parametric curves of ADCC activity of the reference product were unparalleled, and the maximum response value was highly related to the content of %afucose than half-maximal effective concentration (EC50). As ADCC is a potential critical quality attribute of Perjeta®, the glycosylation of Perjeta® and its biosimilars should be tightly monitored and controlled.

Constructing Ultrathin W-Doped NiFe Nanosheets via Facile Electrosynthesis as Bifunctional Electrocatalysts for Efficient Water Splitting.

Exploring cost-effective and efficient bifunctional electrocatalysts via simple fabrication strategies is strongly desired for practical water splitting. Herein, an easy and fast one-step electrodeposition process is developed to fabricate W-doped NiFe (NiFeW)-layered double hydroxides with ultrathin nanosheet features at room temperature and ambient pressure as bifunctional catalysts for water splitting. Notably, the NiFeW nanosheets require overpotentials of only 239 and 115 mV for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively, to reach a current density of 10 mA/cm2 in alkaline media. Their exceptional performance is further demonstrated in a full electrolyzer configuration with the NiFeW as both anode and cathode catalysts, which achieves a low cell voltage of 1.59 V at 10 mA/cm2, 110 mV lower than that of the commercial IrO2 (anode) and Pt (cathode) catalysts. Moreover, the NiFeW nanosheets are superior to various recently reported bifunctional electrocatalysts. Such remarkable performances mainly ascribe to W doping, which not only effectively modulates the electrocatalyst morphology but also engineers the electronic structure of NiFe hydroxides to boost charge-transfer kinetics for both the OER and HER. Hence, the ultrathin NiFeW nanosheets with an efficient fabrication strategy are promising as bifunctional electrodes for alkaline water electrolyzers.

Use of a Noninvasive Brain-Penetrating Peptide-Drug Conjugate Strategy to Improve the Delivery of Opioid Pain Relief Medications to the Brain.

The analgesic potency of morphine-6-glucuronide (M6G) has been shown to be 50-fold higher than morphine after intracerebral injection. However, the brain penetration of M6G is significantly lower than morphine, thus limiting its usefulness in pain management. Here, we created new entities by the conjugation of the angiopep-2 peptide (An2) that crosses the blood-brain barrier (BBB) by low-density lipoprotein receptor-related protein 1 receptor-mediated transcytosis with either morphine or M6G. We demonstrated improvement of BBB permeability of these new entities compared with that of unconjugated M6G and morphine. Intravenous or subcutaneous administration of the An2-M6G conjugate exerted greater and more sustained analgesic activity than equivalent doses of either morphine or M6G. Likewise, subcutaneous An2-morphine induced a delayed but prolonged antinociceptive effect. The effects of these conjugates on the gastrointestinal tract motility were also evaluated. An2-morphine significantly reduced the intestinal transit time, whereas An2-M6G exhibited a reduced constipation profile, as compared with an equimolar dose of morphine. In summary, we have developed new brain-penetrant opioid conjugates exhibiting improved analgesia to side effect ratios. These results thus support the use of An2-carrier peptides as an innovative BBB-targeting technology to deliver effective drugs, such as M6G, for pain management. SIGNIFICANCE STATEMENT: The metabolite morphine-6-glucuronide (M6G) does not efficiently cross the blood-brain barrier. The low-density lipoprotein receptor-related protein 1 peptide ligand angiopep-2 may serve as an effective drug delivery system to the brain. Here, we demonstrated that the coupling of M6G to angiopep-2 peptide (An2) improves its brain penetration and significantly increases its analgesic potency. The An2-M6G conjugate has a favorable side effect profile that includes reduction of developing constipation. An2-M6G exhibits a unique pharmacodynamic profile with a better therapeutic window than morphine.

Direct Synthesis of Conformal Layered Protonated Titanate Nanoarray Coatings on Various Substrate Surfaces Boosted by Low-Temperature Microwave-Assisted Hydrothermal Synthesis.

Layered protonated titanates (LPTs) are promising support materials for catalytic applications because their high surface area and cation exchange capacity provide the possibility of achieving a high metal dispersion. However, the reported LPT nanomaterials are mainly limited to free-standing nanoparticles (NPs) and usually require high temperature and pressure conditions with extended reaction time. In this work, a high-throughput microwave-assisted hydrothermal method was developed for the direct synthesis of conformal LPT nanoarray coatings onto the three-dimensional honeycomb monoliths as well as other substrate surfaces at low temperature (75-95 °C) and pressure (1 atm). Using TiCl3 as the titanium source, H2O2 as the oxidant, and hydrochloric acid as the pH controller, a peroxotitanium complex (PTC) was formed and identified to play an essential role for the formation of LPT nanoarrays. The gaseous O2 released during the decomposition of PTC promotes the mass transfer of the precursors, making this method applicable to substrates with complex geometries. With the optimized conditions, a growth rate of 42 nm/min was achieved on cordierite monolith substrates. When loaded with Pt NPs, the LPT nanoarray-based monolithic catalysts showed excellent low-temperature catalytic activity for CO and hydrocarbon oxidation as well as satisfactory hydrothermal stability and mechanical robustness. The low temperature and pressure requirements of this facile hydrothermal method overcome the size- and pressure-seal restrictions of the reactors, making it feasible for scaled production of LPT nanoarray-based devices for various applications.

Biosynthesis and characterization of a non-repetitive polypeptide derived from silk fibroin heavy chain.

Silk fibroin heavy chain is the major protein component of Bombyx mori silk fibroin and is composed of 12 repetitive and 11 non-repetitive regions, with the non-repetitive domain consisting of a hydrophilic polypeptide chain. In order to determine the biomedical function of the non-repetitive domain or potentially use it to modify hydrophobic biomaterials, high-purity isolation is necessary. Previously, we cloned and extended a gene motif (f(1)) encoding the non-repetitive domain. Here, this motif and its multimers are inserted into a glutathione S-transferase (GST)-tagged fusion-protein expression vector. Motif f(1) and multimers f(4) and f(8) were expressed in Escherichia coli BL21 cells following isopropyl ß-D-1-thiogalactopyranoside induction, purified by GST-affinity chromatography, and single bands of purified fusion proteins GST-F(1), GST-F(4), and GST-F(8), were visualized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Target polypeptides F(1), F(4), and F(8), were cleaved clearly from the GST-fusion tag following thrombin digestion. Mass spectrometry results indicate that the molecular weights associated with fusion proteins GST-F(1), GST-F(4), and GST-F(8) are 31.5, 43.8, and 59.0kDa, respectively, and with the cleaved polypeptides F(1), F(4), and F(8) are 4.8, 16.8, and 32.8kDa, respectively. The F(1), F(4), and F(8) polypeptide chains are negatively charged with isoelectric points (pI) of 3.3, 3.2, and 3.0, respectively. The molecular weight and pI values of the polypeptide chains are consistent with the predicted values and the amino acid compositions similar to predicted sequences. FTIR and CD results show the molecular conformation of F(1) was mainly random coil, and more stable α-helix structure formed in longer molecular chain.

Hemocompatibility and cytocompatibility of the hirudin-modified silk fibroin.

Hirudin (Hir), a thrombin direct inhibitor, was used to modify a polyethylene glycol diglycidyl ether (PEG-DE) crosslinked regenerated silk fibroin (SF) material to improve hemocompatibility. Hemolysis characteristics, platelet adhesion, platelet activity, and plasma recalcification time were investigated using absorption spectrometry, scanning electron microscopy, MTT analysis, and the time counting method. Hirudin could be grafted evenly to the silk fibroin, and the modified material was resistant to hemolysis at ratios of less than 0.5%. Scanning electron microscopy and MTT results showed that platelet adhesion and aggregation activity decreased after modificaton with trace amounts of hirudin, compared with PEG-DE crosslinked and ethanol-treated silk fibroin film. Plasma recalcification of PEG-DE crosslinked silk fibroin film was slower than with ethanol-treated material, and this increased slightly after hirudin modification. Furthermore, L929, HAVSMC, and HUVEC cells adhered to the modified material, grew well, and possessed high proliferation activity on SF/Hir blend films. This study suggests that hirudin could improve the anticoagulation properties of regenerated silk fibroin materials.

Experimental and predicted approaches for biomass gasification with enriched air-steam in a fluidised bed.

Thermo-chemical gasification of sawdust refuse-derived fuel was performed on a bench-scale fluidised bed gasifier with enriched air and steam as fluidising and oxidising agents. Dolomite as a natural mineral catalyst was used as bed material to reform tars and hydrocarbons. A series of experiments were carried out under typical operating conditions for gasification, as reported in the article. A modified equilibrium model, based on equilibrium constants, was developed to predict the gasification process. The sensitivity analysis of operating parameters, such as the fluidisation velocity, oxygen percentage of the enriched air and steam to biomass ratios on the produced gas composition, lower heating value, carbon conversion and cold gas efficiency was investigated. The results showed that the predicted syngas composition was in better agreement with the experimental data compared with the original equilibrium model. The higher fluidisation velocity enhanced gas-solid mixing, heat and mass transfers, and carbon fines elutriation, simultaneously. With the increase of oxygen percentage from 21% to 45%, the lower heating value of syngas increased from 5.52 MJ m(-3) to 7.75 MJ m(-3) and cold gas efficiency from 49.09% to 61.39%. The introduction of steam improved gas quality, but a higher steam to biomass ratio could decrease carbon conversion and gasification efficiency owing to a low steam temperature. The optimal value of steam to biomass ratio in this work was 1.0.

Biosynthesis of a potentially functional polypeptide derived from silk fibroin.

In order to understand the relationship between sequences and biological functions of RGD-containing wild silkworm silk fibroin, it is important to purify the basic RGD-containing motif in large quantities. In this study, a gene monomer encoding RGD-contained motif GSGAGGRGDGGYGSGSS (-RGD-) derived from Antheraea pernyi (the same in Antheraea yamamai) was designed and cloned. (-RGD-)n in various degrees of polymerizations was obtained by gene monomer doubling-extension and expression. Two glutathione-S-transferase (GST)-tagged fusion proteins GST-(-RGD-)12 and GST-(-RGD-)24 were successfully expressed in Escherichia coli (E. coli) BL21. The fusion proteins were isolated and purified by GST affinity chromatography, and the polypeptides (-RGD-)12 and (-RGD-)24 were cleaved from GST fusion proteins by thrombin digestion. Two-dimensional electrophoresis and amino acid composition analysis were performed to confirm the identity of the engineered polypeptides. Results indicated that this technology reliably obtained expected polypeptides (-RGD-)n for future research on structure and functions.

New Angiopep-modified doxorubicin (ANG1007) and etoposide (ANG1009) chemotherapeutics with increased brain penetration.

This report describes the synthesis and preliminary biological characterization of 2 (ANG1007) and 3 (ANG1009), two new chemical entities under development for the treatment of primary and secondary brain cancers. 2 consists of three doxorubicin molecules conjugated to Angiopep-2, a 19-mer peptide that crosses the blood-brain barrier (BBB) by an LRP-1 receptor-mediated transcytosis mechanism. 3 has a similar structure, with the exception that three etoposide moieties are conjugated to Angiopep-2. Both agents killed cancer cell lines in vitro with similar IC(50) values and with apparently similar cytotoxic mechanisms as unconjugated doxorubicin and etoposide. 2 and 3 exhibited dramatically higher BBB influx rate constants than unconjugated doxorubicin and etoposide and pooled within brain parenchymal tissue. Passage through the BBB was similar in Mdr1a (-/-) and wild type mice. These results provide further evidence of the potential of this drug development platform in the isolation of novel therapeutics with increased brain penetration.

Structure-based design and synthesis of macroheterocyclic peptidomimetic inhibitors of the aspartic protease beta-site amyloid precursor protein cleaving enzyme (BACE).

Based on the X-ray cocrystal structure of the Tang-Ghosh heptapeptide inhibitor 1 (OM00-3), a series of macroheterocyclic analogues were designed and synthesized. Analogues containing dithia, dioxa, oxathia, and carbathia macrocycles were synthesized by methods relying on ring-closing olefin metathesis for the dioxa analogues and by alkylation of thiolates or bisthiolates for the others. Molecular modeling suggested that the incorporation of piperidine units appended to the macrocycles improved interactions through additional H-bonds and introduced further rigidity. These were synthesized in enantiomerically pure form using enzyme-catalyzed desymmetrization and diastereomer separation. Inhibitory activity on beta-site amyloid precursor protein cleaving enzyme (BACE) was observed with several macroheterocyclic inhibitors and structure-activity relationship (SAR) correlations were deduced. Cocrystal structures of two synthetic analogues revealed interesting and unexpected binding interactions.

Structure-based design, synthesis, and memapsin 2 (BACE) inhibitory activity of carbocyclic and heterocyclic peptidomimetics.

Molecular modeling based on the X-ray crystal structure of the Tang-Ghosh heptapeptide inhibitor 1 (OM99-2) of BACE led to the design and synthesis of a series of constrained P(1)' analogues. A cyclopentane ring was incorporated in 1 spanning the P(1)' Ala methyl group and the adjacent methylene carbon atom of the chain. Progressive truncation at the P(2)'-P(4)' sites led to a potent truncated analogue 5 with good selectivity over Cathepsin D. Using the same backbone replacement concept, a series of cyclopentane, cyclopentanone, tetrahydrofuran, pyrrolidine, and pyrrolidinone analogues were synthesized with considerable variation at the P and P' sites. The cyclopentanone and 2-pyrrolidinone analogues 45 and 57 showed low nM BACE inhibition. X-ray cocrystal structures of two analogues 5 and 45 revealed excellent convergence with the original inhibitor 1 structure while providing new insights into other interactions which could be exploited for future modifications.