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Spermatogonial stem cells (SSCs) are crucial for maintaining spermatogenesis, studying germ line stem cell biology, and producing transgenic animals. Growth factors, including leukemia inhibitory factor (LIF), epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), and glial cell line-derived neurotrophic factor (GDNF), are essential for in vitro culture of SSCs as well as their self-renewal and maintenance. In this study, we investigated the effects of these growth factors on porcine spermatogonial germ cell (pSGC) colony formation. We determined round alkaline phosphatase (AP)-positive pSGC colonies in the presence and absence of growth factors after 7 days of pSGC culture. EGF was found to be essential to support the formation of AP-positive pSGC colonies. The expression of epidermal growth factor receptor (EGFR) and Erb-B2 receptor tyrosine kinase 2 (ERBB2) was also altered in cultured pSGCs compared to that in feeder cells. We verified the effect of EGF signaling on pSGC colony formation using AG1478 as an EGFR inhibitor and AG879 as an ERBB2 inhibitor. pSGC colonies were observed in low dose AG1478-treated groups with EGF, whereas a high dose of AG1478 suppressed pSGC colony formation. AP-positive colonies were also observed in all AG879-treated groups. Taken together, EGFR and EGF signaling play a critical role in the initiation of colony formation of pSGCs. Our study provides insights into the mechanisms of EGF-mediated colony formation by SGCs derived from porcine testes, and will aid the development of transplantation techniques for the production of transgenic offspring.

ContextContinuous glucose monitoring (CGM) overcomes the limitations of glycated hemoglobin (HbA1c).ObjectiveThis study aimed to investigate the relationship between CGM metrics and laboratory HbA1c in pregnant women with type 1 diabetes.MethodsAn observational study enrolled pregnant women with type 1 diabetes who wore CGM devices during pregnancy and postpartum from 11 hospitals in China from January 2015 to June 2019. CGM data were collected to calculate time in range (TIR), time above range (TAR), time below range (TBR), and glycemic variability parameters. Relationships between the CGM metrics and HbA1c were explored. Linear and curvilinear regressions were conducted to investigate the best-fitting model to clarify the influence of HbA1c on the TIR-HbA1c relationship during pregnancy.ResultsA total of 272 CGM data and corresponding HbA1c from 98 pregnant women with type 1 diabetes and their clinical characteristics were analyzed in this study. Mean HbA1c and TIR were 6.49 ± 1.29% and 76.16 ± 17.97% during pregnancy, respectively. HbA1c was moderately correlated with TIR3.5-7.8(R = –0.429, P = .001), mean glucose (R = 0.405, P = .001) and TAR7.8 (R = 0.435, P = .001), but was weakly correlated with TBR3.5 (R = 0.034, P = .001) during pregnancy. On average, a 1% (11 mmol/mol) decrease in HbA1c corresponded to an 8.5% increase in TIR3.5–7.8. During pregnancy, HbA1c of 6.0%, 6.5%, and 7.0% were equivalent to a TIR3.5–7.8 of 78%, 74%, and 69%, respectively.ConclusionWe found there was a moderate correlation between HbA1c and TIR3.5–7.8 during pregnancy. To achieve the HbA1c target of less than 6.0%, pregnant women with type 1 diabetes should strive for a TIR3.5–7.8 of greater than 78% (18 hours 43 minutes) during pregnancy.

Electrochemical impedance spectroscopy (EIS) is widely used to probe the physical and chemical processes in lithium (Li)-ion batteries (LiBs). The key parameters include state-of-charge, rate capacity or power fade, degradation and temperature dependence, which are needed to inform battery management systems as well as for quality assurance and monitoring. All-solid-state batteries using a solid-state electrolyte (SE), promise greater energy densities via a Li metal anode as well as enhanced safety, but their development is in its nascent stages and the EIS measurement, cell set-up and modelling approach can be vastly different for various SE chemistries and cell configurations. This review aims to condense the current knowledge of EIS in the context of state-of-the-art solid-state electrolytes and batteries, with a view to advancing their scale-up from the laboratory to commercial deployment. Experimental and modelling best practices are highlighted, as well as emerging impedance methods for conventional LiBs as a guide for opportunities in the solid-state.

Angiogenesis is an integral process in many ischemic disorders, and vascular endothelial growth factor (VEGF) plays an important role in it. Protein arginine methyltransferase 4 (PRMT4), a member of the type I PRMT family, is involved in various biological activities, but its role in endothelial cell (EC) remains elusive. Here, we aimed to investigate the role of PRMT4 in ischemic angiogenesis and explore the possible underlying mechanism. We found that PRMT4 was upregulated in ischemic muscles, and VEGF treatment potentiated its expression in ECs. In vitro, adenovirus-mediated PRMT4 overexpression promoted, while its gene disruption inhibited, EC proliferation, migration, and tube formation. In an in vivo hindlimb ischemia model, forced expression of PRMT4 in ECs showed accelerated blood flow recovery and increased capillary density, whereas its knockdown exhibited the opposite effect. Mechanistically, PRMT4 activated the transcription of VEGF via the interaction with Y-box binding protein-1 (YB1), leading to accelerated angiogenesis. Interestingly, the loss of YB1 partially abolished PRMT4-mediated angiogenesis in vitro. Collectively, our data revealed that PRMT4 promoted angiogenesis through interacting with YB1 and the consequential VEGF upregulation, suggesting that PRMT4 may present as a potential therapeutic target in ischemic angiogenesis. KEY MESSAGES: •PRMT4 is induced by VEGF and upregulated in a hindlimb ischemia model. •PRMT4 promotes angiogenesis both in vitro and in vivo. •PRMT4 regulates VEGF expression through interacting with YB1. •YB1 knockdown retards PRMT4-mediated angiogenic effects in vitro.

Background Dexmedetomidine induces a sedative response that is associated with rapid arousal. To elucidate the underlying mechanisms, the authors hypothesized that dexmedetomidine increases the activity of dopaminergic neurons in the ventral tegmental area, and that this action contributes to the unique sedative properties of dexmedetomidine. Methods Only male mice were used. The activity of ventral tegmental area dopamine neurons was measured by a genetically encoded Ca2+ indicator and patch-clamp recording. Dopamine neurotransmitter dynamics in the medial prefrontal cortex and nucleus accumbens were measured by a genetically encoded dopamine sensor. Ventral tegmental area dopamine neurons were inhibited or activated by a chemogenetic approach, and the depth of sedation was estimated by electroencephalography. Results Ca2+ signals in dopamine neurons in the ventral tegmental area increased after intraperitoneal injection of dexmedetomidine (40 μg/kg; dexmedetomidine, 16.917 [14.882; 21.748], median [25%; 75%], vs. saline, –0.745 [–1.547; 0.359], normalized data, P = 0.001; n = 6 mice). Dopamine transmission increased in the medial prefrontal cortex after intraperitoneal injection of dexmedetomidine (40 μg/kg; dexmedetomidine, 10.812 [9.713; 15.104], median [25%; 75%], vs. saline, –0.498 [–0.664; –0.355], normalized data, P = 0.001; n = 6 mice) and in the nucleus accumbens (dexmedetomidine, 8.543 [7.135; 11.828], median [25%; 75%], vs. saline, –0.329 [–1.220; –0.047], normalized data, P = 0.001; n = 6 mice). Chemogenetic inhibition or activation of ventral tegmental area dopamine neurons increased or decreased slow waves, respectively, after intraperitoneal injection of dexmedetomidine (40 μg/kg; delta wave: two-way repeated measures ANOVA, F[2, 33] = 8.016, P = 0.002; n = 12 mice; theta wave: two-way repeated measures ANOVA, F[2, 33] = 22.800, P < 0.0001; n = 12 mice). Conclusions Dexmedetomidine activates dopamine neurons in the ventral tegmental area and increases dopamine concentrations in the related forebrain projection areas. This mechanism may explain rapid arousability upon dexmedetomidine sedation. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

Aerobic respiration is the indispensable physiology of higher organism living on earth, since the required energy for biological activities is supplied mainly by this metabolism. It is well established that mitochondria plays an important role in converting the stable chemical energy stored in foods into the active and utilizable energy supplying to life activities. Upon the process, the energy conversion is carried out by the respiratory electron transport chain, which consists of five distinct and coupled protein complexes (termed complex I−V) embedded in the mitochondria intima. Among them, complex I (NADH-ubiquinone oxidoreductase), III (cytochrome bc 1) and IV (cytochrome c oxidase) are the electron-coupled proton-pumping enzymes. Except for the complex V (i.e., ATP synthase), each complex has several redox cofactors to promote the electron transfer within themselves, and the transfer from complex I and II to complex III is shuttled by membrane-embedded ubiquinones, from complex III to IV by the soluble cytochrome c . When the reductive electron is donated by the initial donors NADH or FADH2 to the final acceptor molecular oxygen O2, a transmembrane proton motive force is formed simultaneously. The latter is the driving force for the ATP synthesis via ATP synthase with a ratio of three protons per ATP. All the aforementioned processes are also known as oxidative phosphorylation, and the arrangement of the electron carriers therein is called as respiratory electron transport chain. In the stepwise electron relay, these carriers undergo the redox changes, giving rise to the respective paramagnetic and diamagnetic spin states. These single-electron relays are prone to the electron paramagnetic resonance spectroscopy (EPR), which is a powerful and noninvasive technique to monitor the unpaired electron in situ . As shown in the overwhelming literatures, EPR technique has been adopted to reveal the electron transfer pathway in different biological activities. Herein, the application of EPR to study the dynamic electron transfer in mitochondria is reviewed briefly. However, this conventional application required rather high concentration of the active center at a level of 1–10 µmol/L. Actually, most of the intermediates of the electron carriers are very active and short-life. In the human body, only a few tissues can accumulate such required concentration of paramagnetic substances, e.g., in blood, heart and liver. For the past decade, a more sensitive single-molecule magnetic resonance technique based on the nitrogen-vacancy (NV) center of diamond has been developing dramatically. In principle, this advanced EPR technique requires the less sample or concentration, even down to the single biomolecule, and provides the time-resolved dynamic information. Lately, the studies of single-biomolecule EPR at room temperature or in aqueous solution have been reported consecutively in single protein (MAD2/mitotic arrest deficient-2) and single DNA (tethered DNA duplexes). Finally, a perspective of single-biomolecule magnetic resonance technique is given for the further study on mitochondrion and relative physiological activities. The single molecule EPR technique is also helpful to unveil the other specific information of biological processes, for example, drug screening, personalized medicine and other major applications.

Bismuth(III) oxidation of 3,5-di-substituted-1,2,4-triazolato anions afforded a paddlewheel 1,2,4-triazolato dibismuth complex [L2(Bi–Bi)L2] (L = η1,η1-3,5-R2tz, R = Ph (3), iPr (4)) with very short Bi(II)–Bi(II) bonds (2.8650(4)−2.8721(3) A). The reaction involved the intermediates of the organobismuth radical [Bi(R2tz)2]˙ and neutral N-1,2,4-triazolyl radical [3,5-R2tz]˙. The dimerization of the former produced the corresponding dibismuth complex while the latter was trapped by using spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) to give the radical adduct of {(3,5-R2tz)(DMPO)}˙ which was unambiguously evidenced by EPR analysis.

The formation and qualification of redox sites in transition metal oxides are always the active fields related to electronics, catalysis, sensors, and energy-storage units. In the present study, the temperature dependence of thermal reduction of MoO3 was surveyed at the range of 350 °C to 750 °C. Upon reduction, the formed redox species characterized by EPR spectroscopy are the MoV ion and superoxide anion radical (O2−) when the reduction was induced at the optimal temperature of 300−350 °C. When heating-up from 350 °C, the EPR signals started to decline in amplitude. The signals in the range of 400−450 °C decreased to half of that at 350 °C, and then to zero at ∼600 °C. Further treatment at even higher temperature or prolonged heating time at 500 °C caused more reduction and more free electrons were released to the MoO3 bulk, which results in a delocalized means similar to the anti-ferromagnetic coupling. These data herein are helpful to prepare and study the metal-oxide catalysts.

Endothelial cells are the fundamental components of blood vessels that regulate several physiological processes including immune responses, angiogenesis, and vascular tone. Endothelial dysfunction contributes to the development of various diseases such as acute lung injury, and endothelial inflammation is a vital part of endothelial dysfunction. Dauricine is an extract isolated fromMenispermum dauricumDC, a traditional Chinese medical plant that can be used for pharyngitis. In this work, we found that IL-1β-induced overexpression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin was inhibited by dauricine in primary human umbilical vein endothelial cells (HUVECs). Correspondingly, adhesion of human acute monocytic leukemia cell line (THP-1) to HUVECs was decreased by dauricine. Further studies showed that dauricine inhibited the activation of nuclear factor-κB (NF-κB) pathway in HUVECs stimulated with IL-1β.In vivo, dauricine protected mice from lipopolysaccharide (LPS)-induced acute lung injury. In lung tissues, the activation of NF-κB pathway and the expression of its downstream genes (ICAM-1, VCAM-1, and E-selectin) were decreased by dauricine, consistent with what was foundin vitro. In summary, we concluded that dauricine could alleviate endothelial inflammation by suppressing NF-κB pathway, which might serve as an effective candidate for diseases related with endothelial inflammation.

Stepwise escalation of glucose-lowering therapy to more intensive regimens is an integral component of type 2 diabetes management (1). Early blood glucose control is associated with beneficial effects on long-term micro- and macrovascular outcomes (2). Understanding factors associated with time to therapy escalation following an elevated glycated hemoglobin (HbA1c) may inform interventions to facilitate timely control. We used linked real-world data to examine time to therapy escalation following a recorded HbA1c ≥8.0% (64 mmol/mol) and associated factors. The EXamining ouTcomEs in chroNic Disease in the 45 and Up Study (EXTEND45 Study) is an Australian population-based linked data study in which participants of the 45 and Up Study have been linked to the Medicare Benefits Schedule (MBS), providing data on government-subsidized medical services, the Pharmaceutical Benefits Scheme (PBS), providing prescription claims data, and community laboratory databases (among others) (3). The 45 and Up Study comprises 267,153 individuals aged ≥45 years living in New South Wales (NSW), Australia, recruited between July 2006 and December 2009. Ethical approval for the EXTEND45 Study was obtained from the NSW Population & Health Services Research Ethics Committee (HREC/13/CIPHS/49). In EXTEND45, 24,430 individuals with diabetes between 2006 and 2014 have been identified using multiple linked data sources (3). In the current study, therapy escalation was assessed during the 6 months following all linked HbA1c results ≥8.0% occurring in non–treatment-naive, non–insulin-using individuals presumed to have type 2 diabetes. As a result, the unit of analysis was the elevated HbA1c, with individuals able to contribute multiple results to the analysis. A threshold of 8.0% was used to reflect the typically higher HbA1c targets recommended for older people (4). To ensure that all included HbA1c results represented separate instances of an elevated HbA1c in the same individual, those results ≥8.0% that occurred …

Aim. DNA methylation is thought to be involved in regulating the expression of key genes and inducing diabetic peripheral neuropathy (DPN). However, clinically, the level of whole-genome DNA methylation and its relationship with DPN remains unclear. Methods. 186 patients with type 2 diabetes mellitus (T2DM) admitted to the Second Affiliated Hospital of Soochow University since Jul. 2016 to Oct. 2017 were enrolled in the study, including 100 patients in the DPN group and 86 patients in the non-DPN group, diagnosed with Toronto Clinical Scoring System (TCSS). Clinical and biochemical characteristics between the two groups were compared, and the correlations with TCSS scores were analyzed. Furthermore, the levels of genomic DNA methylation of leukocytes, measured with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS), were also analyzed between the two groups. Results. Age, duration, triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL-C), creatinine, uric acid (UA), blood urea nitrogen (BUN), and C-reactive protein (CRP) were significantly higher in the DPN group. Estimated glomerular filtration rate (eGFR) and the level of genomic DNA methylation were much lower in the DPN group. Spearman correlation analysis showed that TCSS was positively correlated with age, duration, UA, and CRP and was negatively correlated with body mass index (BMI), eGFR, and the level of genomic DNA methylation. Interestingly, multiple stepwise regression analysis showed that only duration, genomic DNA methylation, and eGFR had impacts on TCSS. The results also showed that the levels of genomic DNA methylation did not change significantly whether or not there was renal injury. Another multiple stepwise regression analysis showed that TCSS and BMI were the influencing factors of genomic DNA methylation. Finally, we found that genomic DNA methylation levels were decreased significantly in the DPN group compared with the non-DPN group when the duration is ≥5 years or BMI≥25 kg/m2. Conclusion. Low level of genomic DNA methylation is a relative specific risk factor of diabetic peripheral neuropathy in patients with type 2 diabetes.

A subgroup analysis of the nationwide, cross-sectional 3B STUDY was performed to understand the current blood pressure (BP) control status and treatment patterns in Chinese diabetes patients as well as to identify factors associated with BP control. The demographic data, anthropometric parameters, and laboratory results were collected from 24 512 type 2 diabetes patients. The BP goal was a systolic BP

Flexible composite polymer electrolytes (CPEs) are fabricated by reversible addition-fragmentation chain transfer (RAFT) polymerization of poly(ethylene glycol) methacrylate (PEGMA) and poly(ethylene glycol) diacrylate (PEGDA), followed by physical doping with ionic bond modified nanoparticles (IBNs) based on nanoscale silica. In reference to PEGMA-PEGDA cross-linked framework prepared by ultraviolet light irradiation directly, RAFT polymerization endows the electrolyte membranes with excellent flexibility, and further increase in yield stress and tensile modulus achieved with IBNs adding in the system. CPEs obey Arrhenius law and its ionic conductivity is found to be maximum of 6.77 × 10−5 S cm−1 at 30 °C, but that of the electrolytes consisted of the same molar feeding ratio of PEGMA/PEGDA without IBNs blending is 3.76 × 10−5 S cm−1 at 30 °C, indicating that the loading of IBNs improves the ionic conductivity, due to the elevated chain mobility. Besides, the electrochemical stability of CPEs is promoted in comparison with the traditional linear poly(ethylene oxide) (PEO) based electrolytes. Moreover, the electrolyte membrane exhibits good cycling performance with lithium iron phosphate and retained 94.3% of capacity after 40 charge-discharge cycles, demonstrating the great potential of this kind of CPEs prepared in this study as electrolyte materials for battery systems.

Warming greatly reshapes carbon cycle of peatlands where soil is water saturated with anaerobic condition prevailing all the year round. However, little is known about the response of anaerobic mineralization of peatlands carbon to global warming, especially when considering the difference of soil from above water table (AWT) and below water table (BWT). This study measured variations in soil carbon anaerobic mineralization as a function of warming and depth by sampling 100-cm soil columns in Zoige plateau. Warming enhanced carbon anaerobic mineralization significantly with different increments among the whole depths. The response of CO2-C and CH4-C to warming varied with depth: at surface soil, both CO2-C and CH4-C emission increased with higher increment; at deep soil, CO2-C emission increased with small increment and CH4-C emission decreased. Substrate availability influenced carbon anaerobic mineralization rate and pathway. Substantial resistant carbon at deep soil lowered CO2 increment and varied CH4 production pathway. The temperature sensitivity of peat carbon anaerobic mineralization varied with depth, suggesting the heterogeneous distribution of soil substrate among the whole depths. AWT soil was higher in temperature sensitivity than BWT soil for the substantial simple carbon and higher microbial/enzyme activity at AWT. BWT soil was a major contributor of the amount of carbon emission and the total increased carbon caused by warming. Further, for the management of peatlands, we should conduct advanced research by focusing more towards the soil of whole depth, especially on the temperature sensitivity of AWT soil and the contribution to total carbon emission of BWT soil.

Arabidopsis thaliana copper-zinc superoxide dismutase 1 (AtSOD1) is a typical metalloenzyme conferring cellular protection against the excessive accumulation of toxic reactive oxygen species, and is therefore considered as a critical protein. However, the structure and function of the vital amino acids around the active site of AtSOD1 remain poorly understood. Herein, the coordinated geometry of the catalytic center in AtSOD1 was reconstructed by electron paramagnetic resonance (EPR) technique, and it was found to be composed of copper and four histidine (H) residues using site-directed mutagenesis. Analysis of the mutants showed that H45 and H62 play essential roles in the catalytic reaction, and H119 plays an accessary role in facilitating substrate or proton transfer. The results indicated that the redox change of the Cu ion and the overall enzymatic activity of the protein were sustained by the H45-Cu-H62 core structure. In contrast, the residue H47 showed nearly no effect on the SOD catalytic activity. These data should contribute to a deeper understanding of the catalytic mechanism of the enzyme, and provide a new approach for the effective molecular modification of copper/zinc SODs to facilitate further research in this field.

Methylglyoxal (MGO), an endogenous reactive carbonyl compound, plays a key role in the pathogenesis of diabetic neuropathy. The aim of this study is to investigate the role of MGO in diabetic itch and hypoalgesia, two common symptoms associated with diabetic neuropathy. Methods: Scratching behavior, mechanical itch (alloknesis), and thermal hypoalgesia were quantified after intradermal (i.d.) injection of MGO in naive mice or in diabetic mice induced by intraperitoneal (i.p.) injection of streptozotocin (STZ). Behavioral testing, patch-clamp recording, transgenic mice, and gene expression analysis were used to investigate the mechanisms underlying diabetic itch and hypoalgesia in mice. Results: I.d. injection of MGO evoked dose-dependent scratching in normal mice. Addition of MGO directly activated transient receptor potential ankyrin 1 (TRPA1) to induce inward currents and calcium influx in dorsal root ganglia (DRG) neurons or in TRPA1-expressing HEK293 cells. Mechanical itch, but not spontaneous itch was developed in STZ-induced diabetic mice. Genetic ablation of Trpa1 (Trpa1-/- ), pharmacological blockade of TRPA1 and Nav1.7, antioxidants, and mitogen-activated protein kinase kinase enzyme (MEK) inhibitor U0126 abrogated itch induced by MGO or in STZ-induced diabetic mice. Thermal hypoalgesia was induced by intrathecal (i.t.) injection of MGO or in STZ-induced diabetic mice, which was abolished by MGO scavengers, intrathecal injection of TRPA1 blockers, and in Trpa1-/- mice. Conclusion: This study revealed that Nav1.7 and MGO-mediated activation of TRPA1 play key roles in itch and hypoalgesia in a murine model of type 1 diabetes. Thereby, we provide a novel potential therapeutic strategy for the treatment of itch and hypoalgesia induced by diabetic neuropathy.

Tetrathiomolybdate (TM) is used in the clinic for the treatment of Wilson’s disease by targeting the cellular copper efflux protein ATP7B (WLN). Interestingly, both TM and WLN are associated with the efficacy of cisplatin, a widely used anticancer drug. Herein, we show that TM induces dimerization of the metal-binding domain of ATP7B (WLN4) through a unique sulfur-bridged Mo2S6O2 cluster. TM expels copper ions from Cu-WLN4 and forms a copper-free dimer. The binding of Mo to cysteine residues of WLN4 inhibits platination of the protein. Reaction with multi-domain proteins indicates that TM can also connect two domains in the same molecule, forming Mo-bridged intramolecular crosslinks. These results provide structural and chemical insight into the mechanism of action of TM against ATPase, and reveal the molecular mechanism by which TM attenuates the cisplatin resistance mediated by copper efflux proteins., Tetrathiomolybdate (TM) and Cu-ATPases, e.g. Wilson (WLN) protein, affect the efficacy of common anticancer drug cisplatin. Here, the authors show that TM generates a protein dimer with a WLN domain by expelling copper and provide insight into the synergy of TM and cisplatin in cancer chemotherapy.

Dialumane 1 reacts with tBuNC to produce a reductive dimerization adduct [LAl(tBuN[double bond, length as m-dash]C-C[double bond, length as m-dash]NtBu)AlL] (2). In the presence of Na, 1 can promote linear- and cyclo-trimerization of isocyanides, affording products [Na][LAl{(tBuNC)3}AlL] (3 and 4) and [Na][LAl{(tBuNC)3}Al(C[triple bond, length as m-dash]N)L] (5), the latter of which features a unique aromatic tri(tert-butylimino)deltate dianion [C3N3(tBu)3]2-.

Carboazidation of alkenes and alkynes holds the promise to construct valuable molecules directly from chemical feedstock therefore is significantly important. Although a few examples have been developed, there are still some unsolved problems and lack of universal methods for carboazidation of both alkenes and alkynes. Here we describe an iron-catalyzed rapid carboazidation of alkenes and alkynes, enabled by the oxidative radical relay precursor t-butyl perbenzoate. This strategy enjoys success with a broad scope of alkenes under mild conditions, and it can also work with aryl alkynes which are challenging substrates for carboazidation. A large number of diverse structures, including many kinds of amino acid precursors, fluoroalkylated vinyl azides, other specific organoazides, and 2H-azirines can be easily produced., Carboazidation of alkenes and alkynes holds the promise to construct valuable, functionalized molecules. Here, the authors report a general and efficient iron-catalyzed carboazidation of both alkenes and alkynes enabled by t-butyl perbenzoate.

The alpine meadow of Zoige Plateau plays a key role in local livestock production of cattle and sheep. However, it remains unclear how animal grazing or its intensity affect nitrous oxide (N2O) emissions, and the main driving factors. A grazing experiment including four grazing intensities (G0, G0.7, G1.2, G1.6 yak ha−1) was conducted between January 2013 and December 2014 to evaluate the soil nitrous oxide (N2O) fluxes under different grazing intensities in an alpine meadow on the eastern Qinghai–Tibet Plateau of China. The N2O fluxes were examined with gas collected by the static chamber method and by chromatographic concentration analysis. N2O emissions in the growing seasons (from May to September) were lower than that in non-growing seasons (from October to April) in 2013, 1.94 ± 0.30 to 3.37 ± 0.56 kg N2O ha−1 yr−1. Annual mean N2O emission rates were calculated as 1.17 ± 0.50 kg N2O ha−1 yr−1 in non-grazing land (G0) and 1.94 ± 0.23 kg N2O ha−1 yr−1 in the grazing land (G0.7, G1.2, and G1.6). The annual mean N2O flux showed no significant differences between grazing treatments in 2013. However, there were significantly greater fluxes from the G0.7 treatment than from the G1.6 treatment in 2014, especially in the growing season. Over the two years, the soil N2O emission rate was significantly negatively correlated with soil water-filled pore space (WFPS) and dissolved organic carbon (DOC) content as well as positively correlated with soil available phosphorus (P). No relationship was observed between soil N2O emission rate and temperature or rainfall. Our results showed that the meadow soils acted as a source of N2O for most periods and turned into a weak sink of N2O later during the sampling period. Our results highlight the importance of proper grazing intensity in reducing N2O emissions from alpine meadow. The interaction between grazing intensity and N2O emissions should be of more concern during future management of pastures in Zoige Plateau.

Background Despite the fundamental clinical significance of general anaesthesia, the cortical mechanism underlying anaesthetic-induced loss of consciousness (aLOC) remains elusive. Methods Here, we measured the dynamics of two major cortical neurotransmitters, gamma-aminobutyric acid (GABA) and glutamate, through in vivo two-photon imaging and genetically encoded neurotransmitter sensors in a cell type-specific manner in the primary visual (V1) cortex. Findings We found a general decrease in cortical GABA transmission during aLOC. However, the glutamate transmission varies among different cortical cell types, where in it is almost preserved on pyramidal cells and is significantly reduced on inhibitory interneurons. Cortical interneurons expressing vasoactive intestinal peptide (VIP) and parvalbumin (PV) specialize in disinhibitory and inhibitory effects, respectively. During aLOC, VIP neuronal activity was delayed, and PV neuronal activity was dramatically inhibited and highly synchronized. Interpretation These data reveal that aLOC resembles a cortical state with a disrupted excitatory-inhibitory network and suggest that a functional inhibitory network is indispensable in the maintenance of consciousness. Funding This work was supported by the grants of the National Natural Science Foundation of China (grant nos. 81620108012 and 82030038 to H.D. and grant nos. 31922029, 61890951, and 61890950 to J.H.).

SHP2 is a nonreceptor protein tyrosine phosphatase encoded by the PTPN11 gene and is involved in cell growth and differentiation via the MAPK signaling pathway. SHP2 also plays an important role in the programed cell death pathway (PD-1/PD-L1). As an oncoprotein as well as a potential immunomodulator, controlling SHP2 activity is of high therapeutic interest. As part of our comprehensive program targeting SHP2, we identified multiple allosteric binding modes of inhibition and optimized numerous chemical scaffolds in parallel. In this drug annotation report, we detail the identification and optimization of the pyrazine class of allosteric SHP2 inhibitors. Structure and property based drug design enabled the identification of protein-ligand interactions, potent cellular inhibition, control of physicochemical, pharmaceutical and selectivity properties, and potent in vivo antitumor activity. These studies culminated in the discovery of TNO155, (3S,4S)-8-(6-amino-5-((2-amino-3-chloropyridin-4-yl)thio)pyrazin-2-yl)-3-methyl-2-oxa-8-azaspiro[4.5]decan-4-amine (1), a highly potent, selective, orally efficacious, and first-in-class SHP2 inhibitor currently in clinical trials for cancer.

Warming and human activities have caused peatland degradation and water table drawdown, which greatly influence the physicochemical characteristics of soil at different depths. How water table drawdown affects soil physicochemical characteristics is not well understood for the Tibetan Plateau, especially the Zoige peatlands. This study measured variations in C/N ratio, ash content, δ13C, and humification index (HI) as a function of water table drawdown and depth by sampling 100-cm soil columns from three sites with different water tables in the Zoige peatlands. C/N ratio decreased while ash content and HI increased with water table drawdown, suggesting greater decomposition of soil organic matter at sites with a lower water table. The response of soil physicochemical characteristics to water table drawdown varied with depth: in the layer above the water table, C/N ratio did not vary, ash content decreased and HI increased; in the layer below the water table, C/N ratio and HI decreased, while ash content increased. The physicochemical characteristics above the water table were influenced mainly by new carbon input, while the characteristics below the water table were influenced mainly by decomposition. The depth profile of C/N ratio, ash content and HI aligned well with peat formation and decomposition and may be indicators of peat degradation. δ13C did not vary with water table drawdown, depth, or decomposition process. These insights into the variation of soil physicochemical characteristics with depths and water table may help elucidate the processes behind peatland degradation.

The grafted polymer modified by ionic bond was synthesized by a simple and scalable method based on sulfonated polystyrene (SPS) and the monoamine-terminated PEO derivative (M2070). Porous polymer electrolytes (PPEs) containing the grafted polymer and poly(vinylidene fluoride) (PVDF) were prepared by phase inversion process. The dense pores distributed in the polymer matrix, which could store liquid electrolyte and provide enough channels for ionic conduction, and the ionic conductivity of PPEs was thus improved effectively. Furthermore, the effect of the mass fraction of grafted polymer on porosity, electrolyte uptake, and ionic conductivity was investigated. The PPE membrane with 30 wt% grafted polymer (PPE-3) exhibited the better pore distribution and superior electrolyte uptake compared with pure PVDF membrane, which resulted in the remarkable ionic conductivity (3.05 × 10−3 S cm−1) of the corresponding PPE-3 at 30 °C. The contact angle of PPE-3 (14.9°) decreased significantly owing to the good affinity of grafted polymer with electrolyte. The LiFePO4/PPE-3/Li cell showed a stable charge/discharge performance with initial discharge capacity of 141 mA h g−1 at room temperature and 96% capacity retention after 130 cycles. Those results suggest that PPEs containing the grafted polymer via ionic band can be promising electrolyte candidates for high-performance lithium ion batteries.

The rapid development and application of nanotechnology have led to increasing concern about the environmental implications of released nanomaterials and potential risks to public health and aquatic ecosystems. Information on the joint effect of nanomaterials and co-existing contaminants such as heavy metals is still inadequate. Our work investigated the effect of Al2O3 nanoparticles (NPs; nano-Al2O3) on the toxic effect of Pb in the unicellular marine phytoplankton Isochrysis galbana. Results showed that a dose–response effect of nano-Al2O3 was found. Significant enhancement of fluorescence in cell cytoplasm rather than cell membrane occurred in the presence of nano-Al2O3, indicating that nano-Al2O3 can penetrate cells and affect the fluorescence emitted from the chloropigments inside them. The presence of nano-Al2O3 has no impact on the toxic effect of Pb at an NP concentration of 1 mg/L but increased that at NP concentrations of 10 mg/L and 100 mg/L. A synergistic effect was also found for the toxic effect of Pb in the presence of 10 mg/L nano-Al2O3. The presence of 100 mg/L nano-Al2O3 significantly increased the bio-uptake of Pb in the range of 0.25 mg/L to 2.0 mg/L Pb, and the maximum accumulated Pb in algae can reach up to 18.22 ng/105 cells with 100 mg/L nano-Al2O3 compared with Pb alone at 2.0 mg/L(12.53 ng/105 cells). Inside cells, Pb loaded onto nano-Al2O3 can be more toxic than the same amount of free Pb species. The results of toxicity tests and accumulated Pb in algae imply that, in addition to the total Pb cell content, the bioavailability of Pb inside algae should be taken into consideration in evaluating the joint toxicity effect. Our work enhances understanding of the combined toxicity of NPs and co-existing heavy metals and is of practical significance in the natural environment.

TiO2 nanoparticles (NPs) could adversely impact aquatic ecosystems. However, the aggregation of these NPs could attenuate this effect. In this work, the biological effects of TiO2 NPs on a marine microalgae Isochrysis galbana were investigated. The aggregation kinetics of TiO2 NPs under different conditions was also investigated to determine and understand these effects. Results showed that, though TiO2 NPs had no obvious impact on the size and reproducibility of algal cells under testing conditions, they caused a negative effect on algal chlorophyll, which led to a reduction in photosynthesis. Furthermore, fast aggregation of TiO2 NPs occurred under all conditions, especially at the pH close to the pHzpc. Increasing ionic strength and NP concentration also enhanced the aggregation rate. The aggregation and the following sedimentation of TiO2 NPs reduced their adverse effects on I. galbana.

The design of functional metallohydrogels is attractive but challenging. A rational approach is introduced for designing functional metallohydrogels using chiral ligands, a phenylalanine derivative with a pyridyl group (l/d-PF). Intriguingly, the as-prepared metallohydrogel exhibits excellent O2 binding and activating properties. Insights into the O2 binding pathway reveals the presence of a novel [(l+d)-PF-Cu3+ -O2- ] species, which can efficiently reduce ferric cytochrome c with the reactive O2- by receiving an electron from reductant ascorbic acid. This study provides helpful instructions for developing new artificial systems with specific functions through the effective combination of chiral ligands with metal ions.

For the first time, the photoexcited charge separation in a metal–organic framework has been evidenced with clear ESR signals, based on efficient and selective photocatalytic oxidative coupling of amines., The selective aerobic oxidative coupling of amines under mild conditions is an important laboratory and commercial procedure yet a great challenge. In this work, a porphyrinic metal–organic framework, PCN-222, was employed to catalyze the reaction. Upon visible light irradiation, the semiconductor-like behavior of PCN-222 initiates charge separation, evidently generating oxygen-centered active sites in Zr-oxo clusters indicated by enhanced porphyrin π-cation radical signals. The photogenerated electrons and holes further activate oxygen and amines, respectively, to give the corresponding redox products, both of which have been detected for the first time. The porphyrin motifs generate singlet oxygen based on energy transfer to further promote the reaction. As a result, PCN-222 exhibits excellent photocatalytic activity, selectivity and recyclability, far superior to its organic counterpart, for the reaction under ambient conditions via combined energy and charge transfer.

The energy-efficient and green synthesis of zeolites that are highly demanded in the chemical industry has been a focus for decades. Here we report a highly efficient radical-route to accelerate the synthesis of zeolites via using sodium persulfate (denoted as SPS) as an additive in the hydrothermal reaction system of SiO2–TPAOH–H2O. The hydrothermal synthesis of highly crystalline silicalite-1 was shortened to 16 h from 24 h in the presence of 0.02 M SPS. Electron paramagnetic resonance (EPR) was used to characterize the radical species induced by SPS. More importantly, as compared with the conventional synthetic system, highly crystalline silicalite-1 can be synthesized with only half of the amount of organic structure-directing agents in the presence of SPS. With this route, we can not only speed up the hydrothermal crystallization of a silicalite-1 zeolite but also greatly reduce the usage of organic structure-directing agents. This radical-route demonstrates an efficient and green route for the synthesis of zeolites.

The selective aerobic oxidative coupling of amines under mild conditions is an important laboratory and commercial procedure yet a great challenge. In this work, a porphyrinic metal–organic framework, PCN-222, was employed to catalyze the reaction. Upon visible light irradiation, the semiconductor-like behavior of PCN-222 initiates charge separation, evidently generating oxygen-centered active sites in Zr-oxo clusters indicated by enhanced porphyrin π-cation radical signals. The photogenerated electrons and holes further activate oxygen and amines, respectively, to give the corresponding redox products, both of which have been detected for the first time. The porphyrin motifs generate singlet oxygen based on energy transfer to further promote the reaction. As a result, PCN-222 exhibits excellent photocatalytic activity, selectivity and recyclability, far superior to its organic counterpart, for the reaction under ambient conditions via combined energy and charge transfer.

The syntheses of fluorinated cyclopentanone derivatives, which have pharmaceutical and agrochemical importance are reported. The catalytic reaction of copper(I) and nickel(II) difluorocarbenes with silyl dienol ethers afforded 4,4-difluoro- and 5,5-difluorocyclopent-1-en-1-yl silyl ethers, respectively. The fluorine-directed and -activated Nazarov cyclization of 1-fluorovinyl vinyl ketones, which were prepared from silyl dienol ethers and free difluorocarbene, proceeded efficiently to afford 2-fluorocyclopent-2-en-1-ones. Moreover, fluorine-­directed Nazarov cyclizations of 2,2-difluorovinyl vinyl ketones and 1-(trifluoromethyl)vinyl vinyl ketones afforded 3-fluorocyclopent-2-en-1-ones and 5-(trifluoromethyl)cyclopent-2-en-1-ones, respectively. In addition, derivatization of ring-difluorinated products also provided 3-fluorocyclopent-2-en-1-ones.

Anaerobic oxidation of methane (AOM), an important biological process to reduce global methane emissions to the atmosphere, can utilize methane as an electron donor to reduce sulfate, nitrate, nitrite, iron, manganese, AQDS (9,10-anthraquinone-2,6-disulfonate), etc.; thus, AOM has been a hot topic in global climate change research in recent years. In addition, nitrogen deposition of terrestrial ecosystems can input more nitrogen to nitrogen-limited peatlands, which could impact the AOM process. However, the effect of nitrogen addition on AOM is not well studied. Here, we investigated the effects of two forms of nitrogen on the vertical distribution (0–100 cm) of AOM in the Zoige peatlands (China) using an anaerobic incubation experiment. The results show that the concentrations of inorganic nitrogen species changed with nitrogen addition, but it did not significantly promote the potential of AOM. The cumulative AOM of treatments without nitrogen (CK) and ammonium chloride (Nred) was 2343.43 ± 18.96 µg·g−1 and 2340.76 ± 16.11 µg·g−1, respectively, which were significantly higher than that of sodium nitrate (Nox) addition treatment (2098.13 ± 13.59 µg·g−1). In addition, the potential of AOM increased with depth, but different soil layers had different responses to the two forms of nitrogen, which could reflect the variable need for different forms of nitrogen in the different soil layers. The soil water content (SWC), dissolved organic carbon (DOC), iron content (Fe3+), and pH played important roles in the potential of AOM in the Zoige peatlands. Overall, our results found that nitrogen addition did not increase the potential of AOM, but instead had an inhibitory effect on it. This study provides a basis for understanding the response of AOM to nitrogen addition in peatlands, which has important implications for global climate change.

The surfaces of rivers are considered important sources of atmospheric methane (CH4), however research on this topic is still constrained, especially in freshwater rivers and with the consideration of spatial heterogeneity. Three regions (upper reaches, midstream and downstream) were selected to examine the CH4 fluxes from a freshwater river surface in a mangrove forest wetland from 2012 to 2013, using floating chambers. Results showed that the CH4 fluxes varied significantly among the three regions, with the lowest fluxes at downstream (0.50 ± 0.20 mg m−2 h−1), and highest at upper reaches (1.19 ± 0.36 mg m−2 h−1). The average emission rate at midstream was 0.95 ± 0.37 mg m−2 h−1. The methane flux also varied with seasons, with higher flux in rain-abundant seasons. On average, the CH4 flux in our research river was 0.88 ± 0.31 mg m−2 h−1, which was less than other tropical rivers. In addition, we found that the CH4 flux was significantly correlated with the water characteristics of temperature and atmospheric pressure. Thereby, this study quantified the methane emission from a freshwater river surface in a tropical mangrove forest, enriching the existing knowledge of river surface CH4 flux.

Solid polymer electrolytes based on a novel comb-like copolymer, polyethylene glycol-grafted sulfonated polyether ether ketone (SPEEK- g -PEG), was designed and synthesized through the reaction between partially hydroxyl-functionalized sulfonated polyether ether ketone (SPEEK) and epoxy-functionalized PEG. The resulting SPEEK- g -PEG was fully characterized by FTIR, 1 H NMR, TGA, and DSC. All data proved the successful grafting of PEG onto the SPEEK main chain. The resulting comb-like structure effectively inhibited the crystallization of PEG. After doping with a lithium salt, the obtained SPEEK- g -PEG polymer electrolyte membrane showed an improved ionic conductivity. The effects of chain length and PEG grafting ratio on the ionic conductivity of SPEEK- g -PEG were also investigated by electrochemical impedance spectroscopy (EIS). Moreover, the effect of this comb-like structure on increasing the ionic conductivity is higher than that of SPEEK/PEG blends, making these comb-like SPEEK- g -PEG copolymers attractive for an application in LIBs.

Neutral N-pyrazolyl radicals [3,5-R2pz]• as reactive intermediates were generated by one-electron oxidization of the corresponding 3,5-disubstituted pyrazolato anions [3,5-R2pz]− (R = tBu, Ph) with BiCl3 and trapped by the use of 5,5-dimethyl-1-pyrroline-N-oxide as a spin trap, which was confirmed by electron paramagnetic resonance spectral analysis. With dimerization of the postulated pyrazolato low-valent BiII radical species, two novel paddlewheel pyrazolatodibismuthanes [L2(Bi–Bi)L2] [L = η1,η1-3,5-R2pz; R = tBu (5α, 5β, and 5γ), Ph (6)] were isolated and structurally characterized.

2′-Aminoacetophenones undergo a C(sp3)–H oxidation followed by intramolecular C–N bond formation by virtue of a simple electrochemical oxidation in the presence of n-Bu4NI, providing various isatins with moderate to good yields. The reaction intermediates were detected, and a radical-based pathway was proposed.

Spirulina was used for the first time as a raw nitrogen-doped porous carbon source to synthesize carbon/sulphur (carbon/S) composite cathodes for lithium-sulphur batteries. The composites consisting of sulphur and spirulina-derived carbon with micro- and meso-pores showed an obvious carbon encapsulating sulphur structure. The carbon/S cathodes exhibited much better electrochemical performance than pristine sulphur, delivering an initial discharge capacity of 662 mAh g−1 with nearly 60% capacity retention after 100 cycles at 1 C current density (1670 mA g−1). The improved electrochemical stability of the composites can be ascribed to the synergistic effects between the encapsulation of sulphur by spirulina-derived carbon and adsorption of polysulfides on N doped carbon lattice. These effects successfully prevented or retarded the shuttle effect of sulphur cathodes.

Novel flexible organic–inorganic hybrid solid electrolytes with controlled network structures (cnHSEs) were formed via thiol–acrylate photopolymerization under UV irradiation, using a series of thiol-modified silica nanoparticles and poly(ethylene glycol) diacrylate. Because of the outstanding lithium ion mobility that is readily identifiable in the solid-state nuclear magnetic resonance spectra, the flexible cnHSEs demonstrate a relatively high ionic conductivity even at low temperature of −20 °C and up to the maximum of 7.3 × 10–4 S cm–1 at 30 °C. The ionic conductivity herein is higher than that for typical solid polymer electrolytes at the identical temperature. Additionally, the lithium ion transference number is also improved simultaneously up to 0.7 more due to the scavenger effect of silica nanoparticles embedded in the system. Moreover, the cnHSEs show a broad electrochemical stability window, and the fabricated cell comprising Li|cnHSEs|LiFePO4 exhibits a highly reversible electrochemical reacti...

Reaction of the Ni-Ni-bonded compound [(NiIL˙-)2] (1, L = [(2,6-iPr2C6H3)NC(Me)]2) with various 1,2-diketones afforded a series of heteroleptic complexes: [LNi(PhC(O)-C(O)Ph)] (2), [LNi(PhC(O)-C(O)Me)] (3), [LNi(3,5-tBu2C6H2O2)] (4), and [(LNi){μ-η2,η2-(MeC(O)-C(O)Me)}(NiL)] (5). Furthermore, the complex [Na(Et2O)][LNi{PhC(O)-C(O)Ph}] (6) was obtained by the reduction of 2 with 1.0 equiv. of Na metal. These complexes, which contain three potential redox-active centers, nickel and both α-diimine and 1,2-diketone ligands, were characterized by X-ray crystallography, NMR, EPR, and UV-vis-NIR spectra, magnetic susceptibility measurements, and DFT computations to elucidate their electronic structures.

A facile and efficient approach to phosphinic amides was developed from diarylphosphine oxides and amines via electrosynthesis. A variety of phosphinic amides were obtained in one step with good to excellent yields under mild and metal-free conditions. The corresponding mechanism was investigated.

Although various types of nanoparticle have been ubiquitously employed as additives to promote the practical performances of composite polymer electrolytes (CPEs) in lithium-ion batteries, the influence of the type of chemical bond between the core and canopy of the modified nanoparticle on the properties of CPEs has rarely been investigated. Herein, two types of nanoparticle additive, namely, ionic bond modified nanoparticles (IBNs) and covalent bond modified nanoparticles (CBNs), were prepared conveniently based on nanosilica with different particle sizes in order to optimize the overall performance of the electrolyte. Furthermore, the CPEs were fabricated by doping IBNs or CBNs as well as lithium salts within a poly(ethylene oxide) matrix and their electrochemical properties were investigated. The dramatic enhancement of the ionic conductivity of the CPEs resulted from the addition of fillers into the system, and the improvement became more significant when the fillers were IBNs that used the smaller silica nanoparticle as the core segment, due to the increased chain mobility, as estimated by the smaller Tg value. Moreover, a broad electrochemical stability window was obtained in the presence of IBNs, and the lithium-ion transference number of the system containing lithium bis(trifluoromethanesulfonimide), which has large anions in the structure, was almost two times higher than the CPEs using lithium perchlorate as the lithium source. Therefore, the synergistic effects of the filler structures and the electrolyte compositions are the key factors to improve the electrochemical performances of CPEs.

Introduction We evaluated the tolerability and efficacy of the addition of sitagliptin in Chinese patients with type 2 diabetes mellitus receiving stable insulin therapy alone or in combination with metformin. Materials and Methods A total of 467 patients with inadequate glycemic control on insulin (glycated hemoglobin [HbA1c] ≥7.5% and ≤11%) were randomized 1:1 to receive sitagliptin 100 mg once daily or a matching placebo for 24 weeks. Randomization was stratified based on metformin use (on or not on metformin) and type of insulin (pre-mixed vs intermediate-/long-acting) at screening. The primary end-point was the change from baseline at week 24 in HbA1c. Results The addition of sitagliptin led to a significantly (P < 0.001) greater week 24 HbA1c reduction (0.7%) compared with the reduction (0.3%) with placebo. A significantly (P = 0.013) greater proportion of patients taking sitagliptin (16%) had an HbA1c of

One of the central questions in the characterization of enzyme inhibitors is determining the mode of inhibition (MOI). Classically, this is done with a number of low-throughput methods in which inhibition models are fitted to the data. The ability to rapidly characterize the MOI for inhibitors arising from high-throughput screening in which hundreds to thousands of primary inhibitors may need to be characterized would greatly help in lead selection efforts. Here we describe a novel method for determining the MOI of a compound without the need for curve fitting of the enzyme inhibition data. We provide experimental data to demonstrate the utility of this new high-throughput MOI classification method based on nonparametric analysis of the activity derived from a small matrix of substrate and inhibitor concentrations (e.g., from a 4S × 4I matrix). Lists of inhibitors from four different enzyme assays are studied, and the results are compared with the previously described IC50-shift method for MOI classification. The MOI results from this method are in good agreement with the known MOI and compare favorably with those from the IC50-shift method. In addition, we discuss some advantages and limitations of the method and provide recommendations for utilization of this MOI classification method.

Magnetic resonance spectroscopy of single biomolecules under near-physiological conditions may substantially advance understanding of biological function, yet remains very challenging. Here we use nitrogen-vacancy centers in diamonds to detect electron spin resonance spectra of individual, tethered DNA duplexes labeled with a nitroxide spin label in aqueous buffer solutions at ambient temperatures. This paves the way for magnetic resonance studies on single biomolecules and their inter-molecular interactions in a native-like environment., 22 pages, 14 figures

Objectives Synthetic oligonucleotides have shown promise in brain imaging. However, delivery of oligonucleotides into live brain cells remains challenging. In this study, we aim to develop a facile yet efficient strategy for local delivery of oligodeoxynucleotide (ODN) to neural cells in live adult mouse brain. Materials and methods A fluorescence‐labelled ODN was diluted with sodium citrate buffer (100 mmol/L, pH = 3). One microlitre of the mixture was injected into a live adult mouse brain. Six hours later, we sacrificed the mouse and prepared brain slices for microscopic imaging. Results We find that the use of sodium citrate buffer in the one‐shot local delivery can improve the diffusion and cell entry efficiency of the unmodified ODN for dozens of times. Only 1 pmol ODN leads to hundreds of positively transferred brain cells. We reason that this promotion is due to the local acidic condition created by the citrate buffer, which leads to the protonation of the ODN and some membrane proteins, thus reduces the Coulomb repulsion between the ODN and the cell membrane. Based on this strategy, we demonstrate fluorescent microscopic imaging of brain cells in different brain regions including striatum, cortex, hippocampus and midbrain. Conclusions The citrate buffer can be used as an adjuvant for facile and effective local injection delivery of ODNs, which may provide a new tool for brain imaging.