Metal–Organic Coordination Networks: Prussian Blue and Its Synergy with Pt Nanoparticles to Enhance Oxygen Reduction Kinetics

Oxygen reduction reaction (ORR) is the cornerstone in the electrochemical energy conversion devices such as fuel cells and metal–air batteries. It remains a great challenge to develop the ORR electrocatalysts with fast kinetics and high durability. Herein, we report the synthesis of a novel metal–organic coordination networks material, prussian blue crystalline nanograins mosaicked within amorphous membrane (PB CNG-M-AM). Such unique PB CNG-M-AM is designed to enhance the electrocatalysis of Pt toward the ORR by the electrostatic self-assembly. Thus, obtained Pt-PB/C catalysts form numerous Pt-PB-gas three-phase boundaries and present rather high intrinsic activity, four-electron selectivity and superior stability. Moreover, a completely new synergetic mechanism between PB and Pt is discovered, which delicately alters the ORR route and significantly enhances the ORR kinetics. This work provides not only a new strategy and mechanism for developing highly efficient ORR electrocatalysts, but also an alternative way to utilize metal–organic coordination networks materials

Genotype and allele frequencies of <i>TNFAIP3</i> promoter variants in AP patients with and without SIRS.

<p>AP indicates acute pancreatitis; CI indicates confidence interval; OR indicates odds ratio; SIRS indicates systemic inflammatory response syndrome.</p

Genotype and allele frequencies of <i>TNFAIP3</i> promoter variants in different individuals with different AP etiologies.

<p>Genotype and allele frequencies of <i>TNFAIP3</i> promoter variants in different individuals with different AP etiologies.</p

Effect of the rs5029924 polymorphism on in vitro LPS stimulation of whole blood.

<p><b>a</b>) After LPS stimulation, mRNA and protein expression levels of TNFAIP3 were significantly different between individuals harboring the CC and individuals harboring the CT+TT genotypes (<i>p</i> = 0.012 and 0.007, respectively). <b>b</b>) NF-κB bound to specific DNA sequences were determined by electrophoretic mobility shift assays on polyacrylamide gels, after LPS stimulation. The IOD of NF-κB complex in individuals harboring the TT was significantly higher than the CC and TT genotype (<i>p</i><0.001), and no significantly difference was recorded between the CC and TT genotype (<i>p</i> = 0.065). <b>c</b>) The TNF-α and IL-1β levels in supernatants were significantly different between individuals harboring the CC or the CT+TT genotypes after LPS stimulation (<i>p</i> = 0.001 and <i>p</i> = 0.011, respectively). * <i>p</i><0.05, ** <i>p</i><0.01 compared with the CC genotype.</p

Demographics and clinical characteristics of all subjects.

<p>AP indicates acute pancreatitis; SIRS indicates systemic inflammatory response syndrome.</p

Effect of the <i>TNFAIP3</i> rs5029924 polymorphisms on transcription activity.

<p>Dual-luciferase activity was assayed in cells transfected with constructs bearing the C allele or the T allele of the rs5029924 <i>TNFAIP3</i> promoter variant. The firefly/<i>Renilla</i> luciferase activity ratio was normalized for transfection efficiency using a control plasmid, pRL-CMV. Results were expressed as fold-increase in firefly/<i>Renilla</i> luciferase activity of the <i>TNFAIP3</i> promoter construct vector as compared with pGL3-Basic. The firefly/<i>Renilla</i> luciferase activity of the C allele-construct was significantly higher than that bearing the T allele (<i>p</i> = 0.026). * <i>p</i><0.05 compared with the T allele.</p

Genotype and allele frequencies of variants in the <i>TNFAIP3</i> promoter in healthy controls and AP patients.

<p>AP indicates acute pancreatitis; SAP indicates severe AP; CI indicates confidence interval; OR indicates odds ratio;</p>a<p>indicates AP patients compare with healthy controls;</p>b<p>indicates SAP patients compare with healthy controls.</p

Anti-PHB autoantibodies induced in IgG4-RD patients.

<p>(A) The prevalence of autoantibodies against human PHB in sera from patients was observed. ELISA was used to detect the reactivity of serum IgG4 against recombinant human PHB protein. The anti-PHB antibodies were detected in 65 of 89 RA patients (73%), 4 of 30 SjS patients (13.3%) and 1 of 70 healthy donors (1.4%). The reactivity of anti-PHB antibodies was significantly higher than HC (***<i>P</i><0.0001). (B) The patients with IgG4-RD were then divided into the following confirmed subtypes: AIP, definite autoimmune pancreatitis (25/34, 73.5%); MD, Mikulicz’s disease (8/15, 53.3%); RPF, retroperitoneal fibrosis (6/11, 54.5%); MIX, affect multiply organs (26/29, 89.7%).</p

Verification of prohibitin.

<p>(A) The cloning, expression and purification of recombinant PHB protein. M, protein markers; lane 1, cell extracts of pET-28a (+)-PHB/BL21 after IPTG induction for 6 hour at 37°C; lane 2, cell extracts of pET-28a (+)-PHB/BL21 before IPTG induction; lane 3, cell extracts of pET-28a (+)-BL21 after IPTG induction. lane 4, cell extracts of BL21 after IPTG induction. (B) Western blot using purified PHB protein showed that only the sera from patients with IgG4-RD (lane 1) rather than HC (lane 2) contain antibodies against a 30 kDa cellular protein. (C) The expressed protein was purified and further identified by MS, which revealed its identity as PHB. (D) PHB protein was also identified in immunoprecipitates; lane 1, supernatant of immunoprecipitation; lane 2, immunoprecipitates; lane 3, control sample (the purified rhPHB). (E) The protein band on lane 2 was excised and identified by MALDI-TOF/TOF MS, which again revealed its identity as PHB.</p

Immunofluorescence analysis.

<p>(A-D) Immunofluorescence was performed on HT-29 by confocal laser microscopy, then compared with other cells including EA.hy926, HEK 293 and HepG2. Total cell fluorescence was analyzed by Image J software and significant differences were found between HT-29 and three other cell lines (<i>p</i><0.0001), indicating positive reactions in HT-29 cells with IgG4-RD sera. (E-F) Control samples including SjS and HC were then tested on HT-29 cells, and the sera of patients with SjS were found to have a weaker specific reaction and no positive signal on HC.</p