Competitive Effect in The Growth of Pd–Au–Pd Segmental Nanorods

Growing other metals on decahedral nanoparticles (NPs) is an important approach to synthesize segmental multimetallic nanorods (NRs) with a penta-fold twinned (PFT) structure. So far, only limited such structures, e.g., Ag–Au–Ag and Pd–Ag or Pd–Cu PFT NRs, can be realized by this approach. To explore more multimetallic structures is important for both synthesizing more multimetallic NRs with a PFT structure for various potential applications and understanding their formation mechanism. Herein, we report the synthesis of Pd–Au–Pd segmental NRs with controlled sizes by growing Pd atoms on Au decahedra using hexa­decyl­trimethyl­ammonium bromide (CTAB) and I^– as growth modifiers. The growth mechanism of Pd–Au–Pd PFT NRs was investigated systematically. It was figured out that the growth of Pd–Au–Pd NRs was determined by two competitions (CTAB competes with I^– in complexing with H₂PdCl₄ and in adsorbing on Au decahedra). It is also demonstrated that Au–Pd–Au NRs had higher activity than commercial Pd/C catalyst in electrocatalytic oxidization of formic acid

Expression of <i>β</i>-Tubulin.

<p>(A) Validation of pCold I-<i>β-tubulin</i> vector by PCR and Bam HI/Sal I enzyme digestion. ~1300 bp products were amplified by PCR or cleaved from recombinant vector. (B) SDS-PAGE of proteins expressed in <i>Escherichia coli</i> Rosetta. Recombinant <i>β-</i>Tubulin protein was induced to express at 37°C and 16°C. pCold I vector transformed <i>E</i>. <i>coli</i> Rosetta were induced for expression at 37°C as a control. (C) Immunoblot for <i>β-</i>Tubulin in total protein of <i>Nosema bombycis</i> mature spore. The antibody recognized a 50 kDa band which was consistent with prediction.</p

Immunofluorescence localization of NbSWP12 in the intracellular parasite.

<p><i>N</i>. <i>bombycis</i>-infected BmE cells were incubated with anti-NbSWP12 (A2-1, A2-2) coupled with Alexa Fluo 488 labeled secondary antibody and anti-<i>β-</i>Tubulin (A3-1, A3-2) coupled with Alexa Fluo 594 labeled secondary antibody. Red fluorescence of <i>β-</i>Tubulin indicated the proliferative phase of <i>N</i>. <i>bombycis</i>. Blue fluorescence of Calcofluor White M2R-stained chitin displayed the sporogonic phase of <i>N</i>. <i>bombycis</i>. Overlapping red and green signals (A1-1) indicated that NbSWP12 was partly co-localized with microtubules in the meront. Overlapping green and blue signals (A1-2) in some early sporonts indicated that NbSWP12 was gradually transferred to the spore wall. (Bars = 5 μm).</p

Labeling the merogony phase (red) and the sporogony phase (blue) of microsporidian in <i>N</i>. <i>bombycis</i>-infected BmE culture cells.

<p>Based on the absence or presence of chitin, parasites in proliferative phase were labeled by <i>β-</i>Tubulin using an indirect immunofluorescence assay, while cells in sporogonic phase were marked by chitin using 0.1 μg/mL Calcofluor White M2R. <i>N</i>. <i>bombycis</i> infected culture cells were incubated with negative serum used as a negative control. (Bars = 10 μm).</p

Labeling the two different intracellular phase of microsporidian <i>N</i>. <i>bombycis</i> by immunofluorescence histochemistry in intestinal tissue slices.

<p><i>β-</i>Tubulin antibody coupled with Alexa Fluo 488 (green) labeled secondary antibody were used to label the proliferative phase of microsporidia. Calcofluor White M2R (blue) were used to stain the chitin layer of sporogony phase. (Bars = 10 μm)</p

Location of <i>β</i>-Tubulin in intracellular microsporidian <i>N</i>. <i>bombycis</i>.

<p>Images were taken by laser scanning confocal microscopy using filter sets for Alexa fluo 488 labeling <i>β-</i>Tubulin proteins and DAPI staining nucleus. Immunofluorescence assay with <i>β-</i>Tubulin antiserum demonstrated that the membrane and cell plasma location contained in <i>N</i>. <i>bombycis</i> cells in the proliferative phase. (Bars = 5 μm)</p