In situ assembly, regeneration and plasmonic immunosensing of a Au nanorod monolayer in a closed-surface flow channel

Herein, a simple and effective approach is reported for the in situ generation and regeneration of a Au nanorod (AuNR) monolayer inside a glass/silica-based, closed-surface flow channel. The density of the AuNR monolayer in the flow channel can be easily modified by varying the concentration of the AuNR and the cetyltrimethylammonium bromide as well as the incubation time. The fabricated AuNR monolayer in the flow channels was stable under harsh conditions, such as in extreme pH, organic solvents and at a fast flow rate. In addition, the flow channel could be reused by removing the immobilized AuNRs via the injection of diluted aqua regia or potassium iodide; the AuNR monolayer can subsequently be regenerated. The AuNRs in the closed flow channel were further exploited as a label-free detection method for a clinical biomarker, neutrophil gelatinase-associated lipocalin (NGAL), based on single-nanoparticle plasmonic assay. The corresponding limit of detection for NGAL was measured to be 8.5 ng mL(-1) (~340 pM) based on a signal-to-noise ratio of 3. The estimated recovery of NGAL in human serum and urine was higher than 80%, which indicates that this technique could potentially be used for the diagnosis of acute kidney injury.     

Basic characteristics of interference image obtained using spatially phase-modulated mirror array

Single-shot full-field optical coherence tomography (OCT) using spatially phase-modulated reference light has been proposed to achieve a higher sensitivity.16) The reference light can be generated by a spatially phase-modulated mirror array (SPMA). The basic characteristics of an interference image using SPMA have been demonstrated using a superluminescent diode (SLD) with a center wavelength of 840 nm as a popular low-coherence light source. SPMA consisted of a small mirror of 10 × 10 mm² and had a full area of 5 × 5mm². The magnifications in the reference arm were 3, 2, and 1. The corresponding magnifications in the signal arm were 18.1, 12.2, and 5.2. The ratios of the interference area to the full CCD area were 0.68, 0.32, and 0.13. Visibilities and ratios for calculations were measured at 0.38 (54%), 0.19 (28%), and 0.062 (8.2%). The periodical background noise was high owing to interferences with scattered lights from SPMA. From the spectra of signal intensity profiles in the subtracted image between two interference images, it was confirmed that the optical phase in the reference light was spatially and periodically modulated by SPMA.     

Periodic Polypeptides Based on Poly(L-Alanylglycine): Biological Synthesis and Verification of the Structure of A Series of Polymers Containing Tandem —(Alagly)xGlugly— Repeats

The experiments reported herein constitute part of an investigation of the relationship between primary sequence and higher order structure in repetitive polypeptides. Three series of artificial DNAs encoding poly-peptides represented by the general formula + (GlyAla)_nGlyGlu]_m— were constructed and cloned in Escherichia coli.Protein expression was monitored by in-vivo labeling with ³H-glycine. Protein products were isolated from the cell lysates by stepwise acidification in yields of 20–50 mg/L of culture, and fusion fragments derived from the cloning vectors were removed by cyanogen bromide cleavage. Amino acid sequence analysis verified the expected sequences through the first 40–50 N-terminal residues.     

Nuclear Monobromination of Alkyl Phenyl Ethers with NaClO2, NaBr,Mn(acac)3, and Moist Silica Gel in Aprotic Solvent

Nuclear monobromination of aromatic ethers can be achieved with a NaClO₂/NaBr/Mn(acac)₃ catalyst/silica gel system in dichloromethane in regioselective and high-yielding manner under mild conditions.     

Computer-aided measurement of kinetic parameters of electrode reactions of cobalt(III)—ammine complexes at mercury electrodes

A computer-aided technique based on Tast polarography is examined for the determination of kinetic parameters of electrode reactions. It is particularly useful for the investigation of unstable species because of the simple and rapid processing of data. Kinetic parameters of cobalt(III)—ammine complexes at mercury electrodes are given for [Co(NH₃)₆]Cl₃, [Co(H₂O)(NH₃)₅](ClO₄)₃, [Co(NO₃)(NH₃)₅](NO₃)₂ [CoF(NH₃)₅](Cl0₄)₂, [Co(C0₃)(NH₃)₅] NO₃ ,cis-[Co(H₂O)₂(NH₃)₄] (Cl0₄)₃ [Co(CO₃)(NH₃)₄] NO₃ · 0.5H₂0, [Co(ox)(NH₃)₄]Cl · H₂0, and NH₄[Co(ox)₂(NH₃)₂] · H₂O, which are obtained in solutions containing 0.1 M acetate buffer and 0.005% gelatin at 25°C.     

Cellulose propionate/poly(N-vinyl pyrrolidone-co-vinyl acetate) blends: dependence of the miscibility on propionyl DS and copolymer composition

Blend miscibility of cellulose propionate (CP) with synthetic copolymers comprising N-vinyl pyrrolidone (VP) and vinyl acetate (VAc) units was examined, and a data map was constructed as a function of the degree of substitution (DS) of CP and the VP fraction in the copolymer component. Results of differential scanning calorimetry and Fourier transform infrared measurements indicated that the pairing of CP/P(VP-co-VAc) formed a miscible or immiscible blend system according to the balance in effectiveness of the following factors: (1) hydrogen bonding between residual hydroxyls of CP and VP carbonyls of P(VP-co-VAc); (2) steric hindrance of propionyl side-groups to the interaction specified in (1); (3) intramolecular repulsion between the two units constituting the vinyl copolymer; and, additionally, (4) structural affinity between two segmental moieties involving the propionyl group and VAc unit, respectively. The factor 3 inducing intercomponent attraction is responsible for the appearance of a so-called “miscibility window” in the miscibility map, and the factor 4 substantially expands the miscible region whole, wider relative to those in the maps for the corresponding blend series based on cellulose acetate and butyrate. In further refined estimation by dynamic mechanical analysis and T _1ρ ^H quantification in solid-state ¹³C NMR, it was found that the miscible blends of hydrogen-bonding type (using CPs of DS < 2.7) were completely homogeneous on a scale within a few nanometers, whereas the polymer pairs situated in the window region (using CPs of DS > 2.7) formed blends exhibiting a somewhat larger size of heterogeneity (ca. 5–20 nm).     

Polyaniline/Silica Hybrid Composite Gels Prepared by the Sol-Gel Process

The preparation of polyaniline/silica hybrid gel was studied by chemical polymerization of aniline with sodium dodecyl sulfate (SDS) during the sol-gel processing. As a typical procedure, aqueous solutions of SDS, aniline, HCl, and tetramethoxysilane (TMOS) were mixed. Then ammonium peroxodisulfate (APS) in an acidic aqueous solution was added as initiator oxidant into the sol-gel systems at different sol-gel stages: (A) just after mixing (sol), (B) after gelation (wet gel), and (C) after 7 d (dried gel). As for the condition (A), several green areas and several tens of dark green spots with absorption peaks at 343, 422, and 802 nm were seen in the xerogel, indicating that emeraldine salt type polyaniline is aggregated in the silica xerogel. Polymerization of aniline little occurred in the dried gel (C), possibly because APS could not soak the silica pores and/or aniline could not polymerize in the gel. The xerogel from (B) showed a homogeneously green color with peaks at 339, 425, and 769 nm, showing that emeraldine salt type polyaniline can be uniformly dispersed in sol-gel silica.     

A Convenient Biphasic System (Alumina-Dichloromethane) for the Efficient Aromatic Monochlorination of Alkyl Phenyl Ethers with Sodium Chlorite in the Catalytic Presence of Manganese(III) Salt

A combination of sodium chlorite, (salen)manganese(III) catalyst, and chromatographic neutral alumina in dichloromethane can be successfully utilized for the aromatic monochlorination of a variety of alkyl phenyl ethers in excellent to quantitative yields under mild and anhydrous conditions.