Chemisorption assembly of Au nanorods on mercaptosilanized glass substrate for label-free nanoplasmon biochip

The fabrication of a localized surface plasmon resonance nanosensor in a chip based format that utilizes Au nanorods (GNRs) as the optical transducer were systematically studied. (3-mercaptopropyl)trimethoxysilane (MPTMS) modified glass substrate offers GNR deposition with maximal sensitivity to local refractive index changes, which subsequently results in better optical recognition of receptor–analyte binding. Kinetics governing the mass transport and chemisorption of nanorods from bulk to solid surface can be dynamically controlled in a predictable fashion. We demonstrate that slight aggregation induced by a low ionic strength (5 mM NaCl) can facilitate the nanorod assembly to result in a dense, well-distributed surface monolayer. In high ionic media (e.g. 40–80 mM), anions present electrostatically bind with the positively charged cetyltrimethylammonium bromide (CTAB) surrounding nanorod surfaces, thereby leading to instability with heavy aggregation in solution. However, once chemically bound on silanized substrates, the nanorods exhibit excellent stability in physiological buffer where high amount of ionic species are present. The fundamental study is followed by demonstration of a practical application of the fabricated biochip in label-free detection based on GNR wavelength shift of the longitudinal palsmon maxima as the optical signature of human IgG model detection.     

Synthesis and Self‐Assembly of Bolaamphiphiles Based on β‐Amino Acids or an Alcohol

The synthesis of bolaamphiphiles from unusual β‐amino acids or an alcohol and C₁₂ or C₂₀ spacers is described. Unusual β‐amino acids such as a sugar amino acid, an AZT‐derived amino acid, a norbornene amino acid, and an AZT‐derived amino alcohol were coupled with spacers under standard conditions to get the novel bolaamphiphiles 5 – 8 (Scheme 1), 12 and 13 (Scheme 2), and 17 and 20 (Scheme 3). Some of these compounds, on precipitation from MeOH/H₂O, self‐assembled into organized molecular structures.     

From Zero‐dimensional to One‐dimensional: Use of Metal‐­Ligand Affinity in Supramolecular Assembly

The self‐assembly of 4 ‐ MTPP [ 4 ‐ MTPP = 2‐(methylthio)‐4‐(pyridin‐4‐yl)pyrimidine] with Cu(NO₃)₂ and AgNO₃ was structurally investigated. For Cu(NO₃)₂, a discrete mononuclear Cu^II coordination compound, [Cu( 4 ‐ MTPP )₂(NO₃)₂] ( 1 ), resulted that is exclusively based on Cu–N coordination. For AgNO₃, a unique one‐dimensional double‐chain structure ( 2 ) was obtained with the Ag–N distances varying from 2.181(9) to 2.223(9) Å, and the average Ag–S distance being 2.98 Å. Compared to zero‐dimensional 1 , the extension to one‐dimensional 2 is considered to result from the specific affinity between Ag⁺ and the ligand 4 ‐ MTPP that is attributed to the strong coordinating tendency of silver for aromatic nitrogen and thioether sulfur atoms.     

Biosensors based on gold nanoelectrode ensembles and screen printed electrodes

Gold nanowires were synthesized within polycarbonate membranes according to an electroless deposition method, obtaining nanoelectrode ensembles (NEEs) with special electrochemical features. NEEs were coupled with home-produced carbon graphite screen printed electrodes and the electrochemical properties of the original nanoelectrode ensemble on screen printed substrate (NEE/SPS) assembly has been tested for sensors application. Glucose oxidase has been used as model enzyme in order to verify the feasibility of disposable gold NEE/SPS biosensors. Finally, different immobilisation and electrochemical deposition techniques based on either self assembled monolayers of cysteamine (CYS) or amino-propyl-triethoxysilane (APTES) and conductive polyaniline (PANI) molecular wires were used. Spatial patterning of the enzyme on the polycarbonate surface and of PANI wires on gold nanoelectrodes was obtained. Possible direct electron transfer between the enzyme and the PANI modified gold nanoelectrodes has been evaluated.     

Preparation of superhydrophobic composite paper mulching film

To study the influence of different concentrations of zinc oxide (ZnO)/silicon dioxide (SiO₂) composite coating on hydrophobic property and mechanical stability of paper mulch film, three kinds of ZnO/SiO₂ composite coating paper mulch films (2%, 4%, 6%) with different coating substance contents were prepared by brush coating method. Through particle size analysis, contact angle, rolling angle and mechanical stability test, combined with scanning electron microscope, three-dimensional morphology and roughness measuring instrument, the optimal concentration of ZnO/SiO₂ composite coated paper mulch film was screened out. Through acid-base salt corrosion test, silver mirror reaction and surface self-cleaning, the optimal concentration of composite coated paper mulch film was compared with the original paper mulch film to prove its excellent chemical stability and hydrophobicity. The results show that the paper mulch film with 4% coating material has excellent hydrophobicity and mechanical stability, can effectively reduce the surface roughness of paper mulch film, and has remarkable effects in resisting acid, alkali and salt and self-cleaning.     

Preparation of Polyaniline/Au0 Nanocomposites Modified Electrode and Application for Hydrazine Detection

The PANI/Au₀ nanocomposite films were successfully prepared on glassy carbon electrode (GCE) using a simple alternate adsorption of water soluble polyaniline (PANI) and . The growth of the films was monitored by UV? Vis spectroscopy and cyclic voltammetry. was in‐situ reduced in the film due to the redox interaction between PANI and , without extra reductant. The ultrafine Au nanoparticles with the size of 2–4 nm were observed by transmission electron spectroscopy. The existence of zero‐valence Au nanocrystals (Au₀) was confirmed by X‐ray photoelectron spectroscopy, X‐ray Diffraction and FTIR. PANI in the nano‐structured PANI/Au₀ composite films displayed a good redox activity in neutral pH solution. The as‐obtained PANI/Au₀/GCE presents an excellent electrocatalytic activity to hydrazine oxidation, and the mechanism of hydrazine oxidation was studied. The calibration curve on (PANI/Au₀)₅/GCE was obtained in the concentration range of 0.01–6 mM with the detection limit of 1 µM (S/N>3). The modified electrode has a great potential for hydrazine sensor application due to its ease of fabrication, good reproducibility and high stability.     

Point‐of‐Care Amperometric Testing of Diabetic Marker (HbA1c) Using Specific Electroactive Antibodies

Specific immune detection of glycated hemoglobin is still a great challenge owing to the small epitopic difference between Hemoglobin (Hb) and HbA1c. We report a new electrochemical immunoassay format for point of care testing of HbA1c. A conducting self‐assembled monolayer of mercaptophenyl boronic acid (MPBA) was used as a capture layer for binding of glycated proteins and ferrocene tagged anti‐HbA1c antibody (FcAb) as a tracer molecule on a gold screen printed electrode. Validation of the new HbA1c assay was carried out using 6 clinical samples with known HPLC values and a correlation coefficient of 98 % was observed.     

pH-Sensitive Wettability Induced by Topologicaland Chemical Transition on the Self AssembledSurface of Block Copolymer简

pH-sensitive wettability of polystyrene-b-poly（4-vinylpyridine） （PS-b-P4VP） self assembled films, exhibiting superoleophobicity under water and hydrophilicity at low pH value, and oleophobicity under water and hydrophobicity at neutral condition, has been realized. The wettability properties resulted from the surface topological and chemical transition, which were confirmed by in situ AFM measurements under water at different pH. At low pH, P4VP chains, which were confined in the hexagonal-packed nanodomains, got protonated into a swollen state, while at high pH, P4VP chains were deprotonated into a collapsed state. The reversible protonation/deprotonation procedure on the molecular scale leads to surface topological and chemical transition, thereby pH-sensitive wettability.     

A Novel Self‐assembled Nickel(II)‐Cerium(III) Heterotetranuclear Dimer Constructed from N2O2‐type Bisoxime and Terephthalic Acid: Synthesis,Structure, and Photophysical Properties

By self‐assembly of a Salamo‐type ligand H₂L [H₂L = 1,2‐bis(3‐methoxysalicylideneaminooxy)ethane] with Ni(OAc)₂ · 4H₂O, Ce(NO₃)₃ · 6H₂O, and H₂bdc (H₂bdc = terephthalic acid), a novel Ni^II‐Ce^III heterometallic complex, [{Ni(L)Ce(NO₃)₂(CH₃OH)(DMF)}₂(bdc)], was obtained. Two crystallographically equivalent [Ni(L)Ce(NO₃)₂(CH₃OH)(DMF)] moieties lie in the inversion center, and are linked by one bdc^2– ligand leading to a heterotetranuclear dimer, in which the carboxylato group bridges the Ni^II and Ce^III atoms. Moreover, the photophysical properties of the Ni^II‐Ce^III complex were studied.     

槲皮素在溶液中的化学交换和自扩散运动

通过对溶于氘代二甲亚砜（DMSO d6）中的槲皮素的自扩散系数和槲皮素羟基质子与溶剂中水质子之间的交换速率常数的NMR测量,研究了交换速率常数与扩散系数随温度和含水量的变化情况.结果表明,化学交换与扩散系数是相互独立的两种运动,活泼质子的化学交换并不需要通过槲皮素分子的扩散而进行.但是活泼质子的表观扩散系数却显著地受化学交换的影响.当以活泼质子为对象时,这种影响需要引起足够的重视.