Anti-galvanic reaction induced interfacial engineering to reconstruct ternary colloid satellite platform for exceptionally high-performance redox-responsive sensor.

The anti-galvanic reaction (AGR), which is a classic galvanic reaction (GR) with an opposite effect, is a unique phenomenon associated with the quantum size effect. This reaction involves the interaction between metal ions and nanoclusters, offering opportunities to create well-defined nanomaterials and diverse reductive behavior. In hence, in our work, we utilize the AGR to generate gold (Au), silver (Ag), and copper (Cu) satellite nanoclusters which have superior electromagnetic properties for Surface-enhanced Raman spectroscopy (SERS) sensor. As the AGR process, weak oxidant Cu2+ is selected to etched matrix Au@Ag NPs, reduced to Cu(0) or Cu(1) and generated the ultrasmall metal nanoparticles (Ag). To facilitate the AGR, we introduce the nucleophilic thiol 4-mercaptopyridine (4-Mpy) to bridge the metal ions or ultrasmall metal nanoparticles to reconstruct the satellite nanoclusters. These experimental displays that the AGR based biosensors has highly sensitivity for reductive molecule glucose. The liner ranges from 1 mmol/L to 1 nmol/L and alongs with a correlation coefficient and detection limit (LOD) of 0.999 and 0.14 nmol/L. Moreover, the AGR based biosensors exhibits remarkable stability and high repeatability with RSD 1.3 %. The food samples are tested to further investigate the accuracy and reliability of the method, which provides a novel and effective SERS method for the reduction molecules detection.

Design of competition nanoreactor with shell-isolated colloidal plasmonic nanomaterials for quantitative sensor platform.

Shell-isolated colloid plasmonic nanomaterials-based nanoreactor is a well-established platform widely applied in catalyst or Surface Enhanced Raman Scattering (SERS) sensors. The potentials versatility of nanoreactor platform is mainly implemented by the well-defined and tailorable structure of colloid plasmonic nanomaterials. Currently, a competitive conjugative-mediated nanoreactor is introduced to determine glucose with SERS. Glucose-conjugating nanoreactor, as convertors of the sensors, are constructed by coordinated deposition colloidal gold nanoparticles with sodium nitroprusside framework (Au@SNF) and covalently bonded 4-mercaptopyridine (4-Mpy) with self-assembly strategy. The nanoreactor contained the signal-amplifier Au@SNF NPs, conjugative-mediated signal receiver 4-Mpy, and signal internal standard molecular CN-. In addition to well-defined morphology and functionality, conjugative-mediated and internal standards method are also employed to benefit the nanoreactor. The two-parameter strategy significantly improves the signal indication and correction. Using this proposed platform, the competitive-mediated nanoreactor provides a quantitative SERS detection of glucose, and extends the applicability of SERS in more complicated and reproducibility analysis. Meanwhile, the nanoreactor based sensors also exhibited better properties to detect glucose in various food samples and bio-samples which provided strongly appliance for glucose sensors.

Highly crosslinking core-shell magnetic nanocomposites based catalyst and heat free polymerization for isolation of glycoprotein.

New approaches for the engineering of well-defined, pore modality, and multi-chemical functionality nanocomposites are crucial to generate the next generation of functional materials with recoverable and easy preparation properties. Here, a catalyst and heat free polymerization reaction is exploited and fabricated zwitterionic system around magnetic nanoparticles. N-aminoethyl piperazine propane sulfonate (AEPPS) and dopamine (DA) are introduced as the zwitterionic system, which provided abundant zwitterionic groups (NH2, SO3-, N+) and strong adhesion and various oxidation state properties. And that, the zwitterionic engineering will assemble between AEPPS and DA whereby Schiff base formation or Michael type addition. Whereafter, a series of sophisticated array of microscopic, spectroscopic, and structure techniques verify the formation of highly crosslinking internal zwitterionic architectures, well-defined core-shell structure, and better porosity. The zwitterionic structure-function relationships and striking porous structure are explored in a multi-interaction adsorption assay. The adsorption capacity of the magnetic nanocomposites was 1065.8 mg/g. And that, the system exhibited with hydrophilic-hydrophobic activity towards glycoprotein and better performance to bioactive protein (Ig-G) isolation form human whole blood sample. The synergistic enhancement interaction in hydrophilic target enrichment, easy preparation, and soft substrate properties of the AEPPS-DA zwitterionic materials make them intriguing candidates for sustainable biomedical loading and chromatographic separation.

Construction of Metal Hydrate-Based Amorphous Magnetic Nanosheets for Enhanced Protein Enrichment and Immobilization.

Inspired by the hierarchical fabrication technique, many self-assembly procedures have improved the construction of nanomaterials with unique physicochemical characteristics and multiple functions. The generation of multiple complexes is always accompanied by hierarchical structures and intriguing properties that are distinct from their individual segments. An interesting composite is amorphous magnetic Zn-Zr phosphate hydrated nanosheets (Zn-Zr APHNs), generated using templated synthesis and nanoparticle codeposition. The special porous structure of this construct, together with the abundance of metal ions and hydrate present, endows it with many interaction sites for proteins, provides high loading efficiency, and enhances bioactivity. Then, a series of proteins, including enzymes, was immobilized by the Zn-Zr APHNs by multiple interactions, high ionization, and larger surface of the nanosheets. In this study, novel methods for the enrichment of bioactive proteins while retaining the activity of protein payloads are presented. As a verification method, it is indicated that the Zn-Zr APHNs can deliver enzyme proteins (i.e., Cyt-c) to increase the catalytic activity with their biological function and structural integrity, resulting in a highly increased activity to free proteins.

Spectroscopic characterization of tetracationic porphyrins and their noncovalent functionalization with graphene.

In this study, the noncovalent functionalization of graphene with cationic porphyrins in an aqueous medium was investigated using UV-vis and fluorescence approaches. To characterize the interaction between graphene and cationic porphyrins, 5,10,15,20-tetra (4-pyridyl)-21H,23H-porphine, 5,10,15,20-tetrakis (1-methyl-4-pyridinio) porphyrin tetra (p-toluenesulfonate) and 5,10,15,20-tetrakis (4-trimethylammoniophenyl) porphyrin tetra (p-toluenesulfonate) porphyrin were chosen as reagents. The intermolecular interactions were found to occur immediately after mixing the cationic porphyrins with graphene. The absorption spectra of the cationic porphyrins after mixing with graphene showed distinct red shifts of the Soret and Q-bands compared to free cationic porphyrins indicating that interactions occur between the cationic porphyrins and graphene. A strong fluorescence quenching of the cationic porphyrins in the presence of graphene indicated that efficient electron or energy transfer occurred from the excited state of the cationic porphyrins to graphene. Cationic porphyrins were immobilized on the surface of graphene through electrostatic and π-π stacking interactions, and the chemical shape of graphene played an important role in the intermolecular interactions and the red shift extent of cationic porphyrins is mostly dependent on the functional groups and charges of the graphene surface. The results show that less functional groups on the graphene's surface and edge would lead to stronger π-π stacking interactions between graphene and cationic porphyrins.

[Study on UV-Vis absorption spectra of tetra-azo-aromaticoxy substituted metallophthalocyanines].

UV-Vis absorption spectras of six series (18 kinds) of tetra- azo-aromaticoxy substituted metallophthalocyanines (R4 PcM, R = 4-pyridyloxy, 8-quinolinoxy, 2-methyl-8-quinolinoxy; substitution position: a position and beta position; M = Ni (II), Cu(II), Zn(II)) were measured. The effects of central mentals, the kinds and the positions of substitution groups, and solvents on the metallophthalocyanines' lamdamax in Q-band were discussed. Experimental data show: The lamdamax in Q-band of title complexes is about 680 nm. In contrast with substitution-free metallophthalocyanines(669-671 nm), the lamdamax in Q-band of the title complexes with the same central metal exhibits a different red-shift. The effect of substitution group's kinds on lamdamax in Q-band of the title complexes is more obvious in a position than in beta position, and with the same substitution group and central metal, lamdamax in Q-band of alpha position substituted complexes exhibits more obvious red-shift than beta position substituted complexes. The effects of central metal and solvent on lamda,ax in Q-band of the title complexes aren't obvious.