Virus-Like Magnetic Heterostructure: an Outstanding Metal-Complex Active Platform Enables High-Efficiency Separation and Catalysis.

Assembled heterostructure systems, as emerging functional materials, have broad applications ranging from enzyme and drug payload to catalysis and purification. However, these require trial- and -error design process and complex experimental environment to generate heterostructure materials. Here, this study describes an easy-to-execute strategy to fabricate magnetic heterostructure as multifunctional delivery system. We utilize first-row transition metal copper and nitroso/amino ligand as modules to assemble around Fe3 O4 magnetic nanoparticles by excessed mild stimuli and fabricate the magnetic heterostructure materials (Fe3 O4 @ TACN NPs (tetraamminecopper (II) nitrate)). Notably, the Fe3 O4 @ TACN NPs present with cat's-whisker structure containing ligand and metal center. The nitroso-group ligands exhibit strong binding affinity to heme-structure enzyme, ensuring effective capture and isolate of cytochrome C (Cyt-c), resulting in their excellent isolation property. The copper complex-powered magnetic heterostructure materials can effectively isolation Cyt-c from complex biological sample (pork heart). Importantly, the Fe3 O4 @ TACN NPs coordinated with heme-structure, induced methionine 80 (Met80) disassociates from heme prosthetic group, and contributed to peroxidase-like (POD-like) activities increasing. These results exhibit that copper complex-powered magnetic heterostructure materials can not only satisfy the Cyt-c isolation and immobilization in an alkaline medium, but also be of the potential for improving the immobilization enzyme reactor performance.

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.

Metal-assisted core-shell plasmonic nanoparticles for small molecule biothiol analysis and enantioselective recognition.

Cysteine (Cys) enantiomorphs, important small-molecule biothiols, participate in various antioxidative, flavoring, and poison-removing processes in the food industry. Current cysteine enantiomorph analysis methods require effective strategies for distinguishing them due to their similar structures and reactivity. Herein, we present a metal ion-assisted enantiomorph-selective surface-enhanced Raman scattering (SERS) biosensor based on an amphiphilic polymer matrix (APM), which can promote cysteine enantiomorph (L/D-Cys) identification. The highly selective molecular orientation is perhaps caused by the intermolecular hydrogen bonding with chiral isomers (metal centers). The experimental results show that the SERS biosensor has a sensitivity-distincting factor toward L-Cys and D-Cys. The linear range is from 1 mmol L-1 to 1 nmol L-1, along with a low limit of detection of 0.77 pmol L-1. Moreover, the fabricated Cu-APM biosensor exhibits remarkable stability and high repeatability, with an RSD of 3.7%. Real food cysteine enantiomorph detection was performed with L-Cys-containing samples of onion, cauliflower, garlic, and apple, and D-Cys-containing samples of vinegar, black garlic, cheese, and beer. The results show that the Cu-APM biosensor can be utilized as a powerful tool for real-time determination of Cys enantiomorphs in different food samples. Thus, the metal-ion-assisted enantiomorph-selective SERS biosensor has potential as an adaptable tool for enantiomorph detection and food sample analysis.

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.

A simple colorimetric device for rapid detection of Hg2+ in water.

A 'turn-on' fluorescent colorimetric device for Hg(2+) sensing was built using a dual light-emitting diode system. Fluorescence generated from a rhodamine derivative (RHD), an indicator for Hg(2+) sensing, was combined with a background red light, and the complex light was captured by a commercial charge coupled device camera or by the naked eye.

Nanoenzyme Reactor-Based Oxidation-Induced Reaction for Quantitative SERS Analysis of Food Antiseptics.

Nanoenzyme reactors based on shell-isolated colloidal plasmonic nanomaterials are well-established and widely applied in catalysis and surface-enhanced Raman scattering (SERS) sensing. In this study, a "double wing with one body" strategy was developed to establish a reduced food antiseptic sensing method using shell-isolated colloidal plasmonic nanomaterials. Gold nano particles (Au NPs) were used to synthesize the colloidal plasmonic nanomaterials, which was achieved by attaching ferrous ions (Fe2+), ferric ions (Fe3+), nitroso (NO-) group, cyanogen (CN-) group, and dopamine (DA) via coordinative interactions. The oxidation-induced reaction was utilized to generate •OH following the Fe2+-mediated Fenton reaction with the shell-isolated colloidal plasmonic nanomaterials. The •OH generated in the cascade reactor had a high oxidative capacity toward acid preservatives. Importantly, with the introduction of the signal molecule DA, the cascade reactor exhibited also induced a Raman signal change by reaction with the oxidation product (malondialdehyde) which improved the sensitivity of the analysis. In addition, the stable shell-isolated structure was effective in realizing a reproducible and quantitative SERS analysis method, which overcomes previous limitations and could extend the use of nanoenzymes to various complex sensing applications.

A dissolved oxygen sensor based on composite fluorinated xerogel doped with platinum porphyrin dye.

A new functional fluorinated material taking n-propyltrimethoxysilicane (n-propyl-TriMOS) and 3,3,3-trifluoropropyltrimethoxysilicane (TFP-TriMOS) as precursors was applied to construct a novel dissolved oxygen sensing film. The sensing film was fabricated by dip-coating the functional fluorinated material-doped [meso-tetrakis(pentafluorophenyl) porphyinato] platinum(II) (PtF(20) TPP) onto a glass slide. The oxygen sensing film exhibited a good linear relationship, fast response time, long stability and high sensitivity to dissolved oxygen. In the developed optical oxygen sensor, an LED and a photodiode were composed to construct a back-detection optical system not needing an optical fiber based on fluorescence intensity detection. The smart optical oxygen sensor based on the PtF(20) TPP fluorescence quenching possesses the advantages of portability and low cost and can be applied to the dissolved oxygen in situ monitoring in seawater.

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.

[Determination of fatty alkyl dimethyl tertiary amines by gas chromatography in the synthesis of cationic surfactants].

A method to determine fatty alkyl dimethyl tertiary amines by gas chromatography (GC) was set up using HP-INNOWax capillary column, hydrogen flame ionization detector (FID) and temperature programming. The linearities were all excellent in the range of 0.005-1.0 g/L with the correlation coefficients being above 0.9996. The limits of detection (LODs, S/N=3) of the method were between 0.001 g/L and 0.002 g/L, and the limits of quantification (LOQs, S/N=10) were between 0.003 g/L and 0.005 g/L. The recoveries ranged between 90% and 130% with relative standard deviations of 1.3%-6.9% (n=6). The proposed method has the advantages of wide linear range, higher recovery, and selectivity, which was suitable for the quantitative analysis of fatty alkyl dimethyl tertiary amines and monitoring process control in industrial production. The method was faster and more accurate than titration, and also precluded the need for pre-column derivatization and determination by liquid chromatography-tandem mass spectrometry.

[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.

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.

A novel approach based on ferricyanide-mediator immobilized in an ion-exchangeable biosensing film for the determination of biochemical oxygen demand.

A novel biochemical oxygen demand (BOD) sensing method employing a ferricyanide (FC) mediator immobilized in an ion-exchangeable polysiloxane was developed. The ion-exchangeable polysiloxane containing alkylammonium groups (PAPS-Cl) was synthesized by sol-gel reaction of 3-(aminopropyl)trimethoxysilane (APTMOS) catalyzed by hydrochloric acid. FC was combined in PAPS-Cl via ion-association and the product was labeled as PAPS-FC, which was employed for a modified glassy carbon electrode. The apparent diffusion coefficient (D(app)) of FC on the modified glassy carbon electrode was 9.8x10(-11) cm(2) s(-1). In a three-electrode system, a linear relationship between the anodic current responses and glucose/glutamate (GGA) concentration was obtained up to 40 mg O2 L(-1) (r=0.994) when the reaction mixture was incubated for 30 min. Single sensor and piece-to-piece reproducibility were less than 3.8 and 7.7%, respectively. The effects of dissolved oxygen, pH, temperature and co-existing substances on the BOD responses were studied. The sensor responses to nine pure organic substances were compared with the conventional BOD5 method and other biosensor methods. Detection results of seawater samples were compared with those obtained from the BOD5 method and showed a good correlation (r=0.988).