Nankai University

About: Nankai University is a education organization based out in Tianjin, China. It is known for research contribution in the topics: Catalysis & Adsorption. The organization has 42964 authors who have published 51866 publications receiving 1127896 citations. The organization is also known as: Nánkāi Dàxué.

Narrowly Dispersed Hydrophilic Molecularly Imprinted Polymer Nanoparticles for Efficient Molecular Recognition in Real Aqueous Samples Including River Water, Milk, and Bovine Serum

Abstract: Molecular imprinting has proven to be a versatile approach to the preparation of synthetic receptors with tailor-made recognition sites. The ultimate goal of molecular imprinting is to generate molecularly imprinted polymers (MIPs) with affinity and specificity approaching those of the biological receptors so that they can eventually replace such biological entities in real applications. However, previously developed MIPs that target small organic molecules are normally only compatible with organic solvents, and they mostly fail to show specific template binding in aqueous solutions (whereas peptideor protein-imprinted polymers are intrinsically water-compatible), which significantly limits their practical application in such areas as molecularly imprinted sorbent assays and biomimetic sensors. Despite some progress made in the development of MIPs applicable for analyte detection in relatively simple aqueous media, such as pure water, surfactant-containing water, aqueous buffer solutions (mostly containing an organic solvent), and beer or solutions that mimic alcoholic beverages, the design of MIPs directly capable of specifically recognizing the targeted small organic molecules in real biological samples remains a formidable challenge owing to the complex nature of the sample matrices. Herein, we report the efficient synthesis of narrowly dispersed hydrophilic MIP nanoparticles with excellent specific molecular-recognition ability in real aqueous solutions, including river water and biological samples (both diluted and undiluted milk and bovine serum). Reversible addition–fragmentation chain-transfer (RAFT) precipitation polymerization (RAFTPP) mediated by hydrophilic macromolecular chain-transfer agents (macro-CTAs) provided for the first time narrowly dispersed highly cross-linked MIP (or polymer) nanoparticles with surface-grafted hydrophilic polymer brushes in a facile one-pot approach (Figure 1). The hydrophilic polymer brushes on the MIP nanoparticles not only significantly improved their surface hydrophilicity and led to their water compatibility, but they also acted as a protective layer to prevent proteins in the biological samples from accumulating on the nanoparticle surface and blocking the imprinting sites and thus enabled the MIP nanoparticles to function properly in such complex matrices. Although studies on the use of MIPs in biological media for specific molecular recognition have been disclosed, either diluted biological solutions (containing 40 vol% of a mixture of ethanol/water (1:1 v/v) and a phosphate buffer) were used or the targeted molecule was a highly water soluble 26 amino acid peptide (i.e., the bee toxin melittin). In this context, there have been many reports on the MIP-based solid-phase extraction of target analytes in real matrices; however, the selectivity of the MIPs in this case is controlled by the choice of solvents in the extraction procedure. The direct use of MIPs in real matrices is more difficult, as the conditions used are mainly fixed by the nature of the sample. To our knowledge, we report herein the first successful example of the synthesis of MIP nanoparticles that can be used directly in undiluted biological samples for the efficient specific recognition of small organic molecules. This finding is a major breakthrough for molecular-imprinting technology, since it opens the door to the facile preparation of nanoscale MIPs (with good dispersion and outstanding performance in real aqueous samples) that are very attractive synthetic substitutes for biological receptors in bioanalytical applications and many other fields. Figure 1. Preparation and characterization of MIP nanoparticles. a) Chemical structures of the RAFT agents used: hydrophilic macroCTAs and CDB. b) Schematic protocol for the one-pot preparation by RAFTPP of MIP nanoparticles compatible with real aqueous solutions. c) Characterization of MIP nanoparticles (Mn,NMR of PHEMA brushes: 4800) by SEM and DLS.

Graphene Plasmonic Metasurfaces to Steer Infrared Light.

Abstract: Metasurfaces utilizing engineered metallic nanostructures have recently emerged as an important means to manipulate the propagation of light waves in a prescribed manner. However, conventional metallic metasurfaces mainly efficiently work in the visible and near-infrared regime, and lack sufficient tunability. In this work, combining the pronounced plasmonic resonance of patterned graphene structures with a subwavelength-thick optical cavity, we propose and demonstrate novel graphene metasurfaces that manifest the potential to dynamically control the phase and amplitude of infrared light with very high efficiency. It is shown that the phase of the infrared light reflected from a simple graphene ribbon metasurface can span over almost the entire 2π range by changing the width of the graphene ribbons, while the amplitude of the reflection can be maintained at high values without significant variations. We successfully realize anomalous reflection, reflective focusing lenses, and non-diffracting Airy beams based on graphene metasurfaces. Our results open up a new paradigm of highly integrated photonic platforms for dynamic beam shaping and adaptive optics in the crucial infrared wavelength range.

Recent advances in microbial fuel cells (MFCs) and microbial electrolysis cells (MECs) for wastewater treatment, bioenergy and bioproducts

Abstract: Bioenergy is a renewable energy that plays an indispensable role in meeting today's ever increasing energy needs. Unlike biofuels, microbial fuel cells (MFCs) convert energy harvested from redox reactions directly into bioelectricity. MFCs can utilize low-grade organic carbons (fuels) in waste streams. The oxidation of the fuel molecules requires biofilm catalysis. In recent years, MFCs have also been used in the electrolysis mode to produce bioproducts in laboratory tests. MFCs research has intensified in the past decade and the maximum MFCs power density output has been increased greatly and many types of waste streams have been tested. However, new breakthroughs are needed for MFCs to be practical in wastewater treatment and power generation beyond powering small sensor devices. To reduce capital and operational costs, simple and robust membrane-less MFCs reactors are desired, but these reactors require highly efficient biofilms. Newly discovered conductive cell aggregates, improved electron transport through hyperpilation via mutation or genetic recombination and other advances in biofilm engineering present opportunities. This review is an update on the recent advances on MFCs designs and operations. © 2012 Society of Chemical Industry

Synthesis and fungicidal activity against Rhizoctonia solani of 2-alkyl (Alkylthio)-5-pyrazolyl-1,3,4-oxadiazoles (Thiadiazoles).

Abstract: Some series of 2-alkyl (alkythio)-5-((4-chloro)-3-ethyl-1-methyl-1H-pyrazole-5-yl)-1,3, 4-oxadiazoles (thiadiazoles) were prepared as potential fungicides. Their fungicidal activity was evaluated against rice sheath blight, which is a major disease of rice in China. Structure-activity relationships for the screened compounds were evaluated and discussed. It was found that 5-(4-chloro-3-ethyl-1-methyl-1H-pyrazole-5-yl)-1,3, 4-thiadiazole-2-thione has the higher fungicidal activity.

Targeting mycobacterium protein tyrosine phosphatase B for antituberculosis agents

Abstract: Protein tyrosine phosphatases are often exploited and subverted by pathogenic bacteria to cause human diseases. The tyrosine phosphatase mPTPB from Mycobacterium tuberculosis is an essential virulence factor that is secreted by the bacterium into the cytoplasm of macrophages, where it mediates mycobacterial survival in the host. Consequently, there is considerable interest in understanding the mechanism by which mPTPB evades the host immune responses, and in developing potent and selective mPTPB inhibitors as unique antituberculosis (antiTB) agents. We uncovered that mPTPB subverts the innate immune responses by blocking the ERK1/2 and p38 mediated IL-6 production and promoting host cell survival by activating the Akt pathway. We identified a potent and selective mPTPB inhibitor I-A09 with highly efficacious cellular activity, from a combinatorial library of bidentate benzofuran salicylic acid derivatives assembled by click chemistry. We demonstrated that inhibition of mPTPB with I-A09 in macrophages reverses the altered host immune responses induced by the bacterial phosphatase and prevents TB growth in host cells. The results provide the necessary proof-of-principle data to support the notion that specific inhibitors of the mPTPB may serve as effective antiTB therapeutics.