Rapid Diagnosis by Microfluidic Techniques

Pathogenic bacteria in an aqueous or airborne environments usually cause infectious diseases in hospital or among the general public. One critical step in the successful treatment of the pathogen-caused infections is rapid diagnosis by identifying the causative microorganisms, which helps to provide early warning of the diseases. However, current standard identification based on cell culture and traditional molecular biotechniques often depends on costly or time-consuming detection methods and equipments, which are not suitable for point-of-care tests. Microfluidic-based technique has recently drawn lots of attention, due to the advantage that it has the potential of providing a faster, more sensitive, and higher-throughput identification of causative pathogens in an automatic manner by integrating micropumps and valves to control the liquid accurately inside the chips. In this chapter, microfluidic techniques for serodiagnosis of amebiasis, allergy, and rapid analysis of airborne bacteria are described. The microfluidic chips that integrate microcolumns, protein microarray, or a staggered herringbone mixer structure with sample to answer capability have been introduced and shown to be powerful in rapid diagnosis especially in medical fields

Electrochemical fabrication of conducting polymer nanowires in an integrated microfluidic system

In this paper, we introduce a new approach for the in situ electrochemical fabrication of an individually addressable array of conducting polymer nanowires (CPNWs) positioned within an integrated microfluidic device and also demonstrate that such an integrated device can be used as a chemical sensor immediately after its construction

Study on the construction technology of β-alanine synthesizing Escherichia coli based on cellulosome assembly

Introduction: β-Alanine is the only β-amino acid in nature; it is widely used in food additives, medicines, health products, and surfactants. To avoid pollution caused by traditional production methods, the synthesis of β-alanine has been gradually replaced by microbial fermentation and enzyme catalysis, which is a green, mild, and high-yield biosynthesis method.Methods: In this study, we constructed an Escherichia coli recombinant strain for efficient β-alanine production using glucose as the raw material. The microbial synthesis pathway of L-lysine-producing strain, Escherichia coli CGMCC 1.366, was modified using gene editing by knocking out the aspartate kinase gene, lysC. The catalytic efficiency and product synthesis efficiency were improved by assembling key enzymes with cellulosome.Results: By-product accumulation was reduced by blocking the L-lysine production pathway, thereby increasing the yield of β-alanine. In addition, catalytic efficiency was improved by the two-enzyme method to further increase the β-alanine content. The key cellulosome elements, dockerin (docA) and cohesin (cohA), were combined with L-aspartate-α-decarboxylase (bspanD) from Bacillus subtilis and aspartate aminotransferase (aspC) from E.coli to improve the catalytic efficiency and expression level of the enzyme. β-alanine production reached 7.439 mg/L and 25.87 mg/L in the two engineered strains. The β-alanine content reached 755.465 mg/L in a 5 L fermenter.Discussion: The content of β-alanine synthesized by constructed β-alanine engineering strains were 10.47 times and 36.42 times higher than the engineered strain without assembled cellulosomes, respectively. This research lays the foundation for the enzymatic production of β-alanine using a cellulosome multi-enzyme self-assembly system

Multistep Synthesis of a Radiolabeled Imaging Probe Using Integrated Microfluidics

Microreactor technology has shown potential for optimizing synthetic efficiency, particularly in preparing sensitive compounds. We achieved the synthesis of an [^(18)F]fluoride-radiolabeled molecular imaging probe, 2-deoxy-2-[18F]fluoro-d-glucose ([^(18)F]FDG), in an integrated microfluidic device. Five sequential processes—[^(18)F]fluoride concentration, water evaporation, radiofluorination, solvent exchange, and hydrolytic deprotection—proceeded with high radio-chemical yield and purity and with shorter synthesis time relative to conventional automated synthesis. Multiple doses of [^(18)F]FDG for positron emission tomography imaging studies in mice were prepared. These results, which constitute a proof of principle for automated multistep syntheses at the nanogram to microgram scale, could be generalized to a range of radiolabeled substrates

Molecular orientation in Langmuir and Langmuir-Blodgett films of disk-shaped molecules including amphiphilic dendrimers and liquid crystalline perylene diimide derivatives

Physical and chemical properties always come from structural features. For the disk shaped macromolecules, face-on and edge-on model are employed to describe the molecular orientation of the discotic molecules in Langmuir and L-B films. Langmuir and Langmuir-Blodgett (L-B) films with different molecular arrangements showed various physical properties, which have wide potential applications in nanoelectronic devices and photovoltaic cells. Two different molecular systems were studied in this thesis. They are the amphiphilic dendrimers and liquid crystalline (LC) perylene diimide derivatives. The interfacial, spectroscopic and topographic properties of these two types of system were studied by Langmuir and L-B techniques. Molecular orientations and the structural differences behind the various molecular arrangements were analyzed.A series of amphiphilic poly (amido amine) (PAMAM) dendrimers were prepared by attaching different functionalized chains to the PAMAM cores of different generations. The chains included pentacosadiynoic acid (PDA) hydroxydodecanoic acid chains (HA). The amphiphilic dendrimer with PDA chains demonstrated face-on orientation; whereas the dendrimers with HA chains showed edge-on orientation. These various orientations were also supported by topographic studies. Besides dendrimer cores\u27 determining molecular orientations, we proved that the functionalized chains can play an important role in determining the molecular arrangements of amphiphilic dendrimers in Langmuir and L-B films.For the LC perylene diimide derivatives, surface chemistry properties of three compounds with different chains have been investigated thoroughly. Among them, PPMEEM showed face-on orientation at air/water interface; whereas PPEEB and PPE4CN demonstrated face-on and edge-on orientations under different surface pressures. The two dimensional self-assembly process was first time observed in the presented research accompanying the appearance of the edge-on orientation. The relationship between the edge-on orientation and two dimensional self-assembly property was proved by the different topographic studies including Brewster angle microscopy (BAM), epifluorescence, environmental scanning electron microscopy (ESEM) and atomic force microscopy (AFM) techniques. Well defined correspondence among these techniques has been identified

Metabolomics reveals significant variations in metabolites and correlations regarding the maturation of walnuts (Juglans regia L.)

The content of walnut metabolites is related to its nutritive value and physiological characteristics, however, comprehensive information concerning the metabolome of walnut kernels is limited. In this study we analyzed the metabolites of walnut kernels at five developmental stages from filling to ripening using GC-MS-based untargeted metabolomics; of a total 252 peaks identified, 85 metabolites were positively identified. Further statistical analysis revealed that these 85 metabolites covered different types of metabolism pathways. PCA scores revealed that the metabolic compositions of the embryo are different at each stage, while the metabolic composition of the endotesta could not be significantly separated into distinct groups. Additionally, 7225 metabolite-metabolite correlations were detected in walnut kernel by a Pearson correlation coefficient approach; during screening of the calculated correlations, 463 and 1047 were determined to be significant with r2≥0.49 and had a false discovery rate (FDR) ≤0.05 in endotesta and embryo, respectively. This work provides the first comprehensive metabolomic study of walnut kernels and reveals that most of the carbohydrate and protein-derived carbon was transferred into other compounds, such as fatty acids, during the maturation of walnuts, which may potentially provide the basis for further studies on walnut kernel metabolism

Ist kombinatorische Oberflächenchemie möglich?

Kombinatorische Peptidbibliotheken können verwendet werden, um in monomolekularen Oberflächenschichten die supramolekulare Struktur eines Proteins nachzuahmen – mit einer spezifischen Rezeptorfunktion, die Maltose erkennt, nicht aber Glucose oder Sucrose (siehe schematische Darstellung)