A microfluidic Braille valve platform for on-demand production, combinatorial screening and sorting of chemically distinct droplets.

Droplet microfluidics is a powerful tool for a variety of biological applications including single-cell genetics, antibody discovery and directed evolution. All these applications make use of genetic libraries, illustrating the difficulty of generating chemically distinct droplets for screening applications. This protocol describes our Braille Display valving platform for on-demand generation of droplets with different chemical contents (16 different reagents and combinations thereof), as well as sorting droplets with different chemical properties, on the basis of fluorescence signals.

Directed and Modular Protein Immobilization on Gold and Silver Nanoparticles.

Conjugation of proteins to gold nanoparticles (AuNP), silver nanoparticles (AgNP), or other metal nanoparticles (NPs) can often be achieved using passive adsorption. Although such an approach is simple and effective, there is usually no control over the orientation of the protein and denaturation due to close contact with the metal surface. The method described here makes use of adapter proteins which have the ability to adsorb to the NP surface in an oriented and stable way and at the same time enable straightforward attachment to other proteins of interest.

[Partial Nitrification and Denitrification of Low C/N Ratio Sewage Based on Zoning Oxygen and Dissolved Oxygen Control].

Poor nitrogen removal from municipal sewage is mainly due to insufficient carbon source and low C/N ratio. The A/O pilot plant was established to investigate the accumulation rate of nitrous nitrogen and the removal of nitrogen pollutants by adjusting the ratio of anoxic/aerobic zoning and dissolved oxygen levels in the aerobic zone. The results showed that when DO is 2.

Modular assembly of proteins on nanoparticles.

Generally, the high diversity of protein properties necessitates the development of unique nanoparticle bio-conjugation methods, optimized for each different protein. Here we describe a universal bio-conjugation approach which makes use of a new recombinant fusion protein combining two distinct domains. The N-terminal part is Glutathione S-Transferase (GST) from Schistosoma japonicum, for which we identify and characterize the remarkable ability to bind gold nanoparticles (GNPs) by forming gold-sulfur bonds (Au-S).

Wash-free magnetic oligonucleotide probes-based NMR sensor for detecting the Hg ion.

An easily applied and sensitive sensor for the detection of heavy metal ion residues based entirely on magnetic nanoparticle and oligonucleotide was developed. The tool is established on the relaxation of magnetic nanoparticles with different dispersion states. The target analyte, Hg ions, induce the aggregation of the MNP oligonucleotide probes.

Rapid on-site detection of Acidovorax avenae subsp. citrulli by gold-labeled DNA strip sensor.

Acidovorax avenae subsp. citrulli (AAC) is one of the most harmful diseases in cucurbit production. A rapid and sensitive DNA strip sensor was constructed based on gold nanoparticle-labeled oligonucleotide probes for the detection of AAC.

An aptamer-based chromatographic strip assay for sensitive toxin semi-quantitative detection.

An aptamer-based chromatographic strip assay method for rapid toxin detection was developed. The aptamer-based strip assay was based on the competition for the aptamer between ochratoxin A and DNA probes. The sensing results indicated that the sensitivity of the aptamer-based strip was better than that of conventional antibody-based strips.

Fluorescent strip sensor for rapid determination of toxins.

Here, we report a simple fluorescent strip sensor based on aptamer-quantum dots technology that can meet toxin monitoring demands using ochratoxin A (OTA) as a model toxin. The limit of the detection (LOD) for the fluorescent strip was 1.9 ng mL(-1), while the time needed for the detection is only 10 min; this conforms to the standards of World Health Organization (WHO) or better.