Fabrication of an Effective Avermectin Nanoemulsion Using a Cleavable Succinic Ester Emulsifier

In this study, a new emulsifier precursor was prepared via esterification of avermectin with succinic anhydride. The chemical structure of the product was confirmed to be monosubstituted avermectin. After neutralization with triethanolamine, it exhibited adequate emulsification ability for avermectin. Avermectin was then encapsulated in nanoparticles in the nanoemulsion with a high drug loading up to 60 wt % and high stability. The nanoemulsion of nanoparticles that serves as a carrier of avermectin shows highly efficient pesticide characteristics, including low surface tension, high affinity to leaves, and improved photostability. In the presence of esterase or under strongly basic conditions, the ester bonds of the emulsifier can be hydrolyzed, and the encapsulated avermectin molecules can be released in an accelerated manner. The nanoemulsion exhibited improved insecticidal effect compared with commercial emulsifiable concentrate, which was attributed to the cleavage of ester bonds of the emulsifier by esterase in vivo

Dual Reaction-Based Multimodal Assay for Dopamine with High Sensitivity and Selectivity Using Functionalized Gold Nanoparticles

A simple and dual chemical reaction-based multimodal assay for dopamine with high sensitivity and selectivity using two types of functionalized gold nanoparticles (FB-AuNPs/NsNHS-AuNPs), i.e. fluorescein modified gold nanoparticles (FB-AuNPs) and Nile blue modified gold nanoparticles (NsNHS-AuNPs), was successfully fabricated. This assay for dopamine presents colorimetric visualization and double channel fluorescence enhancement at 515 and 665 nm. The absorbance and fluorescence changes were linearly proportional to the amounts of dopamine in the range of nanomolar scale (5–100 nM). The detection limits for absorbance and fluorescence were as low as 1.2 nM and 2.9 nM (S/N = 3), respectively. Furthermore, the extent application of this multimodal assay has been successfully demonstrated in human urine samples with high reliability and applicability, showing remarkable promise in diagnostic purposes

Fabrication of Novel Avermectin Nanoemulsion Using a Polyurethane Emulsifier with Cleavable Disulfide Bonds

In this study, a polyurethane emulsifer with various functional groups was prepared from isophorone diisocyanate, avermectin, 2,2-dimethylol propionic acid, and bis­(2-hydroxyethyl) disulfide. The chemical structure of the polymer was confirmed by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, and element analysis. The polymer exhibited adequate emulsification ability for avermectin after neutralization with triethylamine. A satisfaying nanoemulsion was obtained, in which avermectin was encapsulated in nanoparticles with 50 wt % drug loading, low organic solvent content, and high stability under dilution and centrifuging treatment in addition to low surface tension, high affinity to crop leaf, and improved avermectin photostability. The resulting nanoparticles showed degradability in the presence of dl-dithiothreitol or inside the insect as a result of the disulfide bonds, promoting the release of avermectin. As a result, the avermectin nanoparticles showed higher insecticidal ability compared to both the avermectin nanoparticles without a disulfide group and the avermectin emulsifiable concentrate

AFM and TEM images of MNP/DNA complexes.

<p><b>A</b>) and <b>B</b>) AFM height images (scan size  = 1.5 µm and 2 µm, scale bar  = 100 nm). <b>C</b>) and <b>D</b>) Corresponding 3D images. <b>E</b>) and <b>F</b>) TEM images of MNP/DNA complexes.</p

Fluorescence microscopy analyses of co-expressed GFP and DsRed in transfected PK-15 cells.

<p>PK-15 cells were co-magnofected with the MagNP-DNA_GFP and MagNP-DNA_DsRed complexes and images were collected 24 h after transfection. (a–d) Fluorescence (a–c) and bright field imaging (d) of the cells spread between two glass cover slips. GFP and DsRed fluorescence were detected in the green (500–530 nm) and red (552–617 nm) channels, respectively. (Scale bars, 20 µm).</p

AFM images of MNP/DNA complexes.

<p><b>A</b>) and <b>B</b>) Height images of MNP/DNA complexes with mass ratio 1∶1 and 1∶5 (scan size  = 10 µm, scale bar  = 100 nm). <b>C</b>) and <b>D</b>) Corresponding peak force error images.</p

Fluorescence images of intracellular physical traces of red fluorescence MNPs and the expression of GFP in PK15 cells with time.

<p>A) 2 h, MNPs move though the cell membrane. B) 6 h, most MNPs are in the cytoplasm. C) 12 h, MNPs transfer from the cytoplasm to the nucleus. D) 18 h, most MNPs are inside the nucleus. E) 24 h, cells express GFP and MNPs shift back to the cytoplasm. F) and G) 36–48 h, MNPs gradually excrete out the cells and release in culture medium. H) 72 h, most MNPs escape from cells (scale bar  = 50 µm).</p

Agarose gel electrophoresis of plasmid DNA and MNP/DNA complexes.

<p>Co-migration of MNP (red) and DNA (green) on gel (A). Plasmid DNA and MNP/DNA complexes were digested with DNase I (B), and Hind III(C).</p

AFM images of plasmid DNA.

<p><b>A</b>) Height image (scan size  = 5 µm, scale bar  = 4 nm). <b>B</b>) Corresponding peak force error image.</p

TEM image and AFM images of MNPs.

<p><b>A</b>) TEM image. <b>B</b>) AFM height image (scan size  = 2 µm scale bar  = 100 nm). <b>C</b>) 3D rending AFM image.</p