Selective Binding and Elution of Aptamers for Pesticides Based on Sol-Gel-Coated Nanoporous Anodized Aluminum Oxide Membrane

Sol-gel-based mesopores allow the entry of target small molecules retained in their cavity and aptamers to bind to target molecules. Herein, sol-gel-based materials are applied to screen-selective aptamers for small molecules, such as pesticides. To enhance the efficiency of aptamer screening using a sol-gel, it is necessary to increase the binding surface. In this study, we applied the sol-gel to an anodized aluminum oxide (AAO) membrane, and the morphological features were observed via electron microscopy after spin coating. The binding and elution processes were conducted and confirmed by fluorescence microscopy and polymerase chain reaction. The sol-gel coating on the AAO membrane formed a hollow nanocolumn structure. A diazinon-binding aptamer was bound to the diazinon-containing sol-gel-coated AAO membrane, and the bound aptamer was effectively retrieved from the sol-gel matrix by thermal elution. As a proof of concept, a sol-gel-coated AAO disc was mounted on the edge of a pipette tip, and the feasibility of the prepared platform for the systematic evolution of ligands by exponential enrichment (SELEX) of the aptamer binding was also confirmed. The proposed approach will be applied to an automated SELEX cycle using an automated dispenser, such as a pipetting robot, in the near future

Solution-processed white graphene-reinforced ferroelectric polymer nanocomposites with improved thermal conductivity and dielectric properties for electronic encapsulation

The recent surge in graphene research has stimulated interest in the investigation of various two-dimensional (2D) nanomaterials, including 2D boron nitride (BN) nanostructures. Among these, hexagonal boron nitride nanosheets (h-BNNs; also known as white graphene, as their structure is similar to that of graphene) have emerged as potential nanofillers for preparing thermally conductive composites. In this work, hexagonal boron nitride nanoparticles (h-BNNPs) approximately 70 nm in size were incorporated into a polyvinylidene fluoride (PVDF) matrix with different loadings (0–25 wt.%). The PVDF/h-BNNP nanocomposites were prepared by a solution blending technique and characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), polarized optical microscopy (POM) and scanning electron microscopy (SEM). In addition, the thermal conductivity and dielectric properties of the nanocomposites were investigated. The incorporation of h-BNNPs in the PVDF matrix resulted in enhanced thermal conductivity. The highest value, obtained at 25 wt.% h-BNNP loading, was 2.33 W/mK, which was five times that of the neat PVDF (0.41 W/mK). The thermal enhancement factor (TEF) at 5 wt.% h-BNNP loading was 78%, increasing to 468% at 25 wt.% h-BNNP loading. The maximum dielectric constant of approximately 36.37 (50Hz, 150 °C) was obtained at 25 wt.% h-BNNP loading, which was three times that of neat PVDF (11.94) at the same frequency and temperature. The aforementioned results suggest that these multifunctional and high-performance nanocomposites hold great promise for application in electronic encapsulation.Scopu