An aptamer-functionalized photonic crystal sensor for ultrasensitive and label-free detection of aflatoxin B1.

As a novel optical responsive material, photonic crystal is a promising sensing material in the recognition and detection of small molecules. Herein, a label-free composite sensor for aflatoxin B1 (AFB1) based on aptamer-functionalized photonic crystal arrays was successfully developed. Three-dimensional photonic crystals (3D PhCs) with a controllable number of layers were produced by a layer-by-layer (LBL) approach, and the introduction of gold nanoparticles (AuNPs) facilitated the immobilization procedure of recognition element aptamers, thus creating the AFB1 sensing detection system (AFB1-Apt 3D PhCs). The sensing system AFB1-Apt 3D PhCs exhibited a good linearity in the wide range of 1 pg mL-1-100 ng mL-1 AFB1 with a limit of detection (LOD) of 0.28 pg mL-1. Furthermore AFB1-Apt 3D PhC was successfully applied in the determination of AFB1 in the millet and beer samples with good recovery. The sensing system performed ultrasensitive and label-free detection to the target, which could be further applied in the fields of food safety, clinical diagnosis or environmental monitoring, establishing an efficient and rapid universal detection platform.

An ultrasensitive label-free biosensor based on aptamer functionalized two-dimensional photonic crystal for kanamycin detection in milk.

A novel photonic crystal aptamer biosensor SiO2-Au-ssDNA two-dimensional photonic crystal (2D PC), allowing label-free and highly sensitive to kanamycin (KANA), is successfully manufactured. This 2D PC biosensor was prepared via a needle tip flow method, using electrostatic adsorption to introduce negatively charged gold nanoparticles (Au NPs) into the 2D PC, combined with sulfhydryl-modified ssDNA for the rapid measurement. Benefiting from the localized surface plasmon resonance effect of Au NPs and optical response capability of PC, the biosensor has an excellent performance on quantitative analysis of KANA ranging from 5 pg∙mL-1 to 5 µg∙mL-1, with a limit of detection of 1.10 pg∙mL-1. The recovery of KANA is between 97 % and 110 % in the milk samples with relative standard deviation less than 4.8 %, which revealing that the 2D PC biosensor has the excellent performance on the KANA detection in complex conditions.

Near 90% Transparent ITO-Based Flexible Electrode with Double-Sided Antireflection Layers for Highly Efficient Flexible Optoelectronic Devices.

As a widely used substrate for flexible electronics, indium-tin oxide-based polymer electrodes (polymer-ITO electrodes) exhibit poorly visible light transmittance of less than 80%. The inferior transmittance for polymer-ITO electrodes severely limits the performance improvement of polymer-ITO based electronics. Here, a conceptually different approach of the double-sided antireflection coatings (DARCs) strategy is proposed to modulate both the air-polymer substrate interface and ITO-air interface refractive index gradient, to synergistically improve the transmittance of polymer-ITO electrodes. On the basis of SiO2 nanoparticles antireflection layer on polymer substrate, a polymer-metal oxide composite antireflection film is fabricated on the ITO side. Resultantly, the transmittance of ITO-based flexible electrodes is successfully improved from 76.8% to 89.8%, which is the highest transmittance among the reported ITO-based flexible electrodes. Furthermore, the photoluminescence emission intensity of luminescent materials enveloped with the DARCs electrodes increases by 74% over that with reference electrodes, demonstrating the DARCs antireflection strategy can efficiently improve the performance of flexible optoelectronic devices. With DARCs electrode, the flexible perovskite solar cells exhibit an enhanced efficiency from 18.80% to 20.85%.