Dual-component gene detection for H7N9 virus – The combination of optical trapping and bead-based fluorescence assay

Programmable Jigsaw Puzzles of Soft Materials Enabled by Pixelated Holographic Surface Reliefs

Manual intervention in the self-organization of soft matter to obtain a desired superstructure is a complex but significant project. Specifically, optical components made fully or partially from reconfigurable and stimuli-responsive soft materials, referred to as soft photonics, are poised to form versatile platforms in various areas; however, a limited scale, narrow spectral adaptability, and poor stability are still formidable challenges. Herein, a facile way is developed to program the optical jigsaw puzzle of nematic liquid crystals via pixelated holographic surface reliefs, leading to an era of manufacturing for programmable soft materials with tailored functions. Multiscale jigsaw puzzles are established and endowed with unprecedented stability and durability, further sketching a prospective framework toward customized adaptive photonic architectures. This work demonstrates a reliable and efficient approach for directly assembling soft matter, unlocking the long-sought full potential of stimuli-responsive soft systems, and providing opportunities to inspire the next generation of soft photonics and relevant areas.

Optical trapping and fluorescence control with vectorial structured light

Here we functionalized micro-scaled polymer beads with nano-scaled quantum dots and demonstrate optical trapping and tweezing, with in-situ fluorescence measurement, in an all-digital all-optical configuration. We outline the chemistry required to facilitate this, from deactivating the optical trapping environment to size, adhesion and agglomeration control. We introduce a novel holographic optical trapping set-up that leverages on vectorially structured light, allowing for the delivery of tuneable forms of light from purely scalar to purely vector, including propagation invariant flat-top beams for uniform illumination and tailored intensity gradient landscapes. Finally, we show how this has the potential to quench bleaching in a single wavelength trap by linear (spatial mode) rather than non-linear effects, advancing the nascent field of optics for chemistry.

CRISPR-empowered hybridization chain reaction amplification for an attomolar electrochemical sensor

Rapid pathogen screening holds the key against certain viral infections, especially in an overwhelming pandemic. Herein, a CRISPR-empowered electrochemical biosensor was designed for the ultrasensitive detection of the avian influenza A (H7N9) virus gene sequence. Combining the CRISPR/Cas system, a signal-amplification strategy and a high-conductivity sensing substrate, the developed biosensor showed an ultrawide dynamic range, an ultralow detection limit, and excellent selectivity for H7N9 detection, providing a potential sensing platform for the simple, fast, sensitive, and on-site detection of infectious diseases.

High-sensitivity detection of two H7 subtypes of avian influenza viruses (AIVs) by immunochromatographic assay with highly chromatic red silica nanoparticles

In this work, a sensitive and quantitative immunochromatographic assay (ICA) detection method for avian influenza viruses (AIVs) of the H7 hemagglutinin (HA) antigen was established based on highly chromatic red silica nanoparticles (SiNPs). It can detect two H7 subtypes of influenza viruses, H7N2 and H7N9. The highly chromatic red SiNPs were prepared by adsorbing C.I. Direct Red 224 on the surface of the SiNPs for multiple times using the layer by layer (LbL) self-assembly method under the electrostatic action of ethylene imine polymer (PEI) and poly(sodium-p-styrenesulfonate) (PSS). The highly chromatic red silica nanoparticles modified with anti-H7 HA mAb1 were used as immunodetection probes. The accumulated highly chromatic red SiNPs on the T-line can be observed by the naked eye to qualitatively detect the H7 HA antigen. The quantitative analysis is carried out by using a camera and Image J software. Within the range of 0.1-10 ng mL-1, the linear equation between the H7 HA antigen concentration and the peak area of the T-line gray value was y = 868.9722 + 435.4836X (R2 = 0.9716), and the limit of detection (LOD) of this method was 0.08 pg mL-1 (S/N = 3). The highly chromatic red SiNP based ICA for the detection of H7 HA has no cross activity with other subtypes of influenza viruses. This method of combining highly chromatic colored markers with ICA has great potential in practical applications for the rapid and quantitative detection of other types of AIVs.

Advanced nanotechnologies in avian influenza: Current status and future trends - A review

In the last decade, the control of avian influenza virus has experienced many difficulties, which have caused major global agricultural problems that have also led to public health consequences. Conventional biochemical methods are not sufficient to detect and control agricultural pathogens in the field due to the growing demand for food and subsidiary products; thus, studies aiming to develop potent alternatives to conventional biochemical methods are urgently needed. In this review, emerging detection systems, their applicability to diagnostics, and their therapeutic possibilities in view of nanotechnology are discussed. Nanotechnology-based sensors are used for rapid, sensitive and cost-effective diagnostics of agricultural pathogens. The application of different nanomaterials promotes interactions between these materials and the virus, which enables researchers to construct portable electroanalytical biosensing analyser that should effectively detect the influenza virus. The present review will provide insights into the guidelines for future experiments to develop better techniques to detect and control influenza viruses.