Photonic crystal beads from gravity-driven microfluidics.

This Letter reports a simple method for the mass production of 3D colloidal photonic crystal beads (PCBs) by using a gravity-driven microfluidic device and online droplet drying method. Compared to traditional methods, the droplet templates of the PCBs are generated by using the ultrastable gravity as the driving force for the microfluidics, thus the PCBs are formed with minimal polydispersity. Moreover, drying of the droplet templates is integrated into the production process, and the nanoparticles in the droplets self-assemble online.

Binary optical encoding strategy for multiplex assay.

A binary optical encoding strategy is proposed to meet the increasing requirements of multiplex bioassays. As illustrated in fluorescence immunodetection of multiplex antigen molecules, photonic crystal beads (PCBs) and quantum dots (QDs) can be used as biomolecular microcarriers and fluorescence labels, respectively. The categories of antigens were deciphered by the binary combination of optical spectra of PCBs and QDs as independent encoding elements.

Rapid and sensitive biomolecular screening with encoded macroporous hydrogel photonic beads.

We present a new method to prepare inverse opaline photonic beads with good spherical shape and superior optical performance by simply introducing an interfacial tension system into a template replication method. When the scaffolds of these beads were composed of poly(ethylene glycol) diacrylate hydrogel, they could provide a homogeneous water surrounding, which remedied many shortcomings of biomolecular microcarriers introduced by the presence of the solid surface of them. The suspension array, which used these macroporous hydrogel photonic beads as coding elements, showed obvious advantages in multiplexed capability, rapid biomolecular screening (within 12 min), and highly sensitive detection (with limit of detection of approximately 10(-12) M).