Preparation of encoded bar-like core-shell microparticles on a microfluidic chip

This work presented a microfluidic multi-phase droplet system for preparing encoded bar-like core-shell microparticles. The integration of T-junction and flow-focusing junction on one microfluidic chip was designed to form water-in-oil-in-water double emulsions. And the double emulsions were used as templates to fabricate the encoded bar-like core-shell particles on the chip. The encoded particles were of small and uniform size. The core droplets were filled with different quantum dots and dyes for providing encoding information, and the outer oil phase droplets of trimethylolpropane ethoxylate triacrylate were solidified into the shell of the encoded particles for confining the core droplets in them and supplying the surface for capturing targets. The sequence of the core droplets could be confined by the configuration of the micro-channels when the core droplets were encapsulated in the outer droplets. Thus a new multi-mode encoding method was defined by combining dual-optical encoding and graphical encoding. Different quantum dots provided the wavelength code and the intensity code, multiple dyes provided the color code, and the single order of core droplets in the shell offered the position code. Compared with the conventional encoding methods, this approach increases the encoding number by hundred times, and has great potential for high-throughput multiplexed analysis.