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A simple and effective universal serial bus (USB) flash disk type microfluidic chip electrophoresis (MCE) was developed by using poly(dimethylsiloxane) based soft lithography and dry film based printed circuit board etching techniques in this paper. The MCE had a microchannel diameter of 375 μm and an effective length of 25 mm. Equipped with a conventional online electrochemical detector, the device enabled effectively separation of bovine serum albumin, lysozyme, and cytochrome c in 80 s under the ultra low voltage from a computer USB interface. Compared with traditional capillary electrophoresis, the USB flash disk type MCE is not only portable and inexpensive but also fast with high separation efficiency. [ABSTRACT FROM AUTHOR]

An effective microfluidic method to fabricate monodisperse polyethylene glycol (PEG) hydrogel composite microspheres with tunable dimensions and properties is reported in this paper. A T-junction microfluidic chip equipped with rounded channels and online photopolymerization system is applied for the microsphere microfabrication. The shape and size of the microspheres are well controlled by the rounded channels and PEG prepolymer/silicon oil flow rate ratios. The obtained PEG/aspirin composite microspheres exhibit a sustained release of aspirin for a wide time range; the obtained PEG/Fe3O4 nanocomposite microspheres exhibit excellent magnetic properties; and the obtained binary PEG/dye composite microspheres show the ability to synchronously load two functional components in the same peanut-shaped or Janus hydrogel particles. [ABSTRACT FROM AUTHOR]

In this paper, we present a novel rapid-prototyping process for out-of-cleanroom microfabrication of three-dimensional multilayer microfluidic structures with a 10 µm resolution, referred to as the Direct Projection on Dry-film Photoresist (DP2). A commercially available digital projector is customized to function as a direct mask generation and photo exposure system, while easy-processing photosensitive dry films are used as the microfluidic constructs. Multilayer alignments among maskless-patterned layers are reliably achieved by using a Software Alignment technique with less than 10 µm precision, which eliminates the use of mechanical travelling stage. The bonding between different layers of dry film, simply enabled by a plasma-assisted thermal lamination, offers an easy implementation for suspended multilayer microstructures. Development of a complex microfluidic chip from computer layout can thus be accomplished within an hour in a regular chemical or biological lab environment using this approach. [ABSTRACT FROM AUTHOR]