Bottom-Up Fabrication of Paper-Based Microchips by Blade Coating of Cellulose Microfibers on a Patterned Surface

We report a method for the bottom-up fabrication of paper-based capillary microchips by the blade coating of cellulose microfibers on a patterned surface. The fabrication process is similar to the paper-making process in which an aqueous suspension of cellulose microfibers is used as the starting material and is blade-coated onto a polypropylene substrate patterned using an inkjet printer. After water evaporation, the cellulose microfibers form a porous, hydrophilic, paperlike pattern that wicks aqueous solution by capillary action. This method enables simple, fast, inexpensive fabrication of paper-based capillary channels with both width and height down to about 10 μm. When this method is used, the capillary microfluidic chip for the colorimetric detection of glucose and total protein is fabricated, and the assay requires only 0.30 μL of sample, which is 240 times smaller than for paper devices fabricated using photolithography

Responsive Colloidal Crystal for Spectrometer Grating

Diffraction gratings have a demonstrated value in optical applications, such as monochromators and spectrometers. Recent efforts have been directed at finding simple ways to manufacture diffraction gratings at low cost and under mild conditions. Here we present a practical strategy to fabricate a diffraction grating by simply treating an elastic photonic crystal film with a gradient of stress. The film was made of non-close-packed colloidal crystal arrays embedded in hydrogel polymer. Its photonic band gap (PBG) could be tuned precisely by using varying levels of pressure. Thus, when the elastic photonic crystal film was subjected to a stress gradient, a novel diffraction grating with continuously varying PBGs in the whole visible range could be achieved. The practical application of this type of diffraction grating was demonstrated in a miniaturized spectrometer system

Bioinspired Multifunctional Janus Particles for Droplet Manipulation

Inspired by the nipple arrays covering mosquitoes’ eyes and the heterogeneous textured bumps on beetles’ backs, we have developed a new kind of Janus particle with multiplexed features, such as different boss arrays and wettability compartmentalized on the same surface, and an anisotropic color and magnetic properties. The prepared Janus particles can be anchored at the air–water interface and act as a highly flexible barrier for preventing coalescence of water droplets. The incorporation of magnetic nanoparticles can give the Janus particles magnetic responsiveness for controlled transportation and coalescence of liquid marbles, while the structural colors in the Janus particles can be employed for barcoding of the encapsulated liquid marbles. We believe that these small Janus particles have great potential as components for constructing intelligent interfacial objects

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 ∼10−12 M)

Bioinspired Multifunctional Janus Particles for Droplet Manipulation

Inspired by the nipple arrays covering mosquitoes’ eyes and the heterogeneous textured bumps on beetles’ backs, we have developed a new kind of Janus particle with multiplexed features, such as different boss arrays and wettability compartmentalized on the same surface, and an anisotropic color and magnetic properties. The prepared Janus particles can be anchored at the air–water interface and act as a highly flexible barrier for preventing coalescence of water droplets. The incorporation of magnetic nanoparticles can give the Janus particles magnetic responsiveness for controlled transportation and coalescence of liquid marbles, while the structural colors in the Janus particles can be employed for barcoding of the encapsulated liquid marbles. We believe that these small Janus particles have great potential as components for constructing intelligent interfacial objects

Bioinspired Multifunctional Janus Particles for Droplet Manipulation

Inspired by the nipple arrays covering mosquitoes’ eyes and the heterogeneous textured bumps on beetles’ backs, we have developed a new kind of Janus particle with multiplexed features, such as different boss arrays and wettability compartmentalized on the same surface, and an anisotropic color and magnetic properties. The prepared Janus particles can be anchored at the air–water interface and act as a highly flexible barrier for preventing coalescence of water droplets. The incorporation of magnetic nanoparticles can give the Janus particles magnetic responsiveness for controlled transportation and coalescence of liquid marbles, while the structural colors in the Janus particles can be employed for barcoding of the encapsulated liquid marbles. We believe that these small Janus particles have great potential as components for constructing intelligent interfacial objects

Kinetically Controlled Synthesis of Nonspherical Polystyrene Nanoparticles with Manipulatable Morphologies

The morphology of nanoparticles plays a critical role in determining their properties and applications. Herein, we report a versatile approach to the fabrication of nonspherical polystyrene (PS) nanoparticles with controlled morphologies on the basis of kinetically controlled seed-mediated polymerization. By manipulating parameters related to the reaction kinetics including the concentration of monomers, injection rate of reactants, and reaction temperature, the monomers could be directed to polymerize on the selective sites of PS seeds, and after the removal of the second polymer, nonspherical nanoparticles with a variety of thermodynamically unfavored morphologies could be synthesized. We systematically investigated the formation mechanism of these nonspherical nanoparticles by monitoring the evolution of seeds during the reaction. Moreover, we have also successfully extended this strategy to reaction systems containing monomers with different combinations and seeds with different sizes. We believe this work will provide a promising route to the fabrication of nonspherical polymer nanoparticles with controlled morphologies for various applications