Ximin He

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The control of the cell microenvironment on model patterned substrates allows the systematic study of cell biology in well defined conditions, potentially using automated systems. The extreme protein resistance of poly(oligo(ethylene glycol methacrylate)) (POEGMA) brushes is exploited to achieve high fidelity patterning of single cells. These coatings can(More)
In this paper, we demonstrate a double nanoimprinting process that allows the formation of nanostructured polymer heterojunctions of composition and morphology that can be selected independently. We fabricated photovoltaic (PV) devices with extremely high densities (10(14)/mm(2)) of interpenetrating nanoscale columnar features in the active polymer blend(More)
Living organisms have unique homeostatic abilities, maintaining tight control of their local environment through interconversions of chemical and mechanical energy and self-regulating feedback loops organized hierarchically across many length scales. In contrast, most synthetic materials are incapable of continuous self-monitoring and self-regulating(More)
In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: Keywords: Adaptive and dynamic architectures Environmentally responsive systems(More)
The efficient extraction of (bio)molecules from fluid mixtures is vital for applications ranging from target characterization in (bio)chemistry to environmental analysis and biomedical diagnostics. Inspired by biological processes that seamlessly synchronize the capture, transport and release of biomolecules, we designed a robust chemomechanical sorting(More)
A number of physiological processes in living organisms involve the selective "catch and release" of biomolecules. Inspired by these biological processes, we use computational modeling to design synthetic systems that can controllably catch, transport, and release specific molecules within the surrounding solution, and, thus, could be harnessed for(More)
The ability to manipulate the movement of surface microstructures is essential for the development of dynamic, responsive materials. We demonstrate that in addition to bulk actuation upon drying, a unique type of highly localized, directional actuation can be achieved when microstructures embedded in pH responsive gel are exposed to pH gradients. Theory and(More)
We use computational modeling to design a device that can controllably trap and release particles in solution in response to variations in temperature. The system exploits the thermoresponsive properties of end-grafted fibers and the underlying gel substrate. The fibers mimic the temperature-dependent behavior of biological aptamers, which form a hairpin(More)
A polypyrrole (PPy) composite film with a pure PPy zone and a PPy–TiO 2 nanoparticle composite zone in its cross-sectional direction was synthesized by direct oxidation of pyrrole successively in an electrolyte with or without TiO 2 nanoparticles. The volume content of TiO 2 in the composite film was tested to be lower than 0.9%. The actuator fabricated(More)