Wed, 09 Jul 2008 18:48:18 BST CiteULike: dchen's Lee http://www.citeulike.org/user/dchen/author/Lee CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dchen/article/2868082 <i></i><br /><br />Soft lithography using polydimethylsiloxane (PDMS) allows one to fabricate complex microfluidic devices easily and at low cost. However, PDMS swells in the presence of many organic solvents significantly degrading the performance of the device. We present a method to coat PDMS channels with a glass-like layer using sol–gel chemistry. This coating greatly increases chemical resistance of the channels; moreover, it can be functionalized with a wide range of chemicals to precisely control interfacial properties. This method combines the ease of fabrication afforded by soft-lithography with the precision control and chemical robustness afforded by glass. Glass coating for PDMS microfluidic channels by sol–gel methods Adam Abate Daeyeon Lee Thao Do Christian Holtze David Weitz 2008-06-06T00:31:18-00:00 2008 chemistry microdevice microrheology technique weitz http://www.citeulike.org/user/dchen/article/2767637 <i>Physical Review Letters, Vol. 100, No. 10. (2008)</i><br /><br />We introduce a general methodology based on magnetic colloids to study the recognition kinetics of tethered biomolecules. Access to the full kinetics of the reaction is provided by an explicit measure of the time evolution of the reactant densities. Binding between a single ligand and its complementary receptor is here limited by the colloidal rotational diffusion. It occurs within a binding distance that can be extracted by a reaction-diffusion theory that properly accounts for the rotational Brownian dynamics. Our reaction geometry allows us to probe a large diversity of bioadhesive molecules and tethers, thus providing a quantitative guidance for designing more efficient reactive biomimetic surfaces, as required for diagnostic, therapeutic, and tissue engineering techniques. Measuring the Kinetics of Biomolecular Recognition with Magnetic Colloids Cohen Tannoudji E Bertrand J Baudry C Robic C Goubault M Pellissier A Johner F Thalmann Lee CM Marques J Bibette doi:10.1103/PhysRevLett.100.108301 Physical Review Letters, Vol. 100, No. 10. (2008) 2008-05-07T23:01:32-00:00 2008 Physical Review Letters 100 10 APS 2008 colloids magnetic http://www.citeulike.org/user/dchen/article/1875802 <i>The Journal of Chemical Physics, Vol. 116, No. 12. (2002), pp. 5158-5166.</i><br /><br />We present molecular dynamics simulations of a binary Lennard-Jones mixture at temperatures below the kinetic glass transition. The "mobility" of a particle is characterized by the amplitude of its fluctuation around its average position. The 5% particles with the largest/smallest mean amplitude are then defined as the relatively most mobile/immobile particles. We investigate for these 5% particles their spatial distribution and find them to be distributed very heterogeneously in that mobile as well as immobile particles form clusters. We suggest that this dynamic heterogeneity may be due to the fact that mobile/immobile particles are surrounded by fewer/more neighbors which form an effectively wider/narrower cage. The dependence of our results on the length of the simulation run indicates that individual particles have a characteristic mobility time scale which can be approximated via the non-Gaussian parameter. ©2002 American Institute of Physics. Dynamical heterogeneities below the glass transition Vollmayr Lee W Kob K Binder A Zippelius doi:10.1063/1.1453962 The Journal of Chemical Physics, Vol. 116, No. 12. (2002), pp. 5158-5166. 2007-11-07T01:07:08-00:00 2002 The Journal of Chemical Physics 116 12 5158 5166 AIP glass-transition heterogeneity