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DNA-Coated Microspheres and Their Colloidal Superstructures
문정빈,조인성,Etienne Ducrot,오준석,David J Pine,이기라 한국고분자학회 2018 Macromolecular Research Vol.26 No.12
Reversible and specific interaction between single-stranded DNA on colloidal particles have opened up a new path way of building up colloidal superstructures. DNA-coated microspheres can be bound with other particles with complementary DNA brushes below the melting temperature and can be unbound above the melting temperature. However, due to their random Brownian motion, the particles form random (or glassy) structures in most cases or small crystals when cooling is extremely slow. Therefore, toward programmed colloidal superstructures of DNAcoated microspheres, they should reconfigure their kinetically trapped random structure to equilibrium crystalline structures. While nanoparticles can be rearranged into a crystalline structure by a simple conformational change of relatively long DNA brush, microspheres with short DNA brushes cannot be rearranged only by a conformational change of brush. Instead, sub-diffusion of bound DNA-coated microspheres is necessary which can be possible only with uniform DNA coating with high areal density on microspheres. In this article, we have reviewed methods for the synthesis of high-density DNA-coated microspheres and their assembly into crystalline structures. We also discuss future research direction of DNA-coated microspheres.
Active Patchy Colloids with Shape-Tunable Dynamics
Wang, Zuochen,Wang, Zhisheng,Li, Jiahui,Cheung, Simon Tsz Hang,Tian, Changhao,Kim, Shin-Hyun,Yi, Gi-Ra,Ducrot, Etienne,Wang, Yufeng American Chemical Society 2019 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.141 No.37
<P>Controlling the complex dynamics of active colloids-the autonomous locomotion of colloidal particles and their spontaneous assembly-is challenging yet crucial for creating functional, out-of-equilibrium colloidal systems potentially useful for nano- and micromachines. Herein, by introducing the synthesis of active “patchy” colloids of various low-symmetry shapes, we demonstrate that the dynamics of such systems can be precisely tuned. The low-symmetry patchy colloids are made in bulk via a cluster-encapsulation-dewetting method. They carry essential information encoded in their shapes (particle geometry, number, size, and configurations of surface patches, etc.) that programs their locomotive and assembling behaviors. Under AC electric field, we show that the velocity of particle propulsion and the ability to brake and steer can be modulated by having two asymmetrical patches with various bending angles. The assembly of monopatch particles leads to the formation of dynamic and reconfigurable structures such as spinners and “cooperative swimmers” depending on the particle’s aspect ratios. A particle with two patches of different sizes allows for “directional bonding”, a concept popular in static assemblies but rare in dynamic ones. With the capability to make tunable and complex shapes, we anticipate the discovery of a diverse range of new dynamics and structures when other external stimuli (e.g., magnetic, optical, chemical, etc.) are employed and spark synergy with shapes.</P> [FIG OMISSION]</BR>