(684e) Probing the Interactions and Dynamics of DNA-Functionalized Colloids with Scanning-Line Optical Tweezers

DNA hybridization is an ideal tool to direct ?bottom-up? assembly of complex materials and has recently been used to assemble quantum dots¹, polymer microspheres² and other materials made exclusively of DNA³. Even with the significant interest in DNA as a self-assembly platform, very few groups report successful formation of self-assembled, crystalline materials^4-6. Previous work from our group suggests that success in making crystalline assemblies may have been frustrated by a combination of slow binding dynamics and a narrow temperature window for nucleation and crystal growth⁷. To address these issues, we use a scanning-line optical tweezers instrument to measure DNA-induced interactions between colloidal microspheres and then model the pair potentials using well-known concepts in statistical mechanics and chemistry. By measuring and modeling the pair interaction energies of DNA-functionalized particles as a function of temperature and separation distance, we are able to develop a simple toolbox of DNA architectures that can be used to independently tune the dynamics and binding energies in a rational way.

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