Sung Ha Park

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Bottom-up fabrication of nanoscale structures relies on chemical processes to direct self-assembly. The complexity, precision, and yield achievable by a one-pot reaction are limited by our ability to encode assembly instructions into the molecules themselves. Nucleic acids provide a platform for investigating these issues, as molecular structure and(More)
Fig. S1. Cross-DNA motif, tile A: Schematics of strand structures and DNA sequences. Tile A consists of nine different strands indicated by different colors. The red-dot on the A9 strand indicates the site of biotin modification for demonstration of addressability. Arrows in drawings indicate strand direction running from 5' to 3'.
We demonstrate the precise control of periodic spacing between individual protein molecules by programming the self-assembly of DNA tile templates. In particular, we report the application of two self-assembled periodic DNA structures, two-dimensional nanogrids, and one-dimensional nanotrack, as template for programmable self-assembly of streptavidin(More)
This study was undertaken to investigate the potential toxicity and establish the no observed adverse effect level (NOAEL) and target organ(s) of negatively charged colloidal silica particles of different sizes, ie, SiO2 (EN20(-)) (20 nm) or SiO2 (EN100(-)) 2(100 nm), administered by gavage in Sprague-Dawley rats. After verification of the physicochemical(More)
DNA-based nanotechnology is currently being developed as a general assembly method for nanopatterned materials that may find use in electronics, sensors, medicine, and many other fields. Here we present results on the construction and characterization of DNA nanotubes, a self-assembling superstructure composed of DNA tiles. Triple-crossover tiles modified(More)
When confronted with impending slip/fall situations, gait parameters are adjusted accordingly to avoid slipping. This study was conducted to assess age-related slip avoidance strategy by measuring gait parameters and muscle activity characteristics of the lower extremities (hamstrings, calves, and quadriceps) of both young and older participants while(More)
Synthesizing molecular tubes with monodisperse, programmable circumferences is an important goal shared by nanotechnology, materials science, and supermolecular chemistry. We program molecular tube circumferences by specifying the complementarity relationships between modular domains in a 42-base single-stranded DNA motif. Single-step annealing results in(More)
Nanoparticles (NPs) are used commercially in health and fitness fields, but information about the toxicity and mechanisms underlying the toxic effects of NPs is still very limited. The aim of this study is to investigate the toxic effect(s) of 100 nm negatively (ZnO(AE100[-])) or positively (ZnO(AE100[+])) charged zinc oxide (ZnO) NPs administered by gavage(More)
We present a DNA nanostructure, the three-helix bundle (3HB), which consists of three double helical DNA domains connected by six immobile crossover junctions such that the helix axes are not coplanar. The 3HB motif presents a triangular cross-section with one helix lying in the groove formed by the other two. By differential programming of sticky-ends, 3HB(More)