Reciprocal Control of Hierarchical DNA Origami-Nanoparticle Assemblies

Abstract

Biopolymers are feasible materials for preparing biocompatible drug-delivery systemsbecause of their chemical similarityto natural polymers. Poly(succinimide) is an anhydrous form of poly(aspartic acid), hence it has outstanding degradation property at physiological conditions. By the help of electrospinning technique, prolonged drug release can be obtained due to the nanofibrous mesh structure of the polymer conjugates. These systems have large specific surface and porosity, therefore the dissolution kinetics and drug absorption can be increased.The aim of this work was to prepare biocompatible, biodegradable drug conjugates using poly(aspartamide) based nanofibers and dopamine, to characterize the dissolution kinetics and drug release kinetics of these samples and to investigate the incidental cytotoxicity. The dopamine-polymer fibrous conjugates were characterized by FT-infrared spectrometry, scanning electron microscopy, atomic force microscopy and two-photon microscopy. The kinetics of dissolution and dopamine release were monitored by UV-Vis spectrophotometry. The biocompatibility of the conjugates was examined in the presence of human periodontal ligament stem cells (PDLSCs) and the SH-SY5Y neuroblastoma cell line. The cell viability tests were assessed by WST-1 cell proliferation reagent. The morphology of the cells was observed by phase-contrast, confocal and two-photon microscopic techniques. The presence of dopamine receptors on both cell types were investigated by immunocytochemical analysis.Dopamine containing, nanofibrous polymer-drug conjugates were successfully prepared with prolonged dopamine release. The result of cell viability tests shows the biocompatibility of the poly(aspartamide) based conjugates. Applying these materials, the dopamine can be dosed in higher concentration without side-effect compared to the treatment with free dopamine. Acknowledgements

DNA-caged Nanoparticles via Electrostatic Self-Assembly

“…To further characterize DNA tile electrostatic adsorption and interlocking on the micelle surface, we employed a series of fluorescence and fluorescence quenching experiments (Figure 3, Supplementary Figure 3). The first experiment employed micelles comprised of block copolymers with terminal Cy3 fluorophores whose fluorescence could be quenched by adsorption of DNA tiles modified with black hole quencher-1 (BHQ-1) [28] (Figure 3A). DNA tiles were added to polymer micelles at DNA to PEG molar ratios of 2-18.…”

High-Force Application by a Nanoscale DNA Force Spectrometer

“…15,16 Such nanocaliper devices have been used to investigate a range of biomolecular interactions including DNA bending and nucleosome unwrapping 16−18 and have been functionalized with a range of nanomaterials including gold nanoparticles and thermoresponsive polymers to externally control the device conformation. 19 While there has been significant work in the fabrication and application of DNA origami devices, including nanocalipers, their design is still largely driven by structural considerations (e.g., geometry or conformational changes), and the optimization for highperformance mechanical capabilities is not well explored. 20 One area of considerable potential for scaffolded DNA origami devices is force spectroscopy.…”