摘要/Abstract
作为一种精巧的DNA纳米机器, DNA步行器因其优异的可设计性及可编程性在众多研究领域中展示出强大的应用价值. 本工作通过将基于催化发夹组装的双足DNA步行器与DNA功能化的金纳米粒子(即球形核酸)组装相结合, 开发了一种具有时间依赖性的DNA步行器驱动球形核酸恒温有序组装的策略. 以单组分球形核酸组装体系为例, DNA步行器通过发夹催化组装反应驱动在球形核酸表面上随机行走并逐渐产生带有活性粘性末端的DNA杂交结构, 促使球形核酸表面粘性末端间的“键合”速率与其组装速率在时间尺度上保持同步, 从而得到面心立方(FCC)晶型的超晶格结构. 基于类似原理, 作者还构建了一种DNA步行器驱动的双组分球形核酸组装体系并以此得到氯化铯(CsCl)晶型的超晶格结构.
关键词: 动态DNA纳米机器, 双足DNA步行器, 金纳米粒子, 球形核酸组装, 超晶格结构
As a kind of sophisticated dynamic DNA nanomachine, DNA walker has shown powerful application ability in many aspects due to its excellent structural designability and programmability. Taking advantage of stochastic DNA tracks on surface and adaptable DNA outputs of the well-known catalytic hairpin assembly (CHA) circuits, the DNA walkers that move along DNA-coated three-dimensional particle surfaces have attracted much interests. On the other hand, in the field of DNA-mediated nanoparticle assembly, self-assembly of nanoparticles is a thermodynamically driven nonequilibrium process, which is easily trapped at intermediate local free-energy minima, resulting in a disordered structure. Therefore, effective strategies to evade each local free-energy minimum are highly desired. In addition to the traditional annealing strategy, the time-dependent strategy relied on toehold-mediated strand-displacement DNA circuit recently reported by our group has been proven an alternative solution, where interactions between nanoparticles can be tuned in a time-dependent manner for programming dynamic pathway to achieve a free-energy minimum. Through integrating a CHA-based bipedal DNA walker with a DNA-functionalized gold nanoparticle (i.e., spherical nucleic acid; SNA) assembly, a time-dependent strategy for assembly of SNAs programmed by DNA walker at constant temperature was developed in this work. In our strategy, the active sticky ends used for assembly of SNAs can be gradually generated on nanoparticle surface after the walking of the bipedal DNA walker driven by the CHA reaction to induce the synchronization of assembly and bonding between SNAs, thereby obtaining ordered nanoparticle superlattice structure. Take a one-component SNA assembly system for example, the dynamic walking process of the bipedal DNA walker on the surface of SNA was proved to be stable with good walking ability and persistence at first. Then, the SNA assembly kinetics results showed that the bipedal walker concentrations and DNA linker ratios could greatly influence the aggregation of SNA conjugates. Finally, the performance of the integrated SNA assembly system driven by the bipedal DNA walker was investigated under varied concentrations of bipedal walker. In the presence of lower concentrations of the walker strand, the assembly process of SNAs could have a long residence time to switch between the binding and unbinding of the generated sticky ends and achieved a series of near-equilibrium states. Thus, as the interaction between particles grows, the dynamic pathway of nanoparticles assembly can be programmed to achieve a free-energy minimum to form ordered face-centered cubic (FCC) superlattice structure. Based on similar design principle, an asymmetric two-component SNA assembly system programmed by the bipedal DNA walker was constructed to obtain CsCl superlattice structure. Our DNA walker-programmed SNA assembly strategy will have great potential in the creation of functional nanoscale superlattice materials and in the construction of SNA structures with complex phase behaviors.
Key words: dynamic DNA nanomachine, bipedal DNA walker, gold nanoparticle, spherical nucleic acid assembly, superlattice structure
PDF全文下载地址:
点我下载PDF
