Microrheology of DNA Origami

DNA折纸是纳米技术和功能材料领域的一个新兴领域。它利用DNA的信息编码能力形成复杂和响应性强的3D形状，可用于从药物输送到纳米电子电路的广泛应用[1]。传统上，人们是孤立地研究Origamis，但人们越来越有兴趣研究Origamis稠密溶液的集体行为[2]。因此，在这个项目中，我们将探索作为其设计功能的稠密溶液DNA Origamis的微观流变学。这一研究方向仍处于起步阶段，可以发现前所未有的使用DNA折纸的方法，具有潜在的重大学术和工业影响。流变学是研究流体如何流动以及它们在特定时间尺度上的粘性或弹性程度的科学。微观流变学是一种技术，它允许我们使用嵌入流体中的微米大小的颗粒来探测这些粘弹性行为，并且需要极少量的材料[3]。该项目将从研究一类名为“嵌合体”的结构开始，这种结构显示环状和线状DNA的组合[4]。最简单的这种结构是一个“蝌蚪”(图1)，已经从Tilibit纳米系统项目的合作公司那里设计和获得了。经过折纸设计和准备的初步培训后，您将被允许选择和设计折纸进一步调查。你还将接受原子力显微镜(AFM)方面的培训，并在第一年至少花一个学期在K.Voitchovsky的指导下在达勒姆进行AFM实验。根据您的兴趣，您还可以培训和执行这些复杂流体的大规模分子动力学模拟[4]。[1]Seeman，N.C.&Sleiman，H.F.DNA纳米技术。纳特。牧师。3，1(2017).[2]Siavashpouri，M.等人。利用DNA折纸进行手性胶体液晶的分子工程。纳特。马特。16,849-856(2017)。[3]Mason，T.G.使用推广的Stokes-Einstein方程估算复杂流体的粘弹模数。流变液。[4]Rosa，A.，Smrek，J.，Turner，M.S.&Michieleto，D.穿线诱导蝌蚪形状聚合物的动态转变。Arxiv 3-7(2019)。

DNA origami is an emerging field in nanotechnology and functional materials. It harnesses the information-encoding capability of DNA to form complex and responsive 3D shapes that may be used in a broad range of applications, from drug delivery to nanoelectronic circuits [1]. Origamis are traditionally studied in isolation but there is a growing interest to study the collective behaviour of dense solutions of origamis [2]. Thus, in this project we will explore the microrheology of dense solutions DNA origamis as a function of their design. This research direction is still at its beginnings and can uncover unprecedented ways to employ DNA origami with potentially substantial academic and industrial impact. Rheology (from panta rhei, Heraclitus) is the study of how fluids flow and how viscous or elastic they are on certain timescales. Microrheology is a technique that allows us to probe these viscoelastic behaviours using micron-sized particles embedded in the fluid and require minute amount of material [3]. The project will start by investigating a class of structures named "chimeric" that display combinations of looped and linear DNA [4]. The simplest of such structures is a "tadpole" (Fig. 1) and has already been designed and obtained from the company which is collaborating in the project, Tilibit nanosystems. After the initial training on origami design and preparation, you will be allowed to choose and design which origamis to investigate further. You will also be trained on Atomic Force Microscopy (AFM) and will spend at least a term in year 1 performing AFM experiments in Durham supervised by K. Voitchovsky. Depending on your inclination, you will also be able to train and perform large-scale molecular dynamics simulations of these complex fluids [4].[1] Seeman, N. C. & Sleiman, H. F. DNA nanotechnology. Nat. Rev. Mater. 3, 1 (2017).[2] Siavashpouri, M. et al. Molecular engineering of chiral colloidal liquid crystals using DNA origami. Nat. Mater. 16, 849-856 (2017).[3] Mason, T. G. Estimating the viscoelastic moduli of complex fluids using the generalized Stokes-Einstein equation. Rheol. Acta 39, 371-378 (2000).[4] Rosa, A., Smrek, J., Turner, M. S. & Michieletto, D. Threading-Induced Dynamical Transition in Tadpole-Shaped Polymers. arxiv 3-7 (2019).