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的信息编码能力来形成复杂和响应的3D形状，可以用于从药物输送到纳米电子电路的广泛应用。传统上对折纸的研究是孤立的，但对研究稠密解的集体行为越来越感兴趣。因此，在这个项目中，我们将探索致密溶液DNA折纸的微流变学作为其设计的功能。这个研究方向仍处于起步阶段，可以发现前所未有的方法来使用DNA折纸，具有潜在的重大学术和工业影响。流变学（源自赫拉克利特）是研究流体如何流动以及它们在一定时间尺度上的粘性或弹性。微流变学是一种技术，它允许我们使用嵌入流体中的微米级颗粒来探测这些粘弹性行为，并且只需要少量的材料。该项目将从研究一类名为“嵌合”的结构开始，这种结构显示环状和线性DNA[4]的组合。这种结构中最简单的是“蝌蚪”（图1），已经由参与该项目的tilbit纳米系统公司设计并获得。在对折纸设计和准备的初步培训之后，您将被允许选择和设计进一步调查的折纸。您还将接受原子力显微镜（AFM）的培训，并将在第一年至少花一个学期在达勒姆进行AFM实验，由K. Voitchovsky监督。根据你的兴趣，你也将能够训练和执行这些复杂流体的大规模分子动力学模拟西曼，n.c.和斯莱曼，h.f. DNA纳米技术。[j] .自然科学与工程，2016,31 (1):1 - 8 .Siavashpouri等人。利用DNA折纸技术研究手性胶体液晶的分子工程。[j] .自然科学学报，2016,33 (5):849-856 (2017).使用广义Stokes-Einstein方程估计复杂流体的粘弹性模量。Rheol。学报39,371-378 (2000).[j]Rosa， A, Smrek， J, Turner， M. S.和Michieletto， D.蝌蚪形聚合物的螺纹诱导动力学转变。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).