Bulletin of the American Physical Society
APS March Meeting 2020
Volume 65, Number 1
Monday–Friday, March 2–6, 2020; Denver, Colorado
Session A28: Remote Control of Macromolecular DevicesInvited
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Sponsoring Units: DSOFT Chair: Carlos Castro, Ohio State University Room: 405-407 |
Monday, March 2, 2020 8:00AM - 8:36AM |
A28.00001: Electrical actuation of DNA-based nanorobotic structures Invited Speaker: Friedrich Simmel DNA nanotechnology provides efficient methods for the sequence-programmable construction of mechanical devices with nanoscale dimensions. The resulting nanomachines could serve as tools for the manipulation of macromolecules with similar functionalities as mechanical tools and machinery in the macroscopic world. In order to drive and control these machines and to perform specific tasks, fast, reliable and repeatable actuation are required. In this context, we recently developed an effective method for actuating DNA nanostructures using externally applied electric fields. Electrical control allows us to dynamically drive |
Monday, March 2, 2020 8:36AM - 9:12AM |
A28.00002: Real-time magnetic actuation of DNA nanodevices Invited Speaker: Ratnasingham Sooryakumar Recent advances in biomolecular nanotechnology, in particular DNA nanotechnology, have led to molecular devices with precisely designed motion, mechanical properties, and triggered conformational changes. This talk will report an advancement in this field that opens the door to manipulate molecules and nanomaterials with programmed or user-driven magnetic control in real-time. |
Monday, March 2, 2020 9:12AM - 9:48AM |
A28.00003: Rapid photoactuation of a DNA nanostructure using an internal photocaged trigger strand Invited Speaker: Nicholas Stephanopoulos DNA nanotechnology is one of the most powerful methods for constructing nano-mechanical devices. The ability to actuate these devices on-demand would provide a powerful method for creating dynamic nanomachines that can reconfigure nanostructures, apply precisely defined forces, or spatiotemporally control self-assembly. Typically, DNA nanostructures have been temporally modulated by either 1) introducing external toehold-mediated displacement strands, or 2) incorporating photoswitchable azobenzene nucleotides that can reversibly break hybridization. However, these approaches suffer from drawbacks like 1) the need to introduce an exogenous strand (which is not feasible for many applications, especially in biology), and 2) slow kinetics or undesired reversibility. To circumvent these limitations, we have photo-caged the displacement strands within an existing nanostructure, preventing their action until illuminated. These “spring-loaded” nanostructures are in a metastable state until activated by light, whereupon the high local concentration of the displacement strand will drive irreversible nanostructure reconfiguration. To demonstrate this concept, we designed a nano-mechanical tweezer that switches between the closed and open state with UV light. In effect, this device can apply a nano-mechanical force within a few seconds of illumination, paving the way for dynamic nanomachines that can exert controlled motion. The tweezer was analyzed using AFM, FRET, and computational simulations. Our results demonstrate that the photocaged mechanism is efficient and fast, surpassing externally added strand displacement by almost two orders of magnitude. We envision that this approach will allow for light-activated nanomachines in the future for biophysical studies with cells. |
Monday, March 2, 2020 9:48AM - 10:24AM |
A28.00004: Rapid Reconfiguration and Tunable Control of DNA-based Mechanisms Invited Speaker: Alexander E. Marras Precise robotic motion is ever-present within our cells with proteins like ATP synthase and kinesin, functioning much like macroscopic machines using multiple components and defined motion paths. Structural DNA nanotechnology enables researchers to construct mechanisms with similar functionality exhibiting nanoscale spatial and dynamic control by employing its vast physical design space and directed self-assembly methods. Our early work contributed to a library of DNA devices with controllable motion, primarily using strand invasion to bind or displace reconfigurable components with timescales of minutes or longer. Here, we present a strategy for tunable actuation in near real time. We demonstrate an approach using a simple modification to existing devices that adds weak binding sites on complementary components. A network of short DNA handles is activated by increasing cation concentration, raising the avidity of the network to join components. Likewise, reconfiguration is quickly reversible in decreased salt conditions. Actuation kinetics are measured via single molecule FRET using buffer exchange through a simple microfluidic system. This level of temporal control over DNA devices serves as a foundation for real-time manipulation of molecular systems. |
Monday, March 2, 2020 10:24AM - 11:00AM |
A28.00005: Hari Subramanian Invited Talk
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