O09_01

Towards the Construction of Next-Generation Molecular Robots with Quick Motion and Information Processing

Shin-ichiro M. NOMURA *

Department of Robotics, Graduate school of Engineering, Tohoku University
( * E-mail: shinichiro.nomura.b5@tohoku.ac.jp)

Molecular robotics is a pioneering field of engineering that enables the development of robots capable of efficient operation at the micrometer to nanometer scales by designing and constructing sensors, control circuits, and actuators at the molecular level. This technology has the potential to bring about new innovations in various fields, including medicine and environmental monitoring, such as drug delivery and environmental sensing. Lipid vesicles, or liposomes, have been studied as a promising body for these robots to maintain functional separation and targeted operation of molecular systems. These vesicles, at a microscale size, are expected to perform significant functions[1]. However, these vesicles, which typically carry a payload of approximately 10^-15L, contain only a few molecules even at pM concentrations, limiting the processing capabilities that can be achieved by individual vesicles.
This limitation has led to growing interest in multicellular molecular robots that can handle and coordinate multiple types of artificial cellular compartments. Recently, we successfully developed an artificial multicellular platform that spontaneously and stably formed structures with diameters exceeding several centimeters[2]. This platform is currently being studied as a macroscopic drug delivery system.
In conjunction with this, we have discovered a novel mechanism as a molecular sensor, where single-stranded DNA (ssDNA) with specific base sequences can be transmitted across lipid membranes into the interior of artificial cells through hybridization with cholesterol-modified ssDNA—a system we have termed “Chabashira”[3]. With further refinement, this mechanism is expected to enable molecular sensing and processing between the internal environment of the molecular robot and its external surroundings.
As the size of these platforms increases beyond the centimeter scale, the effectiveness of simple diffusion as a means of stirring diminishes. To address this, we have found a phenomenon in which a porous body, utilizing the Marangoni effect at the gas-liquid interface, can achieve high-speed motion (~30 mm/s) to effectively stir molecules within an aqueous solution[4]. We are currently trying to integrate these novel component technologies to construct a “next-generation molecular robot” that operates at high speeds in response to environmental stimuli while performing molecular information processing. In this presentation, we discuss the development and prospects of this research.
[1] Y. Sato et al., Sci Robot 2017, 2, DOI 10.1126/scirobotics.aal3735.
[2] R. J. Archer et al., Langmuir 2023, 39, 4863–4871.
[3] K. Yoshida et al., ChemRxiv 2024, DOI 10.26434/chemrxiv-2024-571kp.
[4] R. Archer et al., ChemRxiv 2024, DOI 10.26434/chemrxiv-2024-3kb8h.