Molecularly Engineered “Janus GroEL”: Application to Supramolecular Copolymerization with a Higher Level of Sequence Control

Herein we report the synthesis and isolation of a shape-persistent Janus protein nanoparticle derived from the biomolecular machine chaperonin GroEL (^AGroEL^B) and its application to DNA-mediated ternary supramolecular copolymerization. To synthesize ^AGroEL^B with two different DNA strands A and B at its opposite apical domains, we utilized the unique biological property of GroEL, i.e., Mg²⁺/ATP-mediated ring exchange between ^AGroEL^A and ^BGroEL^B with their hollow cylindrical double-decker architectures. This exchange event was reported more than 24 years ago but has never been utilized for molecular engineering of GroEL. We leveraged DNA nanotechnology to purely isolate Janus ^AGroEL^B and succeeded in its precision ternary supramolecular copolymerization with two DNA comonomers, A** and B*, that are partially complementary to A and B in ^AGroEL^B, respectively, and programmed to self-dimerize on the other side. Transmission electron microscopy allowed us to confirm the formation of the expected dual-periodic copolymer sequence −(^(B*/B)GroEL^(A/A**/A**/A)GroEL^(B/B*))– in the form of a laterally connected lamellar assembly rather than a single-chain copolymer

Programmable Living Materials Constructed with Dynamic Covalent Interface between Synthetic Polymers and B. subtilis

With advances in the field of synthetic biology increasingly allowing us to engineer living cells to perform intricate tasks, incorporating these engineered cells into the design of synthetic polymeric materials will enable programming materials with a wide range of biological functionalities. However, employable strategies for the design of synthetic polymers that seamlessly integrate cellular functionalities in materials are still largely limited. Herein, we report the first example of programmable living materials constructed with a dynamic covalent interface between designed synthetic polymers and engineered B. subtilis cells. We identified a molecular motif that forms reversible dynamic covalent bonds on B. subtilis cell surface. Combining block copolymers bearing this motif with genetically engineered B. subtilis yields programmable living materials that can be equipped with functionalities such as biosensing and on-demand elution of recombinant proteins. We further demonstrated that encapsulated cells could be reversibly retrieved and subjected to biological analyses. This work advances the current capabilities in engineered living materials, establishes the groundwork for building a myriad of synthetic polymeric materials integrating engineered living cells, and provides a platform for understanding the biology of cells confined within materials

An Open-Source Low-Cost Mobile Robot System with an RGB-D Camera and Efficient Real-Time Navigation Algorithm

Currently, mobile robots are developing rapidly and are finding numerous applications in industry. However, there remain a number of problems related to their practical use, such as the need for expensive hardware and their high power consumption levels. In this study, we propose a navigation system that is operable on a low-end computer with an RGB-D camera and a mobile robot platform for the operation of an integrated autonomous driving system. The proposed system does not require LiDARs or a GPU. Our raw depth image ground segmentation approach extracts a traversability map for the safe driving of low-body mobile robots. It is designed to guarantee real-time performance on a low-cost off-the-shelf single board computer with integrated SLAM, global path planning, and motion planning. We apply both rule-based and learning-based navigation policies using the traversability map. Running sensor data processing and other autonomous driving functions simultaneously, our navigation policies performs rapidly at a refresh rate of 18Hz for control command, whereas other systems have slower refresh rates. Our method outperforms current state-of-the-art navigation approaches within limited computation resources as shown in 3D simulation tests. In addition, we demonstrate the applicability of our mobile robot system through successful autonomous driving in an indoor environment. Our entire works including hardware and software are released under an open-source license (https://github.com/shinkansan/2019-UGRP-DPoom). Our detailed video is available in https://youtu.be/mf3IufUhPPM.Comment: 11 pages, 11 figure

Chemical fuel-driven dissipative living materials

Dissipative behaviors in biology are fuel-driven processes controlled by living cells and shape the structural and functional complexities in biological materials. It has inspired the development of various forms of synthetic dissipative materials controlled by time-dependent consumption of chemical or physical fuels, such as reactive chemical species, light, and electricity. To this date, synthetic living material featuring dissipative behaviors directly controlled by the fuel consumption of their constituent cells is unprecedented. In this paper, we report a chemical fuel-driven dissipative behavior of living materials comprising S. epidermidis and telechelic block copolymers. The macroscopic phase transition is controlled by D-glucose which serves a dual role of a competitive disassembling agent and a biological fuel source for living cells. Our work is a significant step towards constructing a synthetic dissipative living system and provides a new tool and knowledge to design emergent living materials

Engineered living materials

We are exploring the prepn. and properties of soft materials constituted from mixts. of macromols. and bacterial cells. Issues of interest include the roles of cell identity, cellularity, intercellular interaction, macromol. compn. and concn., and macromol.-cellular adhesion in detg. the phys. and biol. behavior of such systems

Engineered living materials

We are exploring the prepn. and properties of soft materials constituted from mixts. of macromols. and bacterial cells. Issues of interest include the roles of cell identity, cellularity, intercellular interaction, macromol. compn. and concn., and macromol.-cellular adhesion in detg. the phys. and biol. behavior of such systems