Engineering pH‐Responsive, Self‐Healing Vesicle‐Type Artificial Tissues with Higher‐Order Cooperative Functionalities

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2024-07, Vol.20 (30), p.e2311255-n/a
• Main Authors: Kojima, Tomoya, Noguchi, Yutaro, Terasaka, Koichi, Asakura, Kouichi, Banno, Taisuke
• Format: Article
• Language: English
• Subjects: actuation; Artificial Cells - chemistry; Artificial tissues; Automation; Damage detection; Functional materials; Healing; Hydrogen-Ion Concentration; Industrial robots; Manufacturing engineering; protocells; Robotics; Robust control; salt bridge; self‐healing; Smart materials; Survivability; Tissue Engineering - methods; Vesicles
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.202311255

Multicellular organisms demonstrate a hierarchical organization where multiple cells collectively form tissues, thereby enabling higher‐order cooperative functionalities beyond the capabilities of individual cells. Drawing inspiration from this biological organization, assemblies of multiple protocells are developed to create novel functional materials with emergent higher‐order cooperative functionalities. This paper presents new artificial tissues derived from multiple vesicles, which serve as protocellular models. These tissues are formed and manipulated through non‐covalent interactions triggered by a salt bridge. Exhibiting pH‐sensitive reversible formation and destruction under neutral conditions, these artificial vesicle tissues demonstrate three distinct higher‐order cooperative functionalities: transportation of large cargoes, photo‐induced contractions, and enhanced survivability against external threats. The rapid assembly and disassembly of these artificial tissues in response to pH variations enable controlled mechanical task performance. Additionally, the self‐healing property of these artificial tissues indicates robustness against external mechanical damage. The research suggests that these vesicles can detect specific pH environments and spontaneously assemble into artificial tissues with advanced functionalities. This leads to the possibility of developing intelligent materials with high environmental specificity, particularly for applications in soft robotics. Inspired by multicellular organisms, new artificial tissues derived from multiple vesicles via salt bridges are reported, exhibiting reversible tissue formation/destruction in response to pH, self‐healing, the ability to perform multiple mechanical tasks, and the potential to control degradability. Among them, three higher‐order cooperative functionalities that cannot be achieved in only one vesicle have emerged: large‐cargo transportation, photo‐induced contractions, and higher survivability against external invasions.