Biohybrid Variable‐Stiffness Soft Actuators that Self‐Create Bone. Issue 8 (17th January 2022)

• Record Type: Journal Article
• Authors: Cao, Danfeng; Martinez, Jose G.; Hara, Emilio Satoshi; Jager, Edwin W. H.
• Is Part Of: Advanced materials. Volume 34:Issue 8(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-01-17
• Subjects: actuators -- biohybrids -- mineralization -- variable stiffness; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202107345
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: Inspired by the dynamic process of initial bone development, in which a soft tissue turns into a solid load‐bearing structure, the fabrication, optimization, and characterization of bioinduced variable‐stiffness actuators that can morph in various shapes and change their properties from soft to rigid are hereby presented. Bilayer devices are prepared by combining the electromechanically active properties of polypyrrole with the compliant behavior of alginate gels that are uniquely functionalized with cell‐derived plasma membrane nanofragments (PMNFs), previously shown to mineralize within 2 days, which promotes the mineralization in the gel layer to achieve the soft to stiff change by growing their own bone. The mineralized actuator shows an evident frozen state compared to the movement before mineralization. Next, patterned devices show programmed directional and fixated morphing. These variable‐stiffness devices can wrap around and, after the PMNF‐induced mineralization in and on the gel layer, adhere and integrate onto bone tissue. The developed biohybrid variable‐stiffness actuators can be used in soft (micro‐)robotics and as potential tools for bone repair or bone tissue engineering. Abstract : Bioinduced variable‐stiffness actuators are prepared by combining polypyrrole and alginate gel functionalized with cell‐derived plasma membrane nanofragments. The actuators can morph in various shapes and change their properties from soft to rigid by growing their own bone, due to mineralization, within 2 days. Different patterning for programmed directional movements, and morphing and adhesion to bone tissue are also demonstrated.