A Review of Soft Microrobots: Material, Fabrication, and Actuation

Abstract

Microrobots have shown great potential in many applications, such as non‐invasive surgery, tissue engineering, precision medicine, and environmental remediation. Within the past decade, soft microrobot has become one of the important branches. It is aimed to create soft and deformable microrobots with high bioaffinity, which can perform complex tasks noninvasively in inaccessible small spaces in the body. Herein, the latest research progress of soft microrobots regarding the three cornerstones of this field is reviewed: material, fabrication, and actuation. First, various materials that are used for the fabrication of soft microrobots are summarized, and their characteristics and functions are discussed. Second, various fabrication methods of soft microrobots are introduced, and their applicability to different materials is discussed. Third, the actuation methods of soft microrobots are discussed, as well as their pros, cons, and adaptability. Moreover, the outstanding behaviors of soft microrobots in biomedical and environmental applications are introduced with some typical examples published recently. Finally, current clinical use challenges of soft microrobots are pointed out, and their intelligentization is proposed and discussed for further innovative development.

A functionalized CNT-azobenzene-PVA-based self-healing aqueous gel as a conductive photo-responsive actuator

“…Recently, switchable conductance with light via photochromic moieties, such as azobenzene, diarylethene, and spiropyran has acquired a lot of attention because of its applications in contact-free manipulation of conductance as optical switches. 63–68 Sciascia et al , used diarylethene as an optical switch for SWCNT-incorporated polymer composite. 69 Heinke and coworkers presented a MOF with spiropyran as a photochromic molecule for electronic conductance switching.…”