3D‐Printed Microrobots with Integrated Structural Color for Identification and Tracking

Abstract

The implementation of two‐photon polymerization (TPP) in the microrobotics community has permitted the fabrication of complex 3D structures at the microscale, creating novel platforms with potential biomedical applications for minimizing procedure invasiveness and diagnosis accuracy. Although advanced functionalities for manipulation and drug delivery tasks have been explored, one remaining challenge is achieving improved visualization, identification, and accurate closed‐loop control of microscale robots. To enable this, distinguishable identifying and trackable features must be included on the microrobot. Toward this end, the construction of micro‐ and nanoscale patterns using TPP is demonstrated for the first time on microrobot surfaces with the intent of mimicking color‐expressing nanostructures present on beetles or butterflies. The patterns provide identification and tracking targets due to their vivid color expression under visible light. Helical and rectangular microrobots are designed with the topical patterns and further functionalized with magnetic materials to be externally actuated by magnetic fields. Vision‐based tracking of a 20 μm × 30 μm colored feature on a 100 μm‐long helical microrobot using a fixed angular position light source during microrobotic motion is shown. This versatile structural color patterning approach shows great potential for the visual differentiation of various microrobots and tracking for improved closed‐loop control.

Multifunctional magnetic soft composites: a review

“…The properties and functionalities of the soft material systems are related to the configurations and deformations of the structures. With the ability to undergo large deformations as programmed, the mechanical [ 46 , 80 , 107 , 121 ], optical [ 112 , 122 ], and acoustic properties [ 120 , 123 – 127 ], or wettability [ 106 , 119 ] of magnetic soft composites are actively tunable under the applied magnetic field. For instance, an array of microplates embedded with aligned Fe microparticles possess a superhydrophobic or hydrophilic surface on each side of the plates ( figure 5(d) [ 119 ]).…”

Light‐Powered Microrobots: Challenges and Opportunities for Hard and Soft Responsive Microswimmers

“…A more elaborate description of the imaging modalities and their applications for biomedical microrobots can be found in a recent review article from Pané et al [185] Recently, an interesting approach based on structural colors was developed for identifying and tracking 3D-printed microrobots. [186] An identification and tracking segment was included in the microrobot body. The segment consisted of a micropattern displaying structural colors upon metallization.…”

“…Recently, an interesting approach based on structural colors was developed for identifying and tracking 3D‐printed microrobots. [ 186 ] An identification and tracking segment was included in the microrobot body. The segment consisted of a micropattern displaying structural colors upon metallization.…”

4D Printing: Enabling Technology for Microrobotics Applications

“…One solution used by multiple studies is to coat the structure in a metallic layer postfabrication, giving it magnetic properties. [156][157][158] Another approach is to use a multiphase material, as will be discussed further in Section 4.2.…”