Application of micro-3D-printing to create tiny, color-expressing robotic parts

Researchers utilized micro-3D-printing to create robotic parts smaller than a human hair, which possessed color-expressing features for identification and tracking of microrobots.

3D printing was initially used to create rapid, scaled prototypes of various parts. While it is commonly known for creating objects that can be seen or held, 3D printing technology has advanced to the point where structures can be fabricated on the micro-scale, making it possible to design intricate structures and use a wider range of materials.

Similarly, microrobotics has made significant progress over the past two decades. Researchers have gone from merely achieving controllable movement of microscale objects to developing advanced microrobot designs that can autonomously deliver therapeutic drugs to target sites and manipulate tiny objects for micro-manufacturing.

One of the major challenges in the field of mobile microrobotics is controlling microrobots operating in teams and swarms to perform collaborative and parallel tasks for medical or micro-manufacturing applications. To control individual microrobots, they must be easily identifiable and tracked in real-time using an imaging system, like a camera.

Two-photon polymerization (TPP) is a micro-3D-printing technique that can create detailed parts smaller than the diameter of a human hair. Recently, researchers at Purdue University’s Multi-Scale Robotics and Automation Lab used TPP to 3D print mobile microrobots with color-expressing features for microrobot identification and tracking. These features are not colors in the traditional sense but rather “structural colors”.

“Structural color occurs when visible light interacts with tiny patterned features that absorb and reflect light in different ways. The spacing, size, and shape of these tiny nanostructures trap light at a particular frequency producing an expression of a specific color,” said Cara Koepele, one of the lead researchers conducting the study. Another, Dr. Maria Guix, stated: “This is the same way that butterflies, beetles, and other insects found in nature express vivid colors.”

The team has successfully utilized a flexible 3D printing technique to integrate various color-expressing features into microrobotic systems, indicating the potential for efficient mass production. Professor David J. Cappelleri, who directs the Multi-Scale Robotics and Automation Lab, said: “We are excited about these results and look forward to exploring this phenomenon in more detail in order to tune the color expression for not only microrobot identifying and tracking purposes but also for creating novel on-board sensing and anti-counterfeiting capabilities for 3D-printed microrobots.”

This news is a creative derivative product from articles published in famous peer-reviewed journals and Govt reports:

1. C. A. Koepele, et al. ‘3D‐Printed Microrobots with Integrated Structural Color for Identification and Tracking‘, Advanced Intelligent Systems (2020). DOI:
R. L. Truby, J. A. Lewis, Nature 2016, 540, 371.
S. Rekštytė, T. Jonavičius, D. Gailevičius, M. Malinauskas, V. Mizeikis, E. G. Gamaly, S. Juodkazis, Adv. Opt. Mater. 2016, 4, 1209.
E. Diller, Found. Trends Robot. 2011, 2, 143.
M. Guix, C. C. Mayorga-Martinez, A. Merkoçi, Chem. Rev. 2014, 114, 6285.


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