Scientists have found a solution to make millimeter-scale robots multi-functional which will revolutionize the methods of microsurgery and endoscopy.

Robotics is an interdisciplinary branch of engineering that generally includes Mechanical Engineering, Computer Science, and Electronics Engineering. In special cases, some other branches of science are also involved. It deals with all the phases of robot construction from designing to operation. Robotics has certainly progressed a lot in the recent decades due to the technological advancement and as a result, we have highly efficient robots who can serve us in various domains. From Military Robots to Household Robots and from Nano Robots to Agricultural Robots, they are everywhere and considering the trend of their growth, their number will only increase in the coming years.

Portability is a massive factor in today’s world and scientists try extremely hard to incorporate maximum features without making a gadget too bulky to carry. Following similar lines, the researchers of the Boston University and John A. Paulson School of Engineering and Applied Sciences (SEAS) at Harvard joined forces to come up with a new manufacturing process through which we can create tiny, spider-shaped robots at the scale of a millimeter with all their features on the micrometer-scale. This invention is expected to revolutionize the future as difficult-to-access places will become examinable. An extremely important application of these multi-functional robots is their use in microsurgery where they will be able to analyze those regions which are too small for rigid robots.

The researching team achieved this milestone by developing an integrated fabrication technique that allows the construction of soft robots on such a minute scale. For sake of demonstrating their discovery, they recreated the millimeter-sized Australian Peacock spider from a single sheet of elastic material. It resembles the original creature completely in terms of its motion, color, and body shape. Dr. Sheila Russo, an Assistant Professor at the Boston University who is also the Co-author of the study, described their invention by saying,

“The smallest soft robotic systems still tend to be very simple, with usually only one degree of freedom, which means that they can only actuate one particular change in shape or type of movement. By developing a new hybrid technology that merges three different fabrication techniques, we created a soft robotic spider made only of silicone rubber with 18 degrees of freedom, encompassing changes in structure, motion, and color, and with tiny features in the micrometer range.”

Russo was serving as a Postdoctoral Fellow in the Dr. Robert Wood’s group that initiated this research at the Wyss Institute and SEAS. He is a Charles River Professor of Engineering and Applied Sciences at SEAS and a Co-leader of the Bio-inspired Soft Robotics Platform at the Wyss Institute. He claims that this new technique will help in achieving similar levels of functionality and complexity within these small-scaled robots as offered by their rigid counterparts. The team of researchers used Microfluidic Origami for Reconfigurable Pneumatic/Hydraulic (MORPH) devices for their research.

The development phase of this spider-shaped robot began with a soft Lithography technique which was used to generate 12 layers of an elastic silicone. Each of these layers is cut with a laser micromachining technique to maintain consistency in their size. All of them are bonded together, with each of them attached to the one under it, to create a rough 3D structure of a soft spider. This structure is then given its final shape by integrating a pre-conceived network of hollow microfluidic channels into individual layers. After that, ‘Injection-Induced Self-Folding’ is used to pressurize one of the microfluidic channels from the outside with a curable resin. This allows the individual and the neighboring layers to bend locally in order to complete the final design once the resin starts to harden. The first author of the study, Dr. Tommaso Ranzani, explained the process in the following words:

“We can precisely control this origami-like folding process by varying the thickness and relative consistency of the silicone material adjacent to the channels across different layers or by laser-cutting at different distances from the channels. During pressurization, the channels then function as actuators that induce a permanent structural change.”

The remaining microfluidic channels are used as additional actuators to add specific colors and movements to these spider-shaped robots. Ranzani told the world that this MORPH system was developed within a few days and its design can be optimized easily through fast iterations. He said,

“This first MORPH system was fabricated in a single, monolithic process that can be performed in few days and easily iterated in design optimization efforts.”