The field of microrobotics deals with miniaturized robotic machines at the millimeter scale. People are particularly excited about how these microrobotics applications could achieve things larger machines can’t. Here are five exciting ways they can push the boundaries.

1. Assembling Microscopic Components in Manufacturing Plants

As robots have gotten smaller, so have many of the products manufacturers rely on robotic equipment to build. Robotics experts have automated many tasks, but the assembly of microscopic parts has remained out of reach until recently.

A recent case involved researchers using lasers to create miniature robots from bubbles. The machines could create inseparable shapes from components, then lift and move tiny parts and drop them into interconnected structures.

The Chinese Academy of Sciences team focused a laser underneath a piece of resin to create tiny bubbles in water. They controlled the size of the bubbles by rapidly turning the laser on and off and discovered that keeping the laser activated for longer periods created larger ones. The group made a tiny robot out of bubbles by changing the laser’s location. Turning the laser off made the bubbles dissolve, which enabled the microbot to drop the resin piece at the desired place.

The group made multiple bubble robots with different functions. Besides lifting and dropping parts, some pushed components or became rotational axes. A miniature 3D vehicle, chain and gears were some of the items produced through this work. Microrobotics applications like these could improve the manufacturing and handling of pieces only a few micrometers long.

Investigating how to use manufacturing robots is a careful, personalized process. People must choose the desired application and redesign their factories before bringing them into the facility. However, small and flexible robots have more opportunities to be used effectively.

2. Improving Oral Hygiene

People are interested in how they could deploy robots as swarms to make them collectively complete tasks faster. Previous research in this area centers on applications in areas such as disaster recovery and military exercises. However, microrobotics applications could also help people improve the results of everyday tasks.

Researchers from the University of Pennsylvania recently used a proof-of-concept study to demonstrate that swarm-capable microrobots could help people have cleaner teeth and gums. The group built the microbots from iron-oxide nanoparticles that show catalytic and magnetic activity.

They used a magnetic field to make the bots move and assume structures resembling either toothbrush bristles or dental floss. Then, once the microbots were in the right formation, a catalytic reaction produced antimicrobial substances that kill oral bacteria. Tests on fabricated and real human teeth showed the microbots could nearly eliminate the biofilms that can lead to cavities or gum disease.

The project suggested these tiny bots could one day get the same results as brushing, flossing and using mouthwash. Many people know the proper steps to take for healthier teeth and gums but fall short of the best practices. These robots could change that.

3. Enabling Movement Through Vibration-Sensing Capabilities

Major considerations of microrobot design center on making the tiny machines move and retain their power during real-world applications. Robot designers that want to make their devices operate without external power often explore piezoelectric materials' potential. They produce voltage in response to interaction with a force. Some efforts use someone’s movement to charge their phone. However, piezoelectric principles could also improve microbotics applications.

In one example, Georgia Tech researchers developed 3D-printed microrobots that move by capturing the vibrational energy from piezoelectric actuators, ultrasounds or tiny speakers. Each microbot is about 2 millimeters long, or approximately the size of the world’s smallest ant. They can move about four times their length every second despite their size.

The microbots have 3D-printed polymer bodies with piezoelectric actuators. The vibrational energy makes the machines move their bristle-like legs up and down. They can also bend their legs in certain directions according to the vibration’s resonant response.

The team developed prototypes they could control by adjusting the vibrational frequency. Each robot has four or six legs, and one of the researchers created hundreds of designs to find the best options.

The team said the robots could eventually move materials, sense environmental changes or be used for various other reasons. However, the manufacturing technique must become more scalable to make these microrobotics applications realistic. Each bot currently takes a while to build, making ramping up production infeasible. Plus, the researchers also want to find ways to connect two robots, increasing their steering capabilities.

4. Destroying Tumor Cells

Cancer treatment options are significantly increasing, largely due to technological advancements. People are particularly interested in how they could improve the outcomes of interventions like chemotherapy. One microbot-related application at the Max Planck Institute for Intelligent Systems involved creating robots with a hybrid approach that added artificial components to E. coli bacteria.

Researchers attached numerous nanoliposomes to the bacteria’s exterior. Each one contained drug carriers that melt after exposure to near-infrared light. The team then placed magnetic nanoparticles on each bot, allowing them to be steered to specific tumor cells. Finally, the researchers secured the nanoliposomes and magnetic nanoparticles to the microbots with rope made from two proteins.

E. coli bacteria can swim quickly through various liquids. However, it also senses chemical characteristics such as low oxygen levels or high acidity. Tumors have both those attributes.

These microrobots activated the patient’s immune system and enabled more precise targeting of therapies. People have used bacteria-mediated tumor therapy for more than a century. However, these researchers believe adding microrobots to the process would lead to significant improvements. They allow using a minimally invasive method for precise delivery.

5. Developing Wireless Autonomous Microrobots

Engineers are always looking for practical ways to improve miniaturized robots. That provides a higher likelihood people can use them in more places.

Consider the results of a collaborative effort where people gave microrobots electronic “brains.” Each brain measured only 100 to 250 micrometers. However, the components allowed tiny machines to move independently without wires or lasers.

Each brain has a complementary metal-oxide-semiconductor (CMOS) clock circuit with 1,000 transistors. The circuit’s signal produces phase-shifted square wave frequencies that inform the robot’s gait. Each bot is approximately 10,000 times smaller than other robotics inventions that use onboard CMOS electronics. They can also walk at speeds surpassing 10 micrometers per second.

People working on this project said the potential use cases span from performing surgeries to detecting chemicals. Eventually, the research will involve giving the robot a command and letting the brain figure out how to execute it.

Microrobotics Applications Have Abundant Potential

The world has come a long way from robots that stayed behind safety cages. Now, people work around them all the time, and some of these machines go inside the body. These microrobotics applications are in the research phase, but more potential use cases will emerge as they develop.