Cell-sized robots can sense their environment

Researchers at MIT have created what may be the smallest robots yet that can sense their environment, store data, and even carry out computational tasks. These nanorobots are the size of a human cell and they could flow through intestines or pipelines to detect problems.

Made of electronic circuits coupled to minute particles, the devices could flow through intestines or pipelines to detect problems.


David L. Chandler | MIT News Office 

Researchers at MIT have created what may be the smallest robots yet that can sense their environment, store data, and even carry out computational tasks. These devices, which are about the size of a human egg cell, consist of tiny electronic circuits made of two-dimensional materials, piggybacking on minuscule particles called colloids.

Colloids, which insoluble particles or molecules anywhere from a billionth to a millionth of a meter across, are so small they can stay suspended indefinitely in a liquid or even in air. By coupling these tiny objects to complex circuitry, the researchers hope to lay the groundwork for devices that could be dispersed to carry out diagnostic journeys through anything from the human digestive system to oil and gas pipelines, or perhaps to waft through air to measure compounds inside a chemical processor or refinery.

“We wanted to figure out methods to graft complete, intact electronic circuits onto colloidal particles,” explains Michael Strano, the Carbon C. Dubbs Professor of Chemical Engineering at MIT and senior author of the study, which was published today in the journal Nature Nanotechnology. MIT postdoc Volodymyr Koman is the paper’s lead author.

“Colloids can access environments and travel in ways that other materials can’t,” Strano says. Dust particles, for example, can float indefinitely in the air because they are small enough that the random motions imparted by colliding air molecules are stronger than the pull of gravity. Similarly, colloids suspended in liquid will never settle out.

Strano says that while other groups have worked on the creation of similarly tiny robotic devices, their emphasis has been on developing ways to control movement, for example by replicating the tail-like flagellae that some microbial organisms use to propel themselves. But Strano suggests that may not be the most fruitful approach, since flagellae and other cellular movement systems are primarily used for local-scale positioning, rather than for significant movement. For most purposes, making such devices more functional is more important than making them mobile, he says.

Tiny robots made by the MIT team are self-powered, requiring no external power source or even internal batteries. A simple photodiode provides the trickle of electricity that the tiny robots’ circuits require to power their computation and memory circuits. That’s enough to let them sense information about their environment, store those data in their memory, and then later have the data read out after accomplishing their mission.

Such devices could ultimately be a boon for the oil and gas industry, Strano says. Currently, the main way of checking for leaks or other issues in pipelines is to have a crew physically drive along the pipe and inspect it with expensive instruments. In principle, the new devices could be inserted into one end of the pipeline, carried along with the flow, and then removed at the other end, providing a record of the conditions they encountered along the way, including the presence of contaminants that could indicate the location of problem areas. The initial proof-of-concept devices didn’t have a timing circuit that would indicate the location of particular data readings, but adding that is part of ongoing work.

Similarly, such particles could potentially be used for diagnostic purposes in the body, for example to pass through the digestive tract searching for signs of inflammation or other disease indicators, the researchers say.

Most conventional microchips, such as silicon-based or CMOS, have a flat, rigid substrate and would not perform properly when attached to colloids that can experience complex mechanical stresses while travelling through the environment. In addition, all such chips are “very energy-thirsty,” Strano says. That’s why Koman decided to try out two-dimensional electronic materials, including graphene and transition-metal dichalcogenides, which he found could be attached to colloid surfaces, remaining operational even after after being launched into air or water. And such thin-film electronics require only tiny amounts of energy. “They can be powered by nanowatts with subvolt voltages,” Koman says.

Why not just use the 2-D electronics alone? Without some substrate to carry them, these tiny materials are too fragile to hold together and function. “They can’t exist without a substrate,” Strano says. “We need to graft them to the particles to give them mechanical rigidity and to make them large enough to get entrained in the flow.”

But the 2-D materials “are strong enough, robust enough to maintain their functionality even on unconventional substrates” such as the colloids, Koman says.

The nanodevices they produced with this method are autonomous particles that contain electronics for power generation, computation, logic, and memory storage. They are powered by light and contain tiny retroreflectors that allow them to be easily located after their travels. They can then be interrogated through probes to deliver their data. In ongoing work, the team hopes to add communications capabilities to allow the particles to deliver their data without the need for physical contact.

Other efforts at nanoscale robotics “haven’t reached that level” of creating complex electronics that are sufficiently small and energy efficient to be aerosolized or suspended in a colloidal liquid. These are “very smart particles, by current standards,” Strano says, adding, “We see this paper as the introduction of a new field” in robotics.

The research team, all at MIT, included Pingwei Liu, Daichi Kozawa, Albert Liu, Anton Cottrill, Youngwoo Son, and Jose Lebron. The work was supported by the U.S. Office of Naval Research and the Swiss National Science Foundation.

Reprinted with permission of MIT News

How to vaccinate the world’s most vulnerable? Build global partnerships.

Pfizer's partnerships strengthen their ability to deliver vaccines in developing countries.

Susan Silbermann, Global President of Pfizer Vaccines, looks on as a health care worker administers a vaccine in Rwanda. Photo: Courtesy of Pfizer.
  • Community healthcare workers face many challenges in their work, including often traveling far distances to see their clients
  • Pfizer is helping to drive the UN's sustainable development goals through partnerships.
  • Pfizer partnered with AMP and the World Health Organization to develop a training program for healthcare workers.
Keep reading Show less
Sponsored

Scientists find a horrible new way cocaine can damage your brain

Swiss researchers identify new dangers of modern cocaine.

Getty Images
Mind & Brain
  • Cocaine cut with anti-worming adulterant levamisole may cause brain damage.
  • Levamisole can thin out the prefrontal cortex and affect cognitive skills.
  • Government health programs should encourage testing of cocaine for purity.
Keep reading Show less

Bespoke suicide pods now available for death in style

Sarco assisted suicide pods come in three different styles, and allow you to die quickly and painlessly. They're even quite beautiful to look at.

The Sarco assisted suicide pod
Technology & Innovation

Death: it happens to everyone (except, apparently, Keanu Reeves). But while the impoverished and lower-class people of the world die in the same ol' ways—cancer, heart disease, and so forth—the upper classes can choose hip and cool new ways to die. Now, there's an assisted-suicide pod so chic and so stylin' that peeps (young people still say peeps, right?) are calling it the "Tesla" of death... it's called... the Sarco! 

Keep reading Show less
Politics & Current Affairs

Political division is nothing new. Throughout American history there have been numerous flare ups in which the political arena was more than just tense but incideniary. In a letter addressed to William Hamilton in 1800, Thomas Jefferson once lamented about how an emotional fervor had swept over the populace in regards to a certain political issue at the time. It disturbed him greatly to see how these political issues seemed to seep into every area of life and even affect people's interpersonal relationships. At one point in the letter he states:

"I never considered a difference of opinion in politics, in religion, in philosophy, as cause for withdrawing from a friend."

Today, we Americans find ourselves in a similar situation, with our political environment even more splintered due to a number of factors. The advent of mass digital media, siloed identity-driven political groups, and a societal lack of understanding of basic discursive fundamentals all contribute to the problem.

Civil discourse has fallen to an all time low.

The question that the American populace needs to ask itself now is: how do we fix it?


Discursive fundamentals need to be taught to preserve free expression

In a 2017 Free Speech and Tolerance Survey by Cato, it was found that 71% of Americans believe that political correctness had silenced important discussions necessary to our society. Many have pointed to draconian university policies regarding political correctness as a contributing factor to this phenomenon.

It's a great irony that, colleges, once true bastions of free-speech, counterculture and progressiveness, have now devolved into reactionary tribal politics.

Many years ago, one could count on the fact that universities would be the first places where you could espouse and debate any controversial idea without consequence. The decline of staple subjects that deal with the wisdom of the ancients, historical reference points, and civic discourse could be to blame for this exaggerated partisanship boiling on campuses.

Young people seeking an education are given a disservice when fed biased ideology, even if such ideology is presented with the best of intentions. Politics are but one small sliver for society and the human condition at large. Universities would do well to instead teach the principles of healthy discourse and engagement across the ideological spectrum.

The fundamentals of logic, debate and the rich artistic heritage of western civilization need to be the central focus of an education. They help to create a well-rounded citizen that can deal with controversial political issues.

It has been found that in the abstract, college students generally support and endorse the first amendment, but there's a catch when it comes to actually practicing it. This was explored in a Gallup survey titled: Free Expression on Campus: What college students think about First amendment issues.

In their findings the authors state:

"The vast majority say free speech is important to democracy and favor an open learning environment that promotes the airing of a wide variety of ideas. However, the actions of some students in recent years — from milder actions such as claiming to be threatened by messages written in chalk promoting Trump's candidacy to the most extreme acts of engaging in violence to stop attempted speeches — raise issues of just how committed college students are to
upholding First Amendment ideals.

Most college students do not condone more aggressive actions to squelch speech, like violence and shouting down speakers, although there are some who do. However, students do support many policies or actions that place limits on speech, including free speech zones, speech codes and campus prohibitions on hate speech, suggesting that their commitment to free speech has limits. As one example, barely a majority think handing out literature on controversial issues is "always acceptable."

With this in mind, the problems seen on college campuses are also being seen on a whole through other pockets of society and regular everyday civic discourse. Look no further than the dreaded and cliche prospect of political discussion at Thanksgiving dinner.

Talking politics at Thanksgiving dinner

As a result of this increased tribalization of views, it's becoming increasingly more difficult to engage in polite conversation with people possessing opposing viewpoints. The authors of a recent Hidden Tribes study broke down the political "tribes" in which many find themselves in:

  • Progressive Activists: younger, highly engaged, secular, cosmopolitan, angry.
  • Traditional Liberals: older, retired, open to compromise, rational, cautious.
  • Passive Liberals: unhappy, insecure, distrustful, disillusioned.
  • Politically Disengaged: young, low income, distrustful, detached, patriotic, conspiratorial
  • Moderates: engaged, civic-minded, middle-of-the-road, pessimistic, Protestant.
  • Traditional Conservatives: religious, middle class, patriotic, moralistic.
  • Devoted Conservatives: white, retired, highly engaged, uncompromising,
    Patriotic.

Understanding these different viewpoints and the hidden tribes we may belong to will be essential in having conversations with those we disagree with. This might just come to a head when it's Thanksgiving and you have a mix of many different personalities, ages, and viewpoints.

It's interesting to note the authors found that:

"Tribe membership shows strong reliability in predicting views across different political topics."

You'll find that depending on what group you identify with, that nearly 100 percent of the time you'll believe in the same way the rest of your group constituents do.

Here are some statistics on differing viewpoints according to political party:

  • 51% of staunch liberals say it's "morally acceptable" to punch Nazis.
  • 53% of Republicans favor stripping U.S. citizenship from people who burn the American flag.
  • 51% of Democrats support a law that requires Americans use transgender people's preferred gender pronouns.
  • 65% of Republicans say NFL players should be fired if they refuse to stand for the anthem.
  • 58% of Democrats say employers should punish employees for offensive Facebook posts.
  • 47% of Republicans favor bans on building new mosques.

Understanding the fact that tribal membership indicates what you believe, can help you return to the fundamentals for proper political engagement

Here are some guidelines for civic discourse that might come in handy:

  • Avoid logical fallacies. Essentially at the core, a logical fallacy is anything that detracts from the debate and seeks to attack the person rather than the idea and stray from the topic at hand.
  • Practice inclusion and listen to who you're speaking to.
  • Have the idea that there is nothing out of bounds for inquiry or conversation once you get down to an even stronger or new perspective of whatever you were discussing.
  • Keep in mind the maxim of : Do not listen with the intent to reply. But with the intent to understand.
  • We're not trying to proselytize nor shout others down with our rhetoric, but come to understand one another again.
  • If we're tied too closely to some in-group we no longer become an individual but a clone of someone else's ideology.

Civic discourse in the divisive age

Debate and civic discourse is inherently messy. Add into the mix an ignorance of history, rabid politicization and debased political discourse, you can see that it will be very difficult in mending this discursive staple of a functional civilization.

There is still hope that this great divide can be mended, because it has to be. The Hidden Tribes authors at one point state:

"In the era of social media and partisan news outlets, America's differences have become
dangerously tribal, fueled by a culture of outrage and taking offense. For the combatants,
the other side can no longer be tolerated, and no price is too high to defeat them.
These tensions are poisoning personal relationships, consuming our politics and
putting our democracy in peril.


Once a country has become tribalized, debates about contested issues from
immigration and trade to economic management, climate change and national security,
become shaped by larger tribal identities. Policy debate gives way to tribal conflicts.
Polarization and tribalism are self-reinforcing and will likely continue to accelerate.
The work of rebuilding our fragmented society needs to start now. It extends from
re-connecting people across the lines of division in local communities all the way to
building a renewed sense of national identity: a bigger story of us."

We need to start teaching people how to approach subjects from less of an emotional or baseless educational bias or identity, especially in the event that the subject matter could be construed to be controversial or uncomfortable.

This will be the beginning of a new era of understanding, inclusion and the defeat of regressive philosophies that threaten the core of our nation and civilization.