{"id":36931,"date":"2019-06-27T12:14:07","date_gmt":"2019-06-27T16:14:07","guid":{"rendered":"https:\/\/sciencebusiness.technewslit.com\/?p=36931"},"modified":"2019-06-27T12:14:07","modified_gmt":"2019-06-27T16:14:07","slug":"engineered-microbe-bio-sensors-added-to-robotic-arm","status":"publish","type":"post","link":"https:\/\/technewslit.com\/sciencebusiness\/?p=36931","title":{"rendered":"Engineered Microbe Bio-Sensors Added to Robotic Arm"},"content":{"rendered":"
\"E.<\/a>
Escherichia coli, or E. coli, bacteria (National Institute of Allergy and Infectious Diseases)<\/figcaption><\/figure>\n

27 June 2019. Genetically-altered E. coli bacteria can act as sensors for certain chemicals, when installed on a programmable robotic arm and gripper. Engineering researchers at University of California in Davis and Carnegie Mellon University in Pittsburgh describe their system and proof-of-concept test results in yesterday’s issue of the journal Science Robotics<\/em><\/a> (paid subscription required).<\/p>\n

A team led by biomedical engineering professor Cheemeng Tang<\/a> at UC-Davis and Carnegie Mellon mechanical engineering professor Carmel Majidi<\/a> is aiming to improve the ability of robots to sense chemical signals in their immediate environment. Achieving this task, say the authors, requires biologically-based sensors that react in the presence of target chemicals, as well as components that convert the signals to electronic data on which other robotic system modules can act.<\/p>\n

Tang’s lab<\/a> at UC-Davis studies synthetic biological systems, including artificial cells and genetically-engineered organisms mainly for protein design, drug discovery, and treatments for disease. At Carnegie Mellon, Majidi’s group<\/a> investigates so-called soft materials that help make robotic systems safer for interacting with humans, including fabrication methods to produce those materials.<\/p>\n

Tang, Majidi, and colleagues first created sensors with engineered E. coli bacteria to react in the presence of IPTG<\/a>, short for isopropyl-beta-D-thiogalactoside, a commercially-available chemical used in lab cloning experiments. E. coli, or Escherichia coli<\/a>, is best known as a bacteria causing intestinal infections, although most strains of E. coli are harmless. Because E. coli is a well-studied bacteria, it is often used as a model organism in labs. In this case, the researchers engineered a form of E. coli to express fluorescing proteins that illuminate in the presence of IPTG. The engineered E. coli are stored and sealed in 3-D printed plastic wells, yet thin enough to allow IPTG signals to permeate.<\/p>\n

The researchers then designed a device to convert light from the altered E. coli into electronic data. For this task, the team uses a circuit with a light-emitting diode or LED that detects light given off by the engineered bacteria, and photo-transistor to convert the detected light into electronic signals. The circuit is printed on soft, flexible materials that can fit on the end of a robotic arm and gripper. Electronic data from the circuit are used to control the actions of a pneumatic network, or pneu-net<\/a>, actuator that bends the gripper device in the desired direction.<\/p>\n

The team tested their system with a hydrogel, a water-based polymer, infused with IPTG and released in a water bath. Sensors on the gripper reacted to the presence of IPTG and reported illumination intensities 300 times greater than a comparison fluid without IPTG. The researchers then devised an exercise, where the robotic gripper is programmed to pick-up and move a plastic ball into a liquid bath, only if the bath tests negative for IPTG. The results, as seen in this video<\/a> hosted by EurekAlert, show the gripper accurately responds to the presence of IPTG in the solution, and deposits the object in the bath only when IPTG is absent.<\/p>\n

The researchers recognize their system is designed to detect only one chemical, and challenges remain in detecting specific concentrations and maintaining stable concentrations of microbes in a robotic device. Nonetheless, says Majidi in a UC-Davis statement<\/a>, “we are closer to future breakthroughs like soft bio-hybrid robots that can adapt their abilities to sense, feel and move in response to changes in their environmental conditions.”<\/p>\n

Carnegie Mellon filed patent applications for some of the technologies in the paper.<\/p>\n

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