System Bits: Jan. 12

Coaxing human stem cells to form human organs
In a step toward personalized drug testing, MIT researchers have coaxed human stem cells to form complex tissues in a new technique, which also has near-term implications for growing organ-like tissues on a chip and that may ultimately allow personalized organs to be grown for transplant patients.

The researchers said growing organs on demand, using stem cells derived from patients themselves, could eliminate the lengthy wait that people in need of a transplant are often forced to endure before one becomes available. It could also reduce the risk of a patient’s immune system rejecting the transplant, since the tissue would be grown from the patient’s own cells.

This image demonstrates tissue patterns that emerge from genetically programmed human pluripotent stem cells, and was taken on day nine of the MIT study. It shows immunostainings of cell nuclei for CEBPA (red, endodermal marker), SOX10 (green, ectodermal marker), and DAPI (blue, binds to DNA in the nucleus). (Source: MIT)

While it is likely to be some time before the technique can be used to generate transplant organs, it could be used almost immediately to grow different human tissue on which to test new drugs. Using human stem cell-derived organ tissue to test new treatments could be far more reliable than testing on animals, since different species may react differently to a drug, the team pointed out. The technique could also allow clinicians to carry out patient-specific drug testing.

Autonomous driving on snow-covered roads
On snow-covered roads, typical autonomous vehicle sensors are useless but researchers at the University of Michigan and Ford are working together to fix that. In Michigan and on U-M’s 32-acre Mcity simulated urban environment, they’ve conducted what they say are the industry’s first tests of autonomous vehicles in wintry conditions.

One of the keys to safe autonomous driving is for a vehicle to know where it is, not just along a road but within a driving lane. Even being off by a few inches can make a big difference, the researchers said. Under sunny skies, Ford’s testbed autonomous Fusion Hybrid sedans rely on LiDAR sensors that can pinpoint lane location with centimeter accuracy. LiDAR emits short pulses of laser light to precisely allow the vehicle to create a real-time, high-definition 3D image of what’s around it. But LiDAR cannot see the road when snow obstructs it from view – like during inclement weather or in high-density traffic. The same is true when the sensor lens is covered by snow, grime, or debris.

(Source: University of Michigan)

As a result, Ford and U-M are working on a system that involves high-resolution 3D maps – complete with information about the road and what’s above it, including road markings, signs, geography, landmarks and topography. U-M researchers have developed these maps and Ford’s test vehicles are equipped with them.

The autonomous vehicles create the maps while driving the test environment in favorable weather. Technologies automatically annotate features like traffic signs, trees and buildings later. Then, when the vehicles cannot see the ground, they detect above-ground landmarks to pinpoint themselves on the map, which they then use to drive successfully.

Gold nanoparticles in electronic, medical apps
In order to take advantage of the unusual optical, electronic and chemical properties of gold nanoparticles applications ranging from nanoelectronics to cancer treatments, McGill University researchers have created the nanoparticle equivalent of the printing press.

They explained that some of the most interesting properties of nanoparticles emerge when they are brought close together – either in clusters of just a few particles or in crystals made up of millions of them. But particles that are just millionths of an inch in size are too small to be manipulated by conventional lab tools, so a major challenge has been finding ways to assemble these bits of gold while controlling the three-dimensional shape of their arrangement.

One approach that researchers have developed has been to use tiny structures made from synthetic strands of DNA to help organize nanoparticles but this approach is intricate and expensive to generate, akin to producing books by hand.

Thus, enter the nanoparticle printing press that the team said is efficient, re-usable and carries more information than previously possible.

(Source: McGill University)

Also, the DNA nanostructures can be re-used, much like stamps in an old printing press.

The McGill researchers hope their new production technique will help pave the way for use of DNA-encoded nanoparticles in a range of cutting-edge technologies. The next step for the lab will be to investigate the properties of structures made from these new building blocks, which could be put to use in areas including optoelectronic nanodevices and biomedical sciences. The patterns of DNA strands could, for example, be engineered to target specific proteins on cancer cells, and thus serve to detect cancer or to selectively destroy cancer cells.