Imaging Uses ‘Photothermal Effect’ to Peer into Living Cells
Infrared spectroscopic imaging has been limited to studies of dried tissue samples because water molecules absorb and interfere with the infrared signal
(West Lafayette, IN)—A new type of imaging technology uses the mid-infrared part of the spectrum and “thermal lensing” to visualize living cells and organisms, an innovation that could bring insights into drug delivery and cancer treatment.
“It’s very important to be able to study and understand the chemistry of living systems for research into drug delivery and disease processes,” said Ji-Xin Cheng, a professor in Purdue University’s Weldon School of Biomedical Engineering and Department of Chemistry.
Infrared spectroscopic imaging has been limited to studies of dried tissue samples because water molecules absorb and interfere with the infrared signal. At the same time, the technology has not been capable of high-resolution imaging or visualizing layered sections, which is needed for detailed studies of three-dimensional samples such as a biological cell.
The mid-infrared photothermal (MIP) approach, a culmination of two years of research, overcomes these limitations, Cheng said.
Researchers have used the system to visualize lipid droplets – a key biomarker for disease – and drugs inside living cells in laboratory cultures and also in a roundworm called C. elegans.
The system provides “label-free” imaging, meaning no fluorescent dyes are needed.
“This is important for understanding the drug-delivery pathways, the drug-action mechanism for treating cancer and other diseases,” Cheng said. “Drugs are small molecules and not fluorescent, so this method provides a way to identify and locate the drug molecule in cells and tissues.”
Findings are detailed in a paper appearing Wednesday (Sept. 28) in the journal Science Advances. The paper’s lead author is Purdue postdoctoral research associate Delong Zhang. A YouTube video is available at https://youtu.be/ObWo2ffkVlw.
The technology makes it possible to study the dynamic chemistry inside cells and tissues.
“The reported MIP imaging technology promises broad applications from monitoring metabolic activities to high-resolution mapping of drug molecules in living systems, which are beyond the reach of current infrared microscopy,” Cheng said.
MIP works by shining a mid-infrared laser on tissue, generating heat and producing a “thermal lensing effect.”
“It’s similar to the mirage effect that you see on a hot summer day over a road surface,” Zhang said.
Because infrared wavelengths are large, they cannot resolve the fine chemical details of the contents of live cells and organisms.
“So we use a second laser at a much shorter wavelength, which gives us sub-micron spatial resolution, 10 times better than traditional infrared microscopy, and this resolution is essential to see the intracellular structure,” Cheng said. “You also produce a photothermal spectrum, and that provides the molecular information.”
The system can determine the chemical composition in “micro-molar” concentrations, which allows mapping of drug molecules and monitoring metabolic activity inside of cells.
The paper was authored by Delong; doctoral student Chen Li; postdoctoral research associate Chi Zhang; research professor Mikhail N. Slipchenko; Gregory Eakins, an instrumentation specialist at the Jonathan Amy Facility for Chemical Instrumentation; and Cheng.
Making the high-resolution imaging possible is a new “resonant amplifier” that picks up the photothermal signal and was designed by Eakins.
The researchers have filed an application for a provisional patent through the Office of Technology Commercialization in the Purdue Research Foundation.
Future research will include work to improve the speed of the technology.
“Now it takes 8 seconds per image, which is too slow because cells and molecules are in constant motion,” Cheng said.
The research is funded by the W.M. Keck Foundation.
NASA’s Gecko-Inspired Robots Can Climb Pretty Much Anything
YOU’RE so hard to explore. Sometimes you bombard spacecrafts with hurtling rocks and deadly cosmic rays, and other times you’re so empty you don’t give astronauts a darn thing to hold on to. But while scientists haven’t quite figured out how to keep radiation at bay, the scientists at NASA’s Jet Propulsion Laboratory—specifically, its Planetary Robotics Laboratory—are building machines that can get a grip on the most difficult surfaces astronauts will find out there.
Adhesion-wise, space presents a couple problems. First, robots typically struggle with uneven surfaces, let alone the kind of cliffs and crags you see on Mars. Second, space is kind of gravity challenged. “Out in zero gravity, even pushing tape against surfaces is difficult,” say Jaakko Karras, a robotics electrical engineer at JPL. Without gravity to anchor your feet to the ground, it’s easy to run afoul of Newton’s third law. (For every action, there is an equal and opposite reaction. So you’ll be pushed away from the wall with the same amount of force you applied to it. Physics!)
And that’s not just a problem in microgravity. Low gravity environments, like asteroids or comets, can be uncooperative too. (Just ask the European Space Agency’sPhilae lander.) “If you got out there and wanted to do some sort of sampling and just started drilling, you’re more likely to spin about the drill bit than the drill bit into the surface,” Karras says.
So what’s a robot to do? “Nature solves the problems around us all the time,” says Karras. “A fairly common path for us is the biomimicry approach.” When Karras and his team would test climbing robots out on vertical rock walls, lizards would blaze right past them. But rather than getting annoyed at the speedy little reptiles, Karras decided to take his cues from evolution instead. His team’s adhesive makes use of van der Waals forces, which geckos use to climb smooth surfaces. For bumpy ones, his team built claw-inspired microspine grippers that can bend and flex. (You can see them in action in the video up top.)
Both gecko adhesive and microspine grippers are well on their way to scoring a ticket to deep space. Gecko adhesive is already being tested on the International Space Station. Right now, astronauts are using it to anchor things to interior panels, but NASA is considering using it as a replacement for Velcro, which kicks off a lot of dust and bristles—particulates aren’t all that welcome in the fragile environment of the ISS. And microspines are a crucial part of NASA’s asteroid redirect mission: The little spikes will cover robotic arms used to snatch up an asteroid’s boulder and deposit it in orbit around our moon.
Karras also hopes that future missions will use microspines’ vertical climbing skills to explore Mars’ caves and lava tubes. “They haven’t been explored yet because they’re difficult from a mobility standpoint,” Karras says. “But they may once have been collection points for liquid water, and they’re sheltered, low-radiation areas. They’re of interest for investigating the possibility of past and present life.” So if we find any Martians in the next couple of decades, you have lizards to thank.
New research undermines ‘RNA world’ of early evolution
SAN DIEGO, Sept. 29 (UPI) — Did RNA evolve DNA, or did the two emerge simultaneously? Until recently, most scientists suggested the former, but new research undermines the theory, inspiring a team of scientists to suggest a second, alternative RNA-DNA origin story.
The idea that primordial Earth hosted an RNA-only chapter of evolution prior to the emergence of DNA is known as the “RNA world” hypothesis. A series of chemical reactions begat RNA, which eventually synthesized proteins and enzymes, which in turn combined with RNA to produce DNA.
The theory holds water for a variety of reasons, but not least of all because DNA looks like a completed version of RNA. DNA’s structure resembles a ladder, with nucleobase pairs as the rungs and sugar molecules forming the two sides. RNA looks like just one side of a ladder.
The RNA world theory implies an intermediary stage, with RNA nucleotides as the rungs and DNA sugar molecules as the sides — so called “heterogeneous” strands.
But when scientists at the Scripps Research Institute built DNA-RNA chimeras, the result was completely unstable.
“We were surprised to see a very deep drop in what we would call the ‘thermal stability,'” Ramanarayanan Krishnamurthy, associate professor of chemistry at TSRI,said in a news release.
In the human body, when RNA accidentally finds its way onto a DNA ladder, enzymes are quickly called to the scene to rectify the mistake. It’s clear evolution favors homogeneous DNA and RNA molecules.
It’s unlikely repair enzymes were around when the first life forms first emerged, which means there must have been some biochemical mechanism keeping DNA and RNA apart.
Researchers believe their latest research, published this week in the journal Angewandte Chemie International Edition, supports the alternative theory that RNA and DNA evolved simultaneously.
“Even if you believe in a RNA-only world, you have to believe in something that existed with RNA to help it move forward,” said Krishnamurthy. “Why not think of RNA and DNA rising together, rather than trying to convert RNA to DNA by means of some fantastic chemistry at a prebiotic stage?”
Incognito mode added to Google Search for iOS
If you are one of those that like to privately surf the web and prefer the app for Google Search instead of the others browsers like Chrome and Safari that are standalone browsers, then you might fancy the latest update that has been introduces as “incognito mode” available on iOS Google Search app by simply making use of Touch ID as well as other changes that have been made.
It is true that the private browsing option is available in many browsers, however, this feature has been lacking in the Google’s app even with many users of iPhone preferring to make use of their browsers.
The app ranks a little higher than Chrome browser and is ranking 2nd Utility and coming in at number 30 overall while Chrome comes in at 3rd and is occupying the 34th position in the iTunes App Store Overall, respectively.
In order to be able to make use of the new private feature, you go to the option and toggle on incognito mode when you get to the Settings if you intend to keep the history of your browsing saved. You can also go to the incognito mode and make use of Touch ID making it impossible for anyone else to re-enter your last incognito session.
You can also open another incognito mode by making use of the 3D Touch found on the app icon.
CRTC report says Bell Fibe offers better than advertised download speeds
A report from the Canadian Radio-Television and Telecommunications Commission says Bell’s Fibe Internet service offers faster broadband speeds than advertised.
The CRTC commissioned SamKnows, a broadband measurement service, to look at the Internet performance of Canada’s providers.
It found that Bell, which owns CTV News, excelled with its fibre-to-the-home (FTTH) Fibe service when it came to download speeds.
FTTH’s download speeds during peak hours were, on average, 121% of what Bell advertised.
“These independent tests prove that Bell’s strategy to lead investment and innovation in broadband is delivering advanced networks that consistently outperform in speed and reliability,” Wade Oosterman, Group President of BCE and Bell Canada, and Bell’s Chief Brand Officer, said in a press release.
“Canadians can be justifiably proud that our country’s broadband fibre and wireless networks rank among the fastest and best in the world.”
Bell’s mobile network has also been shown to offer fast download speeds.
Last month, a report by Speedtest by Ookkla showed that Bell Mobile also had the fastest download speeds in Canada, with its tri-band LTE-Advanced network.
PCMag also named Bell as having better download speeds on its LTE network than Verizon, the fastest carrier in the U.S.
Google Doubles Down on Enterprise by Re-Branding Its Cloud
Welcome to Google Cloud and G Suite.
If there’s one thing that drives Google’s head cloud chief Diane Greene bananas, it’s the idea that the search giant is not serious about becoming a big business technology provider.
Since joining Google last fall, Greene, speaking Thursday at a press event in San Francisco, said she’s talked to over 200 customers and partners about Google’s various enterprise services, from its work document tools to its cloud computing business in which companies can buy computing capacity on demand.
Greene said that Google GOOG -0.84% would “blow customers away” with the amount of tools and services they have to sell. Yet after each discussion, the companies would inevitably ask “Is Google really serious about the enterprise?”
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“It was kind of driving ourselves crazy,” Greene joked to the crowd of reporters, analysts, and business representatives.
Of course, Google has long tried to make a healthy business selling workplace software services like spreadsheets and email to companies. Although those services are popular, most people still consider Google to primarily be an Internet search and advertising company.
Greene wants to change that perception and part of that has to do with a re-branding, which technology news siteThe Information reported in September was in the works.
Now, Google will group together its business apps like Gmail and Calendar under the brand name G Suite, replacing the Google Apps for Work branding. G Suite will also fall under the overarching Google Cloud branding, which is an umbrella term that covers all of the search giant’s various business services like its data analytics tools, Chromebook laptops and Android phones, and cloud computing business.
“When we said this to everybody at Google, there was no question,” Greene said about the rebranding. “Everyone feels that we are Google Cloud.”