An optical device that resembles a miniaturized lighthouse lens can make it easier to peer into Petri dishes and observe molecular-level details of biological processes, including cancer cell growth. Developed by KAUST, the new lens is also very cost effective.
Many bioimaging techniques require fluorescent dyes to be added to specific cell targets. But a recently developed method known as stimulated raman scattering (SRS) microscopy can avoid cumbersome labeling steps by using laser pulses to collect molecular vibrational signals from biological samples. The ability of SRS microscopes to produce high-resolution, noninvasive images at real-time speeds has prompted researchers to deploy them also forin vivodisease diagnostic studies.
One drawback of SRS microscopes, however, is that the detection system is affected by a background signal, known as cross-phase modulation, which is generated by the intense interactions between laser pulses and the samples.
“This background signal is ubiquitous and reduces the contrast during microscopic observation of complex samples, such as live cells,” explains Carlo Liberale from KAUST. “It also makes it difficult to identify target molecules.”
To avoid the effects of cross-phase modulation, most SRS microscopes need to use bulky glass objectives capable of collecting wide angles of light. However, these kinds of lenses are nearly impossible to fit into the stage-top incubators that are used to grow live cells for bioimaging.
Andrea Bertoncini, a researcher in Liberale’s group, spearheaded work to create an ultrathin SRS lens using laser-based three-dimensional (3-D) printing. Taking their cue from the slender design of lighthouse lenses, the KAUST team printed tiny lens-like and mirror-like features into a transparent polymer only a fraction of a millimeter thick.
“This type of lens design is a very efficient way to collect and redirect light coming from wide-angle sources right to our laser detector,” says Bertoncini. “And since it’s so thin, it easily fits into the closed chambers of an incubator.”
After calibration trials confirmed that their new lens could reject the cross phase modulation background, the researchers turned their sights on human cancer cells cultured in a conventional Petri dish. These experiments revealed that the lens could image the cell’s interior components with resolution similar to conventional SRS microscopes, but in a much more convenient and less expensive format.
“The objectives we normally use to collect SRS microscope signals cost a few thousand dollars,” says Bertoncini. “Now we have a lens with similar benefits that we can produce for less than a tenth of that price.”
Custom fabricated microscope lens inspired by lighthouse (2020, October 5)
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At least she didn’t have to wait in line. A US astronaut cast her ballot from the International Space Station on Thursday, making her voice heard in the presidential election despite being 408km above the Earth.
“From the International Space Station: I voted today,” crew member Kate Rubins, who began a six-month stint aboard the orbiting station last week, said on Nasa’s Twitter account.
The post featured a photo of Rubins, her hair floating in the zero-gravity environment, in front of an enclosure with a sign that reads “ISS voting booth”.
Rubins and Nasa described the process as a form of absentee voting. A secure electronic ballot generated by a clerk’s office in Harris County, home of Nasa’s Johnson Space Center in Houston, Texas, was sent up via email to the ISS. Rubins filled out the ballot in the email and it was downlinked and delivered back to the clerk’s office.
Rubins had cast her vote from the ISS during the 2016 election as well. “We consider it an honour to be able to vote from space,” she said in a video before she and two Russian cosmonauts launched from the Baikonur cosmodrome in Kazakhstan on October 14.
However you go about casting your vote, you have to admire this NASA astronaut who managed to cast her vote from space. Kate Rubins, who’s currently on duty aboard the International Space Station, posted a photo of herself in front of a padded booth marked “ISS Voting Booth,” with the text “From the International Space Station: I voted today.”
NASA notes this isn’t Rubins’ first time voting from space. She did so in 2016, when she was also on the ISS.
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“I think it’s really important for everybody to vote,” Rubins said in a video uploaded by NASA. “And if we can do it from space, then I believe folks can do it from the ground, too.” Rubins’ six-month ISS mission began Oct. 14, which was also her 42nd birthday.
Most astronauts choose to vote as Texas residents because they move to Houston for training, NASA said, though, that those who wish to vote as residents of their home state can make special arrangements.
Ballots from the county where the astronaut is registered are tested on a space station training computer, then the real ballot is generated and uplinked to the ISS with crew-member-specific credentials to keep it secure. The completed ballot is electronically delivered back to Earth to be officially recorded.
“Voting in space has been possible since 1997 when a bill passed to legally allow voting from space in Texas,” NASA said in a statement. “Since then, several NASA astronauts have exercised this civic duty from orbit. As NASA works toward sending astronauts to the Moon in 2024 and eventually on to Mars, the agency plans to continue to ensure astronauts who want to vote in space are able to, no matter where in the solar system they may be.”
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