A joint team from the University of Stuttgart in Germany and the University of Melbourne in Australia has developed a new method for the straightforward analysis of tiny nanoplastic particles in environmental samples. One needs only an ordinary optical microscope and a newly developed test strip—the optical sieve. The research results have now been published in Nature Photonics.

“The test strip can serve as a simple analysis tool in environmental and health research,” explains Prof. Harald Giessen, Head of the 4th Physics Institute of the University of Stuttgart. “In the near future, we will be working toward analyzing nanoplastic concentrations directly on site. But our new method could also be used to test blood or tissue for nanoplastic particles.”

Plastic waste is one of the central and acute global problems of the 21st century. It not only pollutes oceans, rivers, and beaches but has also been detected in living organisms in the form of microplastics. Until now, environmental scientists have focused their attention on larger plastic residues.

However, it has been known for some time that an even greater danger may be on the horizon: nanoplastic particles. These tiny particles are much smaller than a human hair and are created through the breakdown of larger plastic particles. They cannot be seen with the naked eye. These particles in the sub-micrometer range can also easily cross organic barriers such as the skin or the blood-brain barrier.

Because of the small particle size, their detection poses a particular challenge. As a result, there are not only gaps in our understanding of how particles affect organisms but also a lack of rapid and reliable detection methods.

In collaboration with a research group from Melbourne in Australia, researchers at the University of Stuttgart have now developed a novel method that can quickly and affordably detect such small particles. Color changes on a special test strip make nanoplastics visible in an optical microscope and allow researchers to count the number of particles and determine their size.

“Compared with conventional and widely used methods such as scanning electron microscopy, the new method is considerably less expensive, does not require trained personnel to operate, and reduces the time required for detailed analysis,” explains Dr. Mario Hentschel, Head of the Microstructure Laboratory at the 4th Physics Institute.

The “optical sieve” uses resonance effects in small holes to make the nanoplastic particles visible. A study on optical effects in such holes was first published by the research group at the University of Stuttgart in 2023. The process is based on tiny depressions, known as Mie voids, which are edged into a semiconductor substrate.

Depending on their diameter and depth, the holes interact characteristically with the incident light. This results in a bright color reflection that can be seen with an optical microscope. If a particle falls into one of the indentations, its color changes noticeably. One can therefore infer from the changing color whether a particle is present in the void.

“The test strip works like a classic sieve,” explains Dominik Ludescher, Ph.D. student and first author of the publication. Particles ranging from 0.2 to 1 µm can thus be examined without difficulty. The particles are filtered out of the liquid using the sieve in which the size and depth of the holes can be adapted to the nanoplastic particles, and subsequently by the resulting color change can be detected. This allows us to determine whether the voids are filled or empty.”

The novel detection method used can do even more. If the sieve is provided with voids of different sizes, only one particle of a suitable size will collect in each hole. “If a particle is too large, it won’t fit into the void and will simply be flushed away during the cleaning process,” says Ludescher.

“If a particle is too small, it will adhere poorly to the well and will be washed away during cleaning.” In this way, the test strips can be adapted so that the size and number of particles in each individual hole can be determined from the reflected color.

For their measurements, the researchers used spherical particles of various diameters. These are available in aqueous solutions with specific nanoparticle. Because real samples from bodies of water with known nanoparticle concentrations are not yet available, the team produced a suitable sample themselves.

The researchers used a water sample from a lake that contained a mixture of sand and other organic components and added spherical particles in known quantities. The concentration of plastic particles was 150 µg/ml. The number and size distribution of the nanoplastic particles could also be determined for this sample using the optical sieve.

“In the long term, the optical sieve will be used as a simple analysis tool in environmental and health research. The technology could serve as a mobile test strip that would provide information on the content of nanoplastics in water or soil directly on site,” explains Hentschel.

The team is now planning experiments with nanoplastic particles that are not spherical. The researchers also plan to investigate whether the process can be used to distinguish between particles of different plastics. They are also particularly interested in collaborating with research groups that have specific expertise in processing real samples from bodies of water.

OpenAI has reached a new tentative agreement with Microsoft and said its nonprofit, which technically controls its business, will now be given a $100 billion equity stake in its for-profit corporation.

The maker of ChatGPT said it had reached a new nonbinding agreement with Microsoft, its longtime partner, “for the next phase of our partnership.”

The announcements on Thursday include a few details about these new arrangements. OpenAI’s proposed changes to its corporate structure have drawn the scrutiny of regulators, competitors and advocates concerned about the impacts of artificial intelligence.

OpenAI was founded as a nonprofit in 2015 and its nonprofit board has continued to control the for-profit subsidiary that now develops and sells its AI products. It’s not clear whether the $100 billion equity stake the nonprofit will get as part of this announcement represents a controlling stake in the business.

California Attorney General Rob Bonta said last week that his office was investigating OpenAI’s proposed restructuring of its finances and governance. His office said they could not comment on the new announcements but said they are “committed to protecting charitable assets for their intended purpose.”

Bonta and Delaware Attorney General Kathy Jennings also sent the company a letter expressing concerns about the safety of ChatGPT after meeting with OpenAI’s legal team earlier last week in Delaware, where OpenAI is incorporated.

“Together, we are particularly concerned with ensuring that the stated safety mission of OpenAI as a non-profit remains front and center,” Bonta said in a statement last week.

Microsoft invested its first $1 billion in OpenAI in 2019 and the two companies later formed an agreement that made Microsoft the exclusive provider of the computing power needed to build OpenAI’s technology. In turn, Microsoft heavily used the technology behind ChatGPT to enhance its own AI products.

The two companies announced on Jan. 21 that they were altering that agreement, enabling the smaller company to build its own computing capacity, “primarily for research and training of models.” That coincided with OpenAI’s announcements of a partnership with Oracle to build a massive new data center in Abilene, Texas.

But other parts of its agreements with Microsoft remained up in the air as the two companies appeared to veer further apart. Their Thursday joint statement said they were still “actively working to finalize contractual terms in a definitive agreement.” Both companies declined further comment.

OpenAI had given its nonprofit board of directors—whose members now include a former U.S. Treasury secretary—the responsibility of deciding when its AI systems have reached the point at which they “outperform humans at most economically valuable work,” a concept known as artificial general intelligence, or AGI.

Such an achievement, per its earlier agreements, would cut off Microsoft from the rights to commercialize such a system, since the terms “only apply to pre-AGI technology.”

OpenAI’s corporate structure and nonprofit mission are also the subject of a lawsuit brought by Elon Musk, who helped found the nonprofit research lab and provided initial funding. Musk’s suit seeks to stop OpenAI from taking control of the company away from its nonprofit and alleges it has betrayed its promise to develop AI for the benefit of humanity.

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Media pundits, journalists, and academics, including MSNBC commentator Matthew Dowd, have also been fired or targeted over their comments about Kirk. Executives from Comcast, which owns NBC Universal, sent out an email to employees seemingly referencing Dowd’s dismissal over an “unacceptable and insensitive comment about this horrific event. That coverage was at odds with fostering civil dialogue.” In response to a request for comment, Comcast redirected WIRED to the aforementioned letter.

Red Hood is also not the only cultural product being disappeared in light of Kirk’s death. Comedy Central has decided not to re-run the South Park episode “Got a Nut,” which satirized the right-wing activist. ButKirk himself had said the episode was “hilarious” and an example of the “cultural domination” of his Prove Me Wrong college campus debates; he even changed his show’s TikTok profile picture to an image of the South Park character Cartman parodying him. (The episode will still be available to stream on Paramount+.)

Kirk was one of the most influential conservative activists in the US. He cofounded Turning Point when he was just 18 and turned it into a multimillion-dollar enterprise. But his political views were frequently inflammatory, racist, and transphobic, and he had many critics, including people like Felker-Martin, who belonged to one of the groups he derided. In his final exchange before he was shot, Kirk was asked about transgender mass shooters. He responded that there were “too many,” repeating a myth that has been used to attack trans people.

Author Roxane Gay, who has spoken out in Felker-Martin’s defense, says that whether she agrees with Felker-Martin’s views “doesn’t matter.”

“Either you believe in free speech or you don’t,” she tells WIRED, describing DC Comics’ decision to pull Red Hood as the “overreaction of the century.”

From Trump’s plan to wipe “race-centered ideology” and trans people from the Smithsonian to the cancellation of The Late Show with Stephen Colbert, the campaign against Kirk’s critics and its impact on pop culture isn’t happening in a vacuum. Humor and satire are particularly triggering for authoritarian figures, according to curator and culture critic Hrag Vartanian, editor-in-chief of arts publication Hyperallergic.

“Authoritarians can deal with violence. They can deal with everything except being laughed at,” Vartanian says.

Vartanian tells WIRED he’s spoken with many artists who have delayed showing works about topics like the war in Gaza or queerness due to the current political environment, in a form of self-censorship.

Gay says because she has a family, she too has to take fewer risks. But she says she is still “shocked” that more writers aren’t openly backing Felker-Martin. “If it’s her today, it’s going to be someone else tomorrow,” she says.

For her part, Felker-Martin, who has also been outspoken in her support of Palestine, says that once she’s back on Bluesky, she’ll likely keep a lower profile.

Asked if there’s anything that’s making her feel positive right now, she recalls a recent baby shower for a queer family member.

“We had this huge crowd of trans and queer people, into which we dropped my very kind and normal parents. And it was just this really pleasant day with all of our lives kind of mixed together, and kids running around,” she says. “I think that living in that is the best thing we can do for ourselves right now. Having and making community by being with each other.”