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Color-changing strip enables affordable nanoplastic analysis using ordinary microscope

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Color-changing strip enables affordable nanoplastic analysis using ordinary microscope


The optical sieve nanoplastic particles fall into holes of the appropriate size in the test strip. The color of the holes changes. The new color provides information about the size and number of particles. Credit: University of Stuttgart

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 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 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 , 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 . The technology could serve as a mobile 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.

More information:
D. Ludescher et al, Optical sieve for nanoplastic detection, sizing and counting. Nature Photonics (2025). DOI: 10.1038/s41566-025-01733-x. www.nature.com/articles/s41566-025-01733-x

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Color-changing strip enables affordable nanoplastic analysis using ordinary microscope (2025, September 13)
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Greg Brockman Officially Takes Control of OpenAI’s Products in Latest Shakeup

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Greg Brockman Officially Takes Control of OpenAI’s Products in Latest Shakeup


OpenAI told staff on Friday that it would reorganize the company as part of an ongoing effort to unify its product offerings, WIRED has learned. OpenAI cofounder and president Greg Brockman will now lead the company’s product strategy, in addition to his work on AI infrastructure, OpenAI confirms to WIRED. Brockman was previously assigned to oversee OpenAI products on an interim basis while CEO of AGI deployment, Fidji Simo, was on medical leave; the change is now official.

“We’re consolidating our product efforts to execute with maximum focus toward the agentic future, to win across both consumer and enterprise,” Brockman said in a memo to staff seen by WIRED. Brockman added that OpenAI’s products are naturally converging, and that the company has decided to merge ChatGPT and Codex into one unified experience.

OpenAI says it’s folding ChatGPT, its AI coding agent Codex, and its developer-facing API into one core product team. The company says that Codex is increasingly powering its consumer and enterprise offerings, which are gaining the ability to perform digital tasks autonomously on behalf of users.

Two other OpenAI leaders are also taking on larger roles at the company as part of the changes. OpenAI’s head of Codex, Thibault Sottiaux, has been tapped to lead the core product and platform across consumer, enterprise, and developer surfaces. Sottiaux was a key leader in building Codex into one of the company’s fastest-growing products of all time. OpenAI’s longtime head of ChatGPT, Nick Turley, is moving to a new role at the company that aims to revamp enterprise products. OpenAI says Turley will continue his work on ChatGPT, which he has helped grow to more than 900 million weekly active users since he took over in 2022.

The changes are the latest shakeup for OpenAI as leadership aims to refocus the company on a few key product areas, including ChatGPT, Codex, and its forthcoming “everything app.” Last month, OpenAI announced many executive changes, including that CEO of AGI dDeployment, Fidji Simo, was taking a medical leave to focus on her health. OpenAI previously said Brockman would oversee product strategy in her absence. The company tells WIRED that Simo remains on medical leave, and worked directly with Brockman on these organizational changes and product strategy.

In the last year, OpenAI has faced increasing pressure from competitors, including Anthropic in coding domains and Google in consumer chatbots. OpenAI leaders are hoping to simplify product offerings ahead of its plan to file for an IPO, which could happen later this year.

Other OpenAI executives left the company entirely last month, including the head of its AI workspace for scientists, Kevin Weil; head of Sora, Bill Peebles; and its chief technology officer of enterprise applications, Srinivas Narayanan.

This is a developing story. Please check back for updates.



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Companies Keep Slashing Employees’ Benefits for the Worst Reasons

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Companies Keep Slashing Employees’ Benefits for the Worst Reasons


Employee benefits are in the spotlight this week, and that’s because of three recent stories about US companies cutting back on non-wage compensations for workers.

A Texas tech consulting firm with a forgettable name—TTEC—suddenly became a lot more memorable when it suspended its discretionary 401(k) match program for 16,000 employees through at least the end of 2026. According to Business Insider, which viewed an internal TTEC memo, the company plans to invest in AI certifications, AI tools and training, and automation, among other things.

The auditing and consulting giant Deloitte is also reportedly slashing benefits for some workers starting next year. This includes reducing PTO, halving parental leave, and eliminating a $50,000 reimbursement for family planning services such as adoption, surrogacy, and IVF. San Francisco-based Zoom, meanwhile, has made a smaller-scale change and reduced its parental leave for employees from 22 weeks to 18 weeks for birthing parents.

So what’s the driving force behind this? And are there more cuts to come? The latter is impossible to answer, and the former is unfortunately more complicated than “corporate ghouls go AI.”

First off, “what Deloitte did is completely unconscionable,’” says Joan C. Williams, a professor at UC Law San Francisco, the author of several books on work culture and class dynamics, and an oft-cited scholar on these topics. The consulting firm is cutting the benefits of a specific class of internal workers—in admin, IT support, and finance—while leaving intact benefits for people in client-facing roles. An affected worker will see their parental leave cut from 16 weeks to just eight weeks.

“It treats people differently based on the type of job they’re in, and cutting any mother down to eight weeks of paid leave is just outlandish,” Williams says. “When labor is tight, employers are more generous. But once the power shifts, the benefits contract.”

AI certainly is a convenient excuse these days for any corporate decision that harms workers. But the impetus here is also the cost of the benefits themselves. Earlier this year subsidies from the Affordable Care Act lapsed, and people began dropping out of health care plans entirely. Insurers have cited this as one reason they’ve raised premiums.

Sarahjane Sacchetti, a former top executive at benefits administration companies Cleo and Collective Health, who is working on a new health care initiative, told me that the costs of employer-sponsored health plans have increased significantly over the past five years. A survey last year of over 1,700 US employers by the Mercer health care consulting group found that the health care cost per worker was expected to rise on average 6.5 percent in 2026, the highest since 2010. And this was after factoring in cost-reduction measures; otherwise, the cost of a plan would go up by nearly 9 percent.

“This just starts to eat into how you think about total compensation as an employer,” Sacchetti says. That doesn’t mean the corporation is the ‘good guy,’ she says, but the poor state of American health care policy and lack of safety net are responsible for a lot of the stress that plagues undercompensated or laid-off workers.

Williams points out that the US is one of the few countries that doesn’t offer a federal paid maternal leave—putting it in league with Papua New Guinea and Suriname. “This just shows how crazy it is to provide employee basics like pension and paid parental leave through private employers rather than how other industrialized countries do it,” Williams says. Her proposed solution? “The US needs to join the rest of the universe.”

The irony, of course, is that the US government professes to be obsessed with women having more babies. If women in the US are—as celebrity doctor Mehmet Oz put it this week in the Oval Office—“underbabied,” a comprehensive paid federal leave policy would be the obvious place to start. (Oz also said that “making babies” is “the most creative thing the universe knows.” Don’t tell the AI CEOs.)



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Gantri’s 3D-Printed Lamps Are Going Wireless

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Gantri’s 3D-Printed Lamps Are Going Wireless


Gantri, a San Francisco-based company known for making soft, stylized 3D-printed lamps, is going wireless. That’s thanks to a new partnership with the design firm Ammunition.

Gantri 3D-prints its lamps using plastics made from corn-based polylactic acid (PLA) in its Bay Area facilities. The result is a collection of carefully designed light fixtures with gentle curves that aim to make luxury-style lighting feel somewhat affordable. (Prices range from $200 to $500.)

Last year, the company introduced a program called Gantri Made, which allows shoppers to customize their lights and gives third-party designers the ability to build their own designs using Gantri’s foundational pieces.

Courtesy of Gantri

Gantri first partnered with Ammunition in 2020, developing a line of stylish lamps aiming to highlight what premium light pieces could look like. You’ve almost certainly seen something built with Ammunition’s flair. The firm designed Beats by Dre headphones, the Square point-of-sale tablets you see in shops everywhere, and many other projects, from robot coffee machines to Jay-Z’s failed weed vape cartridges.

This Gantri new collab is a range of lamps that include floor lamps, table lamps, and ones small enough to hold in your hand. (Those are rectangular, with designs inspired by piers around San Francisco.) All the lights are wireless and can be removed from charging ports to run for what Gantri says is 10 or more hours of battery life. Gantri is also developing an app to control the lights. They will work with Matter, the connectivity standard that aims to make smart home tech from different companies work together, but that compatibility isn’t expected until next year.

Gantri CEO Ian Yang points out that for most of human history, light sources were something people carried with them—torches, candles, lanterns. Lights staying in fixed places has become the norm, but he wants these wireless lamps to show there’s another way.

“I really think this product is going to change the way that people think about lighting, but also think about the power of digital manufacturing, about this new material that’s plant-based,” Yang says.

The lamps have a custom charging port, which allows them to stand upright and face any direction while still receiving a charge. They also require a custom charger and cannot be charged via USB-C or another cord in a different room. That may inhibit the mobility the lamp promises, as you won’t be able to move them from room to room and plug them in with any USB-C cord lying around—you’d have to bring that proprietary cable with you. But Yang says this was a deliberate choice, even though it was much more difficult than finding a spot for a USB-C connection. He wanted the lamps to feel portable while also having a place for them to become a fixture in a home.



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