Posts tagged with "American Chemical Society"

Wearable air sampler assesses personal exposure to COVID-19

January 13, 2022

Masks, social distancing, proper hygiene, and ventilation can help reduce the transmission of COVID-19 in public places—but even with these measures, scientists have detected airborne SARS-CoV-2 in indoor settings, EurekAlert reports.

Now, researchers from Yale University School of Engineering and Applied Science and Yale University School of Public Health—working on behalf of the American Chemical Society—say they have developed a passive air sampler clip that can help assess personal exposure to SARS-CoV-2 that could be especially helpful for workers in high-risk settings, such as restaurants or healthcare facilities.

Reporting in the January 12 edition of ACS’ Environmental Science & Technology Letters, the researchers note that COVID-19 is primarily transmitted through the inhalation of virus-laden aerosols and respiratory droplets that infected individuals expel by coughing, sneezing, speaking, or breathing.

To date, active air sampling devices to detect airborne SARS-CoV-2 have been used in indoor settings; however, these monitors are typically large, expensive, non-portable and require electricity. To better understand personal exposures to the virus, lead author Krystal Pollitt and colleagues wanted to develop a small, lightweight, inexpensive and wearable device that doesn’t require a power source.

The researchers developed a wearable passive air sampler, known as the Fresh Air Clip, that continually adsorbs virus-laden aerosols on a polydimethylsiloxane (PDMS) surface. The team tested the air sampler in a rotating drum in which they generated aerosols containing a surrogate virus, a bacteriophage with similar properties to SARS-CoV-2. They detected virus on the PDMS sampler using the polymerase chain reaction (PCR), showing that the device could be used to reliably estimate airborne virus concentrations.

Then, the researchers distributed Fresh Air Clips to 62 volunteers, who wore the monitors for five days. PCR analysis of the clips detected SARS-CoV-2 RNA in five of the clips: Four were worn by restaurant servers and one by a homeless shelter staff person. The highest viral loads (more than 100 RNA copies per clip) were detected in two badges from restaurant servers.

Although the Fresh Air Clip has not yet been commercialized, these results indicate that it could serve as a semiquantitative screening tool for assessing personal exposure to SARS-CoV-2, as well as help identify high-risk areas for indoor exposure, the researchers say.

Research contact: @EurekAlert

‘Drug sponge’ could minimize side effects of chemotherapy

January 14, 2019

Is there anything more “sponge-worthy” (in the parlance of a 1995 Seinfeld episode) than mitigating the debilitating side effects of toxic cancer treatments? 

On January 9, doctors at UC Berkeley announced that they have developed a “drug sponge” to do just that—and they are hoping to fast-track approval by the FDA.

How does it work? With the help of a sponge inserted into a blood vessel near a tumor site—and designed to absorb excess or residual chemotherapy drugs that an affected organ cannot use—the researchers said that they are hoping to prevent the dangerous side effects of toxic chemotherapy agents; or even to deliver higher doses to knock back tumors, like liver cancer, that don’t respond to more benign treatments.

The “drug sponge” is an absorbent polymer-coated cylinder that is 3D printed to fit precisely into a vein located downstream from the target organ – the liver in liver cancer, for example. There, it would sop up any drug not absorbed by the tumor, preventing it from reaching and potentially poisoning other organs.

In early tests in pigs, the polymer-coated drug absorber took up, on average, 64% of a liver cancer drugthe chemotherapy agent doxorubicin injected upstream.

“Surgeons snake a wire into the bloodstream and place the sponge like a stent, and just leave it in for the amount of time you give chemotherapy, perhaps a few hours,” said Nitash Balsara, a professor of Chemical and Biomolecular Engineering at the University of California-Berkeley, and a faculty scientist at Lawrence Berkeley National Laboratory.

“Because it is a temporary device, there is a lower bar in terms of approval by the FDA,” said Steven Hetts, an interventional radiologist at UC San Francisco who first approached Balsara in search of a way to remove drugs from the bloodstream. “I think this type of chemofilter is one of the shortest pathways to patients.”

Most anticancer drugs are poisonous, so doctors walk a delicate line when administering chemotherapy. A dose must be sufficient to kill or stop the growth of cancer cells, but not high enough to irreparably damage the patient’s other organs. Even so, chemotherapy is typically accompanied by major side effects, including nausea, vomiting, diarrhea and suppression of the immune system—not to mention hair loss and ulcers.

“We are developing this around liver cancer because it is a big public health threat–there are tens of thousands of new cases every year–and we already treat liver cancer using intra-arterial chemotherapy,” Hetts said. “But if you think about it, you could use this sort of approach for any tumor or any disease that is confined to an organ, and you want to absorb the drug on the venous side before it can distribute and cause side effects elsewhere in the body. Ultimately we would like to use this technology in other organs to treat kidney tumors and brain tumors.”

Hetts, Balsara and their colleagues at UC Berkeley, UCSF and the University of North Carolina, Chapel Hill, have published their results in the journal ACS Central Science, an open-access publication of the American Chemical Society.

Research contact: nbalsara@berkeley.edu