The first rapid test for smallpox, more commonly known as monkeypox, was developed by a Penn State-led team of researchers. The selective molecular sensor can detect the virus in a matter of minutes, without the use of any sophisticated automated techniques such as polymerase chain reaction (PCR). Current tests require healthcare providers to swab the lesions and send samples to labs for testing, which can take several days.
The technique was recently published in the journal Advanced functional materialsuses the heterogeneous structures of nanomaterials—zero-dimensional spherical gold nanoparticles and 2D hafnium disulfide nanoplatelets—as building blocks to create a platform technology suitable for detecting trace amounts of genetic material in biological samples.
said Dipanjan Pan, Dorothy Faure Hack Chair Professor J. “While the current number of cases is relatively low, as the weather warms and people get more active, cases could rise as they did last summer.”
“It is also important to note that this new technology can help us prepare for the next epidemic or even a pandemic,” said Pan, who is also a professor of nuclear engineering and materials science and engineering. “With a slight modification of the molecules used to target the genetic sequence, we will be able to specifically detect other viruses, bacteria or fungi using the same method.”
The first human smallpox case dates back to the 1970s and was identified in the Democratic Republic of the Congo (DRC) and considered endemic only in Nigeria and some parts of Central and West Africa. Since May 2022, the virus has spread to more than 100 countries and has caused more than 86,900 infections worldwide with nearly a third of global cases concentrated in the United States.
Mpoxvirus is primarily transmitted through close physical contact and causes an illness with symptoms similar to smallpox, although less severe. A growing body of research from the Centers for Disease Control and Prevention shows that people can spread smallpox virus to others days before symptoms appear, making early detection by testing a crucial tool for mitigating the spread of the disease.
Currently, two-dose treatments and vaccines are still not enough to stop the infection, leaving rapid diagnosis as the only option to contain the disease, Pan explained. PCR is the only FDA-approved test known for smallpox, despite limited complex sample collection and transportation and insufficient access to advanced instrumentation facilities. He added that the rapid test, which requires only a small sample from the lesion swab and a short wait time for results, can significantly slow the transmission rate of the virus.
“We were interested in developing a detection method that is sensitive to pathogens in general, and we also wanted to apply the concept to emerging pathogens such as smallpox, because there is an urgent need in the real world for this rapid DNA test,” Pan said. “There will be a significant public health impact as a result of this technology.”
The technology employs “plasmonic” nanoparticles, which are tiny metal particles with unique optical properties due to their size and shape. In this case, the metal nanoparticle is gold, which is refined to such a small scale that it is considered dimensionless. It is layered with hafnium disulfide, a two-dimensional inorganic compound of hafnium and sulfur only a few atoms thick.
“There are many plasmonic tests for pathogens out there,” Pan said. “But this is the first time we have demonstrated that a zero-dimensional plasmon particle and two-dimensional nanoplatelets form a heterostructure that leads to plasmon enhancement, which in turn provides an improvement in sensitivity.”
Zero-dimensional gold nanoparticles and two-dimensional hafnium sulfide interact to form heterostructures that serve as high-resolution sensors, with optical properties that change dramatically in the presence of external stimuli, such as genetic material.
“Our work deals with plasmonics, which is the manipulation of light flux using nanostructured metallic materials,” said Pan. “By using new materials and chemistry, we are trying to understand how to manipulate the properties of the endoprotein to respond to different biological signals.”
In this case, the signal was from trace amounts of viral DNA, specifically a conserved region of the variola virus genome that is not subject to mutation. Pan said nanoparticles have been used in the past to monitor changes in biological systems, but this is the first time two nanoscale objects have been deployed in two different dimensions to detect emerging pathogens.
“This technology does not require expensive equipment or skilled personnel, and can be tailored for future mutations or emerging pathogens,” Pan said.
He explained that his lab is now testing the system against a range of other pathogens to confirm its broad applicability for detecting viruses. Pan added that once the test is clinically validated, the lab will look for commercial partners to work with to bring the technology to market.
“Scientists are striving to provide the public with the most advanced technologies that enable them to self-diagnose or diagnose at the point of care,” Pan said. “And that’s what we’ve done.”
Parikshit Moitra et al, Nucleotide‐‐driven molecular sensing of monkeypox virus by hierarchical self-assembly of hafnium disulfide disulfide nanoplatelets and gold nanospheres, Advanced functional materials (2023). DOI: 10.1002/adfm.202212569
the quote: First Rapid Test Developed for Smallpox, May Be Adapted to Other Emerging Diseases (2023, April 18), Retrieved April 18, 2023 from https://phys.org/news/2023-04-rapid-mpox-emerging-diseases .html
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