{"id":105403,"date":"2021-03-08T11:26:52","date_gmt":"2021-03-08T15:26:52","guid":{"rendered":"http:\/\/www.bu.edu\/eng\/?p=105403"},"modified":"2022-10-21T16:53:40","modified_gmt":"2022-10-21T20:53:40","slug":"can-droplets-be-used-to-stop-instead-of-spread-disease","status":"publish","type":"post","link":"https:\/\/www.bu.edu\/eng\/2021\/03\/08\/can-droplets-be-used-to-stop-instead-of-spread-disease\/","title":{"rendered":"Can Droplets be Used to Stop, Instead of Spread, Disease?"},"content":{"rendered":"

ENG, CDC researchers quantify how droplet formation might damage microbes, reducing disease transmission<\/strong><\/h3>\n

By Patrick L. Kennedy<\/strong><\/p>\n

It happens in a flash. As you cough up a thread of the fluid that lines your respiratory tract, it breaks into tiny droplets, as small as a micrometer in diameter. Some of those droplets, or aerosols, might hang in the air for minutes or even hours. And some of them might contain pathogenic microbes\u2014bacteria or viruses that cause disease.<\/p>\n

What if you could slow down that moment when the droplets are formed? That\u2019s what researchers from the College of Engineering and the Centers for Disease Control did in a study\u2014recently published in Physical Review Fluids<\/em><\/a>\u2014on the violent, unseen forces unleashed during aerosol formation. Their findings have bearing on the transmission of respiratory diseases such as COVID-19.<\/p>\n

\u201cThese droplets do contain biological life,\u201d explains Mechanical Engineering postdoctoral associate Oliver McRae, the study\u2019s lead author, and to spread disease, \u201cthat life must be able to survive this whole churning and agitation process.\u201d<\/p>\n

The agitation occurs as droplets break off from a liquid thread to go spinning into the air, where someone might inhale them. But, paradoxically, the same churning process that gives the aerosol-borne microbes a chance to spread can also stress and kill them before they get that chance.<\/p>\n

\"\"
Mechanical Engineering postdoctoral associate Oliver McRae (CAS’12, ENG’16, ENG’19), lead author of the new study on aerosol agitation.<\/figcaption><\/figure>\n

\u201cImagine you have a fish in a bucket of water,\u201d says McRae. \u201cAnd now you\u2019re stirring that water faster and faster. At some point, that fish is not likely to survive. That\u2019s kind of what we have in the droplet, albeit on a much smaller scale.\u201d<\/p>\n

McRae and Associate Professor James C. Bird (ME, MSE) studied the droplet formation process in Boston University\u2019s Fluid Lab. They shot extremely fine threads of water through the air and recorded the motion with a high-speed camera capturing up to 350,000 frames per second.<\/p>\n

When they played back the microsecond-by-microsecond images, McRae and Bird witnessed the dynamics of the \u201cpinch-off,\u201d when the droplets break from the thread. The droplets\u2019 movements confirmed the stressors calculated by the researchers\u2019 computer simulations of the churning action that might wreak havoc on microbes.<\/p>\n

The computer simulations showed the stressors to be highly sensitive to the droplet size: The smaller the droplet size, the greater the stressors. \u201cThe stressors increase two-and-a-half orders of magnitude for every order of magnitude decrease in droplet size,\u201d says McRae.<\/p>\n

Some previous studies touched on hydrodynamic agitation as a factor in microbial transmission, but McRae and Bird\u2019s study\u2014done in collaboration with a colleague at the CDC\u2014is the first to quantify it, and it adds to the scientific community\u2019s knowledge of how disease spreads.<\/p>\n

While agitation does not kill all microbes, the research advances the tantalizing possibility that it could be wielded deliberately to tamp down their spread. Earlier research established that saline spray increases surface tension on droplets, which, McRae says, could make the agitation stronger. McRae\u2014who earned doctoral and master\u2019s degrees in Mechanical Engineering from ENG in 2019 and 2016, respectively, and a bachelor\u2019s in biology from the College of Arts & Sciences in 2012\u2014is planning to pursue this research further.<\/p>\n

\u201cIf you can lower the number of viable pathogens in aerosols, then you can lower the infectious load and reduce the likelihood of transmission,\u201d says McRae.<\/p>\n

\u201cWhat I like about this work is that I\u2019m able to combine my undergrad and grad training,\u201d McRae says. \u201cI get very excited about the possibility of being able to help people with reducing transmission and reducing infections.\u201d<\/p>\n

In addition to Physical Review Fluids, <\/em>McRae\u2019s paper will appear in the American Physical Society\u2019s special collection<\/a> of COVID-relevant research.<\/p>\n","protected":false},"excerpt":{"rendered":"

ENG, CDC researchers quantify how droplet formation might damage microbes, reducing disease transmission By Patrick L. Kennedy It happens in a flash. As you cough up a thread of the fluid that lines your respiratory tract, it breaks into tiny droplets, as small as a micrometer in diameter. Some of those droplets, or aerosols, might […]<\/p>\n","protected":false},"author":2662,"featured_media":105428,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[236,252,245],"tags":[597,598,273,302,599,600,601,602,603,604,605,606,607,608],"_links":{"self":[{"href":"https:\/\/www.bu.edu\/eng\/wp-json\/wp\/v2\/posts\/105403"}],"collection":[{"href":"https:\/\/www.bu.edu\/eng\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.bu.edu\/eng\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.bu.edu\/eng\/wp-json\/wp\/v2\/users\/2662"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bu.edu\/eng\/wp-json\/wp\/v2\/comments?post=105403"}],"version-history":[{"count":1,"href":"https:\/\/www.bu.edu\/eng\/wp-json\/wp\/v2\/posts\/105403\/revisions"}],"predecessor-version":[{"id":126952,"href":"https:\/\/www.bu.edu\/eng\/wp-json\/wp\/v2\/posts\/105403\/revisions\/126952"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.bu.edu\/eng\/wp-json\/wp\/v2\/media\/105428"}],"wp:attachment":[{"href":"https:\/\/www.bu.edu\/eng\/wp-json\/wp\/v2\/media?parent=105403"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bu.edu\/eng\/wp-json\/wp\/v2\/categories?post=105403"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bu.edu\/eng\/wp-json\/wp\/v2\/tags?post=105403"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}