Recently,an image has been circulating on social media showing a street filled with red coronavirus particles,with a caption that reads:“The U.S.uses advanced microscopes to see the virus in the air.Would you still dare to go out?”

　　Fact check:This image cannot possibly be a photograph of the virus taken with an advanced microscope.The novel coronavirus is on the nanometer scale and can only be observed with an electron microscope.The size of the virus in the image is completely disproportionate to objects on the street.Current electron microscopes are incapable of producing such a perspective of airborne components.

　　Microorganisms in the air are highly diverse.Without specific staining for a particular virus,an image would not show the entire view filled with SARS?CoV?2.Targeted labeling of a specific virus across the entire airspace is not feasible with current technology.

　　The microscope mentioned later in the text uses an ultra?fast laser scanning technology developed by a team at the University of Hong Kong.It employs a pair of parallel mirrors to generate a train of laser pulses,achieving speeds at least 1,000 times faster than current laser scanning techniques.In experiments,the researchers used this high?speed microscope to project scanning laser beams onto a mouse brain,capturing two?dimensional images of the mouse cerebral cortex at rates of 1,000 to 3,000 scans per second.

　　Professor Chien Wen(Xie Jianwen),Associate Professor of the Department of Electrical and Electronic Engineering and Director of the Biomedical Engineering Program who led the research team,explained that existing technologies for capturing brain electrical signals include implanting electrodes directly into the brain to measure voltage–a highly invasive method–as well as magnetic resonance imaging and conventional optical microscopes,which are relatively slow.The advantage of HKU’s new technology is that it is minimally invasive and can precisely locate individual neurons,tracking their firing pathways on a millisecond timescale.

　　Professor Chien stated that this new technology enables detection of activity changes in single neurons within milliseconds in a living brain.The team aims to further improve the technology over the next one to two years to explore deeper brain structures and gain a more comprehensive understanding of brain function.

　　The research findings have been published in the academic journal Nature Methods.