How do we know exactly what is happening at a molecular level during extremely fast processes, such as burning during combustion? In less than the blink of an eye, one chemical compound and then another are present in a flame only to disperse and give way to more. Understanding which molecules are present gives scientists a way of understanding the inner workings of the chemical processes taking place.
But traditionally used methods for measuring molecule sizes struggle to capture such fast, transient processes. And conventional optical microscopy not only falls short in speed but also cannot spatially resolve molecules, which typically are no larger than a few nanometers, or billionths of a meter, in size.
Now a Caltech team led by Lihong Wang, the Bren Professor of Medical Engineering and Electrical Engineering and an affiliated faculty member with the Tianqiao and Chrissy Chen Institute for Neuroscience at Caltech, has developed a new tool called Compressed Ultrafast Planar Polarization Anisotropy Imaging (CUP2AI), which delivers insights into dynamic events, with potential applications not only in combustion studies but also in such areas as drug design and nanoparticle formation. In a paper that recently appeared in the journal Nature Communications, Wang and his colleagues present the CUP2AI technique and describe its successful use in imaging carcinogenic chemicals in flames and imaging, in water, a common fluorescent chemical used in biomedical applications.