RT Journal Article
SR Electronic
T1 Low-cost, open-access refractive index mapping of algal cells using the transport of intensity equation
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 640755
DO 10.1101/640755
A1 Stephen Grant
A1 Kyle Richford
A1 Heidi Burdett
A1 David McKee
A1 Brian R. Patton
YR 2019
UL http://biorxiv.org/content/early/2019/05/17/640755.abstract
AB Phase contrast microscopy allows stain free imaging of transparent biological samples. One technique, using the transport of intensity equation (TIE), can be performed without dedicated hardware by simply processing pairs of images taken at known spacings within the sample. The resulting TIE images are quantitative phase maps of unstained biological samples. Therefore, spatially resolved refractive index information can also be determined.Using low-cost, open-source hardware, we applied the TIE to living algal cells to measure their refractive index. We obtained refractive index values that were repeatable within species and differed by distinct amounts depending on the species being measured. We suggest TIE imaging as a method of discrimination between different algal species and, potentially, non-biological materials, based on refractive index. Potential applications in biogeochemical modelling and climate sciences are suggested.