Fourier-filtering Based Size-Encoded Images for Label-free Tracking of Sub-cellular Organelles in Neurons

摘要

Mitochondrial dynamics such as fission, fusion and movement can reveal the physiological status of neurons and, mostimportantly, serve as diagnostic measures for several neurodegenerative diseases. Traditionally fluorescent probes havebeen used to track mitochondrial dynamics in neurons. However, neurons show low transfection efficiency, presentingchallenges for the use of genetically-encoded fluorescent markers. Alternatively, synthetic fluorescent dyes are shown tohinder mitochondrial motility. In addition, all types of fluorescent probes are subject to photo-bleaching which precludesimaging for longer periods of time. To circumvent these issues, we propose a light-scattering based label-free techniquecalled Optical Scatter Imaging (OSI) that is sensitive to changes in morphology. In this work, we employ a previouslyreported label-free parameter to probe the change in the size of organelles such as mitochondria as they undergo fusionor fission in neurons. In addition, we present a technique to track organelle motion using kymographs obtained from thelabel-free images and compare them with those obtained from fluorescent images. We demonstrate that the label-freekymograph can track organelles such as mitochondria even after the sample is photo-bleached.