Optical scatter imaging as an apoptosis assay for cells undergoing ALA-mediated photodynamic therapy in vitro

Vincent M. Rossi, Paige J. Baugher, Steven Jacques

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Aminolevulinic acid (ALA) is converted to protoporphyrin-IX (PpIX) within mitochondria, causing the assumption that ALA-mediated photodynamic therapy (PDT) results in mitochondrial damage and therefore an apoptotic response. Mitochondria within apoptosing cells swell, forming pores in their outer mitochondrial membranes which release cytochrome-c, triggering apoptosis. Optical scatter imaging (OSI) makes use of scattered fields in order to indicate the morphology of subcellular components, and is used here in order to measure changes in mitochondrial size as a response to ALA-mediated PDT. Two images of the same field of view are spatially filtered in the Fourier plane of a 4-F system. Both spatial filters block directly transmitted light, while accepting different angles of scattered light through an adjustable iris. The optical scatter image ratio (OSIR) of the local intensities of these two spatially filtered images is indicative of scattering particle size. Mie theory is used to calculate the predicted OSIR as a function of scattering particle size. In this fashion, the OSI system is calibrated using polystyrene microspheres of know sizes. Comparison of the measured OSIR from cellular images to theoretical values predicted for mitochondria then serves as an indication as to whether cells are apoptosing. Cells are treated at varying concentrations of ALA and varying exposures of 635 nm light and imaged at varying time points in order to develop a broader understanding of an apoptotic response of cells undergoing ALA mediated PDT.

Original languageEnglish (US)
Title of host publicationProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume8592
DOIs
StatePublished - 2013
EventBiomedical Applications of Light Scattering VII - San Francisco, CA, United States
Duration: Feb 2 2013Feb 4 2013

Other

OtherBiomedical Applications of Light Scattering VII
CountryUnited States
CitySan Francisco, CA
Period2/2/132/4/13

Fingerprint

Aminolevulinic Acid
Photodynamic therapy
Optical Imaging
Photochemotherapy
apoptosis
Cell death
therapy
Assays
Mitochondria
Apoptosis
Imaging techniques
acids
mitochondria
Acids
cells
Particle Size
Light
Particle size
Scattering
Mitochondrial Size

Keywords

  • aminolevulinic acid
  • MG-63 cells
  • mitochondria morphology
  • Optical Scatter Imaging
  • osteosarcoma
  • photodynamic therapy
  • PpIX

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Radiology Nuclear Medicine and imaging

Cite this

Rossi, V. M., Baugher, P. J., & Jacques, S. (2013). Optical scatter imaging as an apoptosis assay for cells undergoing ALA-mediated photodynamic therapy in vitro. In Progress in Biomedical Optics and Imaging - Proceedings of SPIE (Vol. 8592). [85920O] https://doi.org/10.1117/12.2005229

Optical scatter imaging as an apoptosis assay for cells undergoing ALA-mediated photodynamic therapy in vitro. / Rossi, Vincent M.; Baugher, Paige J.; Jacques, Steven.

Progress in Biomedical Optics and Imaging - Proceedings of SPIE. Vol. 8592 2013. 85920O.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Rossi, VM, Baugher, PJ & Jacques, S 2013, Optical scatter imaging as an apoptosis assay for cells undergoing ALA-mediated photodynamic therapy in vitro. in Progress in Biomedical Optics and Imaging - Proceedings of SPIE. vol. 8592, 85920O, Biomedical Applications of Light Scattering VII, San Francisco, CA, United States, 2/2/13. https://doi.org/10.1117/12.2005229
Rossi VM, Baugher PJ, Jacques S. Optical scatter imaging as an apoptosis assay for cells undergoing ALA-mediated photodynamic therapy in vitro. In Progress in Biomedical Optics and Imaging - Proceedings of SPIE. Vol. 8592. 2013. 85920O https://doi.org/10.1117/12.2005229
Rossi, Vincent M. ; Baugher, Paige J. ; Jacques, Steven. / Optical scatter imaging as an apoptosis assay for cells undergoing ALA-mediated photodynamic therapy in vitro. Progress in Biomedical Optics and Imaging - Proceedings of SPIE. Vol. 8592 2013.
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