Date of Award

8-31-2018

Document Type

Campus Access Thesis

Degree Name

Master of Science (MS)

Department

Physics, Applied

First Advisor

Jonathan Celli

Second Advisor

Stephen Arnason

Third Advisor

Mohamed Amine Gharbi

Abstract

Photodynamic therapy (PDT) is a cancer treatment modality which uses an amalgamation of non-harmful radiation, a light source and a photosensitizer (PS) to cure a cancer with almost no side-effects. Several clinical trials have been made using photodynamic therapy to treat cancer/tumors of interstitial organs which incorporate groundbreaking treatment response of pancreatic cancer as well. With respect to this interpretation, this study has been carried out using PDT to see the treatment response of monolayer pf pancreatic cancer cells using two different photosensitizers- δ- aminolaevulinic acid (ALA) induced protoporphyrin IX (PpIX) & verteporfin.

Even though we notice successful treatment response after different cancer treatments, none of them validates the complete tumor destruction/cell death and the similar drawback can be examined from PDT treatment of pancreatic cancer cells using verteporfin. Even after a high-dose PDT-treatment, it is inevitable that some of the cells within a tumor will not receive a lethal dose & we would like to get an insight of how these populations are distributed & how it changes post-PDT with varying time. Post-PDT analysis of viability measurements & changing cell-esterase activity of live cells are means to approximate their behavior with increasing dose & time, which forms the bases of this study. Variation in cell-esterase activities in this study are examined in two different ways: changes with respect to- (I) temporal variation & (II) with spatial variation. Temporal variation has been carried out using frequency histograms of mean fluorescence intensities of live signal which approximates that the cells, treated with high dose will be more stressed & will have elevated esterase activity which also increases with time and also reflects that these cells need more time to completely react upon the treatment. Even though this analysis gives us a greater picture, we still needed to confirm these results at microscopic level by focusing on the esterase activity of individual live cells and this was achieved using spatial variation.

As the treatment dose increases, the total area of live cells decreases but an interesting thing that we noticed here is that bigger clusters of live cells that survive even at the maximum dose will be more stressed & will have an elevated esterase activity as they struggle to stay alive against the increased dose. This process becomes more pronounced with increase in time.

Comments

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