Engineering semiconductor quantum dots for quantitative imaging of cell motility and invasion

Zhao, Andrew Xin

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https://hdl.handle.net/2142/89161 Copy

Description

Title

Engineering semiconductor quantum dots for quantitative imaging of cell motility and invasion

Author(s)

Zhao, Andrew Xin

Issue Date

2015-12-11

Director of Research (if dissertation) or Advisor (if thesis)

Smith, Andrew M.

Department of Study

Materials Science & Engineerng

Discipline

Materials Science & Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Quantum Dots
• Cancer
• Cell Motility
• Extracellular Matrix (ECM)

Abstract

Quantum dots (QDs) are photo-luminescent nanocrystals that possess unique optical properties such as a narrow emission range and high photo-stability, which makes them useful for a variety of biological imaging applications. In this study, QDs presenting different chemical moieties were used to quantify non-specific binding to different extracellular matrix (ECM) proteins. QDs coated with poly-maleic anhydride (PMA), which had been modified to present alkane, alkene, alkyne, PEG and carboxylic acid, carboxylic acid, and solely PEG, were incubated on poly-l-lysine, collagen, fibronectin, and gelatin coated glass coverslips. Based upon the emission intensity normalized by the quantum yield (QY), the binding of the QDs were directly compared. The QD coated substrates exhibited photoluminescent enhancement (PLE) resulting in an increased emission intensity when excited over time. Based upon this increase, a more accurate QY was calculated, allowing for proper comparison between the QDs. Different ECM proteins possessed different binding affinities to different chemical moieties. Poly-L-lysine was shown to bind well to PEG/carboxylic acid particles, but paradoxically, not as well to carboxylic acid. Collagen exhibited an affinity to the alkyne coated particles. Fibronectin showed high binding to PEG/carboxylic acid QDs, but also bound well to the alkane, alkene, and alkyne. Gelatin, like fibronectin, also showed affinity to most of the particles. Due to differences in the QY and PLE, the QDs that bound the most to each protein did not produce the most uniform and brightest substrates. MDA-MB-231 human breast cancer cells were then seeded on gelatin substrates coated with the QDs for 24 hours. Evidence of uptake and degradation of the matrix was observed, but could not be quantified using wide-field fluorescent microscopy. As a result, confocal images were required to properly characterize the degradation.

Graduation Semester

2015-12

Type of Resource

text

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http://hdl.handle.net/2142/89161

Copyright and License Information

Copyright 2015 Andrew Zhao

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