Gogick, Kristy
(2015)
DESIGN, SYNTHESIS, AND CHARACTERIZATION OF LANTHANIDE-BASED NEAR-INFRARED DENDRIMER COMPLEXES AND METAL-ORGANIC FRAMEWORKS FOR NOVEL MODALITIES IN OPTICAL BIOLOGICAL IMAGING.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Biological imaging in the near-infrared (NIR) region is advantageous because: (i) there is low biological autofluorescence, (ii) less interaction with and perturbation of biological materials, and (iii) NIR light scatters less than visible light. Several lanthanide cations emit in the NIR and in complexes they display: (i) narrow emission bands, (ii) constant emission wavelengths not affected by the environment, and (iii) enhanced photostability relative to organic fluorophores. Initially we studied the generation-3 poly(amido amine) dendrimer as a platform for organizing and sensitizing europium cations. We demonstrated the capability of this functionalized material to preferentially accumulate in tumors and be utilized for both in vivo and ex vivo imaging. In order to more rigidly organize the lanthanides cations we transitioned to using them as the metal in metal-organic frameworks (MOFs). We developed a barcoded MOF, ErxYb1-x-PVDC-1, exhibiting enhanced erbium emission relative to Er-PVDC-1, making it a promising material for telecommunications devices. A slight modification to the synthesis yielded a MOF with a different crystal structure, Yb-PVDC-3. The analogous nanoscale version of this MOF, nano-Yb-PVDC-3 was attained through a reverse microemulsion synthesis. Altering the ratio of the lanthanides in the synthesis resulted in nanoscale barcoded MOFs, nano-NdxYb1-x-PVDC-3, with tunable photophysical properties. The nano-Yb-PVDC-3 was extensively studied for use as a biological imaging agent. It was taken up by cells (HeLa and NIH 3T3) and successfully used for live imaging in both the visible and NIR regions. Focusing on biologically-friendly ligands, a series of size-controllable Yb(BTC)(H2O) MOFs were synthesized using sodium acetate as a modulator. The photophysical properties of these MOFs were not size-dependent, allowing for the selection of material based solely on size considerations. In order to shift the excitation wavelength to the NIR region a dye which absorbs at lower energy was incorporated with a Yb(BTC)(H2O) nanoMOF to produce a dye-incorporated material. Despite the incorporation of only a very small amount of the dye, its excitation generated sensitized Yb3+ emission. The dye-incorporated material was coated with a silica shell to enhance the NIR emission intensity in water. This material has great potential to be used as a biological imaging agent.
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| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
18 June 2015 |
| Date Type: |
Publication |
| Defense Date: |
9 April 2015 |
| Approval Date: |
18 June 2015 |
| Submission Date: |
17 April 2015 |
| Access Restriction: |
5 year -- Restrict access to University of Pittsburgh for a period of 5 years. |
| Number of Pages: |
236 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Chemistry |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Near-infrared
Lanthanides
Luminescence
Metal-organic frameworks
Dendrimers
Biological Imaging |
| Date Deposited: |
18 Jun 2015 19:24 |
| Last Modified: |
18 Jun 2020 05:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/24943 |
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