Upconverting nanoparticles as a new class of optical sensors for visualizing mechanical forces in vivo
Abstract/Contents
- Abstract
- Mechanical forces influence a variety of biological processes, including stem cell differentiation, muscle contractions, and disease. However, few sensors have the nanoscopic size, signal stability, or dynamic range to measure forces in vivo. In my research, I design lanthanide-based upconverting nanoparticles (UCNPs) that emit visible light when excited with near infrared light, thereby enabling background-free imaging. In the presence of a mechanical stimuli, like a push or a squeeze, they change color, allowing us to see differences in mechanical environments and track force-dependent behavior. These mechanosensitive nanoparticles have broad applications, as they can be deployed in a variety of biological systems with minimal invasiveness through the bloodstream, ingested, or even taken up by the roots of a plant. Further, they represent an entirely new class of probes for monitoring mechanotransduction in biology. First, I will discuss how I achieve bright, sub-50 nm mechanosensitive UCNPs. In one strategy, d-metal ions couple to lanthanide ions with an efficiency that varies with pressure. In another strategy, a core-shell architecture enhances upconversion efficiency, while synthetically induced strain at the core-shell interface tunes sensitivity. By looking at different crystal phases and shell materials, I create a toolkit of optical sensors, all with a reproducible and ratiometric color response to mechanical stimuli. Then, I evaluate the biocompatibility and performance of UCNPs in biological environments, including a range of buffers, pH gradients, and in vivo in C. elegans worms. Finally, I demonstrate the first in vivo visualization of mechanical stresses involved in C. elegans digestion. Real-time videos reveal how stresses change both spatially and temporally, opening up future directions for monitoring disease and its impact on mechanotransduction.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2019; ©2019 |
| Publication date | 2019; 2019 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Lay, Alice |
|---|---|
| Degree supervisor | Dionne, Jennifer Anne |
| Degree supervisor | Ganguli, Surya, 1977- |
| Thesis advisor | Dionne, Jennifer Anne |
| Thesis advisor | Ganguli, Surya, 1977- |
| Thesis advisor | Goodman, Miriam Beth |
| Degree committee member | Goodman, Miriam Beth |
| Associated with | Stanford University, Department of Applied Physics. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Alice Lay. |
|---|---|
| Note | Submitted to the Department of Applied Physics. |
| Thesis | Thesis Ph.D. Stanford University 2019. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2019 by Alice Lay
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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