Improved drug development and disease diagnosis using tailored light-molecule interactions

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Abstract/Contents

Abstract
Light-matter interactions are critical for many modern biomedical techniques, from fluorescence-based DNA sequencing to photoablation of tumors. Even so, existing optical diagnostic tools can be slow and existing drug treatments often have adverse side effects. Here, we explore two methods for improving drug purification and disease diagnosis based on tailored light-molecule interactions. First, I will discuss how the optical-frequency magnetic resonances of dielectric nanoparticles can be used to separate chiral molecules for enantiopure pharmaceuticals. Currently, half of pharmaceuticals on the market are chiral, but 90% of these are sold as mixtures since existing chemical methods are expensive and time consuming. Yet, the non-therapeutic enantiomer can reduce efficacy and lead to adverse side effects. Illumination with circularly polarized light provides a potentially cost-effective and versatile alternative but can due to the weak nature of chiral light-matter interactions. Using silicon nanospheres as a model system, I explore electromagnetic design parameters to enhance enantioselective light absorption in chiral molecules while maintaining total molecular absorption rates. With optimized particles, enhancements in the rates of enantioselective absorption can reach 7X, leading to a projected 50% increase in yield for the separation of the molecule camphor. Next, I will discuss how Raman spectroscopy can enable rapid identification of bacteria. I acquire Raman spectra from over 60,000 bacterial cells, spanning 30 strains from 22 species and covering 95% of all bacterial infections treated at Stanford Hospital. This large reference dataset allows us to apply machine learning techniques to accurately identify bacteria strains and antibiotic treatments. I show how this method translates to clinical patient samples, predicting treatment for 25 patient isolates with 99.0±1.9% accuracy. This work lays the foundation for a technique that could allow for accurate and targeted treatment of bacterial infections within hours, reducing healthcare costs and antibiotics misuse, limiting antimicrobial resistance, and improving patient outcomes.

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 Ho, Chi-Sing
Degree supervisor Brongersma, Mark L
Degree supervisor Dionne, Jennifer Anne
Thesis advisor Brongersma, Mark L
Thesis advisor Dionne, Jennifer Anne
Thesis advisor Banaei, Niaz
Degree committee member Banaei, Niaz
Associated with Stanford University, Department of Applied Physics.

Subjects

Genre Theses
Genre Text

Bibliographic information

Statement of responsibility Chi-Sing Ho.
Note Submitted to the Department of Applied Physics.
Thesis Thesis Ph.D. Stanford University 2019.
Location electronic resource

Access conditions

Copyright
© 2019 by Chi-Sing Ho
License
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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