Submission Date

4-25-2022

Document Type

Paper- Restricted to Campus Access

Department

Biochemistry & Molecular Biology

Adviser

Samantha Wilner

Committee Member

Jennifer King

Committee Member

Mark Ellison

Department Chair

Eric Williamsen

Department Chair

Anthony Lobo

Project Description

Lipid micelles represent an important class of nanoparticle with the potential to enhance the solubility and delivery of hydrophobic drugs and imaging agents. Their small size (< 50 nm) makes them ideal candidates for both passive tumor uptake and deep tissue penetration. The use of lipid micelles as delivery vehicles, however, has been challenged by the fact that these particles are inherently unstable in vivo due to concentration dependence and interactions with serum proteins. We seek to stabilize the formation of micelles using lipid monomers covalently modified with short oligonucleotide sequences (16 nucleotides in length) that are predicted to interact with each other through G-quadruplex or double helix formation. These oligonucleotide-lipid conjugates were synthesized manually using standard phosphoramidite chemistry. Lipid phosphoramidite synthesis was confirmed using -phosphorous-31 nuclear magnetic resonance (31P NMR) spectroscopy, and synthesis of lipid-oligonucleotide conjugates was confirmed reversed-phase high performance liquid chromatography (RP-HPLC). Our results show that we have successfully synthesized and purified DNA-lipid conjugates composed of 4 different 16-nucleotide sequences conjugated with either 16 carbon (C16) or 18 carbon (C18) tails bearing diacyl chains. Using these conjugates, we were able to assemble micelles. Florescent lipophilic dyes were incorporated into these micelles to measure stability using Förster Resonance Energy Transfer (FRET) assays. Though G-quadruplexes have been shown to stabilize micelles previously, we confirmed this trend as well as investigated the effect of the quantity of G-quadruplexes on micelle stability. In the future, we plan to perform additional FRET assays to observe the effect DNA duplexes and triple helix formation on micellar stability. This approach allows us to change DNA sequence in order to program micelle destabilization.

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