Item Details

abstract

This work presents research using the natural carbohydrate glycosaminoglycan hyaluronic acid (HLA) as a hydrophilic polymer backbone for the synthesis of nanoscale polymeric micelles loaded with either the near infrared (NIR) fluorophore indocyanine green (ICG) for image guided surgery (IGS), or the fatty acid synthase (FASN) inhibitor Orlistat (ORL) for chemotherapy. Hydrophobic conjugates were synthesized and conjugated to HLA in order to drive self-assembly into nanoparticles (NPs) and load their respective payloads. Chemical composition was confirmed by mass spectrometry and NMR. NP self-assembly was confirmed by dynamic light scattering (DLS) and atomic force microscopy. Optical properties of ICG-loaded NPs, termed NanoICG, were examined and ICG loading was found to be dependent on the structure of the hydrophobic ligand. Fluorescence quenching was observed in aqueous solution, and fluorescence could be reactivated by dissolution in a H2O:DMSO mixture, or in PBS with bovine serum albumin (BSA). ICG release to BSA was observed in vitro. Nano-ICG was found to have negligible cytotoxicity at physiologically relevant concentrations. In vivo results in a xenograft mouse model demonstrated that NanoICG provided superior contrast between tumor and surrounding muscle tissue, and NanoICG successfully identified positive margins (PMs). ORL was successfully loaded into NPs, termed Nano-ORL, at a loading efficiency of approximately 98%. Hydrodynamic diameter was found to be dependent on ORL content. ORL extracted from Nano-ORL successfully inhibited FASN similarly to free ORL, and Nano-ORL inhibited lipid synthesis in cells at approximately the same level as free ORL. Nano-ORL was found to be more cytotoxic than free ORL, and it was found that pre-incubation of both Nano-ORL and free ORL for 24 hours resulted in significantly reduced cytotoxicity of free ORL, while Nano-ORL remained just as cytotoxic. Metabolic analysis showed that Nano-ORL has a similar, negative impact on cellular metabolism as free ORL. These results present novel contributions in the form of the comparison of hydrophobic ligand structure in the loading of ICG into NPs, and the improved tumor accumulation and contrast achieved in vivo. Additionally, these results present the first HLA-derived NP formulation of ORL for use as a FASN inhibitor chemotherapeutic, and show that Nano-ORL has equal or greater activity against cancer cell lines than free ORL.

subject

Hyaluronan

Image guided surgery

Indocyanine green

Nanoparticle

Near infrared

Orlistat

contributor

Hill, Tanner Kinkade (author)

Mohs, Aaron M. (committee chair)

Bickford, Lissett R. (committee member)

Levi, Nicole H. (committee member)

Marini, Frank C. (committee member)

Wadas, Thaddeus J. (committee member)

date

2015-06-23T08:35:36Z (accessioned)

2015-12-22T09:30:08Z (available)

2015 (issued)

degree

Biomedical Engineering (discipline)

embargo

2015-12-22 (terms)

identifier

http://hdl.handle.net/10339/57104 (uri)

language

en (iso)

publisher

Wake Forest University

title

DEVELOPMENT AND APPLICATION OF MODIFIED HYALURONIC ACID DERIVED NANOPARTICLES FOR IMAGE GUIDED SURGERY AND DRUG DELIVERY

type

Dissertation