Near-Infrared Triggered Anti-Cancer Drug Release from Upconverting Nanoparticles

Externally-triggered drug delivery using functional nanoparticles has provided new strategies to improve therapeutic efficacy while concurrently minimizing toxicity. This thesis describes an investigation of photocleavage at the surface of UCNPs to release the chemotherapeutic 5-Fluorouracil (5-FU). Core-shell UCNPs composed of beta-NaYF4: 4.95%Yb, 0.08%Tm / beta-NaYF4 were decorated with o-phosphorylethanolamine ligands that were coupled to an o-nitrobenzyl (ONB) derivative of 5-FU. The UV photoluminescence (PL) was in resonance with the absorption band of the ONB-FU derivative and energy transfer resulted in photocleavage and subsequent release of 5-FU from the surfaces of UCNPs for these in vitro studies. Release of 5-FU was complete within minutes using a 980 nm NIR laser source that operated below 100 mW in power. The efficiency of triggered release was as high as 80% of the total conjugated ONB-FU. This work provides an important first step toward the development of a UCNP platform capable of targeted chemotherapy.