THERAPEUTIC PHOTOACTIVATION USING UPCONVERSION NANOPARTICLES

Abstract

Photoactivation techniques have provided unprecedented control over biological processes, resulting in potentially more specific therapies. However, their clinical potential is limited by the predominant use of UV or visible light which are either toxic or have low tissue penetration. Upconversion nanoparticles (UCNPs) can potentially overcome this problem. These nanoparticles are excited by long wavelength near infrared light (NIR) and can be tuned to emit across the UV and visible ranges. Thus, they can be used as nanotransducers to activate photosensitive molecules used in most photoactivation techniques, with the advantage of greater tissue penetration that near infrared light offers. In this thesis the potential of these UCNPs as nanotransducers for photoactivation applications is demonstrated. UCNPs have been used as both carriers and NIR to UV light transducers for photocontrolled gene expression/knockdown and as NIR to visible light transducers for optogenetics activation of two blue light triggered opsins: melanopsin and channelrhodopsin-2 (ChR2).