Light and nanoparticle-based approaches to the control of ion channels and drug delivery

Abstract

Nanoparticle (NP)-mediated drug delivery typically relies on cargo release to occur passively or in response to environmental stimuli. In the first part of this work, we present a drug delivery method based on light-activated disruption of intracellular vesicles after internalization of bio-functionalized mesoporous silica nanoparticles loaded with cargo. We developed an improved synthesis method to optimize size control of mesoporous silica nanoparticles in the 20-200nm range while preserving porosity. We optimized surface bio-functionalization to obtain a highly stable and targetable nanocarrier, and used an embedded photosensitizer to combine the power of targeted delivery with the spatiotemporal control of light activation. NP-mediated endosomal disruption can be controlled at the single vesicle level. As an example, we delivered a cell-impermeable fluorescent compound exclusively to the cytosol of multidrug resistant cancer cells in a mixed population. The second part of this thesis investigated the use of both photosensitizer-coupled and magnetic nanoparticles as actuators of ion channels. While direct magnetic actuation was not found to promote activation of the receptors tested, several members of the transient receptor potential superfamily (TRP), notably TRPV3 and TRPA1, were found to be activatable by light in conjunction with photosensitizers, including the endogenously present all-trans retinal. The findings were established using a combination of calcium imaging with both chemical and genetically encoded indicators, in addition to whole cell patch clamping. Spontaneous activation of channels in heterologous expression systems was observed upon illumination at selective wavelengths, establishing an effective actuation method, potentially adding native channels to the current opto-genetic toolbox.