A Route to Triggered Delivery via Photocontrol of Lipid Bilayer Properties Using Lanthanide Upconversion Nanoparticles
Résumé
Soft matter shells for nanoparticles provide an alternative approach to the more traditional inorganic core-shell nanoconstructs. In the latter, functionality and biocompatibility often require the addition of a hydrophilic organic coating. Herein, a supported lipid bilayer serves as a soft matter shell that has the physicochemical properties that enable a dynamic system capable of providing biocompatibility, encapsulation, and release of small molecule active agents. Direct coupling of the conformal, supported lipid bilayer containing an azobenzene-derivatized lipid with an upconversion nanoparticle provides the means to photocontrol the bilayer properties, generating a multifunctional coating. The close contact of the bilayer with the nanoparticle surface eliminates problems associated with Brownian motion for the energy transfer; the mechanism of energy transfer was determined to be dominated by radiative reabsorption using time-resolved photoluminescence. Release of an encapsulated dye, as a hydrophobic drug model, was achieved with significantly lower proportions of azobenzene-derivatized lipid than has been reported for UV-triggered release from liposomes. This work highlights the potential of the described nanoconstruct for light controlled delivery applications, especially in a biological context and in vivo applications, for which NIR excitation is of paramount importance for low toxicity and deeper tissue penetration.