Water-Dispersible Silica-Coated Upconverting Liposomes: Can a Thin Silica Layer Protect TTA-UC against Oxygen Quenching?
Light upconversion by triplet-triplet annihilation (TTA-UC) in nanoparticles has received considerable attention for bioimaging and light activation of prodrugs. However, the mechanism of TTA-UC is inherently sensitive for quenching by molecular oxygen. A potential oxygen protection strategy is the coating of TTA-UC nanoparticles with a layer of oxygen-impermeable material. In this work, we explore if (organo)silica can fulfill this protecting role. Three synthesis routes are described for preparing water-dispersible (organo)silica-coated red-to-blue upconverting liposomes. Their upconversion properties are investigated in solution and in A549 lung carcinoma cells. Although it was found that the silica offered no protection from oxygen in solution and after uptake in A549 cancer cells, upon drying of the silica-coated liposome dispersion in an excess of (organo)silica precursor, interesting liposome-silica nanocomposite materials were obtained that were capable of generating blue light upon red light excitation in air.
Leiden Institute of Chemistry and Leiden Institute of Physics, Leiden University , 2300 RA Leiden, The Netherlands.
Sven H C
SH
Askes
Leiden Institute of Chemistry and Leiden Institute of Physics, Leiden University , 2300 RA Leiden, The Netherlands.
Vincent C
VC
Leeuwenburgh
Leiden Institute of Chemistry and Leiden Institute of Physics, Leiden University , 2300 RA Leiden, The Netherlands.
Wim
W
Pomp
Leiden Institute of Chemistry and Leiden Institute of Physics, Leiden University , 2300 RA Leiden, The Netherlands.
Hadi
H
Arjmandi-Tash
Van 't Hoff Institute for Molecular Sciences, University of Amsterdam , 1090 GS Amsterdam, The Netherlands.
Stefania
S
Tanase
Leiden Institute of Chemistry and Leiden Institute of Physics, Leiden University , 2300 RA Leiden, The Netherlands.
Thomas
T
Schmidt
Leiden Institute of Chemistry and Leiden Institute of Physics, Leiden University , 2300 RA Leiden, The Netherlands.
Sylvestre
S
Bonnet
light upconversion; liposomes; nanoparticles; oxygen quenching; photonic materials; silica coating