A class of biocompatible upconverting nanoparticles (UCNPs) with largely amplified red-emissions was developed. The optimal UCNP shows a high absolute upconversion quantum yield of 3.2% in red-emission, which is 15-fold stronger than the known optimal β-phase core/shell UCNPs. When conjugated to aminolevulinic acid, a clinically used photodynamic therapy (PDT) prodrug, significant PDT effect in tumor was demonstrated in a deep-tissue (>1.2 cm) setting in vivo at a biocompatible laser power density. Furthermore, we show that our UCNP–PDT system with NIR irradiation outperforms clinically used red light irradiation in a deep tumor setting in vivo. This study marks a major step forward in photodynamic therapy utilizing UCNPs to effectively access deep-set tumors. It also provides an opportunity for the wide application of upconverting red radiation in photonics and biophotonics.
One of key roadblocks in UCNP development is its extremely limited choices of excitation wavelengths. We report a generic design to program UCNPs to possess highly tunable dye characteristic excitation bands. Using such distinctive properties, we were able to develop a new excitation wavelength selective security imaging. This work unleashed the greater freedom of the excitation wavelengths of the upconversion nanoparticles and we believe it is a game-changer in the field and this method will enable numerous applications that are currently limited by existing UCNPs.
We
designed a unimolecular hyperstar polymer for efficient small
interfering RNA (siRNA) delivery that can be processed under repeated
lyophilization and reconstitution without the need of any excipient.
The hyperstar polymer contains a biodegradable hyperbranched core
and is bound to siRNA through its thousands of cationic arms that
radiate from its core. The siRNA/hyperstar complexes showed siRNA
transfection efficiency that was superior to that of Lipofectamine2000
in regard to the gene for human Cu, Zn superoxide dismutase 1 (SOD1),
whose mutation causes familial amyotrophic lateral sclerosis. More
importantly, hyperstar polymers as unimolecular containers minimized
the multipolymer cross-interaction during lyophilization, and this
maintained the uniquely high transfection efficiency of the siRNA/hyperstar
complexes after repeated freeze-drying and reconstitution without
the conventional need for excipient.
In order to establish a noninvasive cancer therapy with minimal side effects, low cost, and specific in targeting tumor cells. The team engineered novel and biocompatible Upconversion Nanoparticles (UCNPs) with a calcium fluoride shell α-NaYF4:Yb,Er@CaF2 and conjugated with an FDA approved prodrug 5-Aminolevulinic Acid (ALA). In conjunction with photodynamic therapy (PDT), deep tissue penetration was achieved. UCNPs convert near-infrared light into visible light when excited at ~980nm. Emission of the red light from the UCNPs activate the photosensitizer protoporphyrin (PpIX), causing the production of reactive oxygen species (ROS) causing the death of targeted tumor.
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