Alexander Mikhailovsky

TL;DR: In this article, the authors examined the competing dynamical processes involved in optical amplification and lasing in nanocrystal quantum dots and found that, despite a highly efficient intrinsic nonradiative Auger recombination, large optical gain can be developed at the wavelength of the emitting transition for close-packed solids of these dots.

TL;DR: It is observed that in the quantum-confined regime, the Auger constant is strongly size-dependent and decreases with decreasing the quantum dot size as the radius cubed.

TL;DR: It is shown that near-complete liposome release can be initiated within seconds by irradiating hollow gold nanoshells (HGNs) with a near-infrared (NIR) pulsed laser and HGNs can be coupled with any nanocarriers to promote spatially and temporally controlled drug release.

Abstract: An elusive goal for systemic drug delivery is to provide both spatial and temporal control of drug release. Liposomes have been evaluated as drug delivery vehicles for decades, but their clinical significance has been limited by slow release or poor availability of the encapsulated drug. Here we show that near-complete liposome release can be initiated within seconds by irradiating hollow gold nanoshells (HGNs) with a near-infrared (NIR) pulsed laser. Our findings reveal that different coupling methods such as having the HGNs tethered to, encapsulated within, or suspended freely outside the liposomes, all triggered liposome release but with different levels of efficiency. For the underlying content release mechanism, our experiments suggest that the microbubble formation and collapse due to the rapid temperature increase of the HGN is responsible for liposome disruption, as evidenced by the formation of solid gold particles after the NIR irradiation and the coincidence of a laser power threshold for both triggered release and pressure fluctuations in the solution associated with cavitation. These effects are similar to those induced by ultrasound and our approach is conceptually analogous to the use of optically triggered nano-"sonicators" deep inside the body for drug delivery. We expect HGNs can be coupled with any nanocarriers to promote spatially and temporally controlled drug release. In addition, the capability of external HGNs to permeabilize lipid membranes can facilitate the cellular uptake of macromolecules including proteins and DNA and allow for promising applications in gene therapy.

TL;DR: A solid solution strategy helps increase the efficiency of Ce{sup 3+} oxyfluoride phosphors for solid-state white lighting by using a phosphor-capping architecture, and electroluminescence spectra from a 434-nm InGaN LED phosphor are displayed.