A Nano‐in‐Nano Vector: Merging the Best of Polymeric Nanoparticles and Drug Nanocrystals

An advanced approach that can prepare narrowly size distributed nanomaterials with ultrahigh mass fraction of therapeutics, superior colloidal stability, minimal off‐target effects, as well as precisely controlled drug‐release profiles, is strongly desirable. Here, an optimal nano‐in‐nano vector, consisting of a drug (sorafenib, SFN, or itraconazole, ICZ) nanocrystal core and a polymer (folic acid conjugated spermine‐functionalized acetalated dextran, ADS‐FA) shell on a 1:1 ratio (HSFN@ADS‐FA or ICZ@ADS‐FA) is successfully fabricated. With the help of computational fluid dynamics, the concentration and velocity field are computed in the microfluidic domain, as well as the mixing time between the solvent and nonsolvent for nanovector precursors. The favorable features of both polymer nanoparticles and drug nanocrystals are inherited by the obtained nano‐in‐nano vector, showing ultrahigh drug‐loading degree, biodegradability, pH‐responsive fast dissolution, high stability in serum, and ease of surface functionalization. Furthermore, the half‐maximal inhibitory concentration value of the nano‐in‐nano HSFN@ADS‐FA is ≈54 times lower than the conventional nanovector (LSFN@ADS‐FA) with a low drug‐loading degree. Overall, this nano‐in‐nano vector merges the best of polymeric nanoparticles and drug nanocrystals.     

Drug Delivery: Wavelength‐Selective Light‐Induced Release from Plasmon Resonant Liposomes (Adv. Funct. Mater. 6/2011)

Biodegradable, spectrally tunable plasmon resonant nanocapsules are created via the deposition of gold onto the surface of 100 nm diameter thermosensitive liposomes. These nanocapsules exhibit selective release of encapsulated contents upon illumination with light of a wavelength matching their distinct resonance bands. In this study, 760 and 1210 nm laser illumination elicits complete release from gold‐coated liposomes with a corresponding resonance, while causing minimal release from liposomes with an unmatching resonance. Spectrally selective release is accomplished through the use of multiple, low‐intensity laser pulses delivered over a period of minutes, ensuring that illumination affects the gold‐coated liposomes without heating the surrounding media. The use of pulsed illumination to achieve spectral selectivity is validated experimentally and through modeling of the heat equation. The result of this illumination scheme for selective release using multiple wavelengths of light is a biologically safe mechanism for realizing drug delivery, microfluidic, and sensor applications.