Figure 1.

Figure 1A Cutaway drawing showing liposomal nanoparticle lipid bilayer (inset) and cyclic RGD peptides bound to the exterior liposomal surface. The QDs denoted by filled red circles are conjugated to a lipid moiety and reside inside and external to the bilayer. The liposome is in effect initiated at these QD-lipid conjugates and forms around them. The interior volume of this liposome is aqueous, but can be filled with a hydrogel to facilitate the loading of a broad range of drug chemotypes.

Figure 1B Schematic diagram depicting the conjugation of the QD and the DPPE-SH lipid prior to liposomal nanoparticle assembly. The first step is to couple the QD to the linker. The maleamide group of the linker reacts with the lipid-thiol to create a stable thioether bond.

Figure 1C IR spectroscopy, the lower tracing shows the spectrum for QDs alone. The top tracing shows the spectrum of the putative lipid-QD conjugate. The doublet resulting from stretch of the amide bond is clearly indicated and is not present within the QD alone tracing. This data provides strong evidence that QD-lipid conjugation was successful. Fluorescence intensity of the QD800 nanocrystals was not diminished by encapsulation (data not shown).