(4at) Synthesis of Multifunctional Nanoparticles for Cancer Imaging, Diagnostics and Therapy

Synthesis of multifunctional nanoparticles with combined imaging, diagnostic and therapeutic functions is a rapidly developing field that has attracted a great deal of research interest in recent years. The composition and structure uniformity of the multifunctional nanoparticles play an extremely important role in the success and efficacy of their applications in vitro and in vivo.

Although the conventional nanoparticle preparation method, bulk mixing, is straightforward, the formation of nanoparticles is not well controlled. We developed a novel one-step micromixer-electrospraying method to produce multifunctional lipoplex nanoparticles. In this method, a micromixer was used to bring the therapeutic drugs/genes and imaging agents in a well controlled manner and the mixture is dispersed into tiny particles via electrospraying. In our study, cy5 labeled oligonucleotide (Cy5-G3139) was chosen as the model therapeutic agent and quantum dots (QD605-Amine) were chosen as model imaging or diagnostic agents. Cy5-G3139 and QD605-Amine form a fluorescence resonance energy transfer (FRET) pair that provides the ability to study the intracellular fate of the multifunctional lipoplex nanoparticles.

We investigated the effects of synthesis methods, micromixer-electrospraying vs. bulk mixing, on the physical properties (size, surface charge and structure) of multifunctional lipoplex nanoparticles using dynamic light scattering, zeta potential and CryoTEM. The biological properties, i.e. cellular uptake, intracellular trafficking and antisense activity against Bcl-2 protein, of multifunctional lipoplex nanoparticles produced by micromixer-electrospraying and bulk mixing were also examined in KB cells using confocal microscopy, flow cytometry, real time PCR and Western blot.