Design of multifunctional nanoparticles for combined in-vivo imaging and advanced drug delivery

Abstract

Design of multifunctional nanoparticles for multimodal in-vivo imaging and advanced targeting to diseased single cells for massive parallel processing nanomedicine approaches requires careful overall design and a multilayered approach. Initial core materials can include non-toxic metals which not only serve as an x-ray contrast agent for CAT scan imaging, but can contain T1 or T2 contrast agents for MRI imaging. One choice is superparamagnetic iron oxide NPs which also allow for convenient magnetic manipulation during manufacturing but also for re-positioning inside the body and for single cell hyperthermia therapies. To permit real-time fluorescence-guided surgery, fluorescence molecules can be included. Advanced targeting can be achieved by attaching antibodies, peptides, aptamers, or other targeting molecules to the nanoparticle in a multilayered approach producing “programmable nanoparticles” whereby the “programming” means controlling a sequence of multi-step targeting methods. Addition of membrane permeating peptides can facilitate uptake by the cell. Addition of “stealth” molecules (e.g. PEG or chitosan) to the outer surfaces of the nanoparticles can permit greatly enhanced circulation times in-vivo which in turn lead to lower amounts of drug exposure to the patient which can reduce undesirable side effects. Nanoparticles with incomplete layers can be removed by affinity purification methods to minimize mistargeting events in-vivo. Nanoscale imaging of these manufactured, multifunctional nanoparticles can be achieved either directly through superresolution microscopy or indirectly through single nanoparticle zeta-sizing or x-ray correlation microscopy. Since these multifunctional nanoparticles are best analyzed by technologies permitting analysis in aqueous environments, superresolution microscopy is, in most cases, the preferred method.