Targeted drug delivery to selected brain cell types is a crucial step in enhancing therapeutic effects while limiting side effects in non-target cells. Here we report on the development and evaluation of a new cascade targeting delivery system that employs PEG-PCL nanoparticles modified with both an angiopep-2 peptide and a EGFP-EGF1 protein for precise targeting of brain neuroglial cells. Angiopep-2 penetrates the blood-brain barrier and EGFP-EGF1 binds neuroglial cells, providing the system with two stages of targeting. In vitro studies demonstrated that both bEnd.3 cells and neuroglial cells had a higher uptake of angiopep-2 and EGFP-EGF1 conjugated nanoparticles (AENP) as compared to unmodified nanoparticles. Ex vivo imaging showed that AENP had higher accumulation in the brain over unmodified nanoparticles and EGFP-EGF1 modified nanoparticles. Fluorescent in situ hybridization of brain slides demonstrated that AENP co-localized with neuroglial cells. Transmission electron microscopy further showed that AENP could target and enter neuroglial cells. This newly developed cascade targeting delivery system that precisely targets neuroglial cells has great potential in the diagnosis and treatment of neuroglial related diseases. Replacing EGFP-EGF1 and angiopep-2 with other ligands may extend the utility of the system to diagnose and treat organ diseases beyond brain (C) 2011 Elsevier Ltd. All rights reserved.

Nitric oxide (NO) shows great role in tumor biology. Recent years, more and more researches utilized NO donor in tumor targeting drug delivery and treatment. In this review, we summarized the NO donors by their endogenous and exogenous stimuli. Then the application of NO donors, which was the main aim of the review, was discussed in detailed according to their functions, including inducing tumor cell apoptosis, reversing tumor multidrug resistance, inhibiting tumor metastasis and improving drug delivery.