Angiogenesis has long been a desired therapeutic approach to improve clinical outcomes of conditions typified by ischemia. Vascular endothelial growth factor (VEGF) has demonstrated the ability to generate new blood vessels in vivo, but trials using intravenous delivery have not yet produced clinical success. Localized, sustained delivery of VEGF has been proven necessary to generate blood vessels as demonstrated by implantable, controlled release devices. Ultimately, nanoparticles delivered by intravenous injection may be designed to accumulate in target tissues and sustain the local VEGF concentration; however, injectable nanosuspensions that control the release of stabilized VEGF must first be developed. In this study, we utilize the heparin binding domain of VEGF to bind the polyanion dextran sulfate, resulting in an enhanced thermal stability of VEGF. Coacervation of the VEGF-bound dextran sulfate with selected polycations (chitosan, polyethylenimine, or poly-L-lysine) produced nanoparticles approximately 250 nm in diameter with high VEGF encapsulation efficiency (50-85%). Release of VEGF from these formulations persisted for >10 days and maintained high VEGF activity as determined by ELISA and a mitogenic bioassay. Chitosan-dextran sulfate complexes were preferred because of their biodegradability, desirable particle size ( approximately 250 nm), entrapment efficiency ( approximately 85%), controlled release (near linear for 10 days), and mitogenic activity.

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The two main shortcomings of the state-of-the-art method of sorting chromosomes, specificity and the efficiency of fractionating a significant amount of chromosomes, are addressed by this work in the design of a massively parallel approach using magnetic beads binding to a chromosome-specific DNA probe. In an attempt to isolate human chromosome 15 from a lymphoblastoid cell line, a chromosome 15 centromere-specific DNA probe with a fluorescent tag attached was reacted with the chromosomes. Magnetic beads bound to anti-FITC antibody were reacted with the labeled pool of chromosomes and separated by exposure to a magnetic field. The specificity of the fractionated pool was verified by performing fluorescence in situ hybridization on the isolated pool. The chromosome of interest could be enriched to about 75% within a maximum of 3-4 days, regardless of the amount of material.