Advances in Brief Nanoparticle-Aptamer Bioconjugates: A New Approach for Targeting Prostate

Nucleic acid ligands (aptamers) are potentially well suited for the therapeutic targeting of drug encapsulated controlled release polymer particles in a cell- or tissue-specific manner. We synthesized a bioconju-gate composed of controlled release polymer nanoparticles and aptamers and examined its efficacy for targeted delivery to prostate cancer cells. Specifically, we synthesized poly(lactic acid)-block-polyethylene glycol (PEG) copolymer with a terminal carboxylic acid functional group (PLA-PEG-COOH), and encapsulated rhodamine-labeled dextran (as a model drug) within PLA-PEG-COOH nanoparticles. These nanoparticles have the following desirable characteristics: (a) negative surface charge (50 3 mV, mean SD, n 3), which may minimize nonspecific interaction with the negatively charged nucleic acid aptamers; (b) carbox-ylic acid groups on the particle surface for potential modification and covalent conjugation to amine-modified aptamers; and (c) presence o