Aptamer-gated nanoparticles for smart drug delivery

Abstract

Aptamers are functional nucleic acid sequences which can bind specific targets.An artificial combinatorial methodology can identify aptamer sequences for any targetmolecule, from ions to whole cells. Drug delivery systems seek to increase efficacy andreduce side-effects by concentrating the therapeutic agents at specific disease sites in thebody. This is generally achieved by specific targeting of inactivated drug molecules.Aptamers which can bind to various cancer cell types selectively and with high affinityhave been exploited in a variety of drug delivery systems for therapeutic purposes. Recentprogress in selection of cell-specific aptamers has provided new opportunities in targeteddrug delivery. Especially functionalization of nanoparticles with such aptamers has drawnmajor attention in the biosensor and biomedical areas. Moreover, nucleic acids arerecognized as an attractive building materials in nanomachines because of their uniquemolecular recognition properties and structural features. A active controlled delivery ofdrugs once targeted to a disease site is a major research challenge. Stimuli-responsivegating is one way of achieving controlled release of nanoparticle cargoes. Recent reportsincorporate the structural properties of aptamers in controlled release systems of drugdelivering nanoparticles. In this review, the strategies for using functional nucleic acids increating smart drug delivery devices will be explained. The main focus will be onaptamer-incorporated nanoparticle systems for drug delivery purposes in order to assess thefuture potential of aptamers in the therapeutic area. Special emphasis will be given to the very recent progress in controlled drug release based on molecular gating achieved withaptamers. © 2011 by the authors; licensee MDPI, Basel, Switzerland.