ABSTRACT
This chapter discusses various applications of aptamers in targeted drug delivery. It outlines a brief description of aptamer selection by systematic evolution of ligands by exponential enrichment. Aptamers are short oligonucleotide or peptide molecules that can form unique three-dimensional conformations and bind to groves or clefts on specific targets. Aptamers can be produced in large quantities by combinatorial chemistry in a controlled manner and at a cheaper cost when compared to antibodies. In nanomedicine, aptamers are used for diagnosis and therapy, as theranostic tools, and for biosensor development in various diseases. Aptamer–aptamer complexes, aptamer–nanoparticle complexes, or aptamer–biomacromolecule conjugates are used in diagnostic and therapeutic applications. Aptamers are versatile tools for targeted delivery of therapeutic agents. Two major strategies for the aptamer-mediated targeted strategy are aptamer–drug conjugate and aptamer–nanoparticle system. An aptamer-targeted photoresponsive drug delivery system consisting of graphene oxide wrapped and doxorubicin-loaded mesoporous silica nanoparticle was developed for cancer therapy.
