ABSTRACT
This chapter summarizes the range of DNA and ribonucleic acid aptamer applications for in vitro and in vivo diagnostics especially imaging techniques and associated therapeutics or combined theranostics while acknowledging limitations of aptamers. It examines the scope of aptamer applications in diagnostics and medicine and builds toward future theranostic prospects involving aptamers, while acknowledging aptamer weaknesses and suggesting means to overcome these deficiencies. The chapter also summarizes the salient aspects of aptamers, their uses, and current limitations. Like all pharmaceuticals or affinity reagents, aptamers have their strengths and weaknesses. Aptamers coupled to a variety of nanoparticles (NP), including highly fluorescent quantum dots or other reporter molecules by themselves or doped into NPs, are the subject of intense research and development in medical imaging. Aptamers and any oligonucleotides used in vivo face two major challenges, endo- and exonuclease degradation and rapid clearance by the kidneys, and liver.
