Engineering of biomolecules for sensing and imaging applications

Biomolecules such as peptides, oligonucleotides and oligosaccharides are emerging tools for bioimaging applications due to their availability, versatility. biocompatibility and propensity to interact effectively and selectively with biological targets. However, unlike macromolecules such as proteins, their inherent conformational flexibility combined with the limited number of interactions they can establish with their target severely limits their potential for applications as imaging probes and/or pharmaceuticals. We review herein two prominent molecular engineering strategies - conformational restriction and multivalency - that have been successfully and widely applied to peptides, oligonucleotides and oligosaccharides in order to enhance their binding affinity and selectivity. We shall highlight the applications of these nanoconstructs in targeted delivery and bioimaging. Finally we discuss the potential for dynamic biomolecule-based systems where molecular recognition is controlled by a physicochemical effector.