Conformation-based stimuli-response sensors: Strategies for optimizing electrochemical and FRET transduction

Conformation-based stimuli-responsive sensors utilize a wide range of macromolecules (referred to as probe in this manuscript) and read-out methods. The review focuses on the variables associated with the mechanistic confirmation change centered around two transduction outputs: electrochemical and fluorescence resonance energy transfer. The electrochemical readout is limited in that the responsive material is bound between the electrode surface and an electroactive tag; interaction with analyte changes the distance between the electrode surface and the electroactive tag. Variables discussed in electrochemical stimuli-responsive sensor outputs include redox tag choice, electrode surface packing density, probe architectures, and redox tag location. Fluorescence resonance energy transfer readout uses a solution-free polymer distance where a conformational change induces a change in distance between a donor fluorophore and an acceptor fluorophore, thereby affecting the degree of nonradiative energy transfer from the donor to the acceptor. Variables discussed in fluorescence resonance energy transfer readouts include fluorophore types and sensor architecture. While there are already many examples of this in the literature, we believe this to be a fertile area for further development.