title: Equilibrium and dynamic design principles for binding molecules engineered for reagentless biosensors.
abstract: Reagentless biosensors rely on the interaction of a binding partner and its target to generate a change in fluorescent signal using an environment-sensitive fluorophore or Förster resonance energy transfer. Binding affinity can exert a significant influence on both the equilibrium and the dynamic response characteristics of such a biosensor. We here develop a kinetic model for the dynamic performance of a reagentless biosensor. Using a sinusoidal signal for ligand concentration, our findings suggest that it is optimal to use a binding moiety whose equilibrium dissociation constant matches that of the average predicted input signal, while maximizing both the association rate constant and the dissociation rate constant at the necessary ratio to create the desired equilibrium constant. Although practical limitations constrain the attainment of these objectives, the derivation of these design principles provides guidance for improved reagentless biosensor performance and metrics for quality standards in the development of biosensors. These concepts are broadly relevant to reagentless biosensor modalities.
authors.affiliation: Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Seymour
authors.initials: S
authors.lastname: de Picciotto
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Barbara
authors.initials: B
authors.lastname: Imperiali
authors.affiliation: Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Linda G
authors.initials: LG
authors.lastname: Griffith
authors.affiliation: Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. Electronic address: wittrup@MIT.EDU.
authors.forename: K Dane
authors.initials: KD
authors.lastname: Wittrup
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D005818:Genetic Engineering; D007700:Kinetics; D008024:Ligands; D008954:Models, Biological
chemical_list: D008024:Ligands
keywords: Antibody immunoassay; Detection; Dynamic analysis; Reagentless biosensor