Year: 2026
Type: preprint
Abstract: Electrochemical aptasensors combine aptamer-based molecular recognition with electrochemical transduction, but a signal correlated with nominal target concentration alone does not establish aptamer–target binding. Target addition or matrix exposure may alter solution composition, reporter or mediator chemistry, nucleic acid behavior, surface organization, electron-transfer kinetics, interfacial integrity, or surface fouling without aptamer–target complex formation. The Kd gate addresses this upstream problem by requiring auditable, construct-matched verification of aptamertarget binding in homogeneous, non-denaturing solution under sensing-relevant conditions. Passing the gate, however, does not show that an immobilized construct retains recognition or that recognition causes the electrochemical response. We propose a sequential framework in which the Kd gate qualifies the recognition reagent, controlled surface measurements establish retained recognition, transduction measurements determine whether retained recognition generates a measurable response, and signalcausality controls establish whether that response depends on recognition. It distinguishes solutionphase Kd,sol, surface-associated apparent Kd,app, and device-response midpoint C50. It links controls to alternative response pathways and separates claim classes: target-correlated, recognition-linked, mechanistic or thermodynamic, and intended-use. Aminoglycoside and doxorubicin lineages illustrate why sequence conversion, truncation, reporter conjugation, and immobilization require reassessment of recognition and signal attribution. The framework should guide electrochemical aptasensor development with independently supported recognition and intended-use performance claims.
Source: ChemRxiv
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
Funder: York University
OpenAlex ID: W7214218934