Development and label-free investigation of logic-gating biolayers for smart biosensing

Abstract Smart materials that can autonomously implement sensing, analyze information and execute a pre-programmed action are extremely attractive for advanced biosensing and theranostics. Recently, novel smart “biocomputing” nanoagents have emerged, which exhibit remarkable ability to adapt their behavior to changes in microenvironment. These agents use Boolean logic for simultaneous processing of complex combinations of several biochemical stimuli. One of the major challenges in design of such nanoagents is development of biocomputing sensing interfaces and their tuning for proper logic-gating characteristics. Here, we present a versatile method for precise, rapid and controllable design of smart logic-gating layers by means of a label-free optical instrument. We demonstrate real-time monitoring and control of every stage of the logic gating at a molecular level with detailed study of kinetic parameters of interactions between all participating components. Such label-free investigation is exceptionally valuable for fine tuning of the layers’ components for logic-gating biosensing. We show that direct translation onto gold nanoparticles of the optimized smart biolayers, which implement basic YES and NOT logic gates, yields intelligent labels for lateral flow immunoassay. The proposed method is promising for development of advanced biosensors and theranostic agents based on smart biolayers, which can “make decisions” as a result of complex analysis of various biochemical cues.