A single-particle plasmon sensor to monitor proteolytic activity in real-time

06 June 2023, Version 1


We have established a label-free plasmonic platform that monitors proteolytic activity in real-time. The sensor consists of a random array of gold nanorods that are functionalized with a design peptide that is specifically cleaved by thrombin resulting in a blue-shift of the longitudinal plasmon. By monitoring the plasmon of many individual nanorods we determined thrombin’s proteolytic activity in real-time and inferred relevant kinetic parameters. Furthermore, comparison to a kinetic model revealed that the plasmon shift is dictated by a competition between peptide cleavage and thrombin binding, which have opposing effects on the measured plasmon shift. The dynamic range of the sensor is greater than two orders of magnitude, and it is capable of detecting physiologically relevant levels of active thrombin down to 3 nM in buffered conditions. We expect these plasmon-mediated label-free sensors open the window to a range of applications stretching from diagnostic and characterization of bleeding disorders to fundamental proteolytic and pharmacological studies.


Supplementary materials

Supplementary Information for: A single-particle plasmon sensor to monitor proteolytic activity in real-time
Single-particle correlation between peptide loading and response to proteolytic activity Conversion of the intensity signal to plasmon shift: Intensity-based plasmon sensing (detailed description). Kinetic Modelling: A pseudo-first order kinetic model for protease adsorption and cleavage (detailed description). Reaction half-time determination. Lorentzian derivative fitting results vs concentration of active enzyme. Non-trivial response of the plasmonic sensor.


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