We have developed sensors functionalized with peptide ligands as biorecognition moieties to study and better understand the thermodynamics of protein-ligand binding events and develop a method for modulating sensor selectivity and regeneration. To this end, we have utilized quartz crystal microbalance devices and an immunoglobulin G (IgG)-binding peptide with muild affinity chosen from our library of ligands. The combination of these two elements brings about a new fundamental observation, that the vibrational frequency and amplitude of the sensor’s surface cause a tunable perturbation of protein-ligand interactions. This offers a means to modulate the sensor binding strength and selectivity in a multi-protein environment, or remove bound proteins from the sensing surface, thereby regenerating the sensor for subsequent use. In this work, we have performed two main studies. In Study 1, we have focused on the correlation between binding strength and capacity of IgG-binding sensors to vibrational amplitude and frequency; we also identified the values of critical frequency and amplitude at which the IgG is completely desorbed. In Study 2, we have focused on the correlation between sensor’s vibration and binding selectivity and regeneration; using a peptide ligand that binds both IgG and bovine serum albumin (BSA), yet with different affinity, we have evaluated the vibration-dependent binding selectivity of the sensor for IgG at different concentrations of BSA, and optimized our model for predicting protein binding in competitive mode.

Mechanically controlled thermodynamics of biorecognition events

2019 Spring National Meeting

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