Studies have shown that ceramic hydroxyapatite (CHA) combines multiple modes of interactions to create unique selectivity windows for protein separations in the presence of different displacers and mobile phase modifiers. In the present work, atomic force microcopy (AFM) is employed to gain fundamental insights into the principles that govern such selective behavior. Single molecule AFM is used to probe the energetics of protein interaction with CHA by functionalizing the AFM probe with a protein of interest and performing force-distance measurements. The free energy of binding and force of interaction between the immobilized protein and the CHA surface are then investigated in the presence of different mobile phase modifiers and displacers. The relative binding strengths obtained from these experiments are validated qualitatively against column chromatographic retention data. The insights gained from these studies are used to reveal the nature of the selectivity of CHA for protein separations.

Probing protein selectivity in hydroxyapatite using single molecule atomic force microscopy

243rd National Meeting (2012)

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