Physical elution in phage display selection of inorganic-binding peptides

Phage display is a commonly utilized in vivo approach in selecting peptides specific to solid inorganic materials. In this process, traditionally, high affinity peptides are recovered by a chemical elution method, which involves contacting the phage library with the desired inorganic, washing the weak binders, and eluting the tight binders under harsh buffer conditions. This process may result in incomplete removal of all strong binders, separation of the phage from the display protein, or may modify the material surface. To overcome these potential limitations, we developed a physical elution technique based on ultrasonication. Here, we report two optimized ultrasonication protocols by which we selected peptides specific to natural mineral mica. We first performed a 30-s physical elution after the chemical elution step and increased the efficiency of screening strong binders by about 100%. Encouraged by the results, we applied physical elution-only protocol where we obtained 45% of the selected sequences as strong binders. The approach has a far shorter total elution time, i.e., seconds compared to hours in traditional chemical elution. The novel physical elution approach using ultrasonication reported herein can be a highly efficient alternate step in the screening of solid material specific peptides.