Responsive silica-polypeptide colloidal particles of different surface density

COLL 301

Erick Soto-Cantu, esotoc1@lsu.edu, Koch Jerome, Sibel Turksen-Selcuk, and Paul S. Russo. Department of Chemistry and Macromolecular Studies Group, Louisiana State University, 232 Choppin Hall, Baton Rouge, LA 70803
Nearly uniform silica particles were synthesized with different sizes (100-200 nm, hydrodynamic radius). The particles were amino-functionalized and passivated using varying ratios of 3-(trimethoxymethyl)-1-propanamine and trimethoxymethylsilane. The surface density of amino groups was quantified using UV/Vis spectroscopy after reaction with ninhydrin. The zeta potential of these particles was measured as function of the surface density of amino groups. The functionalized/passivated silica particles were dispersed in tetrahydrofuran and reacted with N6-Carbobenzoxy-L-lysine N-carboxyanhydride to yield hybrid particles with a silica core and poly(carbobenzyloxy-L-lysine) shell. Teramoto and coworkers1 showed that poly(carbobenzyloxy-L-lysine) has a coil-to-helix transition when warmed in m-cresol solutions. The existence and nature of that transition when the polymer is tethered to a spherical silica surface will be discussed.

Reference List

1) Matsuoka,M.; Norisuye,T.; Teramoto,A.; Fujita,H. Solution properties of synthetic polypeptides. XV. Helix-coil transition in poly(e-carbobenzyloxy L-lysine). Biopolymers 1973, 12, 1515-1532.