Silica−Polypeptide Composite Particles: Controlling Shell Growth

• Published in: Langmuir 2010-10, Vol.26 (19), p.15604-15613
• Main Authors: Soto-Cantu, Erick, Turksen-Selcuk, Sibel, Qiu, Jianhong, Zhou, Zhe, Russo, Paul S, Henk, Margaret C
• Format: Article
• Language: English
• Subjects: Chemistry; Exact sciences and technology; General and physical chemistry; Magnetic Resonance Spectroscopy; Materials: Nano-and Mesostructured Materials, Polymers, Gels, Liquid Crystals, Composites; Microscopy, Electron, Transmission; Peptides - chemistry; Silicon Dioxide - chemistry; Spectroscopy, Fourier Transform Infrared; Thermogravimetry
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la1023955

A method is presented for preparing core−shell silica−polypeptide composite particles with variable and controllable shell growth. The procedure is demonstrated using poly(carbobenzoxy-l-lysine) and poly(benzyl-l-glutamate); after deprotection, these can lead to the most common basic and acidic homopolypeptides, poly(l-lysine) and poly(l-glutamic acid). Control over shell thickness is made possible by sequential addition of N-carboxyanhydride peptide monomer to surfaces that have been functionalized with an amino initiator combined with a surface passivation agent. This results in a series of particles having different shell thicknesses. Variation of shell thickness was evident both in light scattering and in thermogravimetric assays. The shells were visible by transmission electron microscopy; these images along with light scattering measurements suggest the polymers in the shells are highly solvated.