Patterns of Surface Immobilized Block Copolymer Vesicle Nanoreactors

The immobilization and positioning of ultra small reaction vessels on solid supports open new pathways in applications such as lab-on-a-chip, sensors, microanalyses and microreactors. In our work block copolymer vesicles made from polystyrene-block-polyacrylic acid (PS-b-PAA) were immobilized from aqueous medium onto 3-amino propyl trimethoxysilane functionalized silicon surfaces exploiting electrostatic interactions. The immobilization of the vesicles was investigated by Fourier transform infrared (FTIR) spectroscopy, as well as fluorescence optical and atomic force microscopy (AFM). In addition, the influence of pH and ionic strength on the surface coverage of vesicles bound to the surface was elucidated. Finally micro-molding in capillaries (MIMIC) was utilized to create line patterns of the vesicles containing the enzyme trypsin and the fluorogenic substrate rhodamine 110 bisamide. The selective positioning of vesicle nanoreactors in conjunction with electrostatic immobilization serves as a proof of principle for potential applications in real-time observation of confined chemical reaction inside vesicles as nanocontainers and for the fabrication of integrated microarray systems.