Micro‐assembly of functionalized particulate monolayer on C 18 ‐derivatized SiO 2 surfaces

This work describes a simple approach to immobilize functionalized colloidal microstructures onto a C 18 ‐coated SiO 2 substrate via specific or non‐specific bio‐mediated interactions. Biotinylated bovine serum albumin pre‐adsorbed onto a C 18 surface was used to mediate the surface assembly of streptavidin‐coated microbeads (2.8 μm), while a bare C 18 surface was used to immobilize anti‐ Listeria antibody‐coated microbeads (2.8 μm) through hydrophobic interactions. For a C 18 surface pre‐adsorbed with bovine serum albumin, hydrophobic polystyrene microbeads (0.8 μm) and positively charged dimethylamino microbeads (0.8 μm) were allowed to self‐assemble onto the surface. A monolayer with high surface coverage was observed for both polystyrene and dimethylamino microbeads. The adsorption characteristics of Escherichia coli and Listeria monocytogenes on these microbead‐based surfaces were studied using fluorescence microscopy. Both streptavidin microbeads pre‐adsorbed with biotinylated anti‐ Listeria antibody and anti‐ Listeria antibody‐coated microbeads showed specific capture of L. monocytogenes , while polystyrene and dimethylamino microbeads captured both E. coli and L. monocytogenes non‐specifically. The preparation of microbead‐based surfaces for the construction of microfluidic devices for separation, detection, or analysis of specific biological species is discussed. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 83: 416–427, 2003.