Micro‐assembly of functionalized particulate monolayer on C₁₈‐derivatized SiO₂ surfaces

Abstract

This work describes a simple approach to immobilize functionalized colloidal microstructures onto a C 18 -coated SiO 2 substrate via specific or non-specific biomediated 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 preadsorbed 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.

Microfiber assisted fabrication of microfluidic channels using poly(dimethylsiloxane)

“…beadsrmL for 2 min and air dried to give the fiber of Figure 3b. Rationale and experimental protocols for micropattern-Ž ing beads on oxide surfaces is described elsewhere Huang et . al., 2003 .…”

Smart Microfluidics: The Role of Stimuli- Responsive Polymers in Microfluidic Devices

“…(Peterson, 2005) For instance, functionalized microparticles may be fixed onto surfaces using hydrophobic/hydrophilic interactions or assemblies of oligonucleotides.(T.T. Huang et al, 2003;McNally et al, 2003) A number of different methods have been reported for trapping particles into a microdevice, some using physical barriers to retain beads, others using magnetic fields to manipulate and trap beads. (Linder et al, 2002;J.-W. Choi et al, 2001) An interesting entrapment method is reported in the previous section by Malmstadt et al (Malmstadt et al, 2003(Malmstadt et al, , 2004 As reported by Andersson et al, a series of pillars could constrain beads placed in a microfluidic chip and this approach was useful in fabricating devices for single-nucleotide polymorphism analysis and capillary electrochromatography.…”

Multiplexed microarrays based on optically encoded microbeads

“…The microbead loading efficiency can be enhanced by centrifugation, or by applying electric charges or magnetic fields (Manesse et al 2013). Other techniques such as the use of affinity binding between biotin and streptavidin to functionalize the matrix and the beads to immobilize the beads (Huang et al 2003). Surface modifications based on the composition of beads and matrix, in order to attach microbeads have been described in a patent by Margel (Margel 1997).…”