Figure 1.

Schematic of the selective attachment and release of cargo-carrying bacteria from patterned surfaces. (a) Au patterned Si substrate. The substrate is treated so that Au become his-tag protein adherent (via thiolation with NTA thiol and treatment with Ni²⁺ ions) while Si is protein non-adherent (via PEG silanization and blocking with BSA). The Au surface is further functionalized with protein G and antibody 1 (a cargo specific antibody; goat anti-rabbit IgG). (b) Cargo coated with antibody 2 (rabbit anti-E. coli IgG) are then introduced causing them to bind to the antibodies on the Au patterns (c) Bacteria (E. coli) then specifically attach to the beads and (d) motile bacteria-cargo conjugates can be released on-demand using either imidazole or EDTA. (e) Schematic showing bound and released cargo-carrying bacteria.