A reusable supramolecular platform for the specific capture and release of proteins and bacteria.

In this work, a reusable supramolecular platform for the specific capture and release of proteins and bacteria was developed. Multilayered polyelectrolyte films containing "guest" moieties were first fabricated using the layer-by-layer (LbL) deposition of poly(allylamine hydrochloride) and poly(acrylic acid-co-1-adamantan-1-ylmethyl acrylate), followed by the incorporation of β-cyclodextrin (β-CD) derivatives modified with mannose (CD-M) as "host" molecules with protein (lectin) binding properties. This platform combines three different non-covalent interactions: electrostatic interactions for the LbL deposition of multilayered films, host-guest inclusion for the incorporation of β-CD-conjugated ligands, and carbohydrate-protein affinity recognition for the capture of specific proteins and bacteria. For the mannose system investigated, the capture of Concanavalin A (ConA) and type I fimbriated Escherichia coli was demonstrated. Moreover, due to the inherent reversibility of host-guest interactions, the captured proteins and bacteria could be easily released from the surface by incubation with sodium dodecyl sulfate, and the renewed "guest" surface could be treated with the CD-M "host" to regenerate the ConA and E. coli-binding surface. This "use-regenerate" cycle could be repeated multiple times without significant loss of bioactivity. Given the generality and versatility of this approach, it may provide the basis for the development of re-usable biosensors and diagnostic devices for the detection and measurement of proteins and bacteria.