Directional Immobilisation of SpyTag Bacteriophage on PDMS surfaces for Phage based Microfluidics

The increasing incidence of bacterial infections caused by antibiotic-resistant pathogens worldwide underlines the need to develop novel diagnostic tools enabling the early initiation of targeted antimicrobial therapy. One promising possibility is to unite the high specificity and sensitivity of phage-based applications with the speed and sensitivity provided by microfluidic devices. As a prerequisite of developing such systems, we aimed at the directional immobilization of phages on the surface of Polydimethylsiloxane (PDMS), a material commonly used for building such devices. Our work utilised the covalent interaction between two proteins: SpyTag, genetically encoded on the capsid of the phage, and BslA-SpyCatcher fusion protein, purified and surface displayed on PDMS. We demonstrate a simple methodology for the directional tail up immobilisation of SpyTagged Phage on to user defined locations on the surface of a PDMS device and subsequent on chip capture and infection of a cognate host. Our technique serves to illustrate a generally applicable solution to develop the next generation of phage based bio-sensors.