Design and Testing of a Micro-Scale Cargo Delivery System

Surface aggregation of bacteria can lead to biofilm formation, where microorganisms are protected by an extracellular matrix. Biofilms are inherently resistant to biocides and physical removal, leading to persistent bacterial infections. Novel approaches are needed for dealing with this chronic colonization. Attaching anti-bacterial cargo to cells that can infiltrate biofilm communities may lead to improved treatment for biofilm-mediated bacterial infections. Biofilm-forming bacteria express surface proteins involved in adhesion to a substrate, and cohesion with other organisms. Marinomonas primoryensis is an Antarctic bacterium that secretes a multi-domain long adhesion protein (LAP), capable of both adhesion to ice and cohesion to other microorganisms. Here we have designed a micro-scale cargo delivery system using the LAP of M. primoryensis as a proof-of-concept. Our initial cargo consisted of multiple copies of green fluorescent protein (GFP) and antibody binding protein A from Staphylococcus aureus linked to a highly branched polyamidoamine polymer (PAMAM dendrimer). Antibodies specific to the LAP of M. primoryensis allowed us to specifically attach the dendrimer to the bacteria. Using temperature-controlled microfluidics we tested the efficacy of the system, and visualized the bacteria moving fluorescent cargo to ice. Future plans involve designing bactericidal cargos to eradicate bacteria found within biofilm infections.

Funding for this project was provided by NSERC.