Quantitative mechanical phenotyping of bacterial biofilms on implant surfaces

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PROJECT SUMMARY/ABSTRACT – PROJECT 2 Bacteria accumulation on medical devices puts a patient at serious risk for infection and could be life threatening. Eradication of established biofilm-forming infections remains difficult, in part because the accumulated bacteria are physiologically and metabolically distinct from the planktonic cells (floating single cells) of the same organism. Despite intense efforts in the field, biofilm level response to treatments and changes in environment has been hindered by the lack of robust, quantitative, and accurate biofilm characterization techniques that can be directly correlated to medical device surfaces. Furthermore, antibiotic penetration in implant-associated biofilms, is typically limited due to the dense and complex matrix of biofilms. The overall goal of this project is to develop complementary techniques that yield quantitative information on biofilm adhesion and deformability. Our working hypothesis is that changes in these two mechanical properties, i.e., adhesion and deformability, of biofilms is a direct marker of disease progression. The development of tools that can quantitatively characterize the mechanical properties of biofilms and corresponding material surfaces that control bacterial adhesion—possibly in a species-specific manner—will have a significant impact on medical device compatibility. Aided by access to the CPRI Translational and Computational Cores, the proposed research will first develop a film adhesion measurement technique for evaluation of biofilms to determine the association between biofilm antibiotic resistance and adhesion strength (AIM 1). Parallel to exploration of the role of biofilm adhesion, we will leverage our unique characterization suite that includes a rare confocal-atomic force microscopy platform to evaluate the relationship between biofilm deformability and antibiotic resistance (AIM 2). Lastly, we will evaluate nanoparticle mobility assays as a measure of biofilm confinement and develop computational models regarding drug carrier diffusion (AIM 3). Our expectation is that the results and tools developed here will guide us and others to logically design medical devices with a decreased propensity for the genesis of therapeutic-resistant biofilm infections.