Hook, A. | bioRxiv Science

bioRxiv2022

Polymer-directed inhibition of reversible to irreversible attachment prevents Pseudomonas aeruginosa biofilm formation

Non-toxic, biocompatible materials that inhibit bacterial biofilm formation on implanted medical devices and so prevent infection are urgently required. Weakly amphiphilic acrylate polymers with rigid hydrocarbon pendant groups resist bacterial biofilm formation in vitro and in vivo but the biological mechanism involved is not known. By comparing biofilm formation on polymers with the same acrylate backbone but with different pendant groups, we show that poly(ethylene glycol dicyclopentenyl ether acrylate; pEGdPEA) but not neopentyl glycol propoxylate diacrylate (pNGPDA) inhibited the transition from reversible to irreversible attachment. By using single-cell tracking algorithms and controlled flow microscopy we observed that fewer Pseudomonas aeruginosa PAO1 cells accumulated on pEGdPEA compared with pNGPDA. Bacteria reaching the pEGdPEA surface exhibited shorter residence times and greater asymmetric division with more cells departing from the surface post-cell division, characteristic of reversible attachment. Migrating cells on pEGdPEA deposited fewer exopolysaccharide trails and were unable top adhere strongly. Discrimination between the polymers required type IV pili and flagella. On pEGdPEA, the lack of accumulation of cyclic diguanylate or expression of sadB were consistent with the failure to transit from reversible to irreversible attachment. Constitutive expression of sadB increased surface adhesion sufficient to enable P. aeruginosa to form biofilms in a Mot flagellar stator dependent manner. These findings were extendable to other biofilm resistant acrylates highlighting their unique ability to inhibit reversible to irreversible attachment as a mechanism for preventing biofilm-associated infections. SignificanceBacteria readily attach to surfaces forming biofilms. These are commonly associated with medical device-associated infections and highly refractory to antibiotics. Biocompatible, weakly amphiphilic acrylate polymers with large hydrophobic pendant groups that inhibit biofilm formation and can prevent such infections have been described. However, the biological mechanism involved is not understood. By comparing a biofilm-inhibiting with a biofilm-supporting acrylate, we showed that Pseudomonas aeruginosa PAO1 cells responded differentially to the two polymers and were unable to accumulate and adhere strongly, activate cyclic diguanylate signalling or transit from reversible to irreversible attachment on the inhibitory polymer. Constitutive expression of sadB increased surface adhesion sufficient to enable P. aeruginosa to form biofilms in a flagellar stator dependent manner overcoming the biofilm inhibitory properties of the polymer.

microbiology↗

bioRxiv2020

Topographical biomaterials instruct bacterial surface attachment and the in vivo host-pathogen response

Bio-instructive materials that prevent bacterial biofilm formation and drive an appropriate host immune response have the potential to significantly reduce the burden of medical device-associated infections. Since bacterial surface attachment is known to be sensitive to surface topography, we experimentally survey 2,176 combinatorially generated shapes using an unbiased high-throughput micro topographical screen on polystyrene. This identifies topographies that reduce colonization in vitro by up to 15-fold compared with a flat surface for both motile and non-motile bacterial pathogens. Equivalent reductions are achieved on polyurethane, a polymer commonly used in medical devices. Using machine learning methods, a set of design rules based on generalisable descriptors is established for predicting bacteria-resistant micro topographies. In a murine foreign body infection model, anti-attachment topographies are shown to be refractory to P. aeruginosa and to recruit a productive host response, highlighting the potential of simple topographical patterning of non-eluting implants for preventing medical device associated infections.

microbiology↗

bioRxiv2020

Inkjet based 3D Printing of bespoke medical devices that resist bacterial biofilm formation

We demonstrate the formulation of advanced functional 3D printing inks that prevent the formation of bacterial biofilms in vivo. Starting from polymer libraries, we show that a biofilm resistant object can be 3D printed with the potential for shape and cell instructive function to be selected independently. When tested in vivo, the candidate materials not only resisted bacterial attachment but drove the recruitment of host defences in order to clear infection. To exemplify our approach, we manufacture a finger prosthetic and demonstrate that it resists biofilm formation – a cell instructive function that can prevent the development of infection during surgical implantation. More widely, cell instructive behaviours can be ‘dialled up’ from available libraries and may include in the future such diverse functions as the modulation of immune response and the direction of stem cell fate.Competing Interest StatementThe authors have declared no competing interest.View Full Text

bioengineering↗