2 research outputs found
Building an Antifouling Zwitterionic Coating on Urinary Catheters Using an Enzymatically Triggered Bottom-Up Approach
Catheter
associated urinary tract infections are common during
hospitalization due to the formation of bacterial biofilms on the
indwelling device. In this study, we report an innovative biotechnology-based
approach for the covalent functionalization of silicone catheters
with antifouling zwitterionic moieties to prevent biofilm formation.
Our approach combines the potential bioactivity of a natural phenolics
layer biocatalytically conjugated to sulfobetaine-acrylic residues
in an enzymatically initiated surface radical polymerization with
laccase. To ensure sufficient coating stability in urine, the silicone
catheter is plasma-activated. In contrast to industrial chemical methods,
the methacrylate-containing zwitterionic monomers are polymerized
at pH 5 and 50 °C using as an initiator the phenoxy radicals
solely generated by laccase on the phenolics-coated catheter surface.
The coated catheters are characterized by X-ray photoelectron spectroscopy
(XPS), Fourier transformed infrared (FTIR) analysis, atomic force
microscopy (AFM), and colorimetrically. Contact angle and protein
adsorption measurements, coupled with in vitro tests with the Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus in static and dynamic conditions,
mimicking the operational conditions to be faced by the catheters,
demonstrate reduced biofilm formation by about 80% when compared to
that of unmodified urinary catheters. The zwitterionic coating did
not affect the viability of the human fibroblasts (BJ-5ta) over seven
days, corresponding to the extended useful life of urinary catheters
Quorum-Quenching and Matrix-Degrading Enzymes in Multilayer Coatings Synergistically Prevent Bacterial Biofilm Formation on Urinary Catheters
Bacteria often colonize in-dwelling
medical devices and grow as
complex biofilm communities of cells embedded in a self-produced extracellular
polymeric matrix, which increases their resistance to antibiotics
and the host immune system. During biofilm growth, bacterial cells
cooperate through specific quorum-sensing (QS) signals. Taking advantage
of this mechanism of biofilm formation, we hypothesized that interrupting
the communication among bacteria and simultaneously degrading the
extracellular matrix would inhibit biofilm growth. To this end, coatings
composed of the enzymes acylase and α-amylase, able to degrade
bacterial QS molecules and polysaccharides, respectively, were built
on silicone urinary catheters using a layer-by-layer deposition technique.
Multilayer coatings of either acylase or amylase alone suppressed
the biofilm formation of corresponding Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus. Further assembly of both enzymes
in hybrid nanocoatings resulted in stronger biofilm inhibition as
a function of acylase or amylase position in the layers. Hybrid coatings,
with the QS-signal-degrading acylase as outermost layer, demonstrated
30% higher antibiofilm efficiency against medically relevant Gram-negative
bacteria compared to that of the other assemblies. These nanocoatings
significantly reduced the occurrence of single-species (P. aeruginosa) and mixed-species (P. aeruginosa and Escherichia coli) biofilms on silicone catheters under both static and dynamic conditions.
Moreover, in an in vivo animal model, the quorum quenching and matrix
degrading enzyme assemblies delayed the biofilm growth up to 7 days