Surface topography with ferromagnetic polymer pillars capable of movement in response to magnetic fields
Inventors
Assignees
Publication Number
US-11648374-B2
Publication Date
2023-05-16
Expiration Date
2039-01-16
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Abstract
An anti-fouling surface having micron scale pillars embedded with Fe3O4 nanoparticles is designed. The pillars may be repeatedly induced to move according to a predetermined frequency, such as one that mimic that of the beating movement of natural cilia, through the application of a magnetic field. When square-shaped pillars with a height of 10 μm, width of 2 μm, and inter-pattern distance of 5 μm actuated for three minutes, more than 99.9 percent of biofilm cells were detached and via gentle rinsing from the surface having the pillars. The anti-fouling surface enables effective prevention of biofilm formation and removal of established biofilms, and can be applied to a broad spectrum of polymers.
Core Innovation
The invention relates to an anti-fouling surface topography that mimics the natural beating cilia found in higher organisms, designed to remove bacterial biofilms from surfaces. The innovation comprises a plurality of micron scale pillars embedded with magnetic particles, particularly superparamagnetic iron oxide (Fe3O4) nanoparticles, more concentrated at the free ends of the pillars. These pillars are formed from a polymer, such as poly(dimethylsiloxane) (PDMS), and can be repeatedly actuated to move at predetermined frequencies by application of a magnetic field, including movement patterns similar to natural cilia.
The problem addressed is the long-term control and removal of established biofilms, which are resistant to antimicrobials and disinfectants, causing persistent infections and biofouling. Previous approaches using shape memory polymers allowed on-demand removal of biofilms but were limited by their inability to repeat the shape change, restricting long-term application. The present invention seeks to overcome the limitation of single-use or static surface modifications by providing a surface design capable of repeated cycles of biofilm removal.
The invention enables the assembly of dynamic, programmable anti-fouling surfaces by engineering polymer pillars with high concentrations of magnetic nanoparticles at their tips, allowing complex and remotely-controlled actuation via applied magnetic fields. The magnetic field can be generated by a wire, for example helically embedded in a catheter, driven by a power source with optional pulsed direct current output. The pillars can be arranged in precise patterns, with example dimensions of 10 μm height, 2 μm width, and 5 μm inter-pattern spacing, offering effective detachment of biofilm cells (more than 99.9% removal in minutes) without cytotoxic effects or significant nanoparticle release.
Claims Coverage
The patent contains one independent claim, which features a surface with specific anti-fouling topography based on magnetically actuated polymer pillars containing a concentration gradient of magnetic particles.
Surface with polymeric pillars containing magnetic particles concentrated at free ends
A surface includes: - A plurality of pillars formed from a polymer, extending from a polymer substrate to define corresponding free ends. - Each pillar contains magnetic particles, which are more highly concentrated at the free ends than elsewhere in the pillar. - The substrate comprises a catheter incorporating a wire extending therethrough.
The independent claim focuses on a surface anti-fouling topography based on polymeric pillars with a specific spatial concentration of magnetic particles, and the integration of these structures onto a catheter with an internal wire.
Stated Advantages
Provides repeatable, dynamic removal of established biofilms from surfaces via programmable movement of micron scale pillars.
Enables long-term antifouling effects, overcoming limitations of previous technologies that permitted only single-use or static actuation.
Allows biocompatible and remotely controlled actuation with negligible nanoparticle release and no observed cytotoxicity to mammalian cells.
Can be applied to a broad spectrum of polymers with precisely controlled surface topography dimensions and patterns.
Documented Applications
Use on catheters, including both inner and outer surfaces, to provide anti-fouling and removal of bacterial biofilms in biomedical devices.
General application to external or implanted engineered devices requiring repeatable antifouling surfaces.
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