Structural biofilm resistance of carbon-infiltrated carbon nanotube coatings
Stephanie R Morco1, Dustin L Williams2, Brian D Jensen1
1Department of Mechanical Engineering, Brigham Young University, Provo, Utah, USA.
Abstract:
Periprosthetic joint infection (PJI) is a devastating complication of orthopedic implant surgeries, such as total knee and hip arthroplasties. Treatment requires additional surgeries because antibiotics have limited efficacy due to biofilm formation and resistant bacterial strains such as methicillin-resistant Staphylococcus aureus (MRSA). A non-pharmaceutical approach is needed, and examples of this are found in nature; dragonfly and cicada wings are antibacterial because of their nanopillar surface structure rather than their chemistry. Carbon-infiltrated carbon nanotube (CICNT) surfaces exhibit a similar nanopillar structure, and have been shown to facilitate osseointegration, and it is postulated that they might provide a structurally-derived resistance to bacterial proliferation and biofilm formation. The objective of this study was to test the biofilm resistance of CICNT coatings. Two types of CICNT were produced: a vertically aligned CNT forest on a silicon substrate using a layer of iron as the catalyst (CICNT-Si) and a random-oriented CNT forest on stainless steel (SS) substrate using the substrate as the catalyst (CICNT-SS). These were tested against SS and carbon controls. After 48 h in an MRSA biofilm reactor, samples demonstrated that both types of CICNT coatings significantly (p < 0.0001) reduced MRSA biofilm formation by 60%-80%. Morphologically, biofilm presence on both types of CICNT was also significantly reduced. Clinical Significance: Results suggest that a CICNT surface modification could be suitable and advantageous for medical devices susceptible to MRSA cell attachment and biofilm proliferation, particularly orthopedic implants.
Insights
New carbon nanotube coatings show promise in preventing infections on orthopedic implants. These surfaces significantly reduce bacterial biofilm formation, offering a non-antibiotic approach to combatting infections like MRSA.
Area of Science:
- Biomaterials Engineering
- Nanotechnology
- Infectious Disease Research
Background:
- Periprosthetic joint infection (PJI) is a severe complication of orthopedic implants, often requiring revision surgery.
- Antibiotic treatment for PJI is limited by bacterial biofilm formation and antibiotic-resistant strains like methicillin-resistant Staphylococcus aureus (MRSA).
- Nature-inspired antibacterial surfaces, such as dragonfly wings, utilize physical nanopillar structures.
Purpose of the Study:
- To investigate the potential of carbon-infiltrated carbon nanotube (CICNT) coatings to resist bacterial biofilm formation.
- To evaluate CICNT surfaces as a non-pharmaceutical strategy against MRSA attachment and proliferation on implant materials.
Main Methods:
- Two types of CICNT coatings were fabricated: vertically aligned CNTs on silicon (CICNT-Si) and random-oriented CNTs on stainless steel (CICNT-SS).
- MRSA biofilm formation was assessed on CICNT coatings and control surfaces (stainless steel, carbon) after 48 hours in a biofilm reactor.
- Statistical analysis was performed to determine the significance of biofilm reduction.
Main Results:
- Both CICNT-Si and CICNT-SS coatings significantly reduced MRSA biofilm formation by 60%-80% (p < 0.0001) compared to controls.
- Morphological analysis confirmed a significant reduction in biofilm presence on CICNT surfaces.
- The nanopillar structure of CICNTs appears to provide inherent resistance to bacterial colonization.
Conclusions:
- CICNT surface modification effectively inhibits MRSA biofilm formation.
- These findings suggest CICNT coatings are a promising strategy for developing infection-resistant orthopedic implants.
- This approach offers a potential non-pharmaceutical solution to a critical clinical challenge in joint arthroplasty.
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