Design, characterization, and evaluation of biofilm eradicating hybrid liquid crystalline nano-coatings for new 3D porous orthopedic implants

Project Information

LC-NanoCoat

Grant agreement ID: 101107704

DOI

10.3030/101107704

Project closed

EC signature date 11 April 2023

Start date 7 August 2023

End date 6 August 2025

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 214 934,40

Coordinated by

KOBENHAVNS UNIVERSITET
Denmark

Periodic Reporting for period 1 - LC-NanoCoat (Design, characterization, and evaluation of biofilm eradicating hybrid liquid crystalline nano-coatings for new 3D porous orthopedic implants)

Reporting period: 2023-08-07 to 2025-08-06

Summary of the context and overall objectives of the project

Orthopedic implant-associated biofilm infections represent a major public health and socioeconomic burden due to the intrinsic tolerance of biofilms that behave as protective and immobile scaffolds to conventional antibiotics and immune system. Further, their long-term and repeated antibiotic treatments lead to an increased antibiotic resistance. This necessitates the efforts to effectively prevent and combat biofilm development and associated infections and assist host tissues around the implants in winning 'the race for the surface' through implant surface modifications and use of antibacterial coatings. The project considers the urgent societal needs for introducing an effective and universal approach in orthopedic implant patterning and functionalization for combating and preventing implant-associated infections. It focuses on a priority research area of global importance (biofilm infections) through the development of effective coatings based on non-lamellar liquid crystalline (LLC) phases, which have capability of loading and sustaining release of hydrophobic and hydrophilic drugs. We aimed at investigating the potential of LLC nanostructures generated from amphiphilic lipids, including monounsaturated glycerol monooleate (GMO) and omega-3 polyunsaturated fatty acids (ω-3 PUFAs) for the local delivery of antimicrobial agents to prevent bacterial colonization, biofilm formation, and combat the emergence of antibiotic resistance. In this context, the project particularly focused on: (1) developing a new generation of antibiotic-free and antibiotic-loaded nanocoatings with tunable structural features, and capability of local delivery of antimicrobial agents and tailoring their releases, (2) their advanced characterization by using different modalities including static small-angle X-ray scattering (SAXS) and dynamic grazing incidence small-angle X-ray scattering (GISAXS), in combination with in vitro profiling on model implant-associated biofilm infections. We have developed an innovative antibacterial coatings approach and presented the antibacterial and antibiofilm activities of coatings, which are generated from inverse LLC nanostructures and designed for functionalization of metallic orthopedic implants. The structural characterization of developed coatings was performed by using different state-of-art methodologies, including time-resolved synchrotron GISAXS. The outcomes of the project have provided a new insight in the design of biocompatible nanocoatings with tunable structural features and potent bactericidal activities for orthopedic implants. By this achievement, it is expected to reduce antibiotic use and assist in overcoming antimicrobial resistance development.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

In the first part of the project, experiments were conducted to design and optimize LLC formulations to obtain applicable coatings for implant surface. In this context, amphiphilic lipids including, GMO and docosahexaenoic acid monoglyceride (MAG-DHA) have been investigated with and without antibiotic loaded. The structural features of the designed LLC phases and effects of parameters on structural features have been investigated by using SAXS (or GISAXS) characterizations. To obtained LLC coatings were loaded with commercially available antibiotics (such as colistin, vancomycin, rifampicin, tobramycin, and daptomycin), and their antibacterial efficacy was tested against both gram-positive and gram-negative bacteria. The significant antibacterial properties of LLC coatings suggest that lipid-based self-assembled nanocoatings could be effectively used to prevent biofilm formation on orthopedic implants.
The second goal of WP1 was to develop novel antibiotic-free LLC coatings based ω-3 PUFA monoglyceride of MAG-DHA. This objective was achieved by designing and formation of MAG-DHA and GMO binary LLC coatings at various compositions, testing their antibacterial efficiencies to prevent implant infections. The produced self-assembled coatings, particularly at a high content of MAG-DHA, demonstrated unique inherent antibacterial activities against gram-positive Staphylococcus aureus and Staphylococcus epidermidis strains, without the use of antibiotics.
The third objective of the project was to structurally investigate the topological surface coating with desired durability and stability through advanced characterization techniques. Various metallic substrates including, stainless steel discs, titanium plates, 3D printed porous titanium substrates, and silicon wafers were used as representative surfaces. Spin coating, dip (layer-by-layer) coating and polpolydopamine-assistedating have been employed to generate LLC coatings on various surfaces. The structural properties of the coatings on the surface have been investigated by advanced modalities, including SAXS and GISAXS. It is demonstrated that, depending on lipid composition and relative humidity, the directed self-assembly of MAG-DHA and GMO on solid interfaces led to the generation of different self-assemblies (including swollen micelles, and hexagonal (H2) and bicontinuous cubic (Q2) phases). These studies were important to gain insight into the hydration-induced formation of different inverse non-lamellar liquid crystalline self-assemblies.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The project has made significant impact beyond the state of the art by:
• Suggesting a modified surface that can help to reduce infections and improve the implant’s performance.
• Introducing a new implant coating method using inverse LLC nanostructures and sya stematic investigation of their efficacy against implant infections for the first time.
• Developing and further investigating antibiotic-loaded coatings for local delivery and sustained drug release properties to prevent bacterial attachment and biofilm formation.
• Introducing a novel antibiotic-free implant coating made from natural fatty acids known for their high pharmaceutical value and biocompatibility for the first time.
• Using advanced methodologies for static and dynamic characterization of developed LLC coatings.

Considering the socio-economic impacts of the project, the novel antibacterial coatings can:
• replace traditional antibiotic treatments and provide faster and safer recovery process.
• reduce the need for revision surgeries, extended hospitalization and long-term antibiotic treatments.
• improve patient comfort and minimize healthcare costs.

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