Antibacterial Longevity of a Novel Gallium Liquid Metal/Hydroxyapatite Composite Coating Fabricated by Plasma Spray

Abstract

Hydroxyapatite (HAp)-coated metallic implants are known for their excellent bioactivity and osteoconductivity. However, infections associated with the microstructure of the HAp coatings may lead to implant failures as well as increased morbidity and mortality. This work addresses the concerns about infections by developing novel composite coatings of HAp and gallium liquid metal (GaLM) using atmospheric plasma spray (APS) as the coating technique. Five weight percent Ga was mixed into a commercially supplied HAp powder using an orbital shaker; then, the HAp-Ga particle feedstock was coated onto Ti 6 Al 4 V substrates using the APS technique. The X-ray diffraction results indicated that Ga did not form any Ga-related phases in either the HAp-Ga powder or the respective coating. The GaLM filled the pores of the HAp coating presented both on the top surface and within the coating, especially at voids and cracks, to prevent failures of the coating at these locations. The wettability of the surface was changed from hydrophobic for the HAp coating to hydrophilic for the HAp-Ga composite coating. Finally, the HAp-Ga coating presented excellent antibacterial efficacies against both initial attachments and established biofilms generated from methicillinresistant Staphylococcus aureus and Pseudomonas aeruginosa after 18 h and 7 days of incubation in comparison to the control HAp coating. This study shows that GaLM improves the antibacterial properties of HAp-based coatings without sacrificing the beneficial properties of conventional HAp coatings. Thus, the HAp-Ga APS coating is a viable candidate for antibacterial coatings.

Load-bearing study and interfacial interactions of hydroxyapatite composite coatings for bone tissue engineering

“…The CA for HAP coating was measured as 96°, which shows the comparatively hydrophobic surface of the material. The hydrophobic surface of HAP coatings with CA in the same range was also presented by Pham et al , 42 whose results showed a CA of 107° for the HAP coating. Moreover, the addition of reinforcements provided a hydrophilic surface for the HAP–CNT, HAP–GrO and HAP–hBN coatings (Fig.…”

Toxicity and Biocompatibility of Liquid Metals

“…Liquid metal core–shell composites refer to a kind of material that consists of a functional shell and liquid metal core. [ 83–85 ] In many cases, such shells exhibit enhancements in liquid metal functionality. [ 84,86,87 ] For example, Guo et al.…”

“…Liquid metal core-shell composites refer to a kind of material that consists of a functional shell and liquid metal core. [83][84][85] In many cases, such shells exhibit enhancements in liquid metal functionality. [84,86,87] For example, Guo et al [88] found that in situ reduced gold-coated liquid metal nanodroplets exhibited stronger photothermal conversion effects.…”

Numerical Study of Microstructures and Roughness Design Effects on Surface Hydrophilicity through the Lattice Boltzmann Method

“…The additional coating methods increase the surface hydrophilicity by taking advantage of the hydrophilic biomaterials. Biomaterials used for implant coatings are broadly classified into ceramics (Díaz-Cuenca et al 2022;Li et al 2022), polymers (Tao et al 2020;Tallet et al 2021), and metallic systems (Pham et al 2022;Yan et al 2022). However, the problems of cytotoxicity, shedding of coatings, and a lack of mechanical properties still exist.…”