The mechanical and chemical stability of the interfaces in bioactive materials: The substrate-bioactive surface layer and hydroxyapatite-bioactive surface layer interfaces

Ferraris, Sara; Yamaguchi, Seiji; Barbani, Niccoletta; Cristallini, Caterina; Confiengo, Giovanna Gautier di; Barberi, Jacopo; Cazzola, Martina; Miola, Marta; Verné, Enrica; Spriano, Silvia Maria

doi:10.1016/j.msec.2020.111238

Cited by 30 publications

(18 citation statements)

References 44 publications

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“…On the other hand, the plateau in the basic range has an onset at pH 8.5: the surface treatment creates some acidic groups, but they act as a weak acid and are deprotonated only at a very high pH. The standard deviation of the zeta potential is very small for the entire measurement process (the error bars are almost not visible in the graph), evidencing the good chemical stability [ 49 ] of the surface through the whole pH range explored, and with more stability compared with the untreated Ti surface. Comparing the obtained zeta potential titration curve with the XPS data, we can determine that, in the case of the treated surface, the acidic and basic functionalities are due to the OH groups and that the basic ones play a larger role in determining the surface charge of the treated material because of their chemical reactivity.…”

Section: Resultsmentioning

confidence: 99%

Iodine-Loaded Calcium Titanate for Bone Repair with Sustainable Antibacterial Activity Prepared by Solution and Heat Treatment

Yamaguchi

Shintani

et al. 2021

Nanomaterials

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In the orthopedic and dental fields, simultaneously conferring titanium (Ti) and its alloy implants with antibacterial and bone-bonding capabilities is an outstanding challenge. In the present study, we developed a novel combined solution and heat treatment that controllably incorporates 0.7% to 10.5% of iodine into Ti and its alloys by ion exchange with calcium ions in a bioactive calcium titanate. The treated metals formed iodine-containing calcium-deficient calcium titanate with abundant Ti-OH groups on their surfaces. High-resolution XPS analysis revealed that the incorporated iodine ions were mainly positively charged. The surface treatment also induced a shift in the isoelectric point toward a higher pH, which indicated a prevalence of basic surface functionalities. The Ti loaded with 8.6% iodine slowly released 5.6 ppm of iodine over 90 days and exhibited strong antibacterial activity (reduction rate >99%) against methicillin-resistant Staphylococcus aureus (MRSA), S. aureus, Escherichia coli, and S. epidermidis. A long-term stability test of the antibacterial activity on MRSA showed that the treated Ti maintained a >99% reduction until 3 months, and then it gradually decreased after 6 months (to a 97.3% reduction). There was no cytotoxicity in MC3T3-E1 or L929 cells, whereas apatite formed on the treated metal in a simulated body fluid within 3 days. It is expected that the iodine-carrying Ti and its alloys will be particularly useful for orthopedic and dental implants since they reliably bond to bone and prevent infection owing to their apatite formation, cytocompatibility, and sustainable antibacterial activity.

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Section: Resultsmentioning

confidence: 99%

Iodine-Loaded Calcium Titanate for Bone Repair with Sustainable Antibacterial Activity Prepared by Solution and Heat Treatment

Yamaguchi

Shintani

et al. 2021

Nanomaterials

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“…According to the studies reported by Barry et al [66] the nature of the substrate could influence the surface roughness and coating thickness but there are no significant differences between the interface properties and the coating composition depending on the type of alloy. Moreover, Ferraris et al [67] reported that the substrate also influences the biological properties of the samples.…”

Section: Resultsmentioning

confidence: 99%

Physico-Chemical Properties and In Vitro Antifungal Evaluation of Samarium Doped Hydroxyapatite Coatings

et al. 2020

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Hydroxyapatite (HAp) and samarium doped hydroxyapatite, Ca10−xSmx(PO4)6(OH)2, xSm = 0.05, (5SmHAp), coatings were prepared by sol-gel process using the dip coating method. The stability of 5SmHAp suspension was evaluated by ultrasound measurements. Fourier transform infrared spectroscopy (FTIR) was used to examine the optical characteristics of HAp and 5SmHAp nanoparticles in suspension and coatings. The FTIR analysis revealed the presence of the functional groups specific to the structure of hydroxyapatite in the 5SmHAp suspensions and coatings. The morphology of 5SmHAp nanoparticles in suspension was evaluated by transmission electron microscopy (TEM). Moreover, scanning electron microscope (SEM) was used to evaluate the morphology of nanoparticle in suspension and the morphology of the surface on the coating. The SEM and TEM studies on 5SmHAp nanoparticles in suspension showed that our samples consist of nanometric particles with elongated morphology. The SEM micrographs of HAp and 5SmHAp coatings pointed out that the coatings are continuous and homogeneous. The surface morphology of the 5SmHAp coatings was also assessed by Atomic Force Microscopy (AFM) studies. The AFM results emphasized that the coatings presented the morphology of a uniformly deposited layer with no cracks and fissures. The crystal structure of 5SmHAp coating was characterized by X-ray diffraction (XRD). The surface composition of 5SmHAp coating was analyzed by X-ray photoelectron spectroscopy (XPS). The XRD and XPS analysis shown that the Sm3+ ions have been incorporated into the 5SmHAp synthesized material. The antifungal properties of the 5SmHAp suspensions and coatings were studied using Candida albicans ATCC 10231 (C. albicans) fungal strains. The quantitative results of the antifungal assay showed that colony forming unity development was inhibited from the early phase of adherence in the case of both suspensions and coatings. Furthermore, the adhesion, cell proliferation and biofilm formation of the C. albicans were also investigated by AFM, SEM and Confocal Laser Scanning Microscopy (CLSM) techniques. The results highlighted that the C. albicans adhesion and cell development was inhibited by the 5SmHAp coatings. Moreover, the data also revealed that the 5SmHAp coatings were effective in stopping the biofilm formation on their surface. The toxicity of the 5SmHap was also investigated in vitro using HeLa cell line.

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“…One of the proposed samarium ions antimicrobial mechanisms was due to the fact that samarium ions have the ability to change the fungal cell membrane permeability by attaching to it and affecting in the process the fungal cell's adhesion, ion conductivity and cell signaling [14]. More than that, both Barry et al and Ferraris et al [60,61] reported in their studies that the nature of the substrate could influence the biological properties of the samples. In addition, the studies showed that not only the composite and/or substrate are responsible for the biological properties of the coatings but also the synergic connections that appear between the substrate and the thin layer [60,61].…”

Section: Sionsmentioning

confidence: 99%

“…More than that, both Barry et al and Ferraris et al [60,61] reported in their studies that the nature of the substrate could influence the biological properties of the samples. In addition, the studies showed that not only the composite and/or substrate are responsible for the biological properties of the coatings but also the synergic connections that appear between the substrate and the thin layer [60,61].…”

Section: Sionsmentioning

confidence: 99%

Fabrication and Physico-Chemical Properties of Antifungal Samarium Doped Hydroxyapatite Thin Films

et al. 2021

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Samarium doped hydroxyapatite (Ca10−xSmx(PO4)6(OH)2, xSm = 0.5, 50SmHAp) is a very promising candidate to be used for different coatings in various dental and orthopedic implants. We report, for the first time, the obtaining of 50SmHAp thin films by a cost-effective method, namely spin coating. Thin films of 50SmHAp on silicon substrate have been analyzed by various techniques such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), Metallographic microscopy and Glow Discharge Optical Emission Spectroscopy (GDOES). The stability of 50SmHAp suspension was evaluated by ultrasound measurements. Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were also used to evaluate the 50SmHAp suspension. The antifungal activity of 50SmHAp suspension and coatings was assessed using Candida albicans ATCC 10231 fungal strain (C. albicans). The results of the antifungal assays depicted that both 50SmHAp suspensions and coatings were effective in inhibiting the development of C. albicans fungal cells, thus making them ideal candidates for the development of novel antifungal agents. The obtained results give new perspective for possible applications of 50SmHAp thin films in various medical applications due to their antifungal properties.

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The mechanical and chemical stability of the interfaces in bioactive materials: The substrate-bioactive surface layer and hydroxyapatite-bioactive surface layer interfaces

Cited by 30 publications

References 44 publications

Iodine-Loaded Calcium Titanate for Bone Repair with Sustainable Antibacterial Activity Prepared by Solution and Heat Treatment

Iodine-Loaded Calcium Titanate for Bone Repair with Sustainable Antibacterial Activity Prepared by Solution and Heat Treatment

Physico-Chemical Properties and In Vitro Antifungal Evaluation of Samarium Doped Hydroxyapatite Coatings

Fabrication and Physico-Chemical Properties of Antifungal Samarium Doped Hydroxyapatite Thin Films

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