Abstract
Innovative engineering design for biologically active hydroxyapatites requires enhancing both mechanical and physical properties, along with biocompatibility, by doping with appropriate chemical elements. Herein, the purpose of this investigation was to evaluate and elucidate the model of naturally occurring hydroxyapatite and the effects of doped trace elements on the function of normal human fibroblasts, representing the main cells of connective tissues. The substrates applied (geological apatites with hexagonal prismatic crystal habit originated from Slyudyanka, Lake Baikal, Russia (GAp) and from Imilchil, The Atlas Mountains, Morocco (YAp)) were prepared from mineral natural apatite with a chemical composition consistent with the building blocks of enamel and enriched with a significant F− content. Materials in the form of powders, extracts and single-crystal plates have been investigated. Moreover, the effects on the function of fibroblasts cultured on the analyzed surfaces in the form of changes in metabolic activity, proliferation and cell morphology were evaluated. Apatite plates were also evaluated for cytotoxicity and immune cell activation capacity. The results suggest that a moderate amount of F− has a positive effect on cell proliferation, whereas an inhibitory effect was attributed to the Cl− concentration. It was found that for (100) GAp plate, fibroblast proliferation was significantly increased, whereas for (001) YAp plate, it was significantly reduced, with no cytotoxic effect and no immune response from macrophages exposed to these materials. The study of the interaction of fibroblasts with apatite crystal surfaces provides a characterization relevant to medical applications and may contribute to the design of biomaterials suitable for medical applications and the evaluation of their bioavailability.
Highlights
Hydroxyapatite (HAp) substitutions have the ability to induce both positive and negative effects on cell viability and on the mechanical properties and solubility of biomaterials [1,2,3,4]
An original research model was adapted to examine the influence of single-crystal surfaces with defined crystallographic orientation on viability, growth and proliferation of fibroblasts, the most common cells derived from connective tissue in human body
There is a probable effect of competitive adsorption between proteins present in growth medium and those synthesized by fibroblasts during incubation as intermediating factors in the process of cellular adhesion
Summary
Hydroxyapatite (HAp) substitutions have the ability to induce both positive and negative effects on cell viability and on the mechanical properties and solubility of biomaterials [1,2,3,4]. Due to its structural similarity to biological bone, visible biocompatibility, and bioactivity, HAp has been applied in medicine and dentistry in several forms: as dense sintered ceramics; porous forms; granules; and coatings of metal implants [8,9,10]. The shape of HAp crystallites is highly anisotropic, with at least two types of crystal faces: (100) and (101), and rarely (001), exhibiting different distributions of electrostatic potential, different interactions with water, and different adsorptions of biomolecules [11]. Surface charges measured on individual grains and across grain boundaries of polycrystalline HAp vary in terms of nanoscale and depend on preferentially exposed crystal faces [12]. It has been shown that HAp ceramics with controlled orientation can alter material bioactivity and cell adhesion, in addition to their performance [13,14]. For HAp-coated implant surfaces, the response of living cells to the exposed orientation should be considered, as HAp crystallites may have a preferred orientation, e.g., with (001) parallel to the surface of the coating, as was observed for HAp-coated titanium [15]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
