Cu-doping of calcium phosphate bioceramics: From mechanism to the control of cytotoxicity

Abstract

Biphasic Calcium Phosphates (BCP) are bioceramics composed of hydroxyapatite (HAp, Ca(PO)(OH)) and beta-Tricalium Phosphate (β-TCP, Ca(PO)). Because their chemical and mineral composition closely resembles that of the mineral component of bone, they are potentially interesting candidates for bone repair surgery. Doping can advantageously be used to improve their biological behaviors; however, it is important to describe the doping mechanism of BCP thoroughly in order to fully appraise the benefit of the doping process. The present paper scrutinizes in detail the incorporation of copper cation in order to correctly interpret the behavior of the Cu-doped bioceramic in biological fluid. The understanding of the copper doping mechanism, related to doping mechanism of others 3d-metal cations, makes it possible to explain the rates and kinetic of release of the dopant in biological medium. Finally, the knowledge of the behavior of the copper doped ceramic in biological environment allowed the tuning of its cytotoxicity properties. The present study resulted on pre-treated ceramic disks which have been evaluated as promising biocompatible ceramic for bone substitute and/or prosthesis coating: good adherence of bone marrow cells with good cell viability.

Silver Doping Mechanism in Bioceramics—From Ag+:Doped HAp to Ag°/BCP Nanocomposite

“…They are indicated in CaO equivalent content in Table 1, as calcite decarbonation leads to CaO formation at about 800 • C. The amount of CaO equivalent becomes negligible at high temperatures, where the BCP were mainly composed of HAp (corresponding to the nominal composition). All these observations-on main and minor phases-were similar to those of our previous studies on first-row transition metal doping [48][49][50][51][52][53]. The β-TCP phase is stabilized for intermediate temperatures, with a maximum amount close to 20 wt % around 900 • C for the undoped series and around 700 • C for the two silver-doped series.…”

“…Rietveld refinements were systematically performed for each measurement (13 temperatures for the 3 series) using the FullProf.2k program [54]. The Rietveld strategy was detailed in previous related works [48][49][50][51][52][53]. A new additional phosphate compound was considered here: AgCa 10 (PO 4 ) 7 , which crystallizes in the trigonal R3c space group with a = 10.4372 Å and c = 37.3379 Å [55].…”

“…The case of zinc doping, with an interstitial mode of incorporation into the HAp crystal structure, was first fully characterized [49][50][51], then investigated for iron [52]. In the case of copper, it transpired that control of the doping mechanism allowed an insight into behavior in a biological environment [53]. For a complete understanding of the present paper it is very important to note the difference between the notations used: Ag + : HAp and Ag • /HAp.…”

A Novel Design to Enhance the Mechanical Properties in Cu-Bearing Antibacterial Stainless Steel

“…The average daily release of Cu measured in Cu-bearing antibacterial stainless steel is much smaller than the daily recommended amount for the human body [9]. Low concentration of Cu 2+ under a critical value is nontoxic and can improve the bone density of the human body [10,11]. However, only if the copper element precipitates out as copper precipitation and grows to a certain size can the copper precipitation kill the bacteria.…”

Intrinsic Orientation of Hydroxyapatite Grains on the Surface of Dense Pellets Produced by Uniaxial Pressing

“…Therefore, thorough characterization of the surface crystalline structure is the most appropriate means to study the effect of the microstructure of the biomaterial on the cellular response 9 . However, in most cases, the crystallographic characterization of such bioceramics is performed on the as-synthesized powder after calcination 1,2,10,11 and not on the dense device surface. Calcined devices have been taken into account in only a few cases; however, the X-ray diffraction (XRD) analyses were still focused on bulk characterization and not on the surfaces of the devices themselves [12][13][14] .…”