Novel biodegradable calcium phosphate/polymer composite coating with adjustable mechanical properties formed by hydrothermal process for corrosion protection of magnesium substrate

Abstract

Ceramic type coatings on metallic implants, such as calcium phosphate (Ca-P), are generally stiff and brittle, potentially leading to the early failure of the bone-implant interface. To reduce material brittleness, polyacrylic acid and carboxymethyl cellulose were used in this study to deposit two types of novel Ca-P/polymer composite coatings on AZ31 magnesium alloy using a one-step hydrothermal process. X-ray diffraction and scanning electron microscopy showed that the deposited Ca-P crystal phase and morphology could be controlled by the type and concentration of polymer used. Incorporation of polymer in the Ca-P coatings reduced the coating elastic modulus bringing it close to that of magnesium and that of human bone. Nanoindentation test results revealed significantly decreased cracking tendency with the incorporation of polymer in the Ca-P coating. Apart from mechanical improvements, the protective composite layers had also enhanced the corrosion resistance of the substrate by a factor of 1000 which is sufficient for implant application. Cell proliferation studies indicated that the composite coatings induced better cell attachment compared with the purely inorganic Ca-P coating, confirming that the obtained composite materials could be promising candidates for surface protection of magnesium for implant application with the multiple functions of corrosion protection, interfacial stress reduction, and cell attachment/cell growth promotion. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1643-1657, 2016.

Evaluation of Corrosion Performance of AZ31 Mg Alloy in Physiological and Highly Corrosive Solutions

“…Studies have shown that the degradation rate of Mg could be controlled by surface modification technologies such as chemical conversion, hydrothermal treatment, 37 sol–gel method, 38 polymer coatings, plasma spraying, microarc oxidation, 39 magnetron sputtering, and electrochemical deposition. 40 The electrochemical deposition method has the ability to produce coatings on the surface of samples with different shapes at relatively low temperatures.…”

Micro-/Nano-Structured Biodegradable Pressure Sensors for Biomedical Applications

“…Red arrows indicate the elapse of time. ( b ) Transmission-mode laser diffraction phase microscopic (DPM) image of Si NMs (∼100 nm-thick) at various times of immersion in phosphate-buffered solution (1 M, pH 7.4) at physiological temperature (37 °C) [ 61 ]. Black arrows indicate the elapse of time.…”

Role of calcium phosphate and bioactive glass coating on in vivo bone healing of new Mg–Zn–Ca implant

“…[ 28 – 31 ]), polymer (PGA, PLA, PEO-PCL, PEA-PLLA, PLG, etc. [ 32 ]) and composite (HAp-PCL, F-HAp [ 33 ]) have been used according to the implant requirements. CaP coatings done by ion-beam-assisted deposition or electrochemical and chemical treatment reduce the rate of corrosion, but crystal structure, chemical composition, coating morphology and degradation rates differ.…”