A dual‐task design of corrosion‐controlling and osteo‐compatible hexamethylenediaminetetrakis‐ (methylene phosphonic acid) (HDTMPA) coating on magnesium for biodegradable bone implants application

Abstract

Magnesium as well as its alloys appears increasingly as a revolutionary bio-metal for biodegradable implants application but the biggest challenges exist in its too fast bio-corrosion/degradation. Both corrosion-controllable and bio-compatible Mg-based bio-metal is highly desirable in clinic. In present work, hexamethylenediaminetetrakis (methylenephosphonic acid) [HDTMPA, (H2 O3 P-CH2 )2 -N-(CH2 )6 -N-(CH2 -PO3 H2 )2 ], as a natural and bioactive organic substance, was covalently immobilized and chelating-deposited onto Mg surface by means of chemical conversion process and dip-coating method, to fullfill dual-task performance of corrosion-protective and osteo-compatible functionalities. The chemical grafting of HDTMPA molecules, by participation of functional groups on pretreated Mg surface, ensured a firmly anchored base layer, and then sub-sequential chelating reactions of HDTMPA molecules guaranteed a homogenous and dense HDTMPA coating deposition on Mg substrate. Electrochemical corrosion and immersion degradation results reveal that the HDTMPA coated Mg provides a significantly better controlled bio-corrosion/degradation behavior in phosphate buffer saline solution as compared with untreated Mg from perspective of clinic requirement. Moreover, the HDTMPA coated Mg exhibits osteo-compatible in that it induces not only bioactivity of bone-like apatite precipitation but also promotes osteoblast cells adhesion and proliferation. Our well-controlled biodegradable and biocompatible HDTMPA modified Mg might bode well for next generation bone implant application.

Resorbable bone fixation alloys, forming, and post-fabrication treatments

“…Zomorodian et al [158] developed a composite coating on the AZ31 alloy by adding nano hydroxyapatite particles and an antibiotic, cephalexin, to PCL. Although the addition of the nano hydroxyapatite particles and antibiotic resulted in reduced corrosion protection, the composite coating has enhanced biocompatibility and anti-bacterial functionality.Sheng et al[159] prepared hexamethylenediaminetetrakis-(methylenephosphonic acid) (HDTMPA) surface-modified Mg alloy samples via a covalent immobilization process in conjunction with a sequential deposition process. HDTMPA is an organic phosphate that as a coating is biocompatible and provides corrosion resistance[159].…”

Methods of Topical Administration of Drugs and Biological Active Substances for Dental Implants—A Narrative Review

“…Another study pointed out the role of the combination of methylenephosphonic acid surface-modified magnesium. This study proved that this combination promotes two key functions of osteoblasts: adhesion and proliferation and, in addition, an induced calcium phosphate precipitation [ 56 ]. Secondly, it is also important to provide appropriate antimicrobial properties, especially in combination with these described above.…”

Electrophoretic deposition of colloidal particles on Mg with cytocompatibility, antibacterial performance, and corrosion resistance

“…The measured pH value result of each sample is in agreement with that of Mg 2+ evolution, but its variation is not so remarkable especially at early stage. This phenomenon might be caused by the pH buffering effect of SBF itself, because the SBF solution contains a large amount of HCO 3 À and HPO 4 2À [35,36]. Based on the above results, the coating materials can act as protective layers to reduce the degradation rate of Mg substrate.…”