ABSTRACT
Composite orthopaedic coatings with antibacterial capability containing chitosan, Bioglass® particles (9.8µm) and silver nanoparticles (Ag-np) were fabricated using a single-step electrophoretic deposition (EPD) technique, and their structural and preliminary in vitro bactericidal and cellular properties were investigated. Stainless steel 316 was used as a standard metallic orthopaedic substrate. The coatings were compared with EPD coatings of chitosan and chitosan/Bioglass®. The ability of chitosan as both a complexing and stabilizing agent was utilized to form uniformly deposited Ag-np. Due to the presence of Bioglass® particles, the coatings were bioactive in terms of forming carbonated hydroxyapatite in simulated body fluid (SBF). Less than 7wt.% of the incorporated silver was released over the course of 28days in SBF and the possibility of manipulating the release rate by varying the deposition order of coating layers was shown. The low released concentration of Ag ions (<2.5ppm) was efficiently antibacterial against Staphyloccocus aureus up to 10days. Although chitosan and chitosan/Bioglass® coating supported proliferation of MG-63 osteoblast-like cells up to 7days of culture, chitosan/Bioglass®/Ag-np coatings containing 342 µg of Ag-np showed cytotoxic effects. This was attributed to the relatively high concentration of Ag-np incorporated in the coatings.
Subject(s)
Ceramics/chemistry , Chitosan/chemistry , Coated Materials, Biocompatible/chemical synthesis , Electroplating/methods , Glass/chemistry , Metal Nanoparticles/administration & dosage , Silver/administration & dosage , Staphylococcus aureus/drug effects , Anti-Bacterial Agents/administration & dosage , Anti-Bacterial Agents/chemical synthesis , Cell Survival/drug effects , Coated Materials, Biocompatible/administration & dosage , Materials Testing , Metal Nanoparticles/chemistry , Prostheses and Implants , Silver/chemistry , Staphylococcus aureus/cytologyABSTRACT
The effect of prophylaxis with oral vitamin K (1 mg vitamin K1 given with the first feed) on the rate of detection of acarboxyprothrombin (PIVKA II) and factor II clotting concentration [corrected] were analysed. Introducing such prophylaxis reduced the rates of detection of PIVKA II concentration [corrected] on day 5 from 48% to zero. None of the babies given prophylaxis had factor II clotting concentration [corrected] below 40%, compared with 34 of 95 babies not given prophylaxis. This study has important implications in the prophylaxis of both classical and late onset haemorrhagic disease of the newborn.
