Strategies for alkali-free synthesis, surface modification, and electrophoretic deposition of composite films for biomedical applications

Abstract

This investigation addresses increasing interest in composites for biomedical applications and advanced methods for their synthesis and electrophoretic deposition (EPD). The feasibility of preparation of hydroxyapatite (HA), titania and zirconia particles using branched polyethylenimine polymer (BPEI) or L-arginine amino acid as organic alkalizers is demonstrated. In this new approach, BPEI and L-arginine are used as alkalizers-capping agents instead of inorganic alkalis. The use of BPEI facilitates synthesis of HA nanorods with reduced size. This approach opens an avenue for the fabrication of nanoparticles of other functional inorganic materials using alkalizers-capping agents. It offers advantages of simple procedure, environmental benefits and improved control of particle size. Composite films are obtained by cathodic EPD using linear polyethylenimine (LPEI) as a charging and film-forming agent. A conceptually new approach is developed for anodic EPD of alginic acid polymer (AlgH) and composite films containing drug molecules in AlgH matrix. This strategy involves the use of L-arginine as an alkalizer for solubilization of drugs, which exhibit poor solubility in water. AlgH and drug molecules are solubilized in water and deposited by anodic EPD. Testing results confirm the fabrication of composite films, containing drug molecules. This method allows reduced gas evolution at the electrode, elimination of film porosity, improved stabilization of bioceramic particles in polymer solutions and facilitates composite film formation from stable suspensions. The deposition methods developed in this investigation can be used for deposition of other cationic and anionic polymers and their co-EPD with bioceramics, drugs and other functional materials.