Poly-Lactic Acid Magnetoelectric Microspheres for Drug Release Applications

The study of magnetoelectric (ME) nanomaterials has drawn significant interest due to their novel physical, chemical and mechanical properties. The ME composites, typically made by embedding a magnetic substance in a piezoelectric material, exhibit an ME effect described by a magnetic-to-electrical signal conversion via an elastic interaction. The ME output voltage determines the practicability of the composite for technological applications and biomedical applications. Polymer-based ME composites are emerging due to their ease of fabrication, flexibility and high ME output voltages achieved to date. Furthermore, ME composites are envisaged to function as contactless, dispersible electrodes that have potential for remote control of electrical stimulation, sensing or release of drugs in biomedical applications. However, only ceramic ME composites are recorded in biomedical applications to date. Therefore, the aim of the project was to develop, characterize and apply the mechanism of magnetic-to-electrical conversion using polymer-based ME nanocomposites, specifically for the application of remotely activated drug release. The biodegradable piezoelectric polymer, Polylactic Acid (PLA), was used to synthesize polymer microspheres containing magnetic CoFe2O4 nanoparticles and characterization of their magnetic and piezoelectric properties was undertaken. A key finding was demonstration of controlling the release of drugs (the anti-inflammatory drug, Dexamethasone) from the ME polymer microspheres via a remotely applied magnetic field. While the ME mechanisms affecting the drug release remain unclear, several possible theories are discussed.