UBC Theses and Dissertations
A battery-less MEMS device for on-demand and controlled drug delivery Pirmoradi, Fatemeh
Drug therapy efficacy depends on therapeutic concentrations of drugs at disease sites. An ideal controlled and localized drug delivery system would deliver drugs to a target tissue and would locally maintain the required drug concentration. Furthermore, for many diseases, the delivery of therapeutic concentrations on an “on-demand” basis would be of tremendous benefit. In this thesis, a MEMS (Microelectromechanical Systems) based drug delivery device has been developed that provides on-demand release of defined drug quantities. The device consists of a drug-loaded microreservoir that is sealed with an elastic PDMS (polydimethylsiloxane) magnetic membrane with a laser-drilled aperture. The drug release is triggered in the presence of an external magnetic field by deforming the magnetic membrane and therefore discharging the drug solution. The use of magnetic actuation for on-demand and controlled dose sequencing eliminates the need for an on-board power source. A new magnetic membrane material has been developed for the proposed drug delivery device. The polymeric magnetic composites were developed by incorporating coated iron oxide nanoparticles within a PDMS matrix. The new composites show improvement in reducing particle agglomeration compared to existing polymeric magnetic materials. Free-standing PDMS magnetic membranes with a thickness of 35 µm have been fabricated and have shown to deflect in applied magnetic fields. The MEMS drug delivery device has been used to deliver an antiproliferative, taxane-based drug, docetaxel (DTX). On-demand and controlled release of DTX with a dosage suitable for treatment of diabetic retinopathy has been achieved for 35 days. Biological activity of the released DTX was investigated two months after the drug was packaged in the device. These studies confirmed that the antiproliferative effect of DTX can be maintained for 2 months, and the drug does not degrade within the device. This device is a proof-of-concept development for on-demand and controlled delivery of taxane-based agents for treatment of proliferative retinopathy, which requires accurate delivery of nanomolar drug concentrations.
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