Asymmetric biodegradable microdevices for cell-borne drug delivery.

Use of live cells as carriers for drug-laden particulate structures possesses unique advantages for drug delivery. In this work, we report on the development of a novel type of particulate structures called microdevices for cell-borne drug delivery. The microdevices were fabricated by soft lithography with a disklike shape. Each microdevice was composed of a layer of biodegradable thermoplastic such as poly(lactic-co-glycolic acid). One face of the thermoplastic layer was covalently grafted with a cell-adhesive polyelectrolyte such as poly-l-lysine. This asymmetric structure allowed the microdevices to bind to live cells through bulk mixing without causing cell aggregation. Moreover, the cell-microdevice complexes were largely stable, and the viability and proliferation ability of the cells were not affected by the microdevices over a week. In addition, sustained release of a mock drug from the microdevices was demonstrated. This type of microdevice promises to be clinically useful for sustained intravascular drug delivery.