Fabrication of drug-loaded polymer microparticles with arbitrary geometries using a piezoelectric inkjet printing system.

Carrier geometry is a key parameter of drug delivery systems and has significant impact on the drug release rate and interaction with cells and tissues. Here we present a piezoelectric inkjet printing system as a simple and convenient approach for fabrication of drug-loaded polymer microparticles with well-defined and controlled shapes. The physical properties of paclitaxel (PTX)-loaded poly(lactic-co-glycolic acid) (PLGA) inks, such as volatility, viscosity and surface tension, were optimized for piezoelectric inkjet printing, and PTX-loaded PLGA microparticles were fabricated with various geometries, such as circles, grids, honeycombs, and rings. The resulting microparticles with 10% (w/w) PTX exhibited a fairly homogeneous shape and size. The microparticle fabrication by piezoelectric inkjet printing was precise, reproducible, and highly favorable for mass production. The microparticles exhibited a biphasic release profile with an initial burst due to diffusion and a subsequent, slow second phase due to degradation of PLGA. The release rate was dependent on the geometry, mainly the surface area, with a descending rate order of honeycomb>grid, ring>circle. The PTX-loaded microparticles showed a comparable activity in inhibiting the growth of HeLa cells. Our results demonstrate that a piezoelectric inkjet printing system would provide a new approach for large-scale manufacturing of drug carriers with a desired geometry.