Shape-Programmable Particles from Photocurable Poly(β-Amino Esters) for Drug Delivery Applications

Micro- and nanoparticle shape plays a critical role in their fate for drug delivery applications. However, few methods exist that enable the facile and scalable manufacturing of biodegradable particles with precise control over shape. To address this, photolithographic methods to fabricate particles from poly(β-amino esters) (PBAEs) are reported, where small changes to the prepolymer formulation result in diverse physical properties. By adjusting the molar ratio and chemical structure of component monomers, 1000-fold changes in elastic moduli and a range of degradation rates were readily achieved, all while retaining cytocompatibility. To explore the potential of this platform in a drug delivery context, particles were fabricated for two emerging biomedical applications in which shape is critical to function: discoidal cellular backpacks and helical magnetic microrobots. Using contact photolithography, rapid manufacturing (>10⁷ discoidal backpacks per hour), slowed release of a model drug, and efficient attachment to macrophages were achieved. To demonstrate the manufacture of magnetic microrobots, helical microparticles were printed and coated with iron, enabling control over locomotion in a rotating magnetic field while maintaining complete biodegradability. Overall, these methods offer advantages for applications where nonspherical particle shapes are enabling, such as drug delivery systems, biosensing, and microscale robotics.