Printing on Particles: Combining Two-Photon Nanolithography and Capillary Assembly to Fabricate Multimaterial Microstructures

摘要

Additive manufacturing at the micro- and nanoscale has seen a recentupsurge to suit an increasing demand for more elaborate structures. However,the integration of multiple distinct materials at small scales remainschallenging. To this end, capillarity-assisted particle assembly (CAPA) andtwo-photon polymerization direct laser writing (2PP-DLW) are combined torealize a new class of multimaterial microstructures. 2PP-DLW and CAPAboth are used to fabricate 3D templates to guide the CAPA of soft- and hardcolloids, and to link well-defined arrangements of functional microparticlearrays produced by CAPA, a process that is termed “printing on particles.”The printing process uses automated particle recognition algorithms toconnect colloids into 1D, 2D, and 3D tailored structures, via rigid, soft, orresponsive polymer links. Once printed and developed, the structures can beeasily re-dispersed in water. Particle clusters and lattices of varying symmetryand composition are reported, together with thermoresponsive microactuators,and magnetically driven “micromachines”, which can efficiently move,capture, and release DNA-coated particles in solution. The flexibility of thismethod allows the combination of a wide range of functional materials intocomplex structures, which will boost the realization of new systems anddevices for numerous fields, including microrobotics, micromanipulation, andmetamaterials.