Patterned soft-micropolyhedra by self-folding and molding

It is extremely challenging to mass-produce polymeric microstructures with patterns in all three dimensions (3D). In this paper, we describe a highly parallel strategy to create such patterned soft-micropolyhedra with a range of polymers and even live mammalian cell-laden hydrogels. Specifically, we first patterned metallic micropolyhedra using photolithography and capillary force assisted self-folding. Inverse molds were created in the elastomer polydimethylsiloxane (PDMS); interestingly, the patterns were imprinted on the side walls of the molds. The molds were then filled with pre-polymers such as NOA73, PEGDA, and pNIPAM-AAc and cell-laden hydrogel solutions and cross-linked to form soft patterned micropolyhedra. Our results suggest that the combination of self-folding and molding could be used to create a variety of smart particles and building blocks with precisely patterned surfaces for applications in colloidal science, self-assembly, drug delivery and tissue engineering.