katch wreck`We developed a #hydrogel infusion-based additive manufacturing (AM) technique using two-photon #lithography to produce metals in prescribed 3D-shapes with ∼100 nm feature resolution. We demonstrate hierarchical microstructures of as-AM-fabricated Ni #nanopillars (D ∼ 130–330 nm) to be #nanoporous and #nanocrystalline, with d ∼ 30–50 nm nanograins subtending each ligament in bamboo-like arrangements and pores with critical dimensions comparable to d.`