Microscale zirconia structures with intricate three-dimensional (3D) shapes and nanoscale features were synthesized using diatom (single-celled algae) microshells as transient scaffolds. After exposure to a zirconium alkoxide-bearing solution and firing at 550–850 °C, silica-based diatom microshells were coated with a thin, continuous nanocrystalline zirconia layer. Predominantly tetragonal or monoclinic zirconia could be produced with appropriate heat treatments. Selective silica dissolution then yielded freestanding zirconia micro-assemblies that retained the microshell shape and fine features. Such hybrid (biological/synthetic chemical) processing may be used to mass-produce nanostructured micro-assemblies with a variety of 3D, biologically replicable shapes and tailored compositions for use in numerous applications.

Microscale polymeric structures with intricate three-dimensional (3D) shapes and nanoscale features were synthesized by using silica-based microshells of diatoms (unicellular algae) as transient scaffolds. Diatom microshells were immersed in dilute solutions of polymer precursors in volatile solvents. After extraction and solvent evaporation, the resulting thin films on the microshells were cross-linked to form rigid polymer coatings. Selective silica dissolution then yielded freestanding polymeric structures that retained the microshell shapes and fine features. By utilizing bioscaffolds capable of genetically precise and massively parallel replication, enormous numbers of polymeric micro/nanostructures with identical 3D shapes may be generated for various applications.