Merging biological self-assembly with synthetic chemical tailoring: The potential for 3-D genetically engineered micro/nano-devices (3-D GEMS)

Appreciable global efforts are underway to develop processes for fabricating three-dimensional (3-D) nanostructured assemblies for advanced devices. Widespread commercialization of such devices will require: (i) precise 3-D fabrication of chemically tailored structures on a fine scale and (ii) mass production of such structures on a large scale. These often-conflicting demands can be addressed with a revolutionary new paradigm that couples biological self-assembly with synthetic chemistry: Bioclastic and Shape-preserving Inorganic Conversion (BASIC). Nature provides numerous examples of microorganisms that assemble biominerals into intricate 3-D structures. Among the most spectacular of these microorganisms are diatoms (unicellular algae). Each of the tens of thousands of diatom species assembles silica nanoparticles into a microshell with a distinct 3-D shape and pattern of fine (nanoscale) features. The repeated doubling associated with biological reproduction enables enormous numbers of such 3-D microshells to be generated (e.g., only 40 reproduction cycles can yield > 1 trillion 3-D replicas!). Such genetic precision and massive parallelism are highly attractive for device manufacturing. However, the natural chemistries assembled by diatoms (and other microorganisms) are rather limited. With BASIC processes, biogenic assemblies can be converted into a wide variety of new functional chemistries, while preserving the 3-D morphologies. Ongoing advances in genetic engineering promise to yield microorganisms tailored to assemble nanoparticle structures with device-specific shapes. Large-scale culturing of such genetically tailored microorganisms, coupled with shape-preserving chemical conversion (via BASIC processes), would then provide low-cost 3-D Genetically Engineered Micro/nano-devices (3-D GEMs).