Diamond is a natural choice when it comes to making nanoscale devices but patterning is expensive and time-consuming. An EU-funded project has investigated DNA templates for patterning any shape. Nanocrystalline diamond thin films are seeded and then grown to produce material for nanoscale devices used in a whole array of fields, from medicine to quantum information processing. However, the precise nanoscale patterning required for these new technologies is a lengthy and costly process.
The DIAMONDDNA (DNA origami templates for nanocrystalline diamond nanostructures) project aimed to create self-assembled DNA patterns to order, which can then be decorated with nanodiamond or diamondoid particles. The resulting feature resolution surpasses currently used processes such as electron beam lithography (EBL).
For DNA self-assembly, nanoparticles must be small enough and have a negative charge so it does not interfere with the electrostatics. To satisfy these criteria, researchers developed a robust method to functionalise and disperse detonation nanodiamond (DND) structures.
The resulting nanoparticles with negatively charged zeta potentials are sufficiently small, monodispersed and have chemically accessible functional groups for subsequent biomodification with DNA or other probe molecules.
DIAMONDDNA were successful in assembling DNA origami structures and they collected a considerable amount of data on surface properties of DND. They were however unable to assemble DND-DNA-origami structures but future modifications and knowledge gained should enable structure assembly.
Applications for the chemical preparatory method include biolabeling, where fluorescent nanodiamond is conjugated to selected antibodies and in the design of bioscaffolds for synthetic bone.
The researchers also produced pristine colour centres in nanodiamonds from ultrapure diamondoid seeds, resulting in a patent. The diamondoid colour-centre patent outlines a pathway for production of two types of nanoparticle.
Nanoparticles that have non-quenching, bright near infrared fluorescence with silicon vacancies can be used in bioimaging whereas those with nitrogen vacancies and magnetic/electrical field sensitivity can be used in magnetometry.
The DIAMONDDNA project has enabled the positioning of diamond colour centres with nanoscale precision. Technological advances in new medical therapy and diagnosis could now be possible through high-speed, long-term imaging.