What if materials could be assembled with molecular-level precision, then taken apart and rebuilt on demand? Using DNA as a programmable scaffold, researchers can control how nanoscale components come together, opening new possibilities for optoelectronics, biosensing and responsive devices.
This approach was explored by Prof. Matteo Palma of Queen Mary University of London in a QAMSS lecture on DNA-programmable nanoscale heterostructures. The talk examined how one- and two-dimensional nanomaterials, including carbon nanotubes, graphene and molybdenum disulfide, can be combined with nanoparticles to create hybrid systems with precisely controlled interfaces.
Programming nanoscale interfaces with DNA
At the heart of the approach is DNA's ability to act as both a structural linker and a functional component. Rather than relying on materials simply sticking together, complementary DNA base-pairing can determine where components are positioned and how far apart they sit.
“DNA's core advantage is sequence-programmability,” explained Palma, allowing “sub-nanoscale spatial control – by design – over exactly where and at what separation nanoscale moieties attach”.
This control over distance is particularly important because the interactions between components can change significantly at the nanoscale. Conventional approaches such as non-specific adsorption or stacking cannot provide the same degree of precision.
DNA also makes it possible to create structures that can respond to their surroundings. “DNA further adds reversibility and stimuli-responsiveness,” Palma said, with assemblies that can be “built and then selectively taken apart or reconfigured on demand”.
These changes can be triggered by factors including temperature, pH or the introduction of competing DNA strands, while taking place under mild aqueous conditions.
From molecular control to responsive devices
Precise control over nanoscale interfaces offers a way to tailor how hybrid materials behave, rather than simply combining components and hoping they work together effectively. In optoelectronics, this could help researchers design devices with specific electronic and light-responsive properties.
“In optoelectronics, for example, positioning different nanoparticles at defined distances from MoS₂ tunes doping, trion formation, and photoresponse,” Palma said.
In biosensing, the challenge is to position biological recognition molecules so that their interaction with a target can be detected effectively. DNA offers a means of adjusting these arrangements, while dynamic strand displacement could provide a way to enhance sensitivity or trigger the release of molecules when needed.
“In biosensing, controlling the position of an aptamer (a DNA-based recognition element) relative to a transducer's Debye length can permit the tuning of the sensing response,” Palma explained.
By combining precise assembly with the ability to reconfigure structures, this research offers a versatile strategy for developing nanoscale systems whose properties can be adjusted for different applications.
About the interviewee
Prof. Matteo Palma, Queen Mary University of London
Matteo Palma is Professor of Physical Chemistry and Nanomaterials in the Department of Chemistry at Queen Mary University of London (UK). Since September 2013, he has led a research group focusing on the controlled assembly of functional nanohybrids of low-dimensional materials, from solution to nanopatterned substrates: carbon nanotubes, 2D nanomaterials and DNA nanostructures are employed to this end. Applications range from optoelectronics to biosensing and single-molecule biological investigations. Trained as a physical chemist, he graduated (MSc) from the University of Rome "La Sapienza" in 2004 and received a PhD in 2007 from the Institute of Supramolecular Science and Engineering (ISIS), University of Strasbourg, France. He then worked as a postdoctoral scientist (2008–2013) in the Departments of Mechanical Engineering and Applied Physics at Columbia University (New York, USA) before starting his independent career at Queen Mary.
By Dr Karen Steward