Utilizing the Organizational Power of DNA Scaffolds for New Nanophotonic Applications

AbstractRapid development of DNA technology has provided a feasible route to creating nanoscale materials. DNA acts as a self‐assembled nanoscaffold capable of assuming any three‐dimensional shape. The ability to integrate dyes and new optical materials such as quantum dots and plasmonic nanoparticles precisely onto these architectures provides new ways to exploit their near‐ and far‐field interactions. A fundamental understanding of these optical processes will help drive development of next‐generation photonic nanomaterials. This review is focused on latest progress in DNA‐based photonic materials and highlights DNA scaffolds for rapidly assembling and prototyping nanoscale optical devices. Three areas are discussed including intrinsically active DNA structures displaying chiral properties, DNA scaffolds hosting plasmonic nanomaterials, and fluorophore‐labeled DNAs that engage in Förster resonance energy transfer and give rise to complex molecular photonic wires. An explanation of what is desired from these optical processes when harnessed sets the tone for what DNA scaffolds are providing toward each focus. Examples from the literature illustrate current progress along with a discussion of challenges to overcome for further improvements. Opportunities to integrate diverse classes of optically active molecules including light‐generating enzymes, fluorescent proteins, nanoclusters, and metal–chelates in new structural combinations on DNA scaffolds are also highlighted

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements