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Two-dimensional (2D) graphene emerged as an outstanding material for plasmonic and photonic applications due to its charge-density tunability, high electron mobility, optical transparency and mechanical flexibility. Recently, novel fabrication processes have realised a three-dimensional (3D) nanoporous configuration of high-quality monolayer graphene which provides a third dimension to this material. In this work, we investigate the optical behaviour of nanoporous graphene by means of terahertz and infrared spectroscopy. We reveal the presence of intrinsic 2D Dirac plasmons in 3D nanoporous graphene disclosing strong plasmonic absorptions tunable from terahertz to mid-infrared via controllable doping level and porosity. In the far-field the spectral width of these absorptions is large enough to cover most of the mid-Infrared fingerprint region with a single plasmon excitation. The enhanced surface area of nanoporous structures combined with their broad band plasmon absorption could pave the way for novel and competitive nanoporous-graphene based plasmonic-sensors. Recently, fabrication processes have realised three-dimensional nanoporous graphene. Here, the authors reveal two-dimensional Dirac plasmons in three-dimensional nanoporous graphene disclosing strong plasmonic absorptions tunable from terahertz to mid-infrared via controllable doping level and porosity.

Polymeric materials are widely used in industries ranging from automotive to biomedical. Their mechanical properties play a crucial role in their application and function and arise from the nanoscale structures and interactions of their constitutive polymer molecules. Polymeric materials behave viscoelastically, i.e. their mechanical responses depend on the time scale of the measurements; quantifying these time-dependent rheological properties at the nanoscale is relevant to develop, for example, accurate models and simulations of those materials, which are needed for advanced industrial applications. In this paper, an atomic force microscopy (AFM) method based on the photothermal actuation of an AFM cantilever is developed to quantify the nanoscale loss tangent, storage modulus, and loss modulus of polymeric materials. The method is then validated on a styrene-butadiene rubber (SBR), demonstrating the method's ability to quantify nanoscale viscoelasticity over a continuous frequency range up to five orders of magnitude (0.2 Hz to 20,200 Hz). Furthermore, this method is combined with AFM viscoelastic mapping obtained with amplitude-modulation frequency-modulation (AM-FM) AFM, enabling the extension of viscoelastic quantification over an even broader frequency range, and demonstrating that the novel technique synergizes with preexisting AFM techniques for quantitative measurement of viscoelastic properties. The method presented here introduces a way to characterize the viscoelasticity of polymeric materials, and soft matter in general at the nanoscale, for any application.

Small solid-state devices are candidates for accelerating biomedical assays/drug discovery, however their potential remains unfulfilled. Here, we demonstrate that graphene-field effect transistors (FET) can be used to successfully detect the key molecular events underlying viral infections and the effect of antiviral drugs. Our device success is achieved by bio-mimicking the host-cell surface during an influenza infection at the graphene channel. In-situ AFM confirms the biological interactions at the sialic acid-functionalized graphene: viral hemagglutinin (HA) binds to sialic acid, and neuraminidase (NA) reacts with the sialic acid-HA complex. The graphene-FET detects HA binding to sialic acid, and NA cleavage of sialic acid. The inhibitory effect of the drug \"zanamivir\" on NA-sialic acid interactions is monitored in real-time; the reaction rate constant of NA-sialic acid reaction was successfully determined. We demonstrate that graphene-FETs are powerful platforms for measurement of biomolecular interactions and contribute to future deployment of solid-state devices in drug discovery/biosensing.