Wearable plasmonic paper-based microfluidics for continuous sweat analysis.

Wearable sweat sensors have the potential to provide clinically meaningful information associated with the health and disease states of individuals. Current sensors mainly rely on enzymes and antibodies as biorecognition elements to achieve specific quantification of metabolite and stress biomarkers in sweat. However, enzymes and antibodies are prone to degrade over time, compromising the sensor performance.

Twist-Dependent Raman and Electron Diffraction Correlations in Twisted Multilayer Graphene.

Twisted multilayer graphene (tMLG), in contrast to twisted bilayer graphene, offers a range of angular rotations for tuning the properties of the system. In this work, a turbostratic graphene system with a high degree of two-dimensional (2D) crystallinity is chosen to represent tMLG. We have investigated the distribution and population of twist angles from distributed sextets in electron diffraction (SAED) patterns with the collective Raman behavior at the same locations.

Formation of Two-Dimensional Network of Organic Charge-Transfer Complexes at the Air-Water Interface.

The air-water interface is an ideal platform to produce two-dimensional (2D) structures involving anything from simple organic molecules to supramolecular moieties by exploiting hydrophobic-hydrophilic interactions. Here, we show, using grazing incidence X-ray scattering, the formation of a 2D ordered structure of a charge-transfer (C-T) complex, namely, dodecyl methyl viologen (DMV) as acceptor and coronene tetracarboxylate potassium salt (CS) as donor, at the air-water interface. We have observed a phase transition in the 2D ordered structure as the area per molecule is decreased with increasing surface pressure in a Langmuir trough.

A Supramolecular Nanofiber-Based Passive Memory Device for Remembering Past Humidity.

Memorizing the magnitude of a physical parameter such as relative humidity in a consignment may be useful for maintaining recommended conditions over a period of time. In relation to cost and energy considerations, it is important that the memorizing device works in the unpowered passive state. In this article, we report the fabrication of a humidity-responsive device that can memorize the humidity condition it had experienced while being unpowered.

In-Situ GISAXS Study of Supramolecular Nanofibers having Ultrafast Humidity Sensitivity.

Self assembled nanofibers derived from donor-acceptor (D-A) pair of dodecyl methyl viologen (DMV) and potassium salt of coronene tetracarboxylate (CS) is an excellent material for the development of organic electronic devices particularly for ultrafast response to relative humidity (RH). Here we have presented the results of in-situ grazing incidence small angle x-ray scattering (GISAXS) measurements to understand aridity dependent self reorganization of the nanofibers. The instantaneous changes in the organization of the nanofibers was monitored with different equilibrium RH conditions.

Highly Decoupled Graphene Multilayers: Turbostraticity at its Best.

The extraordinary properties of graphene are truly observable when it is suspended, being free from any substrate influence. Here, a new type of multilayer graphene is reported wherein each layer is turbostratically decoupled, resembling suspended graphene in nature, while maintaining high degree of 2D crystallinity. Such defect-free graphene multilayers have been made over large areas by Joule heating of a Ni foil coated with a solid hydrocarbon.

Ultrafast response humidity sensor using supramolecular nanofibre and its application in monitoring breath humidity and flow.

Measuring humidity in dynamic situations calls for highly sensitive fast response sensors. Here we report, a humidity sensor fabricated using solution processed supramolecular nanofibres as active resistive sensing material. The nanofibres are built via self- assembly of donor and acceptor molecules (coronene tetracarboxylate and dodecyl methyl viologen respectively) involved in charge transfer interactions.

High-mobility field effect transistors based on supramolecular charge transfer nanofibres.

Self-assembled charge transfer supramolecular nanofibres of coronene tetracarboxylate (CS) and dodecyl substituted unsymmetric viologen derivative (DMV) behave as active channel in field effect transistors exhibiting high mobility. These devices work in ambient conditions and can regenerate in the presence of a single drop of water.

Dynamic self-assembly of charge-transfer nanofibers of tetrathiafulvalene derivatives with F4TCNQ.

One-dimensional charge-transfer nanostructures were constructed by the supramolecular coassembly of amphiphilic (Amph-TTF) and hydrophobic (TDD-TTF) tetrathiafulvalene (TTF) donor derivatives with the acceptor 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F(4)TCNQ), in appropriate solvent composition mixtures. Microscopic analyses show that TDD-TTF retains its self-assembled fibrillar morphology even in the charge-transfer state, whereas Amph-TTF undergoes a spherical to nanorod transition upon coassembly. Time-dependent optical spectroscopy studies have shown a spontaneous change in molecular organization in TDD-TTF-based donor-acceptor costacks, which suggests a dynamic behavior, in contrast to the kinetically stable amphiphilic TTF assemblies.

Binding of DNA nucleobases and nucleosides with graphene.

Interaction of two different samples of graphene with DNA nucleobases and nucleosides is investigated by isothermal titration calorimetry. The relative interaction energies of the nucleobases decrease in the order guanine (G)>adenine (A)>cytosine (C)>thymine (T) in aqueous solutions, although the positions of C and T seem to be interchangeable. The same trend is found with the nucleosides.