Lateral flow assays (LFA) are quick, simple and cheap assays to analyse a variety of samples at the point of care or in the field, making them one of the most widespread biosensors currently available. They have been successfully employed for the detection of a myriad of different targets (ranging from atoms up to whole cells) in all type of samples (including water, blood, foodstuff and environmental samples). Their operation relies on the capillary flow of the sample within a series of sequential pads with different functionalities aiming to generate a signal indicating the absence/presence (and, in some cases, the concentration) of the analyte of interest. In order to have a user-friendly operation, their development requires the optimization of multiple, interconnected parameters that may overwhelm new developers. In this Tutorial we provide the readers with: 1) the basic knowledge to understand the principles governing an LFA and to take informed decisions during lateral flow strip design and fabrication, 2) a roadmap for optimal LFA development independent of the specific application, 3) a step by step example protocol for the assembly and operation of an LF strip for the detection of Human Immunoglobulin G and 4) an extensive troubleshooting section addressing the most frequent issues in designing, assembling and using LFAs.

The electronic properties of thiol-functionalized 2D MoS2 nanosheets are investigated. Shifts in the valence and conduction bands and Fermi levels are observed while bandgaps remain unaffected. These findings allow the tuning of energy barriers between 2D MoS2 and other materials, which can lead to improved control over 2D MoS2 -based electronic and optical devices and catalysts.

Grinding-assisted sonication exfoliation of stratified materials such as MoS 2 is a widely used method for the preparation of their single and few layer thick flakes. This work introduces a two-solvent step approach utilizing a separate solvent during the grinding phase, while implementing ethanol during exfoliation. It is found that the grinding solvent played a critical role, determining exfoliation yield, flake dimensions and morphology, highlighting the importance of such parameters in the process. Furthermore, it is found that the commonly used N-methyl-2-pyrrolidone (NMP) lead to persistent residues on the exfoliated flakes which may alter the properties of the flakes and interfere with the development of electronic devices and other applications. A solvent residue free exfoliation method is presented herein, which may be advantageous for future studies.

Planar two-dimensional (2D) materials are possibly the ideal channel candidates for future field effect transistors (FETs), due to their unique electronic properties. However, the performance of FETs based on 2D materials is yet to exceed those of conventional silicon based devices. Here we present a 2D channel thin film made from liquid phase exfoliated molybdenum oxide nanoflake inks with highly controllable sub-stoichiometric levels. The ability to induce oxygen vacancies by solar light irradiation in an aqueous environment allows the tuning of electronic properties in 2D sub-stoichiometric molybdenum oxides (MoO 3-x ). The highest mobility is found to be ~ 600 cm 2 V −1 s −1 with an estimated free electron concentration of ~ 1.610 21 cm -3 and an optimal I On /I Off ratio of >10 5 for the FETs made of 2D flakes irradiated for 30 min (x = 0.042). These values are significant and represent a real opportunity to realize the next generation of tunable electronic devices using electronic inks.