Selective Discrimination of Toxic Polycyclic Aromatic Hydrocarbons in Water by Targeting π-Stacking Interactions

Synthetic Nanoarchitectonics of Functional Organic-Inorganic 2D Germanane Heterostructures via Click Chemistry

Succeeding graphene, 2D inorganic materials made of reactive van der Waals layers, like 2D germanane (2D-Ge) derivatives, have attracted great attention because their physicochemical characteristics can be entirely tuned by modulating the nature of the surface substituent. Although very interesting from a scientific point of view, almost all the reported works involving 2D-Ge derivatives are focused on computational studies. Herein, a first prototype of organic-inorganic 2D-Ge heterostructure has been synthesized by covalently anchoring thiol-rich carbon dots (CD-SH) onto 2D allyl germanane (2D-aGe) via a simple and green "one-pot" click chemistry approach. Remarkably, the implanted characteristics of the carbon nanomaterial provide new physicochemical features to the resulting 0D/2D heterostructure, making possible its implementation in yet unexplored optoelectronic tasks-e.g., as a fluorescence resonance energy transfer (FRET) sensing system triggered by supramolecular π-π interactions-that are inaccessible for the pristine 2D-aGe counterpart. Consequently, this work builds a foundation toward the robust achievement of functional organic-inorganic 2D-Ge nanoarchitectonics through covalently assembling thiol-rich carbon nanoallotropes on commercially available 2D-aGe.

MoS2 Defect Healing for High-Performance Chemical Sensing of Polycyclic Aromatic Hydrocarbons

The increasing population and industrial development are responsible for environmental pollution. Among toxic chemicals, polycyclic aromatic hydrocarbons (PAHs) are highly carcinogenic contaminants resulting from the incomplete combustion of organic materials. Two-dimensional materials, such as transition metal dichalcogenides (TMDCs), are ideal sensory scaffolds, combining high surface-to-volume ratio with physical and chemical properties that are strongly susceptible to environmental changes. TMDCs can be integrated in field-effect transistors (FETs), which can operate as high-performance chemical detectors of (non)covalent interaction with small molecules. Here, we have developed MoS₂-based FETs as platforms for PAHs sensing, relying on the affinity of the planar polyaromatic molecules for the basal plane of MoS₂ and the structural defects in its lattice. X-ray photoelectron spectroscopy analysis, photoluminescence measurements, and transfer characteristics showed a notable reduction in the defectiveness of MoS₂ and a p-type doping upon exposure to PAHs solutions, with a magnitude determined by the correlation between the ionization energies (E_I) of the PAH and that of MoS₂. Naphthalene, endowed with the higher E_I among the studied PAHs, exhibited the highest output. We observed a log-log correlation between MoS₂ doping and naphthalene concentration in water in a wide range (10^-9-10^-6 M), as well as a reversible response to the analyte. Naphthalene concentrations as low as 0.128 ppb were detected, being below the limits imposed by health regulations for drinking water. Furthermore, our MoS₂ devices can reversibly detect vapors of naphthalene with both an electrical and optical readout, confirming that our architecture could operate as a dual sensing platform.

Methodological Approaches for Monitoring Five Major Food Safety Hazards Affecting Food Production in the Galicia-Northern Portugal Euroregion

The agri-food industry has historically determined the socioeconomic characteristics of Galicia and Northern Portugal, and it was recently identified as an area for collaboration in the Euroregion. In particular, there is a need for action to help to ensure the provision of safe and healthy foods by taking advantage of key enabling technologies. The goals of the FOODSENS project are aligned with this major objective, specifically with the development of biosensors able to monitor hazards relevant to the safety of food produced in the Euroregion. The present review addresses the state of the art of analytical methodologies and techniques-whether commercially available or in various stages of development-for monitoring food hazards, such as harmful algal blooms, mycotoxins, Listeria monocytogenes, allergens, and polycyclic aromatic hydrocarbons. We discuss the pros and cons of these methodologies and techniques and address lines of research for point-of-care detection. Accordingly, the development of miniaturized automated monitoring strategies is considered a priority in terms of health and economic interest, with a significant impact in several areas, such as food safety, water quality, pollution control, and public health. Finally, we present potential market opportunities that could result from the availability of rapid and reliable commercial methodologies.

3D-Printed COVID-19 immunosensors with electronic readout

3D printing technology has brought light in the fight against the COVID-19 global pandemic event through the decentralized and on-demand manufacture of different personal protective equipment and medical devices. Nonetheless, since this technology is still in an early stage, the use of 3D-printed electronic devices for antigen test developments is almost an unexplored field. Herein, a robust and general bottom-up biofunctionalization approach via surface engineering is reported aiming at providing the bases for the fabrication of the first 3D-printed COVID-19 immunosensor prototype with electronic readout. The 3D-printed COVID-19 immunosensor was constructed by covalently anchoring the COVID-19 recombinant protein on a 3D-printed graphene-based nanocomposite electrode surface. The electrical readout relies on impedimetrically monitoring changes at the electrode/electrolyte interface after interacting with the monoclonal COVID-19 antibody via competitive assay, fact that hinders the redox conversion of a benchmark redox marker. Overall, the developed 3D-printed system exhibits promising electroanalytical capabilities in both buffered and human serum samples, displaying an excellent linear response with a detection limit at trace levels (0.5 ± 0.1 μg·mL^-1). Such achievements demonstrate advantage of light-of-speed distribution of 3D printing datafiles with localized point-of-care low-cost printing and bioelectronic devices to help contain the spread of emerging infectious diseases such as COVID-19. This technology is applicable to any post-COVID-19 SARS diseases.