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The detection of volatile organic compounds (VOCs) in breath has become a potential method for early cancer screening. Although this approach has attracted increasing attention from the both scientific and medical communities, it has not received appreciable traction in the clinical setting. There are two main obstacles. One involves the identification of specific biomarkers or combinations thereof especially in early cancer. The other is the lack the specialized equipment for breath analysis having the appropriate sensitivity and specificity. Using metabolomics, this chapter examines the research strategies involving gas biomarkers in cancer patient breath, cancer cell gas metabolites and synthetic biomarkers. We briefly explore gas biomarkers of seven cancers and introduce principles of detection and clinical application. Large analytical instruments and small sensor technology are highlighted. Challenges to VOC analysis are presented including clinical use, extraction and detection, miniaturization efforts and examination of metabolic VOC pathways. Finally, VOCs in cancer and in exhaled breath detection technology are summarized and future prospects explored., (Copyright © 2024. Published by Elsevier Inc.)

Lamellar nanomaterials with specific architectures and novel properties have received increasing attention from both scientific and technological fields in recent years because of their potential applications in catalysis, energy conversion, and storage devices. Bulk supercluster pellets with well-defined lamellar structures were fabricated by assembling silver clusters and mercaptoalkyl acids (MXA) to investigate the mechanical properties. The relationship between the assembled structure and pressure resistance was surveyed for the first time. The enhanced interlayer interactions were found to increase the elastic modulus of the Ag-MXA supercluster architectures., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A simple method was adopted in which ultrathin cerium oxide nanoplates (<1.4 nm) were synthesized to increase the surface atomic content, allowing transformation from a face-centered cubic (fcc) phase to a body-centered tetragonal (bct) phase. Three types of cerium oxide nanoparticles of different thicknesses (1.2 nm ultrathin nanoplates, 2.2 nm nanoplates, and 5.4 nm nanocubes) were examined using transmission electron microscopy and X-ray diffraction. The metastable bct phase was observed only in ultrathin nanoplates. Thermodynamic energy analysis confirmed that the surface energy of the ultrathin nanoplates is the cause of the remarkable stabilization of the metastable bct phase. The mechanism of surface energy regulation can be expanded to other metallic oxides, thus providing a new means for manipulating and stabilizing novel materials under ambient conditions that otherwise would not be recovered., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Graphene quantum dots (GQDs) have been widely used as fluorescence probes to detect metal ions with satisfactory selectivity. However, the diverse chemical structures of GQDs lead to selectivity for multiple metal ions, and this can lead to trouble in the interpretation of selectivity due to the lack of an in depth and systematic analysis. Herein, bare GQDs were synthesized by oxidizing carbon black with nitric acid and used as fluorescent probes to detect metal ions. We found that the specific ability of GQDs to recognize ferric ions relates to the acidity of the medium. Specifically, we demonstrated that the coordination between GQDs and Fe 3+ is regulated by the pH of the aqueous GQDs solution. Dissociative Fe 3+ can coordinate with the hydroxyl groups on the surface of the GQDs to form aggregates (such as iron hydroxide), which induces fluorescence quenching. A satisfactory selectivity for Fe 3+ ions was achieved under relatively acidic conditions; this is because of the extremely small K sp of ferric hydroxide compared to those of other common metal hydroxides. To directly survey the key parameter for Fe 3+ ion specificity, we performed the detection experiment in an environment free of interference from the buffer solution, noninherent groups, and other complex factors. This study will help researchers understand the selectivity mechanisms of GQDs as fluorescence probes for metal ions, which could guide the design of other GQD-based sensor platforms.

Copper sulfides (Cu 2-x S), are a novel kind of photothermal material exhibiting significant photothermal conversion efficiency, making them very attractive in various energy conversion related devices. Preparing high quality uniform Cu 2-x S nanocrystals (NCs) is a top priority for further energy-and sustainability relevant nanodevices. Here, a shape-controlled high quality Cu 7 S 4 NCs synthesis strategy is reported using sulfur in 1-octadecene as precursor by varying the heating temperature, as well as its forming mechanism. The performance of the Cu 7 S 4 NCs is further explored for light-driven water evaporation without the need of heating the bulk liquid to the boiling point, and the results suggest that as-synthesized highly monodisperse NCs perform higher evaporation rate than polydisperse NCs under the identical morphology. Furthermore, disk-like NCs exhibit higher water evaporation rate than spherical NCs. The water evaporation rate can be further enhanced by assembling the organic phase Cu 7 S 4 NCs into a dense film on the aqueous solution surface. The maximum photothermal conversion efficiency is as high as 77.1%., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)