Heat is abundantly available from various sources including solar irradiation, geothermal energy, industrial processes, automobile exhausts, and from the human body and other living beings. However, these heat sources are often overlooked despite their abundance, and their potential applications remain underdeveloped. In recent years, important progress has been made in the development of high-performance thermoelectric materials, which have been extensively studied at medium and high temperatures, but less so at near room temperature. Silver-based chalcogenides have gained much attention as near room temperature thermoelectric materials, and they are anticipated to catalyze tremendous growth in energy harvesting for advancing internet of things appliances, self-powered wearable medical systems, and self-powered wearable intelligent devices. This review encompasses the recent advancements of thermoelectric silver-based chalcogenides including binary and multinary compounds, as well as their hybrids and composites. Emphasis is placed on strategic approaches which improve the value of the figure of merit for better thermoelectric performance at near room temperature via engineering material size, shape, composition, bandgap, etc. This review also describes the potential of thermoelectric materials for applications including self-powering wearable devices created by different approaches. Lastly, the underlying challenges and perspectives on the future development of thermoelectric materials are discussed.

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Purpose Early evaluation of tumor response to thermal ablation therapy can help identify untreated tumor cells and then perform repeated treatment as soon as possible. The purpose of this work was to explore the potential of rhein‐based necrosis‐avid contrast agents (NACAs) for early evaluation of tumor response to microwave ablation (MWA). Methods 3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5‐diphenyl tetrazolium bromide (MTT) assay was performed to test the cytotoxicity of rhein‐based NACAs against HepG2 cells. Rat models of liver MWA were used for investigating the effectiveness of rhein‐based NACAs in imaging the MWA lesion, the optimal time period for post‐MWA MRI examination, and the metabolic behaviors of 68Ga‐labeled rhein‐based NACAs. Rat models of orthotopic liver W256 tumor MWA were used for investigating the time window of rhein‐based NACAs for imaging the MWA lesion, the effectiveness of these NACAs in distinguishing the residual tumor and the MWA lesion, and their feasibility in early evaluating the tumor response to MWA. Results Gadolinium 2,2',2''‐(10‐(2‐((4‐(4,5‐Dihydroxy‐9,10‐dioxo‐9,10‐dihydroanthracene‐2‐carboxamido)butyl)amino)‐2‐oxoethyl)‐1,4,7,10‐tetraazacyclododecane‐1,4,7‐triyl)triacetic acid (GdL2) showed low cytotoxicity and high quality in imaging the MWA region. The optimal time period for post‐MWA MRI examination using GdL2 was 2 to 24 h after the treatment. During 2.5 to 3.5 h postinjection, GdL2 can better visualize the MWA lesion in comparison with gadolinium 2‐[4,7,10‐tris(carboxymethyl)‐1,4,7,10‐tetraazacyclododec‐1‐yl]acetic acid (Gd‐DOTA), and the residual tumor would not be enhanced. The tumor response to MWA as evaluated by using GdL2‐enhanced MRI was consistent with histological examination. Conclusion GdL2 appears to be a promising NACA for the tumor response assessment after thermal ablation therapies.

Integrating magnetic resonance (MR) and photoacoustic (PA) contrast agents into porous nanomaterials is a way favorable for the screening out of potential theranostic nanomedicines. Hollow carbon nanospheres (HCSs) dotted with...