Biomarkers are crucial biological indicators in medical diagnostics and therapy. However, the process of biomarker discovery and validation is hindered by a lack of standardized protocols for analytical studies, storage and sample collection. Wearable chemical sensors provide a real-time, non-invasive alternative to typical laboratory blood analysis, and are an effective tool for exploring novel biomarkers in alternative body fluids, such as sweat, saliva, tears and interstitial fluid. These devices may enable remote at-home personalized health monitoring and substantially reduce the healthcare costs. This Review introduces criteria, strategies and technologies involved in biomarker discovery using wearable chemical sensors. Electrochemical and optical detection techniques are discussed, along with the materials and system-level considerations for wearable chemical sensors. Lastly, this Review describes how the large sets of temporal data collected by wearable sensors, coupled with modern data analysis approaches, would open the door for discovering new biomarkers towards precision medicine.

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The quantum of research in the area of supercapacitors is typically focused on the electrode materials. As such, there are many opportunities for the optimization of the other components, such as the separators, to further increase the power, efficiency, and longevity of supercapacitors. To contribute to this field of research, we present an innovative alternative for the fabrication of separators; using polymer/ceramic composites (PCC) based on polyvinylidene fluoride (PVDF) and polypropylene (PPG) mixed with different alkaline earth metal‐based titanates (eg barium, calcium, and strontium). The PCC separators were prepared via phase inversion precipitation technique, a feasible and scalable method for the fabrication of these composites. Different additives were used to modulate the porosity and thus, improve the charge transfer rates. Then, a heating process ensured a uniform organization of the composites. Furthermore, we tested the effect of thermally annealing the ceramics on the separators’ performance. The precursor materials and the PCC's were extensively characterized by means of X‐ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical, mechanical, and dielectric properties of the PCC's were measured and compared to common commercial separators used today. Results suggest that thermal treatment improves tensile strength of the separators by at least ca. 60% without compromising the similar electrochemical profile to the commercial separators (44.52 ± 2.82 Ω vs 67.65 ± 29.01 Ω). Lastly, all of the fabricated PCC's showed higher dielectric constants (4.52 in average for the as prepared separators and 2.99 for the heated PCC's) than the polymer based commercial separators (2.2).

Polyphenols are natural compounds with strong antioxidant properties synthesized by plants and widely distributed in plant tissues. They compose a broad class of compounds that are commonly employed for multiple applications such as food, pharmaceutical, adhesives, biomedical, agricultural, and industrial purposes. Runoffs from these sources result in the introduction of polyphenols into aquatic environments where they further transform into highly toxic pollutants that can negatively affect aquatic ecosystems and humans. Therefore, the development of extraction and remediation methods for such compounds must be addressed. This study describes the identification and operation of a method to recover polyphenolic compounds from water environments by utilizing membrane-based separation. Composite membranes derived from electrospun cellulose acetate (CA) fibers and diblock copolymer (DiBCP) PEO-b-P4VP were prepared to evaluate the adsorption of polyphenolic compounds from aqueous environments. The highly porous CA fibers were developed using the electrospinning technique, and the fabricated DiBCP/CA membranes were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FT-IR) spectroscopy, and tensile testing. Finally, the ability of the composite membranes to adsorb the soluble polyphenolic compounds catechol (CAT) and gallic acid (GA), from a wetland environment, was studied via batch adsorption experiments and by solid-phase extraction (SPE). Results revealed a successful recovery of both polyphenols, at concentrations within the parts per million (ppm) range, from the aqueous media. This suggests a novel approach to recover these compounds to prevent their transformation into toxic pollutants upon entrance to water environments.

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