Hollow mesoporous hetero-NiCo2S4/Co9S8 submicro-spindles were fabricated in high yield, and delivered excellent pseudocapacitance with high energy density and desirable cycling duration at high rates for advanced hybrid supercapacitors.

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Background: Human gut microbiota can provide lifelong health information and even influence mood and behaviour. We currently lack the tools to obtain a microbial sample, directly from the small intestine, without contamination. Methods: Shape memory alloy springs are used in concentric configuration to develop an axial actuator. A novel design of sampling mechanism is fabricated for collecting the sample from the gut. Storage chamber (500 µl) is used to protect the sample from downstream contamination. Results: The developed actuator occupies a small space (5 � Ø5.75 mm) and produces sufficient output force (1.75 N) to operate the sampling mechanism. A noninvasive capsule robot was tested ex vivo on the animal intestine, and it captured an average of 134 µl content which was sufficient for microbiome assessment. Conclusions: Laboratory testing revealed that the collected sample had an amino acid signature indicative of microbiota, mucus and digesta, which provided a proof of concept for the proposed design. K E Y W O R D S capsule robot, GI tract, gut microbiota, intestine, micro robot 1 | INTRODUCTION A significant population of microorganisms (bacteria, archaea and fungi) live inside the gastrointestinal (GI) tract, play a major role in fibre fermentation and the synthesis of short-chain fatty acids, and some nutrients (e.g., vitamins), and are collectively known as microbiota. 1 Human intestinal microbiota consist of 10 13-10 14 microorganisms which can act as biomarkers. 2 The microbiota, present in the GI tract, contain lifelong information on the health of an individual and can assist in early diagnosis of diseases such as cancer, diabetes and obesity. 3-5 Several researchers believe that analysis of microbiota could be helpful in predicting obesity, diabetes and inflammatory bowel disease. 3-6 Microbiota can also help to study the relationship or interaction between nutrition and human health. 3 Given the significance of gut microbiota, it is critical to explore its ecology. Microbiota colonise the mucous layer which covers the columnar epithelium of the GI tract and the digesta within the intestinal lumen. 7 The population of microorganisms (microbiota) inside the intestine has been studied using various methods. The most common samples used as a proxy for intestinal microbiota are fecal samples; however, they do not categorise spatial inhabitants, and it is not possible to localise them. Similarly, they lack temporal information and cannot reciprocate real-time gut environment as they are examined after travelling through the entire GI tract, which exposes the sample to contamination. 8 Some efforts have been made in obtaining samples from the human gut with biopsy; however, it is a tethered method which largely restricts its use to the large intestine. 9,10 Furthermore, tethered methods involve a high risk of gut perforation, bleeding and require sedation, and the procedure is also invasive and unpleasant for a patient in terms of comfort. 10 Most importantly, the sample obtained by biopsy is a tissue s...

In this contribution, a facile two‐step hydrothermal protocol to prepare hierarchical uniform hollow mesoporous NiCo2S4 microdumbbells (NCS‐MDs) for advanced supercapacitors is developed. Physicochemical investigations reveal that the as‐obtained NCS‐MDs with mesoporous channels in nanoshells possess high‐content Co(III) and Ni(III) species, large surface area (≈80 m2 g−1)/pore volume (≈0.12 m3 g−1), and high tap density (≈0.8 g cm−3). When evaluated as an attractive pseudocapacitive electrode, the unique NCS‐MDs with mass loading of 7 mg cm−2 exhibit remarkable gravimetric/volumetric specific capacitances of ≈912 F g−1 (≈729 F cm−3) at 3 A g−1, and even ≈767 F g−1 (≈613 F cm−3) at high current density of 10 A g−1. Additionally, capacitive degradations of ≈13% and ≈18% are observed over 5000 continous cycles at current rates of 6 and 10 A g−1, respectively. Furthermore, a high‐energy‐density hybrid device is fabricated by using hollow NCS‐MDs and biomass‐derived activated carbon as positive and negative electrodes, respectively, and delivers striking energy density of ≈35.4 Wh kg−1 at power density of ≈381.2 W kg−1, and excellent electrochemical stability at various rates over 11 000 consecutive cycles. These fascinating features strongly highlight that the as‐resulted hollow mesoporous NCS‐MDs could be highly anticipated as a promising electrode platform for next‐generation hybrid supercapacitors.