Wearable pressure sensors have been attracting great attention for a variety of practical applications, including electronic skin, smart textiles, and healthcare devices. However, it is still challenging to realize wearable pressure sensors with sufficient sensitivity and low hysteresis under small mechanical stimuli. Herein, we introduce simple, cost-effective, and sensitive capacitive pressure sensor based on porous Ecoflex-multiwalled carbon nanotube composite (PEMC) structures, which leads to enhancing the sensitivity (6.42 and 1.72 kPa–1 in a range of 0–2 and 2–10 kPa, respectively) due to a synergetic effect of the porous elastomer and percolation of carbon nanotube fillers. The PEMC structure shows excellent mechanical deformability and compliance for an effective integration with practical wearable devices. Also, the PEMC-based pressure sensor shows not only the long-term stability, low-hysteresis, and fast response under dynamic loading but also the high robustness against temperature and humidity changes. Finally, we demonstrate a prosthetic robot finger integrated with a PEMC-based pressure sensor and an actuator as well as a healthcare wristband capable of continuously monitoring blood pressure and heart rate.

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Tunable erosion of polymeric materials is an important aspect of tissue engineering for reasons that include cell infiltration, controlled release of therapeutic agents, and ultimately to tissue healing. In general, the biological response to proteinaceous polymeric hydrogels is favorable (e.g., minimal inflammatory response). However, unlike synthetic polymers, achieving tunable erosion with natural materials is a challenge. Keratins are a class of intermediate filament proteins that can be obtained from several sources including human hair and have gained increasing levels of use in tissue engineering applications. An important characteristic of keratin proteins is the presence of a large number of cysteine residues. Two classes of keratins with different chemical properties can be obtained by varying the extraction techniques: (1) keratose by oxidative extraction and (2) kerateine by reductive extraction. Cysteine residues of keratose are “capped” by sulfonic acid and are unable to form covalent crosslinks upon hydration, whereas cysteine residues of kerateine remain as sulfhydryl groups and spontaneously form covalent disulfide crosslinks. Here, we describe a straightforward approach to fabricate keratin hydrogels with tunable rates of erosion by mixing keratose and kerateine. SEM imaging and mechanical testing of freeze-dried materials showed similar pore diameters and compressive moduli, respectively, for each keratose-kerateine mixture formulation (~1200 kPa for freeze-dried materials and ~1.5 kPa for hydrogels). However, the elastic modulus (G’) determined by rheology varied in proportion with the keratose-kerateine ratios, as did the rate of hydrogel erosion and the release rate of thiol from the hydrogels. The variation in keratose-kerateine ratios also led to tunable control over release rates of recombinant human insulin-like growth factor 1.

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Scope Black raspberries (BRB) are a rich source of bioactive phytochemicals, including anthocyanins and ellagitannins. These phytochemicals are poorly absorbed and may be transformed by gut microbiota into various metabolites that may impact the colonic mucosa or upon absorption have systemic bioactivity. The objective of this study is to define the impact of a BRB‐containing diet on the colon microbiome in mice and quantify the phytochemical metabolites in the colon contents and circulation. Methods and results Male mice were fed 10% w/w freeze‐dried BRB powder for 6 weeks. The colonic microbiota was evaluated by 16S rRNA gene sequencing. Anthocyanin and ellagitannin metabolites, protocatechuic acid, and urolithins were analyzed by HPLC‐MS/MS. The BRB diet impacted colon mucosal microbial composition with a more robust effect observed on the luminal microflora. BRB‐derived protocatechuic acid and urolithins were quantified in the colon, luminal contents, plasma, liver, and prostate with protocatechuic acid present in higher concentrations compared to urolithins. Conclusion This study highlights the complex interactions between dietary phytochemicals, the host microbiome, and metabolism. It is demonstrated that microbially produced phytochemical metabolites are present in the colon and systemic circulation where they may exert biological activity.