Self-healing, ultra-stretchable, and highly sensitive conductive hydrogel reinforced by sulfate polysaccharide from Enteromorpha prolifera for human motion sensing.

The synthesis of multifunctional conductive hydrogel has attracted extensive attention worldwide due to their integrated properties of stretchability, self-adhesion, self-healing, and high sensitivity, while it is still a challenge. Although various kinds of polysaccharides and their derivatives are used to achieve the aforementioned objective, there are few researches about hydrogel design introducing sulfated polysaccharide from Enteromorpha prolifera (SPE), which is rich in hydroxyl, sulfate, and carboxyl groups providing amounts of reaction sites for hydrogel synthesis. Herein, conductive hydrogel (PAA-Al3+-SPE3) reinforced by SPE was designed by simple one pot hot polymerization method. This hydrogel demonstrated charming extension ratio (up to 4027.40 %), strain stress (up to 59.94 kPa), compressive strength (19.71 Mpa), and high conductivity sensibility (GF 6.76, 300 % - 700 %). Additionally, PAA-Al3+-SPE3 showed good self-healing property (repaired autonomously after 60 s) and satisfied self-adhesion (31.11 kPa) due to the reversible hydrogen bonds and metal coordination interactions. Furthermore, the PAA-Al3+-SPE3 hydrogel showed great real-time sensing performance to monitor various motions. These findings suggest the potential of PAA-Al3+-SPE3 hydrogel as an affordable and reliable conductive sensing material. Meantime, the first utilization of SPE to construct flexible wearable sensors offers new route for the high-value application of Enteromorpha prolifera.

Response surface methodology optimization and HPLC-ESI-QTOF-MS/MS analysis on ultrasonic-assisted extraction of phenolic compounds from okra (Abelmoschus esculentus) and their antioxidant activity.

Okra (Abelmoschus esculentus) has attracted a growing attention for its nutritional and medicinal values, while few studies focused on systemic study of okra polyphenols (OP). In order to obtain the maximum extracted efficiency, response surface methodology was used to optimize ultrasonic-assisted extraction conditions. The maximum TPC was 7.02 mg GAE/g dw under the condition of solid-liquid ratio 1:25, ethanol concentration 70 %, 40 min, and 142 W at 46 °C. Then 27 compounds in OP were identified by HPLC-ESI-QTOF-MS/MS, among which 7-hydroxycoumarin, scopoletin, luteolin and et al were firstly identified from okra. Furthermore, OP exhibited antioxidant activity in reducing power (FRAP, 9.77 mM Fe2+/g OP) and radical scavenging (DPPH, IC50 19.31 µg/mL; SARC, IC50 210.81 µg/ml). Moreover, OP significantly inhibited cell apoptosis and ROS generation, and alleviated oxidative damage in t-BHP induced HUVECs. Overall, our findings could provide perspective for further potential employments of okra as functional food.

Adsorption behavior and mechanism of Lead (Pb2+) by sulfate polysaccharide from Enteromorpha prolifera.

Lead (Pb2+) pollution poses severe healthy and ecological risks to humans. In this work, sulfate polysaccharide from Enteromorpha prolifera (SPE) was utilized for Pb2+ adsorption from simulated intestinal fluid. In order to evaluate its adsorption behaviors comprehensively, batch adsorption of Pb2+ was investigated under different conditions. Results showed that SPE presents high adsorption ability for Pb2+ through chemical adsorption process and the maximum adsorption capacity for Pb2+ was 278.5 mg/g. And SPE exhibited higher removal efficiency (≥60%) for trace Pb2+ (<10 mg/L) compared to that of other adsorbents based on polysaccharide. Besides, its adsorption can be described by Langmuir isotherm and pseudo-second-order kinetic models. Further, XRD, FTIR, and XPS were used to characterize the possible interaction of Pb2+ with SPE, and the results showed that carboxyl and hydroxyl groups in SPE play more important role than that of sulfate group. Our work represents the first assessment of Pb2+ adsorption properties of SPE. This investigation highlights the potential application of SPE to protect the body from hazard of food-derived heavy metals.