An integrated portable bio-monitoring system based on tough hydrogels for comprehensive detection of physiological activities

Advanced soft ion-conducting hydrogels have been developed rapidly in the integrated portable health monitoring equipment due to their higher sensitivity,sensory traits,tunable conductivity,and stretchability for physiological activities and personal healthcare detection.However,traditional hydrogel conductors are normally susceptible to large deformation and strong mechanical stress,which leads to inferior electro-mechanical stability for real application scenarios.Herein,a strong ionically conductive hydrogel(poly(vinyl alcohol)-boric acid-glycerol/sodium alginate-calcium chloride/electrolyte ions(PBG/SC/EI))was designed by engineering the covalently and ionically crosslinked networks followed by the salting-out effect to further enhance the mechanical strength and ionic conductivity of the hydrogel.Owing to the collective effects of the energy-dissipation mechanism and salting-out effect,the designed PBG/SC/EI with excellent structural integrity and robustness exhibits exceptional mechanical properties(elongation at break for 559.1%and tensile strength of 869.4 kPa)and high ionic conductivity(1.618 S·m^(-1)).As such,the PBG/SC/EI strain sensor features high sensitivity(gauge factor=2.29),which can effectively monitor various kinds of human motions(joint motions,facial micro-expression,faint respiration,and voice recognition).Meanwhile,the hydrogel-based Zn||MnO_(2)battery delivers a high capacity of 267.2 mAh·g^(-1)and a maximal energy density of 356.8 Wh·kg^(-1)associated with good cycle performance of 71.8%capacity retention after 8000 cycles.Additionally,an integrated bio-monitoring system with the sensor and Zn||MnO_(2)battery can accurately identify diverse physiological activities in a real-time and non-invasive way.This work presents a feasible strategy for designing high-performance conductive hydrogels for highly-reliable integrated bio-monitoring systems with excellent practicability.

Could gingko foliage serve as a bio-monitor for organochlorine pesticides in air?

The feasibility of gingko (Gingo Biloba) foliage as a passive bio-monitor for organochlorine pesticides in air was explored. The accumulation patterns of hexachlorocyclohexanes (HCHs), dichlorodiphenyl- trichloroethanes (DDTs) and hexachlorobenzene (HCB) in gingko foliage were similar; the amounts of HCHs, DDTs and HCB increased with foliage growth in spring and decreased thereafter. This accumu-lation pattern is likely related to the growing process of the gingko foliage, which was observed for the first time in our work, giving a piece of evidence for the "bud burst effect" in plants. Compared with those in pine needles in 1980's, the residual levels of HCHs and DDTs have declined obviously in Bei-jing, indicating that the ban on the production and use of organochlorine pesticides (OCPs) in our country is effective; however, the amount of HCB has increased, indicating great progress of chemical industry in Beijing. The analysis for the source of OCPs in the gingko foliage showed that the technical HCHs and DDTs were used largely in history, but were not used in recent years. A little lidane has been used and there was a new input of o,p′-DDT in recent years; dicofol usage may be the main source of o,p′-DDT. Concentrations of HCHs, DDTs and HCB in gingko foliages were similar to those in pine nee-dles in the corresponding period and there is a strong positive correlation between the OCPs concen-tration data obtained from these two kinds of trees. It presents no difference in the accumulation style between these two kinds of trees. The level of OCPs in the gingko foliage reflects the pollution status of OCP in air. The result of this work shows that the gingko foliage can be used as a bio-monitor of OCPs in air.