Recent progress on biodegradable materials and transient electronics

Transient electronics(or biodegradable electronics)is an emerging technology whose key characteristic is an ability to dissolve,resorb,or physically disappear in physiological environments in a controlled manner.Potential applications include eco-friendly sensors,temporary biomedical implants,and datasecure hardware.Biodegradable electronics built with water-soluble,biocompatible active and passive materials can provide multifunctional operations for diagnostic and therapeutic purposes,such as monitoring intracranial pressure,identifying neural networks,assisting wound healing process,etc.This review summarizes the up-to-date materials strategies,manufacturing schemes,and device layouts for biodegradable electronics,and the outlook is discussed at the end.It is expected that the translation of these materials and technologies into clinical settings could potentially provide vital tools that are beneficial for human healthcare.

Anaerobic biodegradation of PAHs in mangrove sediment with amendment of NaHCO_3

Mangrove sediment is unique in chemical and biological properties. Many of them suffer polycyclic aromatic hydrocarbon（PAH） contamination. However, the study on PAH biological remediation for mangrove sediment is deficient. Enriched PAH-degrading microbial consortium and electron acceptor amendment are considered as two effective measures. Compared to other electron acceptors, the study on CO2, which is used by methanogens, is still seldom. This study investigated the effect of Na HCO3 amendment on the anaerobic biodegradation of four mixed PAHs, namely fluorene（Fl）, phenanthrene（Phe）,fluoranthene（Flua） and pyrene（Pyr）, with or without enriched PAH-degrading microbial consortium in mangrove sediment slurry. The trends of various parameters, including PAH concentrations, microbial population size, electron-transport system activities, electron acceptor and anaerobic gas production were monitored. The results revealed that the inoculation of enriched PAH-degrading consortium had a significant effect with half lives shortened by 7–13 days for 3-ring PAHs and 11–24 days for 4-ring PAHs. While Na HCO3 amendment did not have a significant effect on the biodegradation of PAHs and other parameters, except that CO2 gas in the headspace of experimental flasks was increased.One of the possible reasons is that mangrove sediment contains high concentrations of other electron acceptors which are easier to be utilized by anaerobic bacteria, the other one is that the anaerobes in mangrove sediment can produce enough CO2 gas even without adding Na HCO3.

Comparison of sequential with intimate coupling o photolysis and biodegradation for benzotriazole

Benzotriazole （BTA） is an emerging contaminant that also is a recalcitrant compound. Sequential and intimate coupling of UV-photolysis with biodegradation were investigated for their impacts on BTA removal and mineralization in aerobic batch experiments. Special attention was given to the role of its main photolytic products, which were aminophenol （AP）, formic acid （FA）, maleic acid （MA）, and phenazine （PHZ）. Experiments with sequential coupling showed that BTA biodegradation was accelerated by photolytic pretreatment up to 9 min, but BTA biodegradation was slowed with longer photolysis. FA and MA accelerated BTA biodegradation by being labile electron-donor substrates, but AP and PHZ slowed the rate because of inhibition due to their competition for intracellular electron donor. Because more AP and PHZ accumulated with increasing photolysis time, their inhibitory effects began to dominate with longer photolysis time. Intimately coupling photolysis with biodegradation relieved the inhibition effect, because AP and PHZ were quickly biodegraded and did not accumulate, which accentuated the beneficial effect of FA and MA.