Polyelectrolytes have many important functions in both living organisms and man-made applications. One key property of polyelectrolytes is the ionic conductivity due to their porous networks that allow the transport of water and small molecular solutes. Among polyelectrolytes, zwitterionic polymers have attracted huge attention for applications that involve ion transport in a polyelectrolyte matrix; however, it is still unclear how the functional groups of zwitterionic polymer side chains affect their ion transport and swelling properties. In this study, zwitterionic poly(carboxybetaine acrylamide), poly(2-methacryloyloxyethyl phosphorylcholine), and poly(sulfobetaine methacrylate) hydrogels were synthesized and their ionic conductivity was studied and compared to cationic, anionic, and nonionic hydrogels. The change of the ionic conductivity of zwitterionic and nonionic hydrogels in different saline solutions was investigated in detail. Zwitterionic hydrogels showed much higher ionic conductivity than that of the widely used nonionic poly(ethylene glycol) methyl ether methacrylate hydrogel in all tested solutions. For both cationic and anionic hydrogels, the presence of mobile counterions led to high ionic conductivity in low salt solutions; however, the ionic conductivity of zwitterionic hydrogels surpassed that of cationic and ionic hydrogels in high salt solutions. Cationic and anionic hydrogels showed much higher water content than that of zwitterionic hydrogels in deionized water; however, the cationic hydrogels shrank significantly with increasing saline concentration. This work provides insight into the effects of polyelectrolyte side chains on ion transport. This can guide us in choosing better polyelectrolytes for a broad spectrum of applications, including bioelectronics, neural implants, battery, and so on.

The electrochemical pitting behavior of UNS C11000 copper was investigated in a synthetic potable water found to cause pitting. Tests were also conducted in several other HCO 3 − , SO 4 2− , and Cl − containing waters with systematic variations in concentrations of these species. Studies of the effect of water chemistry on passivity, uniform corrosion, and pitting were accomplished using the cyclic voltammetry method complemented by various diagnostic methods. Certain water chemistry concentrations promote pitting. Critical pitting potentials ͑E Pit ͒ for copper pitting are decreased by certain water chemistry variables. High ͓SO 4 2− ͔/͓OH − ͔, ͓SO 4 2− ͔/͓HCO 3 − ͔, and Cl − /͓HCO 3 − ͔ ratios lower pitting potentials while an increase in alkalinity ͑increasing ͓OH − ͔ or ͓HCO 3 − ͔/͓CO 3 2− ͔͒ improves passivity and raises pitting potentials. HCO 3 − /CO 3 2− can protect copper surfaces by forming carbonate containing minerals. However, carbonated species are less beneficial toward passivity compared to OH − with respect to passivation efficiency. Empirical equations that forecast pitting and repassivation potentials as a function of selected water chemistry variables were developed by linear regression analysis based on experimental pitting and repassivation potential trends with HCO 3 − , Cl − , and SO 4 2− content. The origins of the trends with water chemistry variables are discussed.

A multifunctional zwitterionic PSBEDOT material, which can switch between antifouling and antimicrobial states by controlling the potential of the surface, is synthesized.

Epidemiological and experimental studies have suggested that deregulated hepcidin-ferroportin (FPN) signaling is associated with the increased risk of cancers. However, the effects of deregulated hepcidin-FPN signaling on tumor behaviors such as metastasis and epithelial to mesenchymal transition (EMT) have not been closely investigated. In this study, LL/2 cancer cells were found to exhibit an impaired propensity to home into lungs, and a reduced ability to develop tumors was also demonstrated in lungs of Hamp1 −/− mice. Moreover, hepatic hepcidin deficiency was found to considerably favor tumor-free survival in Hamp1 −/− mice, compared with wild-type mice. These data thus underscored a contributive role of hepatic hepcidin in promoting lung cancer cell homing and fostering tumor progression. To explore the role of FPN in regulating tumor progression, we genetically engineered 4T1 cells with FPN over-expression upon induction by doxycycline. With this cell line, it was discovered that increased FPN expression reduced cell division and colony formation in vitro, without eliciting significant cell death. Analogously, FPN over-expression impeded tumor growth and metastasis to lung and liver in mice. At the molecular level, FPN over-expression was identified to undermine DNA synthesis and cell cycle progression. Importantly, FPN over-expression inhibited EMT, as reflected by the significant decrease of representative EMT markers, such as Snail1, Twist1, ZEB2, and vimentin. Additionally, there was also a reduction of lactate production in cells upon induction of FPN over-expression. Together, our results highlighted a crucial role of the hepcidin-FPN signaling in modulating tumor growth and metastasis, providing new evidence to understand the contribution of this signaling in cancers.