Molecular composition, grafting density and film area affect the swelling-induced Au-S bond breakage.

In previous studies, we reported the first observation of the Au-S bond breakage induced mechanically by the swelling of the surface-tethered weak polyelectrolyte brushes in phosphate buffered saline (PBS), a phenomenon with broad applications in the fields of biosensors and functional surfaces. In this study, three factors, namely the molecular composition, grafting density and film area of the weak polyelectrolyte, carboxylated poly(oligo(ethylene glycol) methacrylate-random-2-hydroxyethyl methacrylate) (poly(OEGMA-r-HEMA)), were studied systematically on how they affected the swelling-induced Au-S bond breakage (ABB). The results showed that, first, the swelling-induced ABB is applicable to a range of molecular compositions and grafting densities; but the critical thickness (Tcritical,dry) varied with both of the two factors.

A proton shelter inspired by the sugar coating of acidophilic archaea.

The acidophilic archaeons are a group of single-celled microorganisms that flourish in hot acid springs (usually pH < 3) but maintain their internal pH near neutral. Although there is a lack of direct evidence, the abundance of sugar modifications on the cell surface has been suggested to provide the acidophiles with protection against proton invasion. In this study, a hydroxyl (OH)-rich polymer brush layer was prepared to mimic the OH-rich sugar coating.

Swelling induced Au-S bond breakage is determined by the molecular composition of surface tethered copolymers-carboxylated poly(OEGMA-r-HEMA).

We developed a novel method to determine the molecular composition of surface tethered carboxylated poly(OEGMA-r-HEMA), which in turn determines the swelling induced Au-S bond breakage (CBB) event. More accurate control over CBB will eventually lead to many applications in mechanochemistry and controlled release.

A quartz crystal microbalance-based molecular ruler for biopolymers.

We developed a quartz crystal microbalance (QCM) based molecular ruler that measures the length of surface immobilized, hydrated biopolymers (DNA and proteins). These biopolymers acted as stakes that solidified surrounding liquid at high frequency vibration in QCM measurements, which led to a simple linear frequency-thickness relation.