Tumor-derived extracellular vesicles (EVs) present in bodily fluids are emerging liquid biopsy markers for non-invasive cancer diagnosis and treatment monitoring. Because the majority of EVs in circulation are not of tumor origin, it is critical to develop new platforms capable of enriching tumor-derived EVs from the blood. Herein, we introduce a biostructure-inspired NanoVilli Chip, capable of highly efficient and reproducible immunoaffinity capture of tumor-derived EVs from blood plasma samples. Anti-EpCAM-grafted silicon nanowire arrays were engineered to mimic the distinctive structures of intestinal microvilli, dramatically increasing surface area and enhancing tumor-derived EV capture. RNA in the captured EVs can be recovered for downstream molecular analyses by reverse transcription Droplet Digital PCR. We demonstrate that this assay can be applied to monitor the dynamic changes of ROS1 rearrangements and epidermal growth factor receptor T790M mutations that predict treatment responses and disease progression in non-small cell lung cancer patients.

A molecular dynamics simulation of ultrathin gold nanowires for tensile behaviour has been carried out. Ultrathin nanowires, unlike the bulk FCC structure, have a multi-shell helical structure. This work compares the mechanical properties of the 7-1 multi-shell helical structure with those of the FCC structure. The results reveal that the temperature and the strain rate influence the yielding stress. One atom chain was detected before the nanowire broke when the temperature was near absolute zero. At room temperature, severe interaction between atoms caused successive yielding and a cluster of three atoms in cross-section was formed before the nanowire broke.

All-atom molecular dynamics simulations are used to study a single chain of poly(methacrylic acid) in aqueous solutions at various degrees of charge density. Through a combination of analysis on the radial distribution functions of water and snapshots of the equilibrated structure, we observe that local arrangements of water molecules, surrounding the functional groups of COO- and COOH in the chain, behave differently and correlated well to the resulting chain conformation behavior. In general, due to strong attractive interactions between water and charged COO- via the formation of hydrogen bonds, water molecules tend to form shell-like layers around the COO- groups. Furthermore, water molecules often act as a bridging agent between two neighboring COO- groups. These bridged water molecules are observed to stabilize the rodlike chain conformation that the highly charged chain reveals, as they significantly limit torsional and bending degrees of the backbone monomers. In addition, they display different dynamic properties from the bulk water. Both the resulting oxygen and hydrogen spectra are greatly shifted due to the presence of strong H-bonded interactions.

Temperature and size effects on the behavior of nanoscale water molecule clusters are investigated by molecular dynamics simulations. The flexible three-centered (F3C) water potential is used to model the inter-and intramolecular interactions of the water molecule. The differences between the structural properties for the surface region and those for the interior region of the cluster are also investigated. It is found that as the temperature rises, the average number of hydrogen bonds per water molecule decreases, but the ratio of surface water molecules increases. After comparing the water densities in interior regions and the average number of hydrogen bonds in those regions, we find there is no apparent size effect on water molecules in the interior region, whereas the size of the water cluster has a significant influence on the behavior of water molecules at the surface region.

We have studied the mechanism of the waterÀgas shift reaction (WGS, CO + H 2 O f CO 2 + H 2 ) catalyzed by nanosized gold particles by using density functional theory calculations. The molecular structures and adsorbate/ substrate interaction energies of H 2 O/Au 38 , CO/Au 38 , HO/Au 38 , and H/Au 38 configurations were predicted. Several adsorption sites on the Au 38 nanoparticle were considered in this study and characterized as top, bridge, hollow, and hcp sites. A potential energy surface for WGS reaction on the Au 38 nanoparticle has been constructed using the nudged elastic band method. It was found that water dissociation (H 2 O f H + OH) is the rate-limiting step, with an energy barrier of 31.41 kcal/mol. The overall reaction CO + H 2 O + Au 38 f CO 2 + H 2 + Au 38 is exothermic by 16.18 kcal/mol. To gain insights into the high catalytic activity of the gold nanoparticles, the nature of the interaction between adsorbate and substrate is also analyzed by the detailed electronic local density of states.