Interfacial Structures and Fibrinogen Adsorption at Blood-Compatible Polymer/Water Interfaces

The interfacial structures of a blood-compatible polymer, poly­(2-methoxyethyl acrylate) (PMEA), and several analogues were investigated by atomic force microscopy (AFM). The blood-compatible polymers exhibited nanometer-scale protrusions that spontaneously and homogeneously formed at polymer/water and polymer/phosphate-buffered saline interfaces. AFM observation also revealed that fibrinogen adsorption occurred locally on the protrusions rather than uniformly at the interface, with the regions adjacent to the protrusions apparently preventing the adsorption of fibrinogen. The formation of these interfacial structures may be due to in-plane microphase separation of polymer and water at the interface

Synthesis of Sequence-Specific Polymers with Amide Side Chains via Regio-/Stereoselective Ring-Opening Metathesis Polymerization of 3‑Substituted <i>cis</i>-Cyclooctene

Highly regio-/stereoregular (<i>trans</i>-head-to-tail) polymers with amide side chains on every eighth backbone carbon were successfully synthesized by ring-opening metathesis polymerization (ROMP) of 3-substituted <i>cis-</i>cyclooctene (3RCOE) using Grubbs second-generation catalyst (<b>G2</b>). Regioregular linear ethylene–acrylamide copolymers were also prepared via hydrogenation of the obtained poly­(3RCOE)­s. The thermal properties and solubility of the obtained polymers were strongly influenced by the presence of amide hydrogen in the side chains, the presence of unsaturated bonds in the carbon backbone, and the side chain density. The presence of amide hydrogen in the side chains resulted in the formation of crystalline polymers and the lack of solubility of these polymers in common organic solvents. In contrast, the absence of amide hydrogen in the side chains led to the formation of amorphous polymers exhibiting good solubility in common organic solvents, and decreasing values of <i>T</i>_g were observed for amorphous polymers as a result of the saturation of double bonds in the backbone via hydrogenation

Location of post-tsunami visual censuses.

<p>(A) Map of the Japanese archipelago showing major ocean currents (blue arrows), locations of the survey sites (asterisks), and earthquake epicenter (double circle). <i>Pb</i>, <i>Pm</i>, and <i>Pr</i>, respectively, represent the previously recorded northern distribution limits of <i>Parupeneus barberinus</i>, <i>Parupeneus multifasciatus</i>, and <i>Plagiotremus rhinorhynchos</i> in the Pacific Ocean and the Sea of Japan according to Nakabo [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0168261#pone.0168261.ref023" target="_blank">23</a>]. <i>P</i>. <i>barberinus</i> has never been reported in the Sea of Japan. (B) Magnified map of the survey area. (C) Four survey stations in and around the Moune Bay, Kesennuma, Miyagi Prefecture.</p

Poly(ω-methoxyalkyl acrylate)s: Nonthrombogenic Polymer Family with Tunable Protein Adsorption

A series of polyacrylates with different <i>n</i>-alkyl side chain lengths (1 to 6, and 12 carbons) and a ω-methoxy terminal group (poly­(ω-methoxyalkyl acrylate): PMC<i>x</i>A) were prepared to study their nonthrombogenicity using human platelet adhesion, micro bicinchoninic acid (micro BCA) protein assay, and enzyme-linked immunosorbent assay (ELISA) tests. In all cases, human platelet adhesion was suppressed on the PMC<i>x</i>A-coated substrates, and the number of human platelets adhered to the PMC3A (poly­(3-methoxypropyl acrylate))-coated surface was comparable to that of commercialized nonthrombogenic coating agent poly­(2-methoxyethyl acrylate) (PMEA, equal to PMC2A). The amount of protein adsorbed onto the PMC<i>x</i>A was investigated by micro BCA using bovine serum albumin (BSA) and human fibrinogen (hFbn), revealing that PMC3A exhibited significantly high resistance to nonspecific BSA adsorption. Additionally, the amount of hFbn adsorbed onto the PMC3A was suppressed to the same extent as PMEA. The exposure degree of platelet adhesion sites in adsorbed hFbn was evaluated using an ELISA test, and the degree on the PMC<i>x</i>A with three to six methylene carbons was comparable to the PMEA. The hydration water structure in the hydrated PMC<i>x</i>A was also characterized using differential scanning calorimetry (DSC). The amount of intermediate water, which is the hydration water molecules that moderately interact with the polymer matrix, was maximum in the PMEA with two methylene run lengths, whereas the amount decreased by increasing the number of methyelnes in the side chain. The amount of adsorbed protein increased with a decrease in the amount of intermediate water, suggesting that the protein adsorption amount is tunable by simply changing the number of methylene carbons in the side chain. The present study revealed that poly­(ω-methoxyalkyl acrylate)­s are useful for blood-contacting medical devices, and PMC3A is the best mode of PMC<i>x</i>A to apply as an antiprotein adsorption coating agent

(A) Seafloor temperature, (B) fish abundance, (C) species richness, (D) fish biomass, and (E) center of distribution in the northern hemisphere of coastal fauna in the Nishi-Moune Bay in the first five years following the 2011 tsunami.

<p>Different letters indicate significant differences (<i>p</i> < 0.05) among years. Significantly different stations (st.) are underscored by different horizontal lines in the legend in each figure.</p

Thermosensitive Polymer Biocompatibility Based on Interfacial Structure at Biointerface

The interfacial structure of a thermosensitive biocompatible polymer, poly­[2-(2-methoxyethoxy)­ethyl methacrylate] (PMe2MA), at the polymer/phosphate-buffered saline (PBS) interface was investigated by atomic force microscopy. A number of nanometer scale protrusions appeared at 37 °C and disappeared at 22 °C, reversibly. This structural change occurred above the lower critical solution temperature of PMe2MA in PBS (19 °C), indicating that the formation of protrusions was explained by the microphase separation of polymer and water at the interfacial region. The protein adsorption and platelet adhesion onto PMe2MA interface were drastically restrained at 22 °C compared to that at 37 °C. Detachment of NIH3T3 cells accompanied by the dissipation of protrusions on the PMe2MA interface was also demonstrated. These results indicate that the protrusions act as the scaffold for the protein adsorption and cell adhesion

nMDS ordination plot depicting Bray-Curtis similarities of total annual biomass for each fish species observed in surveys in the Nishi-Moune Bay in the first five years post-tsunami.

<p>Each plot represents a station (st.) and year, e.g., 1_5 represents the data for St. 1 in the fifth year. The stress level was 0.14. The community structure continued to change for the entire study period at st. 1, whereas major shifts in fish communities were observed from the first to the second year only at stations 2–4.</p

Average number of individuals across four locations in the Nishi-Moune Bay of major fish and invertebrate species over the first five years after the 2011 tsunami.

<p>(A) Banded goby, <i>Pterogobius elapoides</i>, (B) beauty goby, <i>Pterogobius zacalles</i>, (C) striped sandgoby, <i>Acentrogobius virgatulus</i>, (D) sevenspine goby, <i>Gymnogobius heptacanthus</i>, (E) surfperch, <i>Neoditrema ransonnetii</i>, (F) black rockfish, <i>Sebastes cheni</i>, (G) sunrise sculpin, <i>Pseudoblennius cottoides</i>, (H) greenling, <i>Hexagrammos otakii</i>, (I) moon jellyfish, <i>Aurelia</i> sp., (J) sea cucumber, <i>Apostichopus japonicus</i>, and (K) abalone, <i>Haliotis discus hannai</i>. Different symbols and colors correspond to stations shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0168261#pone.0168261.g001" target="_blank">Fig 1</a>. Different letters indicate significant differences among years.</p

Maximum depth (m), substrate, and vegetation characteristics of each station surveyed in the first five years after the 2011 tsunami.

<p>Maximum depth (m), substrate, and vegetation characteristics of each station surveyed in the first five years after the 2011 tsunami.</p

Body length of (A) sea cucumber, <i>Apostichopus japonicus</i>, and (B) abalone, <i>Haliotis discus hannai</i>, recorded in each survey across four sites in the Nishi-Moune Bay in the first five years after the 2011 tsunami.

<p>Raw data (open circles: all stations combined) and mean ± SD for each survey date (solid squares: only calculated when three or more data points were available) are shown. Different letters indicate significant differences among years at <i>p</i> < 0.05.</p