Preparation and characterization of glycopolymers with biphenyl spacers via Suzuki coupling reaction.

Poly(vinylbiphenyl)s bearing glycoside ligands at the side chains were prepared using the Suzuku coupling reaction. Effects of glycoside reactant concentration, halide species, glycoside species, and catalyst species on the incorporation of glycoside ligand into the polymer were investigated. The obtained glycopolymers exhibited specific binding to proteins corresponding to the glycoside ligands. In addition, the biphenyl spacers formed by the Suzuki coupling reaction in the glycopolymer were fluorescent, whereas the polymer precursor was not.

Formation of glyco-functionalized interfaces for protein binding using polyphenolic glycoside.

In this study, a polyphenolic glycoside (α-glucosyl rutin) was used to form glyco-functionalized interfaces for protein binding. α-Glucosyl rutin was coated onto precious metals, metal oxides, and synthetic polymers, including polyethylene and polytetrafluoroethylene with poor surface modifiability. The glyco-functionalized interfaces bound strongly and specifically to concanavalin A and Bauhinia purpurea lectin, which have different carbohydrate specificities. Competitive adsorption tests demonstrated that the binding sites for the abovementioned lectins were glucosyl and rhamnosyl residues, respectively. The glyco-functionalized interfaces maintained the protein binding ability after being stored in aqueous solution for 1 day and in air for 160 days. Once the glyco-functionalized interfaces were formed on gold, silicon dioxide, polystyrene, and polytetrafluoroethylene using α-glucosyl rutin, all the glyco-functionalized interfaces bound to concanavalin A rather than peanut agglutinin.

Effect of interfacial serum proteins on the cell membrane disruption induced by amorphous silica nanoparticles in erythrocytes, lymphocytes, malignant melanocytes, and macrophages.

It is very important to examine carefully the potential adverse effects of engineered nanoparticles (NPs) on human health and environments. In the present study, we have investigated the impact of interfacial serum proteins on the cell membrane disruption induced by silica NPs of primary diameter of 55-68 nm in four types of cells (erythrocytes, Jurkat, B16F10, and J774.1). The silica-induced membranolysis was repressed by addition of 1-2% serum into culture media, where the adhesion amount of the FBS-coated silica NPs onto a cell surface seemed comparable with that of the bare silica NPs. The nonspecific attraction between the bare silica and J774.1 cell membrane surfaces was masked by pretreatment of the silica surface with serum albumin, whereas the serum proteins-coated silica surface exhibited the attractive interactions with the cell membrane due to specific binding between some of adsorbed proteins thereon and the membrane receptors. The difference in silica-cell interaction between the nonspecific and specific attractions would explain the reason why interfacial serum proteins reduced the membranolysis without prevention of silica NPs adhering to cell surfaces.

Amplification of Sensor Signals from Metal Mesh Device with Fine Periodic Structure.

Two types of metal mesh devices with hole diameters of 1.7 and 0.3 µm were prepared by an electroforming method. The metal mesh devices with hole diameters of 1.7 and 0.3 µm transmitted electromagnetic waves with frequencies of approximately 100 and 285 THz, respectively. These spectral frequencies shifted depending on the adsorption amount of protein. The slope in the linear relationship between the adsorption amount and spectral shift (i.e. sensitivity) of the metal mesh device with a hole diameter of 0.3 µm was seven times as great as that of the device with a hole diameter of 1.7 µm. These results agreed with the theoretical concept of the sensitivity for the metal mesh device sensor being proportional to the square of the transmittance frequency. As biosensors, the structurally refined metal mesh devices amplified the output signals.