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Octanethiol (C8-SH) was shaken with an aqueous solution containing Au(III) and/or Ag(I) ions. The C8-SH molecules reacted with the Au(III) ions to form red-luminescent Au thiolates. The addition of...

Silver nanoparticles are known to have strong antibacterial activity and constitute a novel material to treat infectious diseases caused by pathogenic bacteria. The antimicrobial activity of silver...

A PLGA-AgNPL film was fabricated to demonstrate antibiofilm formation activity against Staphylococcus aureus. The film with a PLGA concentration of 25 mg mL−1 with 0.1% silver nanoplates showed promising (94%) reduction of biofilm formation. The PLGA-AgNPL film did not produce many silver ions. The mode of action of the film was hypothesized to be contact killing when bacteria were attached to the surface to commence biofilm formation.

Among the several types of nanoparticles in existence, anisotropic gold-based nanoparticles demonstrate special advantages because of their unique properties. Gold nanoparticles can be prepared and...

Gene transfection can be enhanced by heat treatment. In this study, we examined the enhancement mechanism. Heat treatment before transfection showed higher enhancement than during or after the transfection. The heat treatment enhanced the total uptake of plasmid DNA, and increased caveolar endocytosis. As caveolar endocytosis is advantageous for escaping from lysosomal digestion, the amount of intact DNA may increase, resulting in enhanced gene expression.

Silver nanoparticles are known to have antimicrobial activity. In this study, we investigated the effect of silver nanoparticles on biofilms of different human pathogenic bacteria. Silver nanoparti...

Gold nanorods were intravenously injected into tumor-bearing mice. The distribution of gold in tumor-tissue sections was mapped by imaging mass spectrometry (IMS) using a MALDI mass spectrometer. T...

Dendritic poly(L-lysine) polymers were modified with stable nitroxyl radicals through the substrate peptides of a protease specifically expressed in tumors. Cleavage of the peptides by the protease...

A rapid and quantitative measurement of protein kinase activity based on MALDI-TOF-MS was developed. Here, biotinylated substrate peptides with stable isotope labeling were used to enable the rapid...

Laser-induced desorption and ionization (LDI) of gold ions (Aun+: n = 1–3) were observed from gold nanorods in a liver tissue section (thickness: 10 µm). Larger amounts of gold nanorods produced st...

Cationic model peptides containing simple repeats, H-(LARL)3-(LRAL)n-NH2 (n = 0, 1, 2, and 3), were synthesized, and their antibacterial and hemolytic activities were investigated. Antibacterial ac...

H-Arg-Phe-Arg-Pro-Pro-Ile-Arg-(Arg-Pro-Pro-Phe)n-NH2 (n = 2—5 and 7), models of antibacterial bactenecin 5, were synthesized. The CD measurement showed that they took polyproline II-like conformations in neutral lipid vesicles at 25 and 50 °C, and in acidic ones at 25 °C. However, their conformations changed in acidic lipid vesicles at 50 °C. The membrane perturbation activity of the peptides was also found only for acidic lipid vesicles at 50 °C. The perturbation activity increased with increasing in the peptide chain length. All peptides exhibited negligible hemolytic activity for rabbit erythocytes, whereas they, except for the shortest peptide, had moderate or strong antibacterial activity against Gram-positive and Gram-negative bacteria. Together with the previous results, the N-terminal cationic portion and a certain peptide chain length were found to be important for antibacterial activity.

The 24-peptide 46, designed to take an amphiphilic α-helix structure, had strong activity toward phospholipid membranes and could form ion-channels selective for cations on a planar membrane [J. Biol. Chem., 266, 20218 (1991)]. Four, six, and eight segments of the peptide 46 were bundled (4α-46, 6α-46, and 8α-46) on dendrimers consisting of Lys residues. These bundled peptides had highly α-helical structures with an enhanced α-helicity compared with the original 46 peptide. These peptides had hydrophobic pockets inside the bundle structures in aqueous solution in which the fluorescent hydrophobic probe, 1-anilino-8-naphthalenesulfonate (ANS), bound strongly. The peptides caused much leakage of carboxyfluorescein from small unilamellar vesicles of phospholipids at much lower concentrations of peptides than 46 did. Furthermore, the peptides induced the vesicle fusion at lower concentrations than those of the leakage. Four segments of the analogous 24-peptide 46S, in which six Ser residues were introduced in...

A plasmid DNA and gold nanorods were directly injected to tumor in mice, and the tumor was heated to 39–42 °C through the photothermal effect of the gold nanorods. The heat treatment enhanced trans...

Gold nanorods were modified with two types of double-stranded DNAs (dsDNA) with different melting temperatures. Irradiated by near-infrared laser light, the modified gold nanorods were heated, and ...

A synthetic peptide, Td3717, showed selective affinity for anionic phospholipids, phosphatidylserine and phosphatidylglycerol, and formed an amphiphilic α-helical structure. This specificity origin...

A novel cationic oligopeptide has been developed for bioprocessing-triggered nonviral gene delivery systems. Intracellular fragmentation of the carrier in response to endogenous enzyme, furin, led ...

Pulsed-laser irradiation induced release of modified PEG chains on gold nanorods. A maximum release efficiency of 65% is obtained. The efficient release was occurred by combination of cleavage of A...

Plasmid DNA adsorbed onto a glass surface could be transferred into cells by pressing the glass onto the cells, and the gene encoded in the DNA was expressed in the cells. This novel transfection t...

Near-infrared pulsed-laser irradiation of silica-coated gold nanorods loaded with single-stranded oligonucleotides induced the release of the oligonucleotides without changing the morphology of the...

Pulsed-laser irradiation induced the release of plasmid DNA from conjugates of DNA and gold nanorods (GNRs). Gel electrophoresis indicated that 1% of the plasmid DNA conjugated with GNRs was releas...

The temperature-responsive poly(dehydroalanine derivative)s having two substituents at the α-position were successfully synthesized. By varying the combination of the structures of the two substitu...

Pulsed near-infrared (near-IR) laser irradiation damaged cultured cells in the presence of phosphatidylcholine-passivated gold nanorods (PC-NRs). When single cells were irradiated with a focused pu...

A protected peptide containing phosphoserine was successfully synthesized by the solid-phase method using the oxime resin. The protected phosphopeptide was utilized to further elongation to a longer peptide and conjugation to a template molecule.

Peptides were efficiently synthesized by the catalysis of chemically engineered protease, thiolsubtilisin, with peptide thioesters as substrate building blocks. The ligation method was successfully...