Aligning Amyloid-Like Fibrils on Nanopatterned Graphite

Amyloid-like fibrils have been obtained upon incubation of a diluted aqueous solution of cytochrome c at neutral pH in the presence of gold nanoparticles. The interaction of the cytochrome c suspension, containing proteins in both the monomeric and fibrillar state, with the freshly cleaved highly ordered pyrolytic graphite (HOPG) surface results in a double process. First, it leads to a nanopatterning of the HOPG surface and, second, it promotes the self-aligning of cytochrome c protofilaments on the nanopatterned HOPG surface

Optical properties of disulfide-functionalized diacetylene self-assembled monolayers on gold: a spectroscopic ellipsometry study

Spectroscopic ellipsometry (SE) has been applied to study the optical properties of thiolate polydiacetylene (PDA) self-assembled monolayers (SAMs) deposited on low-roughness polycrystalline gold. A systematic investigation of methyl-terminated diacetylene (dihexacosa-7,9-diyn disulfide, DS9) SAMs is presented. The results have been compared with experiments on carbazolyl-derivatized diacetylene (14-(9H-9-carbazolyl)tetradeca-10,12-diyn-1-yl-disulfide, CDS9) SAMs and with findings recently obtained on SAMs of alkanethiols. The SE measurements have been complemented with X-ray photoelectron spectroscopy and atomic force microscopy data. The difference between SE spectra measured after and before the monolayer assembly (\uf0b6\uf059= \uf059SAM-\uf059Au and \uf0b6\uf044= \uf044SAM-\uf044Au) showed specific absorptions of the adsorbed molecules, including narrow features in the 500-700 nm wavelength range which have been interpreted as markers of the SAM polymerization state. To our knowledge, these results represent the first unambiguous optical detection of polymer-induced absorptions in the case of diacetylene SAMs. Polymerization mainly occurred in the so-called red phase (absorption peak around 550 nm) on very flat surface regions obtained by flame-annealing the sample. The polymeric phase was stable against moderate UV irradiance. The detection of the blue phase was questionable as specific absorptions (around 640 nm) overlap with an absorption band related to the formation of the S-Au interface

Microtopography of the eye surface of the crab Carcinus maenas:an atomic force microscope study suggesting a possible antifouling potential

Marine biofouling causes problems for technologies based on the sea, including ships, power plants and marine sensors. Several antifouling techniques have been applied to marine sensors, but most of these methodologies are environmentally unfriendly or ineffective. Bioinspiration, seeking guidance from natural solutions, is a promising approach to antifouling. Here, the eye of the green crab Carcinus maenas was regarded as a marine sensor model and its surface characterized by means of atomic force microscopy. Engineered surface micro-and nanotopography is a new mechanism found to limit biofouling, promising an effective solution with much reduced environmental impact. Besides giving a new insight into the morphology of C. maenas eye and its characterization, our study indicates that the eye surface probably has antifouling/fouling-release potential. Furthermore, the topographical features of the surface may influence the wettability properties of the structure and its interaction with organic molecules. Results indicate that the eye surface micro-and nanotopography may lead to bioinspired solutions to antifouling protection