title: Anisotropic organization and microscopic manipulation of self-assembling synthetic porphyrin microrods that mimic chlorosomes: bacterial light-harvesting systems.
abstract: Being able to control in time and space the positioning, orientation, movement, and sense of rotation of nano- to microscale objects is currently an active research area in nanoscience, having diverse nanotechnological applications. In this paper, we demonstrate unprecedented control and maneuvering of rod-shaped or tubular nanostructures with high aspect ratios which are formed by self-assembling synthetic porphyrins. The self-assembly algorithm, encoded by appended chemical-recognition groups on the periphery of these porphyrins, is the same as the one operating for chlorosomal bacteriochlorophylls (BChl's). Chlorosomes, rod-shaped organelles with relatively long-range molecular order, are the most efficient naturally occurring light-harvesting systems. They are used by green photosynthetic bacteria to trap visible and infrared light of minute intensities even at great depths, e.g., 100 m below water surface or in volcanic vents in the absence of solar radiation. In contrast to most other natural light-harvesting systems, the chlorosomal antennae are devoid of a protein scaffold to orient the BChl's; thus, they are an attractive goal for mimicry by synthetic chemists, who are able to engineer more robust chromophores to self-assemble. Functional devices with environmentally friendly chromophores-which should be able to act as photosensitizers within hybrid solar cells, leading to high photon-to-current conversion efficiencies even under low illumination conditions-have yet to be fabricated. The orderly manner in which the BChl's and their synthetic counterparts self-assemble imparts strong diamagnetic and optical anisotropies and flow/shear characteristics to their nanostructured assemblies, allowing them to be manipulated by electrical, magnetic, or tribomechanical forces.
authors.affiliation: ISM2-Chirosciences, Faculté des Sciences, Aix-Marseille Univ. UMR 6263, Saint-Jérôme, Case A62, Avenue Escadrille Normandie-Niemen, F-13397 Marseille, Cedex 20, France.
authors.forename: Cyril
authors.initials: C
authors.lastname: Chappaz-Gillot
authors.forename: Peter L
authors.initials: PL
authors.lastname: Marek
authors.forename: Bruno J
authors.initials: BJ
authors.lastname: Blaive
authors.forename: Gabriel
authors.initials: G
authors.lastname: Canard
authors.forename: Jochen
authors.initials: J
authors.lastname: Bürck
authors.forename: Gyozo
authors.initials: G
authors.lastname: Garab
authors.forename: Horst
authors.initials: H
authors.lastname: Hahn
authors.forename: Tamás
authors.initials: T
authors.lastname: Jávorfi
authors.forename: Loránd
authors.initials: L
authors.lastname: Kelemen
authors.forename: Ralph
authors.initials: R
authors.lastname: Krupke
authors.forename: Dennis
authors.initials: D
authors.lastname: Mössinger
authors.forename: Pál
authors.initials: P
authors.lastname: Ormos
authors.forename: Chilla Malla
authors.initials: CM
authors.lastname: Reddy
authors.forename: Christian
authors.initials: C
authors.lastname: Roussel
authors.forename: Gábor
authors.initials: G
authors.lastname: Steinbach
authors.forename: Milán
authors.initials: M
authors.lastname: Szabó
authors.forename: Anne S
authors.initials: AS
authors.lastname: Ulrich
authors.forename: Nicolas
authors.initials: N
authors.lastname: Vanthuyne
authors.forename: Aravind
authors.initials: A
authors.lastname: Vijayaraghavan
authors.forename: Anita
authors.initials: A
authors.lastname: Zupcanova
authors.forename: Teodor Silviu
authors.initials: TS
authors.lastname: Balaban
mesh_terms: D016880:Anisotropy; D001429:Bacteriochlorophylls / Q000737:chemistry; D002942:Circular Dichroism; D045342:Light-Harvesting Protein Complexes / Q000138:chemical synthesis*; D008567:Membranes, Artificial; D008855:Microscopy, Electron, Scanning; D008958:Models, Molecular; D015394:Molecular Structure; D011166:Porphyrins / Q000138:chemical synthesis*
chemical_list: D001429:Bacteriochlorophylls; D045342:Light-Harvesting Protein Complexes; D008567:Membranes, Artificial; D011166:Porphyrins