title: Optical properties of in-vitro biomineralised silica.
abstract: Silicon is the second most common element on the Earth's crust and its oxide (SiO(2)) the most abundant mineral. Silica and silicates are widely used in medicine and industry as well as in micro- and nano-optics and electronics. However, the fabrication of glass fibres and components requires high temperature and non-physiological conditions, in contrast to biosilica structures in animals and plants. Here, we show for the first time the use of recombinant silicatein-α, the most abundant subunit of sponge proteins catalyzing biosilicification reactions, to direct the formation of optical waveguides in-vitro through soft microlithography. The artificial biosilica fibres mimic the natural sponge spicules, exhibiting refractive index values suitable for confinement of light within waveguides, with optical losses in the range of 5-10 cm(-1), suitable for application in lab-on-chips systems. This method extends biosilicification to the controlled fabrication of optical components by physiological processing conditions, hardly addressed by conventional technologies.
authors.affiliation: National Nanotechnology Laboratory of Istituto Nanoscienze-CNR, Università del Salento, Lecce, Italy. apolini@lbl.gov
authors.forename: Alessandro
authors.initials: A
authors.lastname: Polini
authors.forename: Stefano
authors.initials: S
authors.lastname: Pagliara
authors.forename: Andrea
authors.initials: A
authors.lastname: Camposeo
authors.forename: Roberto
authors.initials: R
authors.lastname: Cingolani
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Wang
authors.forename: Heinz C
authors.initials: HC
authors.lastname: Schröder
authors.forename: Werner E G
authors.initials: WE
authors.lastname: Müller
authors.forename: Dario
authors.initials: D
authors.lastname: Pisignano
mesh_terms: D000818:Animals; D002403:Cathepsins / Q000737:chemistry* / Q000235:genetics; D005336:Fiber Optic Technology; D005898:Glass / Q000737:chemistry; D008958:Models, Molecular; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry*
chemical_list: D011994:Recombinant Proteins; C009753:fiberglass; C112571:silicatein alpha; D002403:Cathepsins