Three-Dimensional Reconstruction of Halamphora coffeaeformis Frustule from Scanning Electron Micrographs

FRANCISCO NAVARRO; CECILIA POPOVICH; MIGUEL SÁNCHEZ; IGNACIO COSTILLA ; CECILIA GUTIERREZ AYESTA; PATRICIA LEONARDI

Congreso; 17th Interamerican Microscopy Congress; 2019

Microscopy Society of America

 The diatom Halamphoracoffeaeformis represents an alternative feedstock of oils for the biodieselproduction. In addition, its siliceous cell wall (named frustule) presentspossible industrial applications that have not been reported in the literatureyet. Thus, the main objective of this study was to perform a three-dimensionalreconstruction of H. coffeaeformis´ frustule from scanning electronmicrographs, in order to have a study model. For this, the biomass of thespecies growing in a photobioreactor was harvested and treated as follows: a)some samples were dehydrated and subjected to a critical point; and b) othersamples were treated with H2O2 inorder to analyse the frustule´s ornamental pattern. All samples were metallizedwith gold, using an Argon plasma metal evaporator (Pelco model3) and they wereobserved with a LEO Scanning Electron Microscope, model EVO 40 XVP 2004. Thefrustules were elliptical to lanceolate with protracted ends. Valves presentedconvex dorsal margin and straight ventral margin. Dorsal striae were biseriateand radiate; ventral striae were short, uniseriate, radiate at the center andconvergent at the ends of the valves. The raphe was straight and close to theventral margin. The micrographs were analysed and separated into layers withthe Adobe Photoshop CS6 software. The layers were vectorised with the Inkscapesoftware and loaded and assembled in the Tinkercad software. The final aspectsof the digital model were moulded on the pagehttps://stephaneginier.com/sculptgl/. Finally, 3D printing was done with aCoLiDoTM 3.0 L printer, obtaining a three-dimensional replica representative ofthe H. coffeaeformis´ morphology. This replica will serve as a model forstudies of its frustules related to nanotechnology and /or catalyst support applications.