by Keyword: Nanotopography

By year:[ 2019 | 2018 | 2017 | 2016 | 2015 | 2014 | 2013 | 2012 | 2011 | 2010 | 2009 | 2008 | 2007 | 2006 | 2005 ]

Fernandez, Javier G., Mills, C. A., Martinez, E., Lopez-Bosque, M. J., Sisquella, X., Errachid, A., Samitier, J., (2008). Micro- and nanostructuring of freestanding, biodegradable, thin sheets of chitosan via soft lithography Journal of Biomedical Materials Research - Part A , 85A, (1), 242-247

A technique for imparting micro- and nano-structured topography into the surface of freestanding thin sheets of chitosan is described. Both micro- and nanometric surface structures have been produced using soft lithography. The soft lithography method, based on solvent evaporation, has allowed structures similar to 60 nm tall and similar to 500 X 500 nm(2) to be produced on freestanding similar to 0.5 mm thick sheets of the polymer when cured at 293 K, and structures similar to 400 nm tall and 5 X 5 mu m(2) to be produced when cured at 283 K. Nonstructured chitosan thin sheets (similar to 200 mu m thick) show excellent optical transmission properties in the visible portion of the electromagnetic spectrum. The structured sheets can be used for applications where optical microscopic analysis is required, such as cell interaction experiments and tissue engineering.

Keywords: Chitin/chitosan, Microstructure, Nanotopography, Polymerization, Soft lithography

Martinez, E., Engel, E., Lopez-Iglesias, C., Mills, C. A., Planell, J. A., Samitier, J., (2008). Focused ion beam/scanning electron microscopy characterization of cell behavior on polymer micro-/nanopatterned substrates: A study of cell-substrate interactions Micron , 39, (2), 111-116

Topographic micro and nanostructures can play an interesting role in cell behaviour when cells are cultured on these kinds of patterned substrates. It is especially relevant to investigate the influence of the nanometric dimensions topographic features on cell morphology, proliferation, migration and differentiation. To this end, some of the most recent fabrication technologies, developed for the microelectronics industry, can be used to produce well-defined micro and nanopatterns on biocompatible polymer substrates. In this work, osteoblast-like cells are grown on poly(methyl methacrylate) substrates patterned by nanoimprint lithography techniques. Examination of the cell-substrate interface can reveal important details about the cell morphology and the distribution of the focal contacts on the substrate surface. For this purpose, a combination of focused ion beam milling and scanning electron microscopy techniques has been used to image the cell-substrate interface. This technique, if applied to samples prepared by freeze-drying methods, allows high-resolution imaging of cross-sections through the cell and the substrate, where the interactions between the nanopatterned substrate, the cell and the extracellular matrix, which are normally hidden by the bulk of the cell, can be studied.

Keywords: Electron microscopy, Interface, Nanotopography, Osteoblast, Adhesion molecule, Cell morphology