A new method for the preparation of biocompatible silica coated-collagen hydrogels Maria Lucia Foglia, * a Daniela Edhit Camporotondi, a Gisela Solange Alvarez, a Sascha Heinemann, b Thomas Hanke, b Claudio Javier Perez, c Luis Eduardo Diaz a and Martin Federico Desimone * a Silica–collagen scaffolds were obtained by covalent binding of an aminosilane to glutaraldehyde fixed collagen hydrogels, rendering a three dimensional network of silicon coated collagen fibrils. When compared to non-silicified collagen, silica containing matrices exhibited a 60 fold increment in the rheological properties. Moreover, acellular degradation by collagenase type I indicated that enzymatic digestion occurred at a slower rate for silica modified hydrogels, hence enabling a controlled degradation of the obtained material. In addition, fibroblastic cells seeded on silicified collagen matrices were able to adhere, proliferate and migrate within the scaffold for over 3 weeks as shown by MTT tests and hematoxylin–eosin staining. These results suggest that the herein described method could be useful in the design of materials for tissue engineering purposes. 1. Introduction The interest in new biomaterials has risen during the past years due to the necessity to ll tissue loss areas caused by trauma or surgical extraction. In the eld of tissue engineering, one of the main challenges is to design materials with improved mechanical and biocompatible properties capable of promoting tissue regeneration and/or wound healing. 1 Currently, research involving a combination of molecular biology and mechanical engineering focuses on the interaction between stromal cells and biopolymer interfaces. 2 For this purpose, a number of biodegradable and bio- resorbable materials, as well as scaffold designs, have been experimentally and/or clinically studied. Ideally, a scaffold should present the following characteristics: (i) a three-dimen- sional and highly porous interconnected network for cell growth and transport of nutrients and metabolic products; (ii) must be biocompatible and bioresorbable with controllable degradation and resorption rates to match cell/tissue growth in vitro and/or in vivo; (iii) a suitable surface chemistry for cell attachment, proliferation, and differentiation and (iv) mechanical properties to match those of the tissue at the site of implantation. 3 Hence, a variety of synthetic and naturally derived materials could be potentially used to form hydrogels suitable for tissue engineering applications. Synthetic materials include poly(ethylene oxide) (PEO), poly(vinyl alcohol) (PVA), poly(acrylic acid) (PAA), poly(propylene furmarate-co-ethylene glycol) (P(PF-co-EG)), and polypeptides. Representative naturally derived polymers include agarose, alginate, chitosan, collagen, brin, gelatin, and hyaluronic acid (HA). 4 Among naturally derived polymers, collagen is attractive for biomedical applications as it is the most abundant protein in mammalian tissues and the main constituent of the extracel- lular matrix. 5 Therefore, the use of type I collagen in the prep- aration of materials for medical purposes has been favored because it provides a natural anchoring moiety for attachment and survival of the cells, 6 it is highly biocompatible and can be tailored into highly porous implantable devices. However, its lack of mechanical stability has stimulated its use in combi- nation with other compounds, especially for load bearing applications. 7 As an example, Hong et al. mixed polycaprolactone (PCL), type I collagen, and b-tricalcium phosphate resulting in biocompatible microsized porous scaf- folds. 8 Similarly, Ahn et al. constructed hybrid materials con- sisting of solid freeform-fabricated PCL and collagen struts with appropriate pore interconnectivity for bone regeneration. 9 Other approaches to increase collagen's mechanical strength include the use of calcium phosphate phases, either alone 10 or mixed with other additives such as silicon. 11 Silicon has been recently chosen to be used along with collagen rendering hybrids and nanocomposite materials 12 a IQUIMEFA-CONICET Facultad de Farmacia y Bioqu´ ımica, Universidad de Buenos Aires, Jun´ ın 956 Piso 3  , (1113) Ciudad Aut´ onoma de Buenos Aires, Argentina. E-mail: mlfoglia@ffyb.uba.ar; desimone@ffyb.uba.ar; Fax: +54-1149648254; Tel: +54-1149648254 b Max Bergmann Center of Biomaterials and Institute of Materials Science, Technische, Universit¨ at Dresden, Budapester Str. 27, D-01069 Dresden, Germany c Institute of Materials Science and Technology (INTEMA), University of Mar del Plata and National Research Council (CONICET), J.B. Justo 4302, 7600 Mar del Plata, Argentina Cite this: J. Mater. Chem. B, 2013, 1, 6283 Received 1st August 2013 Accepted 22nd September 2013 DOI: 10.1039/c3tb21067g www.rsc.org/MaterialsB This journal is ª The Royal Society of Chemistry 2013 J. Mater. Chem. B, 2013, 1, 6283–6290 | 6283 Journal of Materials Chemistry B PAPER Published on 24 September 2013. Downloaded by Universite Pierre et Marie Curie on 19/11/2013 10:18:30. View Article Online View Journal | View Issue