title: Relationship between cell compatibility and elastic modulus of silicone rubber/organoclay nanobiocomposites.
abstract: BACKGROUND
  Substrates in medical science are hydrophilic polymers undergoing volume expansion when exposed to culture medium that influenced on cell attachment. Although crosslinking by chemical agents could reduce water uptake and promote mechanical properties, these networks would release crosslinking agents. In order to overcome this weakness, silicone rubber is used and reinforced by nanoclay.
  
  
  OBJECTIVE
  Attempts have been made to prepare nanocomposites based on medical grade HTV silicone rubber (SR) and organo-modified montmorillonite (OMMT) nanoclay with varying amounts of clay compositions.
  
  
  METHODS
  Incorporation of nanocilica platelets into SR matrix was carried out via melt mixing process taking advantage of a Brabender internal mixer. The tensile elastic modulus of nanocomposites was measured by performing tensile tests on the samples. Produced polydimetylsiloxane (PDMS) composites with different flexibilities and crosslink densities were employed as substrates to investigate biocompatibility, cell compaction, and differential behaviors.
  
  
  RESULTS
  The results presented here revealed successful nanocomposite formation with SR and OMMT, resulting in strong PDMS-based materials. The results showed that viability, proliferation, and spreading of cells are governed by elastic modulus and stiffness of samples. Furthermore, adipose derived stem cells (ADSCs) cultured on PDMS and corresponding nanocomposites could retain differentiation potential of osteocytes in response to soluble factors, indicating that inclusion of OMMT would not prevent osteogenic differentiation. Moreover, better spread out and proliferation of cells was observed in nanocomposite samples.
  
  
  CONCLUSIONS
  Considering cell behavior and mechanical properties of nanobiocomposites it could be concluded that silicone rubber substrate filled by nanoclay are a good choice for further experiments in tissue engineering and medical regeneration due to its cell compatibility and differentiation capacity.
authors.affiliation: Biomedical Group, Faculty of Biomedical Engineering (Center of Excellence), Amirkabir University of Technology, Tehran, IR Iran ; Polymer Group, Faculty of Polymer Engineering and Color Technology (Center of Excellence), Amirkabir University of Technology, Tehran, IR Iran.
authors.forename: Motahare Sadat
authors.initials: MS
authors.lastname: Hosseini
authors.affiliation: Biomedical Group, Faculty of Biomedical Engineering (Center of Excellence), Amirkabir University of Technology, Tehran, IR Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Tazzoli-Shadpour
authors.affiliation: Biomedical Group, Faculty of Biomedical Engineering (Center of Excellence), Amirkabir University of Technology, Tehran, IR Iran.
authors.forename: Issa
authors.initials: I
authors.lastname: Amjadi
authors.affiliation: National Cell Bank of Iran, Pasteur Institute of Iran, Tehran, IR Iran.
authors.forename: Nooshin
authors.initials: N
authors.lastname: Haghighipour
authors.affiliation: National Cell Bank of Iran, Pasteur Institute of Iran, Tehran, IR Iran.
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Shokrgozar
authors.affiliation: Nanotechnology Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran ; Immunology Department, Medical College, Ahvaz Jundishapur University of Medical Science, Ahvaz, IR Iran.
authors.forename: Mehri
authors.initials: M
authors.lastname: Ghafourian Boroujerdnia
keywords: Cytotoxicity Tests; Elastic Modulus; Nanocomposite