@article {19080,
	title = {Chitosan - Alginate Multilayered Films with Gradients of Physical Cues},
	journal = {TERMIS },
	year = {2014},
	month = {2014-06-10 00:00:00},
	address = {Genova},
	abstract = {<p>In general cell types are sensitive to mechanical stimulus of the surrounding environment which affects several cell properties. This study aimed to develop chitosan and alginate polyelectrolyte multilayers with gradients of physical cues generated by changing the reaction time of genipin crosslinking as a function of controlled distance. This methodology allows the production of stiffness gradients in the cm scale by varying the reaction time of genipin crosslinking with a simple adjustment of the flow. Quartz crystal microbalance, colorimetric measurements, trypan blue assay, attenuated total reflection - Fourier transform infrared, swelling ability, water contact angle and dynamic mechanical analysis were used to find the suitable conditions for stiffness gradient. The PEMs can be successfully built-up and cross-linked with genipin to yield surfaces with uniform or with gradients of physical cues. It was found that a large reduction in the hydrophobic nature of the films could be produced with higher cross-linking reaction times, regardless the decrease on their swelling ability. Moreover, the mechanical properties were evaluated using an innovative and non-conventional DMA to monitor crosslinking reaction in situ. The results confirm an enhancement on the storage modulus with increasing reaction times from 60 to 140 MPa. The in vitro biological performance demonstrates that L929 adhere and spread toward stiffer regions. The present findings highlight the feasibility of LbL technique to generate stable and tunable modulus gradients that influence the cell-material interactions.</p>
<p>\&nbsp;</p>},
	keywords = {gradients, Multilayered films, Tissue engineering},
	author = {Silva, J. M. and Caridade, S. G. and Oliveira, N. M. and Reis, R. L. and Mano, J. F.}
}
