**In Vitro Blood Compatibility of Novel Hydrophilic Chitosan Films for Vessel Regeneration and Repair**

Antonello A. Romani, Luigi Ippolito, Federica Riccardi, Silvia Pipitone, Marina Morganti, Maria Cristina Baroni, Angelo F. Borghetti and Ruggero Bettini

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/52706

**1. Introduction**

Tissue and organ failure treatments include drug therapy, surgical repair, medical devices but they do not always provide satisfactory restoration of organ function.

At present transplants represent an actual solution in treating organ failure once overcom‐ ing immunological rejection even though its application is largely affected by the paucity of available donors.

In the vascular field, currently, the best graft performance is given by saphenous vein auto‐ grafts [1] whose main failures are related to thrombosis development, emboli production, and intimal hyperplasia. Synthetic non-bio-resorbable vascular prosthesis (such as Dacron® or extended-PTFE) exhibited very low incidences of thrombosis or hyperplasia and showed good clinical results in medium- and large-diameter graft sites.

Strategies based on polymeric materials (synthetic or natural) appear to be a valid alterna‐ tive for the production of tissue graft materials. However, synthetic polymers are not able to induce any biological response leading to tissue regeneration, due to the lack of biomimetic activity. On the contrary, natural biodegradable polymeric supports, resembling extracellu‐ lar matrix component, can provide a useful platform in tissue engineering and regenerative medicine applications [2-5].

© 2013 Romani et al.; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Among them, chitosan (CS) a biodegradable [6], non-amphiphilic polymer of D-glucosamine obtained by partial de-acetylation of chitin [3], has shown interesting properties including biomimetism due to the similarity of is structure with that of glycosaminoglycanes [4].

Kind *et al*. [7] reported that it promotes plasma protein adsorption, platelet adhesion and ac‐ tivation, and thrombus development [8]. The positive charged CS surface induces a great degree of platelet adhesion. In fact, the Food and Drug Administration approved its use as haemostatic dressing for reducing haemorrhage [9-11]. Furthermore, it has been reported that the negatively charged-modified surface of CS prolongs clot formation after re-calcifica‐ tion of plasma [12].

Up to now, few data, often conflicting, on the haemocompatibility of negative chargedmodified surfaces of CS films are available[11,12].

In a previous work [13] we developed novel CS hydrogel prepared in the presence of phos‐ phate salts and relatively high amount of disaccharides such as D-(+)raffinose or D-(+)sac‐ charose and investigated the physico-chemical characteristics as well as the cytocompatibility of films obtained with this hydrogel. These sugars were not retained in the final structure of the film but were able to act as viscosity modifiers during the solidifica‐ tion/gelation process. The interference of salts and disaccharides resulted in smooth, amor‐ phous film with improved hydrophilicity and cytocompatibility compared to CS films produced with the same procedure but in low viscosity milieu. Differentiated human cells showed a great affinity for these sugar-modified chitosan (smCS) films, thus suggesting their candidature as promising biomaterial for tissue regeneration and repair.

The aim of the present study was to investigate qualities and aspects of the haemocompati‐ bility (platelet activation, haemolysis and activation of coagulation cascade) of smCS films produced according to Bettini*et al.* [13]. Moreover, the cytotoxicity of fragmented smCS was investigated in view of its bio-resorbability.

These films were compared to materials able to activate platelets and induce thrombus for‐ mation such as plastic (standard polystyrene for cell culture) and glass (cover slips) as well as a material able to trigger cell death such as latex.
