Photocrosslinkable Polymers for Biomedical Applications

Photopolymerization techniques provide a number of economic advantages over the usual thermal techniques. These include: rapid cure reaction, low energy requirements, use of room temperature and solvent free formulations as well as low cost. Light beams are used to start the photochemical reactions in organic materials (monomers, oligomers, polymers) to form a new polymeric system This technique allows us to prepare materials with several applications in industry (UV curable inks, printing plates and adhesives, among others). Photopolymerization has also been used in electronic materials, optical materials, membranes, coatings and surface modifications. The efficiency of the polymerization reaction is dependent on the monomers, the photoinitiator and the beam wavelength. More recently, this technique has been used in the preparation of biomaterials with applications in important areas as tissue engineering, (Nguyen & West, 2002), biosensors, (Alves et al., 2009), development of drug delivery systems (Rydhholm et al., 2007) dental restorations in situ (Gatti et al. 2007)) and surface modifications to control the materials cell adhesion (Alves et al., 2011). Photopolymerizable polymers have found numerous applications in the field of tissue engineering for the engineering of tissues as bone, cartilage and liver (Ifkovits & Burdick, 2007) as they may be photopolymerized in vivo and in vitro. Here we will report some of the literature scientific reports in this field. Ortega and co-workers (2008) showed that the photopolymerization kinetics as well as the resulting structure of the methacrylate based structures are influenced by the monomers and oligomers properties, the reaction conditions, e.g. light intensity, reaction temperature and type of photoinitiator. Gatti et al. (2007) referred that photopolymers have been widely used in several dentistry applications. Different monomers have been used for this purpose. Gatti et al. (2007) prepared and characterized copolymers obtained from bisphenylglycidyl dimethacrylate, triethylene glycol dimethacrylate and urethane dimethacrylate. These copolymers were used to obtain dentistry resins. The kinetic parameters of the reaction were evaluated by using photocalorimetry As it is well known, hydrogels are three-dimensional, hydrophilic, polymeric networks capable of imbibing large amounts of water or biological fluids. They represent an important class of materials to be applied in biotechnology and medicine. These networks have been used as membranes for separating solutes, wound dressings, delivery systems for gene therapy and protein controlled-released systems. Hydrogels have also been applied as