Applications for controlled release of bioactive compounds

This section aims to illustrate some of the most common systems normally associated with a tissue regeneration goal. Thus, such systans are incorporated into the scaffolds or constitute the scaffolds themselves or aim at the delivery of factors affecting cell fate growth factors or differentiation factors. 

With the nnmber of factors affecting the delivery of the bioactive compounds, namely, the nature of the polymers constituting the system, the nature of the drug, the structural and chemical featnres of the system, among others, the development of an appropriate drug delivery system needs to be addressed in a case-by-case scenario. Below, several examples of drng delivery systems based in marine biopolymers will be assessed. 

Chitosan is probably the most studied marine biopolymer for application in the development of drug delivery devices. More recently, the advent of chitosan-based nanomaterials has opened new possibilities in drug delivery, with particles exhibiting superior 

Carrageenans, sulfated polysaccharides isolated from red algae, has been also used for the development of polyelectrolyte complexes with chitosan, resulting in nanoparticles (Grenha et al., 2010) able to deliver drugs in a sustained way, with the potential to be uptaken by cells, thus exploring intracellular therapeutic approaches. 

Hollow capsules can be also produced with marine origin biopolymers following a layer-by-layer strategy onto a sacrificial template, as is the case of capsules formed by hyaluronic acid with polyallylamine (Szarpak et al 2008). Equivalent strategy has been also used to develop capsules with chitosan and elastin-like recombinamers (Costa et al., 2014). These capsules feature peptide sequences in their surface, bioactive RGD or nonfunctional RDG, proven to promote the viability of human mesenchymal Stan cells. Additionally, they were also able to intracellularly deliva ovalbumin, promising application with other therapeutic compounds (Costa et al., 2014). 

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