| Resumo: | Owing to their potential beneficial effects on human health, polyphenols (e.g. resveratrol, polydatin, catechin, etc) have been considered in many research works and also for applications in pharmaceutic, biomedical, cosmetic or food industries. The development of carriers allowing to stabilize and protect polyphenols from degradation, thus preserving biological activity and enlarging their bioavailability, is a key issue to achieve the effective benefits of such compounds. On other hand, the use of cellulose materials in many application fields (including the aforementioned industrial areas) is also nowadays an important theme due to the abundance, sustainability and biocompatibility of this natural polymer. Supercritical fluid technology, namely with carbon dioxide, often avoids the use unwanted organic solvents (enabling a more “green” approach) and combines good solubility conditions (associated to liquids) with high diffusion rates (intrinsic to gases). These issues are especially relevant for the transport of high size molecules (as many polyphenols) in complex matrices (such cellulose polymers). Our research combines these three working lines through the synthesis of cellulose-based hydrogels, the supercritical CO2 uploading of polyphenols in the produced materials and the posterior assessment of their liberation for controlled-release purposes (see Figure 1). Chemical crosslinking of cellulose with epichlorohydrin is used to prepare the cellulose-based hydrogels and physically crosslinked alginate hydrogels are considered for comparison purposes. Amphiphilic materials are also synthesized through esterification of OH-groups with a RAFT agent, followed by grafting of synthetic polymer chains. We show that tailored controlled-release vehicles can be obtained by designing the synthesis conditions.
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