Browsing by Author "Alves, L."
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- Development of carboxymethyl cellulose-chitosan hybrid micro- and macroparticles for encapsulation of probiotic bacteriaPublication . Singh, P.; Medronho, B.; Alves, L.; da Silva, G. J.; Miguel, M. G.; Lindman, B.Novel carboxymethyl cellulose-chitosan (CMC-Cht) hybrid micro- and macroparticles were successfully prepared in aqueous media either by drop-wise addition or via nozzle-spray methods. The systems were either physically or chemically crosslinked using genipin as the reticulation agent. The macroparticles (ca. 2 mm) formed are found to be essentially of the core-shell type, while the microparticles (ca. 5 tim) are apparently homogeneous. The crosslinked particles are robust, thermally resistant and less sensitive to pH changes. On the other hand, the physical systems are pH sensitive presenting a remarkable swelling at pH 7.4, while little swelling is observed at pH 2.4. Furthermore, model probiotic bacteria (Lactobacillus rhamnosus GG) was for the first time successfully encapsulated in the CMC-Cht based particles with acceptable viability count. Overall, the systems developed are highly promising for probiotic encapsulation and potential delivery in the intestinal tract with the purpose of modulating gut microbiota and improving human health. (C) 2017 Elsevier Ltd. All rights reserved.
- Probing cellulose amphiphilicityPublication . Medronho, B.; Duarte, H.; Alves, L.; Antunes, F.; Romano, Anabela; Lindman, B.Cellulose dissolution and regeneration is an increasingly active research field due to the direct relevance for numerous production processes and applications. The problem is not trivial since cellulose solvents are of remarkably different nature and thus the understanding of the subtle balance between the different interactions involved becomes difficult but crucial. There is a current discussion in literature on the balance between hydrogen bonding and hydrophobic interactions in controlling the solution behavior of cellulose. This treatise attempts to review recent work highlighting the marked amphiphilic characteristics of cellulose and role of hydrophobic interactions in dissolution and regeneration. Additionally, a few examples of our own research are discussed focusing on the role of different additives in cellulose solubility. The data does support the amphiphilic behavior of cellulose, which clearly should not be neglected when developing new solvents and strategies for cellulose dissolution and regeneration.