Publications

A plethora of applications using polysaccharides have been developed in recent years due to their availability as well as their frequent nontoxicity and biodegradability. These polymers are usually obtained from renewable sources or are byproducts of industrial processes, thus, their use is collaborative in waste management and shows promise for an enhanced sustainable circular economy. Regarding the development of novel delivery systems for biotherapeutics, the potential of polysaccharides is attractive for the previously mentioned properties and also for the possibility of chemical modification of their structures, their ability to form matrixes of diverse architectures and mechanical properties, as well as for their ability to maintain bioactivity following incorporation of the biomolecules into the matrix. Biotherapeutics, such as proteins, growth factors, gene vectors, enzymes, hormones, DNA/RNA, and antibodies are currently in use as major therapeutics in a wide range of pathologies. In the present review, we summarize recent progress in the development of polysaccharide-based hydrogels of diverse nature, alone or in combination with other polymers or drug delivery systems, which have been implemented in the delivery of biotherapeutics in the pharmaceutical and biomedical fields. © 2021 American Chemical Society.

JTD Keywords: biodegradable dextran hydrogels, biotherapeutics, bone morphogenetic protein-2, carrageenan-based hydrogels, chitosan-based hydrogels, controlled delivery, controlled-release, cross-linked hydrogels, growth-factor delivery, hydrogels, in-vitro characterization, polysaccharides, self-healing hydrogel, stimuli-responsiveness, tissue engineering, Antibodies, Bioactivity, Biodegradability, Biomedical fields, Biomolecules, Biotherapeutics, Chemical modification, Circular economy, Controlled delivery, Controlled drug delivery, Delivery systems, Drug delivery system, Functional polymers, Hyaluronic-acid hydrogels, Hydrogels, Industrial processs, Polysaccharides, Recent progress, Renewable sources, Stimuli-responsiveness, Targeted drug delivery, Tissue engineering, Waste management

© 2021 Wiley-VCH GmbH One limitation of wearable electronics, and at the same time a challenge, is the lack of energy storage devices with multiple functionalities produced using clean and environmental-friendly strategies. Here, a multifunctional conductive hydrogel containing poly(3,4-ethylenedioxythiophene) (PEDOT) and alginate is fabricated, to be used as electrodes in supercapacitors, by applying water-mediated self-assembly and polymerization processes at room temperature. The interpenetration of both polymers allows the combination of flexibility and self-healing properties within the same hydrogel together with the intrinsic biocompatibility and sustainability of such materials. Initially, PEDOT:polystyrene sulfonate and alginate aqueous solutions are mixed in two different proportions (1:1 and 1:3) and ionically crosslinked with CaCl2. Subsequently, re-interpenetration of poly(hydroxymethyl-3,4-ethylenedioxythiophene) by anodic polymerization in CaCl2 aqueous solution is achieved. Re-interpenetrated 1:3 PEDOT/alginate hydrogels show excellent capacitance values (35 mF cm−2) and good capacitance retention. In addition, the electrochemical properties are not significantly changed after many cutting/self-healing cycles as observed by cyclic voltammetry. Therefore, this sustainably produced hydrogel shows promising properties for use in wearable energy storage devices.

JTD Keywords: flexibility, pedot:pss-alginate hydrogels, self-healing, sustainability, Electrochemical supercapacitors, Flexibility, Pedot:pss-alginate hydrogels, Self-healing, Sustainability

The microscopic mechanism accounting for the self-healing attribute of aromatic ionene-forming hydrogels derived from 1,4-diazabicyclo [2.2.2]octane (DABCO) and N,N’-(x-phenylene)dibenzamide (x = ortho-/meta-/para-) is unknown. Interestingly, the self-healing property of such DABCO-containing hydrogels is largely dependent on the polymer topology, the ortho ionene being the only self-healable without adding oppositely charged species. In this work, Molecular Dynamics (MD) simulations have been conducted to evaluate the influence of the topology on ionene···ionene and ionene··water interactions, as well as their effect on the self-healing behavior. For this purpose, destabilized and structurally damaged models were produced for ionene hydrogels with ortho, meta and para topologies and used as starting geometries for simulations. These models were allowed to evolve without any restriction during MD production runs and, subsequently, the temporal evolution of ionene···ionene and water···ionene interactions was examined. Analysis of the results indicated that the ortho-isomer rapidly forms unique interactions that are not detected for other two isomers. Thus, in addition to the interactions also identified for the meta-and para-ionenes, the ortho-isomer exhibits the formation of strong intermolecular three-centered (N–)H⋯O (=C)⋯H (–N) hydrogen bonds, intramolecular planar sandwich π-π stacking interactions and Cl−···N+ electrostatic interactions. Furthermore, the amount of intermolecular π-π stacking interactions and the strength of water···polymer interaction are also influenced by the topology, favoring the stabilization of the ortho-ionene reconstituted hydrogels. Overall, the arrangement of the functional groups in the ortho topology favors the formation of more types of ionene···ionene interactions, as well as stronger interactions, than in the meta and para topologies.

JTD Keywords: DABCO, Econstituted hydrogels, Molecular dynamics, Polyelectrolyte hydrogels, Self-healing mechanism

Biological function requires cell-cell adhesions to tune their cohesiveness; for instance, during the opening of new fluid-filled cavities under hydraulic pressure. To understand the physical mechanisms supporting this adaptability, we develop a stochastic model for the hydraulic fracture of adhesive interfaces bridged by molecular bonds. We find that surface tension strongly enhances the stability of these interfaces by controlling flaw sensitivity, lifetime, and optimal architecture in terms of bond clustering. We also show that bond mobility embrittles adhesions and changes the mechanism of decohesion. Our study provides a mechanistic background to understand the biological regulation of cell-cell cohesion and fracture.

JTD Keywords: Biomimetic & bio-inspired materials, Cell adhesion, Fracture, Self-healing