Recapitulating the biophysical and biochemical complexity of the extracellular matrix (ECM) remains a major challenge in tissue engineering. Hydrogels derived from decellularized ECM provide a unique opportunity to replicate the architecture and bioactivity of native ECM, however, they exhibit limited long-term stability and mechanical integrity. In turn, materials assembled through supramolecular interactions have achieved considerable success in replicating the dynamic biophysical properties of the ECM. Here, we merge both methodologies by promoting the supramolecular assembly of decellularized human amniotic membrane (hAM), mediated by host-guest interactions between hAM proteins and acryloyl-beta-cyclodextrin (AcBetaCD). Photopolymerization of the cyclodextrins results in the formation of soft hydrogels that exhibit tunable stress relaxation and strain-stiffening. Disaggregation of bulk hydrogels yields an injectable granular material that self-reconstitutes into shape-adaptable bulk hydrogels, supporting cell delivery and promoting neovascularization. Additionally, cells encapsulated within bulk hydrogels sense and respond to the biophysical properties of the surrounding matrix, as early cell spreading is favored in hydrogels that exhibit greater susceptibility to applied stress, evidencing proper cell-matrix interplay. Thus, this system is shown to be a promising substitute for native ECM in tissue repair and modelling.

Recapitulating the biophysical and biochemical complexity of the extracellular matrix (ECM) remains a major challenge in tissue engineering. Hydrogels derived from decellularized ECM provide a unique opportunity to replicate the architecture and bioactivity of native ECM, however, they exhibit limited long-term stability and mechanical integrity. In turn, materials assembled through supramolecular interactions have achieved considerable success in replicating the dynamic biophysical properties of the ECM. Here, we merge both methodologies by promoting the supramolecular assembly of decellularized human amniotic membrane (hAM), mediated by host-guest interactions between hAM proteins and acryloyl-β-cyclodextrin (AcβCD). Photopolymerization of the cyclodextrins results in the formation of soft hydrogels that exhibit tunable stress relaxation and strain-stiffening. Disaggregation of bulk hydrogels yields an injectable granular material that self-reconstitutes into shape-adaptable bulk hydrogels, supporting cell delivery and promoting neovascularization. Additionally, cells encapsulated within bulk hydrogels sense and respond to the biophysical properties of the surrounding matrix, as early cell spreading is favored in hydrogels that exhibit greater susceptibility to applied stress, evidencing proper cell-matrix interplay. Thus, this system is shown to be a promising substitute for native ECM in tissue repair and modelling.

There is a strong interest in phenolic compounds and nitrocompounds in the function of their diverse and significant biological activities. Such compounds can participate in electron transfer reactions and produce metabolites that influence the redox state at the cellular level, with consequent effect on vital biochemical processes. This work aimed to determine the electrodic mechanism involved in the oxidation of bergenin and the reduction of nitrobenzyl derivatives and to evaluate possible supramolecular interactions of bergenin with β-cyclodextrin (β-CD) and deoxyribonucleic acid (DNA) in order to increase its solubility in aqueous medium and help in understanding the molecular mechanism of biological action. The electrochemical studies in protic and aprotic medium were performed in potentiostat PGSTAT302 (AUT 73222) from Autolab® using voltammetric techniques. The influence of the interaction of different cyclodextrins on the solubility of bergenin in aqueous medium was verified through the phase transfer study by cyclic voltammetry. The bergenin:β-CD complex was prepared in 1:1 and 1:2 proportions by the coevaporation technique and characterized by spectroscopic techniques. The theoretical studies were performed through the Gaussian program 09. Bergenin in the free and complexed form were evaluated against antioxidant capacity (lipid peroxidation assays), cytotoxicity (cell viability versus macrophages), and interaction with estimated DNA through the use of dsDNA (double strand) electrochemical sensor and with ssDNA (single strand) for UV-Vis spectrophotometry in solution. The electrochemical results obtained for bergenin demonstrated that its oxidation mechanism in aprotic and protic environments involves, respectively, loss of 1e-/1H+ and 2e-/2H+, when using a glassy carbon electrode. Theoretical data contributed to clarify that oxidative mechanisms involve phenolic hydroxyls. The antioxidant activity of bergenin in the lipoperoxidation inhibition assays was favored in its complexed form with β-CD 1:1. The cytotoxicity of bergenin evaluated in macrophages was also influenced by interaction with β-CD. The electrochemical studies involving ssDNA demonstrated interaction between bergenin and the constituent bases of DNA, suggesting a possible mechanism of biological action. However, the dsDNA biosensor studies showed no interaction. Investigation of the interaction with dsDNA through UV-Vis spectrophotometry resulted in a binding constant between DNA and bergenin in the free and complexed form on the order of 103 and 104 M-1, respectively. The electrochemical behavior of the nitrobenzyl derivatives obtained in aprotic medium presented a voltammetric profile of great complexity, involving patterns related to autoprotonation and dissociative electron transfer reactions. The order of ease of reduction, based on values of first wave reduction potential, was found: ANB > EANBEN > EANB > AANB > ANOH > ATN = ENF > ANBNa > ENM > ANF, obtaining a positive correlation between the compounds with (less negative) with more pronounced biological activity (leishmanicidal and antitumor activities), already described in the literature, which justifies the importance of the electrochemical investigation of bioactive compounds as a tool in medical chemistry, in processes related to the transfer of electrons.

Monoclonal antibody (mAb) delivery is gaining importance for local, systemic, and route-specific targeting. The mucus constitutes the main barrier for this type of delivery. In the present study, we aimed to develop a drug delivery platform by integrating mucus penetrating and mucoadhesive agents into a single system. Our hypothesis is that by combining these opposing functions, this system could have its properties modulated according to specific purposes. Self-assembly studies were conducted using three classes of building blocks: the protein drug bevacizumab (BVZ), mucus-penetrating polyanion dextran sulfate (DS), mucoadhesive polycations trimethylchitosan (TMC) and chitosan oligosaccharides (COS). We obtained two types of nanoparticles by manipulating supramolecular interactions between the components. Binary protein-polyanion (BVZ/DS) nanoparticles showed size of approximately 150 nm and a negative zeta potential. Ternary protein-polyanion-polycation (BVZ/DS/COS) nanoparticles were obtained using COS and exhibited 350 nm and a positive zeta potential. Assisted by calorimetric information, we demonstrated that building stable ternary nanoparticles carrying positive charges were not possible using the polycation TMC due to its thermodynamic constraints. Furthermore, spectroscopy analysis and CAM assay indicated that BVZ continued structurally and functionally stable after its incorporation into the nanoparticles. These two types of nanoparticles exhibited different behaviors when interacting with mucin, as shown by DLS and AFM studies. While the negatively charged particles promoted dispersion of the mucin network, suggesting a mucus penetrating effect of DS, the positively charged particles formed aggregates, probably caused by the mucoadhesive effect of COS. These results highlight the importance of understanding the role of supramolecular interactions, responsible for forming drug delivery systems containing complex molecules, such as proteins and polymers.

During the synthesis of the bioactive complex [Ag(phen)(μ-tu)]<inf>2</inf>(NO<inf>3</inf>)<inf>2</inf> (1), some crystals of a new compound were isolated. This crystalline compound, [Ag<inf>4</inf>(μ-tu)<inf>5</inf>(tu)<inf>6</inf>](NO<inf>3</inf>)<inf>4</inf>·7Phen (2) (tu = thiourea, Phen = 1,10-phenanthroline), is a novelty for at least two reasons: (i) it is the first tetranuclear silver and thiourea cluster; (ii) it is the first crystal structure with seven neutral, and uncoordinated, phen molecules. Phen molecules pack forming an infinite column, and the tu ligands form an intricate network of hydrogen bonds with the Phen and nitrate entities.

Anti-vascular endothelial growth factor (anti-VEGF) therapy applied to solid tumors is a promising strategy, yet, the challenge to deliver these agents at high drug concentrations together with the maintenance of therapeutic doses locally, at the tumor site, minimizes its benefits. To overcome these obstacles, we propose the development of a bevacizumab-loaded alginate hydrogel by electrostatic interactions to design a delivery system for controlled and anti-angiogenic therapy under tumor microenvironrnental conditions. The tridimensional hydrogel structure produced provides drug stability and a system able to be introduced as a flowable solution, stablishing a depot after local administration. Biological performance by the chick embryo chorioallantoic membrane (CAM) assay indicated a pH-independent improved anti-angiogenic activity (similar to 50%) compared to commercial available anti-VEGF drug. Moreover, there was a considerable regression in tumor size when treated with this system. Immunohistochemistry highlighted a reduced number and disorganization of microscopic blood vessels resulting from applied therapy. These results suggest that the developed hydrogel is a promising approach to create an innovative delivery system.that offers the possibility to treat different solid tumors by intratumoral administration.