Bioactive Self-Regulated Liquified Microcompartments to Bioengineer Bone-Like Microtissues.

Designing a microenvironment that drives autonomous stromal cell differentiation toward osteogenesis while recapitulating the complexity of bone tissue remains challenging. In the current study, bone-like microtissues are created using electrohydrodynamic atomization to form two distinct liquefied microcapsules (mCAPs): i) hydroxypyridinone (HOPO)-modified gelatin (GH mCAPs, 7.5% w/v), and ii) HOPO-modified gelatin and dopamine-modified gelatin (GH+GD mCAPs, 7.5%+1.5% w/v). The ability of HOPO to coordinate with iron ions at physiological pH allows the formation of a semipermeable micro-hydrogel shell. In turn, the dopamine affinity for calcium ions sets a bioactive milieu for bone-like microtissues. After 21 days post encapsulation, GH and GH+GD mCAPs potentiate autonomous osteogenic differentiation of mesenchymal stem cells accompanied by collagen type-I gene upregulation, increased alkaline phosphatase (ALP) expression, and formation of mineralized extracellular matrix. However, the GH+GD mCAPs show higher levels of osteogenic markers starting on day 14, translating into a more advanced and organized mineralized matrix. The GH+GD system also shows upregulation of the receptor activator of nuclear factor kappa-B ligand (RANK-L) gene, enabling the autonomous osteoclastic differentiation of monocytes. These catechol-based mCAPs offer a promising approach to designing multifunctional and autonomous bone-like microtissues to study in vitro bone-related processes at the cell-tissue interface, angiogenesis, and osteoclastogenesis.

Novel naphthoquinone-1H-1,2,3-triazole hybrids: Design, synthesis and evaluation as inductors of ROS-mediated apoptosis in the MCF-7 cells.

The search for novel anticancer drugs is essential to expand treatment options, overcome drug resistance, reduce toxicity, promote innovation, and tackle the economic impact. The importance of these studies lies in their contribution to advancing cancer research and enhancing patient outcomes in the battle against cancer. Here, we developed new asymmetric hybrids containing two different naphthoquinones linked by a 1,2,3-1H-triazole nucleus, which are potential new drugs for cancer treatment. The antitumor activity of the novel compounds was tested using the breast cancer cell lines MCF-7 and MDA-MB-231, using the non-cancer cell line MCF10A as control. Our results showed that two out of twenty-two substances tested presented potential antitumor activity against the breast cancer cell lines. These potential drugs, named here 12g and 12h were effective in reducing cell viability and promoting cell death of the tumor cell lines, exhibiting minimal effects on the control cell line. The mechanism of action of the novel drugs was assessed revealing that both drugs increased reactive oxygen species production with consequent activation of the AMPK pathway. Therefore, we concluded that 12g and 12h are novel AMPK activators presenting selective antitumor effects.

Menadione: a platform and a target to valuable compounds synthesis.

Naphthoquinones are important natural or synthetic compounds belonging to the general class of quinones. Many compounds in this class have become drugs that are on the pharmaceutical market for the treatment of various diseases. A special naphthoquinone derivative is menadione, a synthetic naphthoquinone belonging to the vitamin K group. This compound can be synthesized by different methods and it has a broad range of biological and synthetic applications, which will be highlighted in this review.

A Supramolecular Injectable Methacryloyl Chitosan-Tricine-Based Hydrogel with 3D Printing Potential for Tissue Engineering Applications.

Printable hydrogels have attracted significant attention as versatile, tunable, and spatiotemporally controlled biomaterials for tissue engineering (TE) applications. Several chitosan-based systems are reported presenting low or no solubility in aqueous solutions at physiological pH. Herein, a novel neutrally charged, biomimetic, injectable, and cytocompatible dual-crosslinked (DC) hydrogel system based on a double functionalized chitosan (CHT) with methacryloyl and tricine moieties (CHTMA-Tricine), completely processable at physiological pH, with promising three-dimensional (3D) printing potential is presented. Tricine, an amino acid typically used in biomedicine, is capable of establishing supramolecular interactions (H-bonds) and is never explored as a hydrogel component for TE. CHTMA-Tricine hydrogels demonstrate significantly greater toughness (ranging from 656.5 ± 82.2 to 1067.5 ± 121.5 kJ m-3 ) compared to CHTMA hydrogels (ranging from 382.4 ± 44.1 to 680.8 ± 104.5 kJ m-3 ), highlighting the contribution of the supramolecular interactions for the overall reinforced 3D structure provided by tricine moieties. Cytocompatibility studies reveal that MC3T3-E1 pre-osteoblasts cells remain viable for 6 days when encapsulated in CHTMA-Tricine constructs, with semi-quantitative analysis showing ≈80% cell viability. This system's interesting viscoelastic properties allow the fabrication of multiple structures, which couple with a straightforward approach, will open doors for the design of advanced chitosan-based biomaterials through 3D bioprinting for TE.

Bioinspired Oxidation-Resistant Catechol-like Sliding Ring Polyrotaxane Hydrogels.

Adaptable hydrogels have been used in the biomedical field to address several pathologies, especially those regarding tissue defects. Here, we describe unprecedented catechol-like functionalized polyrotaxane (PR) polymers able to form hydrogels. PR were functionalized with the incorporation of hydroxypyridinone (HOPO) moieties into the polymer backbone, with a degree of substitution from 4 to 22%, depending on the PR type. The hydrogels form through the functionalized supramolecular systems when in contact with a Fe(III) solution. Despite the hydrogel formation being at physiological pH (7.4), the HOPO derivatives are extremely resistant to oxidation, unlike common catechols; consequently, they prevent the formation of quinones, which can lead to irreversible bounds within the matrix. The resulting hydrogels demonstrated properties lead to unique hydrogels with improved mechanical behavior obtained by metallic coordination crosslinking, due to the synergies of the sliding-ring PR and the non-covalent (reversible) catechol analogues. Following this strategy, we successfully developed innovative, cytocompatible, oxidative-resistant, and reversible crosslinked hydrogels, with the potential of being used as structural self-materials for a variety of applications, including in the biomedical field.

Biomimetic Adhesive Micropatterned Hydrogel Patches for Drug Release.

The optimized physical adhesion between bees' leg hairs and pollen grains-whereby the latter's diameter aligns with the spacing between the hairs-has previously inspired the development of a biomimetic drug dressing. Combining this optimized process with the improved natural mussels' adhesion in wet environments in a dual biomimetic process, it is herein proposed the fabrication of a natural-derived micropatterned hydrogel patch of methacrylated laminarin (LAM-MET), with enriched drug content and improved adhesiveness, suitable for applications like wound healing. Enhanced adhesion is accomplished by modifying LAM-MET with hydroxypyridinone groups, following the patch microfabrication by soft lithography and UV/vis-irradiation, resulting in a membrane with micropillars with a high aspect ratio. Following the biomimetics rational, a drug patch is engineered by combining the microfabricated dressing with drug particles milled to fit the spaces between pillars. Controlled drug release is achieved, together with inherent antibacterial activity against Escherichia coli and Pseudomonas aeruginosa, and enhanced biocompatibility using the bare micropatterned patches. This new class of biomimetic dressings overcomes the challenges of current patches, like poor mechanical properties and biocompatibility, limited adhesiveness and drug dosage, and lack of prolonged antimicrobial activity, opening new insights for the development of high drug-loaded dressings with improved patient compliance.

Comparative photodynamic inactivation of antibiotic resistant bacteria by first and second generation cationic photosensitizers.

Photodynamic inactivation (PDI) is an efficient approach against a wide range of microorganisms and can be viewed as an alternative for the treatment of microbial infections. In this work we synthesized "first" and "second" generation photosensitizers (PSs), the tetra-cationic porphyrin and the new penta-cationic chlorin , respectively, and evaluated their efficiency against two antibiotic resistant bacterial strains, Staphylococcus aureus and Pseudomonas aeruginosa. The PS was obtained in very good yield by an easy synthesis method. The PDI studies were performed in parallel with 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin tetra-iodide (), a widely studied PS in PDI, and the obtained results were compared. Two different light ranges were used: white light (400-800 nm) and red light (530-800 nm) delivered at a fluence rate of 150 mW cm(-2). The results show that both strains, even though antibiotic resistant, were efficiently inactivated by the three PSs, chlorin being the most effective. For the Gram positive bacterium S. aureus a 7.0 log reduction was observed after 5-10 min of irradiation, at a concentration of 0.5 µM, whereas for the Gram negative P. aeruginosa, similar photoinactivation occurred at a higher PS concentration (10 µM) and after a longer irradiation period (30 min). The synthetic chlorin can be regarded as promising for the treatment of bacterial infections under red light, which penetrates deeper in living tissues. The results of this study open the possibility to prepare a new series of chlorin-type derivatives to efficiently photoinactivate Gram (+) and (-) antibiotic resistant bacteria. The efficient PDI with the chlorin indicates high potential for the use of a scaffold in the preparation of new generation PSs based on cationic chlorin derivatives.

Universal Strategy for Designing Shape Memory Hydrogels.

Smart polymeric biomaterials have been the focus of many recent biomedical studies, especially those with adaptability to defects and potential to be implanted in the human body. Herein we report a versatile and straightforward method to convert non-thermoresponsive hydrogels into thermoresponsive systems with shape memory ability. As a proof of concept, a thermoresponsive polyurethane mesh was embedded within a methacrylated chitosan (CHTMA), gelatin (GELMA), laminarin (LAMMA) or hyaluronic acid (HAMA) hydrogel network, which afforded hydrogel composites with shape memory ability. With this system, we achieved good to excellent shape fixity ratios (50-90%) and excellent shape recovery ratios (∼100%, almost instantaneously) at body temperature (37 °C). Cytocompatibility tests demonstrated good viability either with cells on top or encapsulated during all shape memory processes. This straightforward approach opens a broad range of possibilities to convey shape memory properties to virtually any synthetic or natural-based hydrogel for several biological and nonbiological applications.

Design of Protein-Based Liquefied Cell-Laden Capsules with Bioinspired Adhesion for Tissue Engineering.

Platforms with liquid cores are extensively explored as cell delivery vehicles for cell-based therapies and tissue engineering. However, the recurrence of synthetic materials can impair its translation into the clinic. Inspired by the adhesive proteins secreted by mussels, liquefied capsule is developed using gelatin modified with hydroxypyridinones (Gel-HOPO), a catechol analogue with oxidant-resistant properties. The protein-based liquefied macrocapsule permitted the compartmentalization of living cells by an approachable and non-time-consuming methodology resorting to i) superhydrophobic surfaces as a processing platform of hydrogel beads, ii) gelation of gelatin at temperatures < 25 °C, iii) iron coordination of the hydroxypyridinone (HOPO) moieties at physiological pH, and iv) core liquefaction at 37 °C. With the design of a proteolytically degradable shell, the possibility of encapsulating human adipose-derived mesenchymal stem cells (hASC) with and without the presence of polycaprolactone microparticles (µPCL) is evaluated. Showing prevalence toward adhesion to the inner shell wall, hASC formed a monolayer evidencing the biocompatibility and adequate mechanical properties of these platforms for proliferation, diminishing the need for µPCL as a supporting substrate. This new protein-based liquefied platform can provide biofactories devices of both fundamental and practical importance for tissue engineering and regenerative medicine or in other biotechnology fields.

A Novel Triazole Derivative Drug Presenting In Vitro and In Vivo Anticancer Properties.

BACKGROUND: Cancer is a major cause of death worldwide, despite many different drugs available to treat the disease. This high mortality rate is largely due to the complexity of the disease, which results from several genetic and epigenetic changes. Therefore, researchers are constantly searching for novel drugs that can target different and multiple aspects of cancer. EXPERIMENTAL: After a screening, we selected one novel molecule, out of ninety-four triazole derivatives, that strongly affects the viability and proliferation of the human breast cancer cell line MCF-7, with minimal effects on non-cancer cells. The drug, named DAN94, induced a dose-dependent decrease in MCF-7 cells viability, with an IC50 of 3.2 ± 0.2 µM. Additionally, DAN94 interfered with mitochondria metabolism promoting reactive oxygen species production, triggering apoptosis and arresting the cancer cells on G1/G0 phase of cell cycle, inhibiting cell proliferation. These effects are not observed when the drug was tested in the non-cancer cell line MCF10A. Using a mouse model with xenograft tumor implants, the drug preventing tumor growth presented no toxicity for the animal and without altering biochemical markers of hepatic function. RESULTS AND CONCLUSION: The novel drug DAN94 is selective for cancer cells, targeting the mitochondrial metabolism, which culminates in the cancer cell death. In the end, DAN94 has been shown to be a promising drug for controlling breast cancer with minimal undesirable effects.

Synthesis and evaluation of the cytotoxic activity of Furanaphthoquinones tethered to 1H-1,2,3-triazoles in Caco-2, Calu-3, MDA-MB231 cells.

Naphthoquinones and 1,2,3-triazoles are structural pharmacophore that is known to impart several cancer cells. This work shows a synthetic methodology to obtain hybrid molecules involving naphthoquinone and triazol scaffold as multiple ligands. A simple and efficient synthetic route was used to prepare a series of sixteen compounds being eight 2-(1-aryl-1H-1,2,3-triazol-4-yl)-2,3-dihydronaphtho[1,2 b]furan-4,5-diones and eight 2-(1-aryl-1H-1,2,3-triazol-4-yl)-2,3-dihydronaphtho[2,3-b]furan-4,9-diones. These compounds were tested in MDA-MB231, Caco-2 and Calu-3 human cancer cells, and among them 7a was the most selective compound on Caco-2 cells, the most sensitized cell line in this study. In silico study suggest that the blockage of topoisomerase I and IIα may be one of the mechanisms of action responsible for the cytotoxic effect of 7a in Caco-2 cells.

Hetero-Diels-Alder reactions of novel 3-triazolyl-nitrosoalkenes as an approach to functionalized 1,2,3-triazoles with antibacterial profile.

The generation and reactivity of 3-triazolyl-nitrosoalkenes are reported for the first time. The study showed that hetero-Diels-Alder reaction of these heterodienes is an interesting synthetic strategy to functionalized 1,2,3-triazoles, including 1,2,3-triazolyl-pyrroles, 1,2,3-triazolyl-dipyrromethanes and 1,2,3-triazolyl-indoles. The evaluation of the antibacterial profile against Gram-positive and Gram-negative strains revealed the new 5,5'-diethyldipyrromethane bearing a side chain incorporating a triazole and oxime moieties. The antibacterial profile detected was within the Clinical and Laboratory Standard Institute (CLSI) range and against important Staphylococcus species including Methicillin-resistant strain (S. aureus ATCC 25923, S. epidermidis ATCC 12228 and S. simulans ATCC 27851 and MRSA). Interestingly, this new 1,2,3-triazole presented hemocompatibility and low in silico toxicity profile similar to antibiotics current in use. It also has an usual antibiofilm activity against MRSA, which reinforced its potential as a new antibacterial prototype.

Synthesis and Biological Evaluation of Coumarins Derivatives as Potential Inhibitors of the Production of Pseudomonas aeruginosa Virulence Factor Pyocyanin.

Antimicrobial Resistance (AMR) is a serious problem for the humans since it threatens the effective prevention and treatment of an ever-increasing range of infections caused by bacteria, parasites, viruses and fungi. One way around this problem is to act on the virulence factors, produced by bacteria, which increase their infection effectiveness. In view of these facts, new coumarin derivatives were synthesized and evaluated for their anti-virulence biological activity towards Pseudomonas aeruginosa. The results suggest that coumarin derivatives with a secondary carbon at C-3 position reduces P. aeruginosa growth whereas compounds with one additional substituent have a significant effect over pyocyanin production (10k EC50 7 ± 2 µM; 10l EC50 42 ± 13 µM). Moreover, 10k reduces P. aeruginosa motility and biofilm formation, what is compatible with a quorum sensing related mechanism of action.