Proving the Antimicrobial Therapeutic Activity on a New Copper-Thiosemicarbazone Complex.

The misuse and overdose of antimicrobial medicines are fostering the emergence of novel drug-resistant pathogens, providing negative repercussions not only on the global healthcare system due to the rise of long-term or chronic patients and inefficient therapies but also on the world trade, productivity, and, in short, to the global economic growth. In view of these scenarios, novel action plans to constrain this antibacterial resistance are needed. Thus, given the proven antiproliferative tumoral and microbial features of thiosemicarbazone (TSCN) ligands, we have here synthesized a novel effective antibacterial copper-thiosemicarbazone complex, demonstrating both its solubility profile and complex stability under physiological conditions, along with their safety and antibacterial activity in contact with human cellular nature and two most predominant bacterial strains, respectively. A significant growth inhibition (17% after 20 h) is evidenced over time, paving the way toward an effective antibacterial therapy based on these copper-TSCN complexes.

Preparation and Characterization of Plasma-Derived Fibrin Hydrogels Modified by Alginate di-Aldehyde.

Fibrin hydrogels are one of the most popular scaffolds used in tissue engineering due to their excellent biological properties. Special attention should be paid to the use of human plasma-derived fibrin hydrogels as a 3D scaffold in the production of autologous skin grafts, skeletal muscle regeneration and bone tissue repair. However, mechanical weakness and rapid degradation, which causes plasma-derived fibrin matrices to shrink significantly, prompted us to improve their stability. In our study, plasma-derived fibrin was chemically bonded to oxidized alginate (alginate di-aldehyde, ADA) at 10%, 20%, 50% and 80% oxidation, by Schiff base formation, to produce natural hydrogels for tissue engineering applications. First, gelling time studies showed that the degree of ADA oxidation inhibits fibrin polymerization, which we associate with fiber increment and decreased fiber density; moreover, the storage modulus increased when increasing the final volume of CaCl2 (1% w/v) from 80 µL to 200 µL per milliliter of hydrogel. The contraction was similar in matrices with and without human primary fibroblasts (hFBs). In addition, proliferation studies with encapsulated hFBs showed an increment in cell viability in hydrogels with ADA at 10% oxidation at days 1 and 3 with 80 µL of CaCl2; by increasing this compound (CaCl2), the proliferation does not significantly increase until day 7. In the presence of 10% alginate oxidation, the proliferation results are similar to the control, in contrast to the sample with 20% oxidation whose proliferation decreases. Finally, the viability studies showed that the hFB morphology was maintained regardless of the degree of oxidation used; however, the quantity of CaCl2 influences the spread of the hFBs.

New Platinum(II) Triazole Thiosemicarbazone Complexes: Analysis of Their Reactivity and Potential Antitumoral Action.

The synthesis and characterization of three new platinum complexes, with 3,5-diacetyl-1,2,4-triazole bis(4-N-isopropylthiosemicarbazone) as a ligand, are reported. The specific conditions under which solvent coordination takes place are reported and the X-ray structure of the complex with one solvent molecule of dimethyl sulfoxide is resolved. Analysis of the reactivity of these platinum compounds aids in finding the best solution profile for biological investigations. Then, the interactions of the complexes with biological models, such as calf-thymus DNA, are studied by using UV spectroscopy and tracking the changes in electrophoretic mobility produced in the supercoiled plasmid DNA model. Initial screening of these potential antitumoral compounds indicates possible selective antitumoral action.

Thiosemicarbazone Derivatives as Inhibitors of Amyloid-ß Aggregation: Effect of Metal Coordination.

Three thiosemicarbazone derivatives, namely 4-(dimethylamino)benzaldehyde 4,4-dimethylthiosemicarbazone (HL1), 4-(dimethylamino)benzaldehyde thiosemicarbazone (HL2), and 4-(dimethylamino)benzaldehyde 4-methylthiosemicarbazone (HL3), have been synthesized and characterized. The three palladium(II) complexes 1-3 were prepared respectively from HL1, HL2, and HL3. The crystal structures of two coordination compounds, namely Pd(L2)2 (2) and Pd(L3)2 (3), were obtained, which showed the expected square-planar environment for the metal centers. The ligand HL3 and the Pd(II) complexes 1-3, which are stable in buffered solutions containing up to 5% DMSO, exhibit remarkable inhibitory properties against the aggregation of amyloid-ß, reducing the formation of fibrils. HL1, HL3, 2, and 3 display IC50 values (i.e., the concentrations required to reduce Aß fibrillation by 50%) below 1 µM, lower that of the reference compound catechin (IC50 = 2.8 µM). Finally, in cellulo studies with E. coli cells revealed that the palladium(II) compounds are significantly more efficient than the free ligands in inhibiting Aß aggregation inside bacterial inclusion bodies, thus illustrating a beneficial effect of metal coordination.

Versatile Route to trans-Platinum(II) Complexes via Manipulation of a Coordinated 3-(Pyridin-3-yl)propanoic Acid Ligand.

We describe the direct coupling of alcohols and amines to a 3-(pyridin-3-yl)propanoic acid ligand coordinated to a Pt(II) to afford ester and amide derivatives. Using this approach, a family of trans-Pt(II) compounds with amine ligands bearing long perfluorinated chains was prepared, as these chains potentially endow the complexes with thermoactivatable properties. Related compounds with alkyl chains in place of the perfluorinated chains were also prepared as controls using the same direct coupling method. The stability of the complexes in solution, their reactivity with DNA and proteins, and their antiproliferative activity evaluated in tumorigenic (A2780 and A2780cisR) and nontumorigenic (HEK293) cells at 37 °C and following exposure to elevated temperatures (that mimic the temperatures employed in thermotherapy) were also studied to assess their utility as putative (thermoactivated) anticancer agents.

Light-Responsive and Antibacterial Graphenic Materials as a Holistic Approach to Tissue Engineering.

While the continuous development of advanced bioprinting technologies is under fervent study, enhancing the regenerative potential of hydrogel-based constructs using external stimuli for wound dressing has yet to be tackled. Fibroblasts play a significant role in wound healing and tissue implants at different stages, including extracellular matrix production, collagen synthesis, and wound and tissue remodeling. This study explores the synergistic interplay between photothermal activity and nanomaterial-mediated cell proliferation. The use of different graphene-based materials (GBM) in the development of photoactive bioinks is investigated. In particular, we report the creation of a skin-inspired dressing for wound healing and regenerative medicine. Three distinct GBM, namely, graphene oxide (GO), reduced graphene oxide (rGO), and graphene platelets (GP), were rigorously characterized, and their photothermal capabilities were elucidated. Our investigations revealed that rGO exhibited the highest photothermal efficiency and antibacterial properties when irradiated, even at a concentration as low as 0.05 mg/mL, without compromising human fibroblast viability. Alginate-based bioinks alongside human fibroblasts were employed for the bioprinting with rGO. The scaffold did not affect the survival of fibroblasts for 3 days after bioprinting, as cell viability was not affected. Remarkably, the inclusion of rGO did not compromise the printability of the hydrogel, ensuring the successful fabrication of complex constructs. Furthermore, the presence of rGO in the final scaffold continued to provide the benefits of photothermal antimicrobial therapy without detrimentally affecting fibroblast growth. This outcome underscores the potential of rGO-enhanced hydrogels in tissue engineering and regenerative medicine applications. Our findings hold promise for developing game-changer strategies in 4D bioprinting to create smart and functional tissue constructs with high fibroblast proliferation and promising therapeutic capabilities in drug delivery and bactericidal skin-inspired dressings.

Dithiobiureas Palladium(II) complexes' studies: From their synthesis to their biological action.

Dithiobiureas coordination chemistry towards palladium (II) ions and their possible application is presented and discussed. 1,6-(4-Methoxyphenyl)-2,5-dithiobiurea and 1,6-(4-chlorophenyl)-2,5-dithiobiurea afford two Pd(II) complexes with the general formula [Pd2(H2L)Cl2(PPh3)2]. The metal ion forms one chelate ring with the dithiobiurea, and binds to a triphenylphosphine and an additional leaving group cisplatin like. One of the complexes (1) is endowed not only with stability in DMSO and aqua solutions containing a biological buffer but also with cytotoxicity versus gastric cancer cell lines. Complex 1 does not interact covalently to DNA models, neither activates p53 or Checkpoint Kinase 1 key proteins for DNA damage response. Thus, we propose that complex 1 exerts its action by activating Mitogen-Activated Protein Kinases [p38, Extracellular signal-regulated kinases (ERKs), c-Jun N-terminal kinases (JNKs)] as cell death inductors.

Technological advances in fibrin for tissue engineering.

Fibrin is a promising natural polymer that is widely used for diverse applications, such as hemostatic glue, carrier for drug and cell delivery, and matrix for tissue engineering. Despite the significant advances in the use of fibrin for bioengineering and biomedical applications, some of its characteristics must be improved for suitability for general use. For example, fibrin hydrogels tend to shrink and degrade quickly after polymerization, particularly when they contain embedded cells. In addition, their poor mechanical properties and batch-to-batch variability affect their handling, long-term stability, standardization, and reliability. One of the most widely used approaches to improve their properties has been modification of the structure and composition of fibrin hydrogels. In this review, recent advances in composite fibrin scaffolds, chemically modified fibrin hydrogels, interpenetrated polymer network (IPN) hydrogels composed of fibrin and other synthetic or natural polymers are critically reviewed, focusing on their use for tissue engineering.

Chemical and Biological Evaluation of Thiosemicarbazone-Bearing Heterocyclic Metal Complexes.

Thiosemicarbazones (TSCNs) constitute a broad family of compounds (R1R2C=N-NH-C(S)- NR3R4), particularly attractive because many of them display some biological activity against a wide range of microorganisms and cancer cells. Their activity can be related to their electronic and structural properties, which offer a rich set of donor atoms for metal coordination and a high electronic delocalization providing different binding modes for biomolecules. Heterocycles such as pyrrole, imidazole and triazole are present in biological molecules such as Vitamine B12 and amino acids and could potentially target multiple biological processes. Considering this, we have explored the chemistry and biological properties of thiosemicarbazones series and their complexes bearing heterocycles such as pyrrole, imidazole, thiazole and triazole. We focus at the chemistry and cytotoxicity of those derivatives to find out the structure activity relationships, and particularly we analyzed those examples with the TSCN units in which the mechanism of action information has been profoundly studied and pathways determined, to promote future studies for heterocycle derivatives.

Exploring DNA binding ability of two novel α-N-heterocyclic thiosemicarbazone palladium(II) complexes.

One mononuclear and another dinuclear Pd(II) complexes bearing a α-N-heterocyclic thiosemicarbazone ligand have been synthesized, fully characterized and studied as biological agents. In both complexes, the palladium center is coordinated to 3,5-diacetyl-1,2,4-triazol bis(N4,N4-dimethylthiosemicarbazone) via three sites (N, N and S). Their binding ability to DNA has been evaluated using spectroscopic and biophysical techniques. Molecular docking and molecular dynamics calculations supports the existence of a minor groove binding mode between the studied compounds and DNA.

Novel structures of platinum complexes bearing N­bisphosphonates and study of their biological properties.

Novel bisphosphonate platinum complexes: [Pt(isopropylamine)2(BP)]NO3 (BP = pamidronate and alendronate) have been synthesized and characterized. Their monomeric structure contains a bisphosphonate acting as chelate ligand through its oxygen atom donors, conferring the compound's cationic structure with a good solubility in water. The study of the compounds in solution showed high stability up to 24 h. The cytotoxicity in cancer cell lines has been assessed. We also present preliminary studies on the evaluation of the affinity towards biological targets such as DNA (both calf thymus DNA and supercoiled plasmid DNA) and hydroxyapatite where the complexes showed a low DNA interaction, but a clear affinity for hydroxyapatite comparing to their precursors.

Novel cyclopalladated and coordination palladium and platinum complexes derived from alpha-diphenyl ethanedione bis(thiosemicarbazones): structural studies and cytotoxic activity against human A2780 and A2780cisR carcinoma cell lines.

The preparation of new palladium(II) and platinum(II) complexes derived from alpha-diphenyl ethanedione bis(thiosemicarbazone), 1, and alpha-diphenyl ethanedione bis(4-ethylthiosemicarbazone), 2, is described. The palladium complexes 3 and 4 and platinum complexes 5 and 6 have been characterized by elemental analyses, fast atom bombardment mass spectrometry (FAB(+)) and spectroscopic studies (IR, (1)HNMR). The crystal and molecular structures of the dimeric cyclopalladated compound 4 and the mononuclear platinum complex 6 have been determined by single crystal X-ray diffraction. The cytotoxic activity of the free ligands and palladium and platinum complexes against human A2780 and A2780cisR (acquired resistance to cisplatin) epithelial ovarian carcinoma cells lines is also reported. The IC(50) values for compounds 1, 5 and 6 were found to be higher than that of cisplatin but the maximum antiproliferative activity was similar. Furthermore, the compounds largely retain their activity in the A2780cisR cell line, having a much better resistance factor than cisplatin in the pair of cell lines tested.

Palladium and platinum 3,5-diacetyl-1,2,4-triazol bis(thiosemicarbazones): chemistry, cytotoxic activity and structure-activity relationships.

The preparation of platinum(II) complexes derived from 3,5-diacetyl-1,2,4-triazol bis(4-phenylthiosemicarbazone) (H(5)L(1)), 3,5-diacetyl-1,2,4-triazol bis(thiosemicarbazone) (H(7)L(2)), 3,5-diacetyl-1,2,4-triazol bis(4-methylthiosemicarbazone) (H(5)L(3)) and 3,5-diacetyl-1,2,4-triazol bis(4-ethylthiosemicarbazone) (H(5)L(3)) is described. The new complexes [Pt(mu-H(3)L(1))](2), [Pt(mu-H(5)L(2))](2), [Pt(mu-H(3)L(3))](2) and [Pt(mu-H(3)L(4))](2) have been characterized by elemental analyses, fast atom bombardment mass spectrometry (FAB(+)) and spectroscopic studies. The crystal and molecular structure of compounds [Pt(mu-H(3)L(1))](2), parent ligand H(5)L(1) and [Pt(mu-H(3)L(3))](2) have been determined by single crystal X-ray diffraction. The ligands coordinate, in a dideprotonate form to the platinum ions in a new tridentate fashion (NNS) and S-brigding bonding modes. Thus the molecular units of the platinum complexes are stacked as dimers. The testing of the cytotoxic activity of the synthesized compounds together with their palladium analogues against human A2780 and A2780cisR epithelial ovarian carcinoma cells lines suggests that the compounds may be endowed with important antitumor properties since they show IC(50) values in a micromolar range similar to those of cisplatin. The structure and antitumor activity relationships of platinum and palladium complexes are also discussed.

New bioactive 2,6-diacetylpyridine bis(p-chlorophenylthiosemicarbazone) ligand and its Pd(II) and Pt(II) complexes: synthesis, characterization, cytotoxic activity and DNA binding ability.

Preparation and characterization of 2,6-diacetylpyridine bis((4)N-p-chlorophenylthiosemicarbazone) ligand, H2L, and its palladium(II) and platinum(II) complexes [PdL] and [PtL], is described. The molecular structure of the two new complexes has been determined by single crystal X-ray diffraction. The ligand acts as dianionic tetradentate donor coordinating to the metal center in a square planar geometry through the pyridine nitrogen atom and the azomethine nitrogen and thione sulfur atoms from one thiosemicarbazone arm, the fourth coordination position is occupied by the hydrazine nitrogen atom of the other arm. New free ligand and its metal complexes have been evaluated for antiproliferative activity in vitro against NCI-H460, T-47D, A2780 and A2780cisR human cancer cell lines. The cytotoxicity data suggest that these compounds may be endowed with important antitumor properties, especially H2L and [PtL] since they are capable of not only circumvent cisplatin resistance in A2780cisR cells but also exhibit high antiproliferative activity in breast cancer T-47D cells. The interaction of H2L with calf thymus DNA was also investigated and its binding constant (Kb) determined.

Palladium(II) and platinum(II) bis(thiosemicarbazone) complexes of the 2,6-diacetylpyridine series with high cytotoxic activity in cisplatin resistant A2780cisR tumor cells and reduced toxicity.

Preparation and characterization of four novel 2,6-diacetylpyridine bis((4)N-tolylthiosemicarbazonato) palladium(II) and platinum(II) complexes, [PdL(1-2)] and [PtL(1-2)], are described. All compounds have been characterized by elemental analysis and by IR and NMR spectroscopy, and the crystal and molecular structures of complexes [PdL(2)] and [PtL(2)] have been determined by a single crystal X-ray diffraction. The ligands act as dianionic tetradentate donors coordinating to the metal center in a square planar geometry through the Npyridinic atom and the Niminic and the S atoms from one thiosemicarbazone arm, the fourth coordination position is occupied by the Nhydrazinic of the other arm. The new compounds synthesized have been evaluated for antiproliferative activity in vitro against NCI-H460, HepG2, MCF-7, A2780 and A2780cisR human cancer cell lines. The cytotoxicity data suggest that [PdL(1)], [PdL(2)] and [PtL(2)] may be endowed with important antitumor properties since they are capable of not only circumventing cisplatin resistance in A2780cisR cells but also exhibiting high antiproliferative activity in breast cancer MCF-7 cells. Subsequent toxicity study, in LLC-PK1 cells, has also been carried out and shows that none of these compounds are in vitro toxic in the tested concentration range.

New palladium and platinum complexes with bioactive 3,5-diacetyl-1,2,4-triazol bis(4-cyclohexyl thiosemicarbazone) ligand: chemistry, antiproliferative activity and preliminary toxicity studies.

The preparation and characterization of the new 3,5-diacetyl-1,2,4-triazol bis(4-cyclohexyl thiosemicarbazone) ligand, H(5)L(1), is described. Treatment of H(5)L(1) with K(2)PtCl(4) gave the dinuclear complex [Pt(H(3)L(1))](2), 1, but using MCl(2)(PPh(3))(2) where M = Pd or Pt, mononuclear complexes 2 and 3, of general formula [M(H(3)L(1))PPh(3)], were obtained. Subsequent reaction of the [Pd(H(3)L(1))PPh(3)] complex with PdCl(2)(PPh(3))(2) yielded a new dinuclear complex [(PPh(3))Pd(H(2)L(1))PdCl], 4. All compounds have been characterized by elemental analysis and FAB(+) spectrometry and by IR and NMR spectroscopy. The molecular structures of mononuclear complexes 2 and 3 and dinuclear complex 4 have been determined by X-ray crystallography. The new compounds synthesized have been evaluated for antiproliferative activity in vitro against NCI-H460, HepG2, MCF-7, A2780 and A2780cisR human cancer cell lines. The cytotoxicity data suggest that the H(5)L(1) ligand and [Pt(H(3)L(1))](2), complex 1, may be endowed with important cytotoxic properties since they are capable of not only circumventing cisplatin resistance in A2780cisR but also exhibit antiproliferative activity in NCI-H460. The interactions of these compounds with calf thymus DNA were investigated by UV-vis absorption and a nephrotoxic study, in LLC-PK1 cells, has also been carried out.

3,5-diacetyl-1,2,4-triazol bis(4N-substituted thiosemicarbazone) palladium(II) complexes: synthesis, structure, antiproliferative activity and low toxicity on normal kidney cells.

Treatment of (4)N-monosubstituted bis(thiosemicarbazone) ligands of 3,5-diacetyl-1,2,4-triazol series with lithium tetrachloridopalladate gave the dinuclear complexes of general formula [Pd(µ-H(3)L(1-5))](2), but using dichloridobistriphenylphosphinepalladium(II) salt, the first mononuclear bis(thiosemicarbazone)-palladium-triphenylphosphine complexes of the 3,5-diacetyl-1,2,4-triazol series, [Pd(H(3)L(1-5))PPh(3)], have been obtained. All the compounds have been characterized by elemental analysis and by IR and NMR spectroscopy, and the crystal and molecular structures of dinuclear complexes [Pd(µ-H(3)L(3))](2) and [Pd(µ-H(3)L(5))](2) as well as mononuclear complexes [Pd(H(3)L(1))PPh(3)], [Pd(H(3)L(2))PPh(3)], [Pd(H(3)L(3))PPh(3)] and [Pd(H(3)L(4))PPh(3)] have been determined by X-ray crystallography. The new compounds synthesized have been evaluated for antiproliferative activity in vitro against NCI-H460, A2780 and A2780cisR human cancer cell lines. Subsequent toxicity study, on normal renal LLC-PK1 cells, shows that all compounds investigated exhibit very low toxicity on kidney cells with respect to cisplatin.

Novel bis(thiosemicarbazones) of the 3,5-diacetyl-1,2,4-triazol series and their platinum(II) complexes: chemistry, antiproliferative activity and preliminary nephrotoxicity studies.

The preparation and characterization of three novel (4)N-monosubstituted bis(thiosemicarbazone) ligands of 3,5-diacetyl-1,2,4-triazol series and their dinuclear platinum complexes are described. The crystal and molecular structure of the [Pt(µ-H(3)L(3))](2) complex derived of 3,5-diacetyl-1,2,4-triazol bis((4)N-p-tolylthiosemicarbazone), H(5)L(3), has been resolved by single crystal X-ray diffraction. The ligands coordinate, in an asymmetric dideprotonate form, to the platinum ions in a tridentate fashion (NNS) and S-bridging bonding modes. Thus the molecular units of the platinum complexes are stacked as dimers. The new compounds synthesized have been evaluated for antiproliferative activity in vitro against NCI-H460, A2780 and A2780cisR human cancer cell lines. The cytotoxicity data suggest that these compounds may be endowed with important antitumour properties since are capable of not only circumventing cisplatin resistance in A2780cisR cells but also exhibit high antiproliferative activity in human non-small cell lung cancer NCI-H460 cells. The interactions of these compounds with calf thymus DNA was investigated by UV-vis absorption and a nephrotoxic study, in LLC-PK1 cells, has also been carried out.

Chemistry, antiproliferative activity and low nephrotoxicity of 3,5-diacetyl-1,2,4-triazol bis(4N-thiosemicarbazone) ligands and their platinum(II) complexes.

The preparation and characterization of 3,5-diacetyl-1,2,4-triazol bis(4,4-dimethylthiosemicarbazone) ligand, H(3)L(1), and its dinuclear platinum complex [Pt(mu-HL(1))](2) is described. The crystal and molecular structure of the platinum complex has been resolved by single crystal X-ray diffraction. The ligands coordinate, in an asymmetric dideprotonate form, to the platinum ions in a tridentate fashion (NNS) and S-bridging bonding modes. Thus the molecular units of the platinum complexes are stacked as dimers. The new compounds synthesized together with the analogous monosubstituted ligand 3,5-diacetyl-1,2,4-triazol bis(4-methylthiosemicarbazone) (H(5)L(2)) and its dinuclear platinum(ii) complex [Pt(mu-H(3)L(2))](2) have been evaluated for antiproliferative activity in vitro against NCI-H460, A2780 and A2780cisR human cancer cell lines. The cytotoxicity data suggest that these compounds may be endowed with important antitumor properties, especially H(3)L(1) and [Pt(mu-H(3)L(2))](2) since they not only circumvent cisplatin resistance in A2780cisR cells but also exhibit high antiproliferative activity in human non-small cell lung cancer NCI-H460 cells. Subsequent nephrotoxic study, in LLC-PK1 cells, show that the four compounds investigated exhibit very low nephrotoxicity with respect to cisplatin.