Effects of Bis(imino)acenaphthene (Bian)-Derived Ligands on the Cytotoxicity, DNA Interactions, and Redox Activity of Palladium(II) Bipyridine Complexes.

A series of heteroleptic bipyridine Pd(II) complexes based on 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (dpp-Bian) or 1,2-bis[(2,4,6-trimethylphenyl)imino]acenaphthene (tmp-Bian) were prepared. All complexes were fully characterized by spectrochemical methods, and their crystal structures were confirmed by X-ray diffraction analysis. The 72 h stability of heteroleptic bipyridine Pd(II) complexes with Bian ligands under physiological conditions was investigated using 1H NMR spectroscopy. The anticancer activity of all complexes was assessed in a panel of cancer cell lines in comparison with uncoordinated ligands and clinically used drugs cisplatin and doxorubicin. The ability of the complexes to bind DNA was investigated using several methods, including EtBr replacement assay, density functional theory calculations, circular dichroism spectroscopy, DNA gel electrophoresis, and TUNEL assay. The electrochemical activity of all complexes and the uncoordinated ligands was studied using cyclic voltammetry, and reactive oxygen species production in cancer cells was investigated using confocal microscopy. Heteroleptic bipyridine PdII-Bian complexes were cytotoxic in a low micromolar concentration range and showed some selectivity toward cancer cells in comparison with noncancerous MRC-5 lung fibroblasts.

Chain-End Functionalization of Poly(ε-caprolactone) for Chemical Binding with Gelatin: Binary Electrospun Scaffolds with Improved Physico-Mechanical Characteristics and Cell Adhesive Properties.

Composite biocompatible scaffolds, obtained using the electrospinning (ES) technique, are highly promising for biomedical application thanks to their high surface area, porosity, adjustable fiber diameter, and permeability. However, the combination of synthetic biodegradable (such as poly(ε-caprolactone) PCL) and natural (such as gelatin Gt) polymers is complicated by the problem of low compatibility of the components. Previously, this problem was solved by PCL grafting and/or Gt cross-linking after ES molding. In the present study, composite fibrous scaffolds consisting of PCL and Gt were fabricated by the electrospinning (ES) method using non-functionalized PCL1 or NHS-functionalized PCL2 and hexafluoroisopropanol as a solvent. To provide covalent binding between PCL2 and Gt macromolecules, NHS-functionalized methyl glutarate was synthesized and studied in model reactions with components of spinning solution. It was found that selective formation of amide bonds, which provide complete covalent bonding of Gt in PCL/Gt composite, requires the presence of weak acid. With the use of the optimized ES method, fibrous mats with different PCL/Gt ratios were prepared. The sample morphology (SEM), hydrolytic resistance (FT-IR), cell adhesion and viability (MTT assay), cell penetration (fluorescent microscopy), and mechanical characteristics of the samples were studied. PCL2-based films with a Gt content of 20 wt% have demonstrated the best set of properties.

Antibacterial Poly(ε-CL)/Hydroxyapatite Electrospun Fibers Reinforced by Poly(ε-CL)-b-poly(ethylene phosphoric acid).

In bone surgery and orthopedics, bioresorbable materials can be helpful in bone repair and countering post-op infections. Explicit antibacterial activity, osteoinductive and osteoconductive effects are essential to achieving this objective. Nonwoven electrospun (ES) fibers are receiving the close attention of physicians as promising materials for wound dressing and tissue engineering; potentially, in high contrast with dense materials, ES mats hamper regeneration of the bone extracellular matrix to a lesser extent. The use of the compositions of inherently biodegradable polyesters (poly(ε-caprolactone) PCL, poly(lactoglycolide), etc.), calcium phosphates and antibiotics is highly prospective, but the task of forming ES fibers from such compositions is complicated by the incompatibility of the main organic and inorganic ingredients, polyesters and calcium phosphates. In the present research we report the synthesis of hydroxyapatite (HAp) nanoparticles with uniform morphology, and demonstrate high efficiency of the block copolymer of PCL and poly(ethylene phosphoric acid) (PEPA) as an efficient compatibilizer for PCL/HAp mixtures that are able to form ES fibers with improved mechanical characteristics. The materials obtained in the presence of vancomycin exhibited incremental drug release against Staphylococcus aureus (St. aureus).