Reconstruction of jaw bone defects present a significant problem because of specific aesthetic and functional requirements. Although widely used, the transplantation of standard autograft and allograft materials is still associated with significant constraints. Composite scaffolds, combining advantages of biodegradable polymers with bioceramics, have potential to overcome limitations of standard grafts. Polyethyleneimine could be an interesting novel biocompatible polymer for scaffold construction due to its biocompatibility and chemical structure. To date, there have been no in vivo studies assessing biological properties of hydroxyapatite bioceramics scaffold modified with polyethyleneimine. The aim of this study was to evaluate in vivo effects of composite scaffolds of hydroxyapatite ceramics and poly(lactide-co-glycolide) and novel polyethyleneimine on bone repair in swine’s mandibular defects, and to compare them to conventional bone allograft (BioOss). Scaffolds were prepared using the method of polymer foam template in three steps. Pigs, 3 months old, were used and defects were made in the canine, premolar, and molar area of their mandibles. Four months following the surgical procedure, the bone was analyzed using radiological, histological, and gene expression techniques. Hydroxyapatite ceramics/polyethyleneimine composite scaffold demonstrated improved biological behavior compared to conventional allograft in treatment of swine’s mandibular defects, in terms of bone density and bone tissue histological characteristics.

The synthesis and structural characterization of a newly synthesized mononuclear rhodium(III) complex, Rhtrz, with a ligand (2,2,6-bis((4S,7R)-7,8,8-trimethyl-4,5,6,7-tetrahydro-1H-4,7-methanoindazol-3-yl)pyridine) and a ligand of 1,2,4-triazole, are presented in this paper. The kinetic interactions of the Rhtrz complex with essential biomolecules such as 5-GMP, L-Met, and GSH were examined. The study of the biological interactions was focused on the binding properties of the Rhtrz complex with CT-DNA and serum albumin. These interactions were investigated using UV-vis spectrophotometry, fluorescence spectroscopy, viscosity measurements, thermal denaturation studies, and electrophoresis. Fluorescence competition experiments with site-markers for BSA were used to locate the binding site of the Rhtrz-complex to the BSA. Molecular docking studies were carried out to obtain detailed binding information of the complex with CT-DNA, BSA, and HSA. Furthermore, the apparent distance between the donor (HSA) and acceptor (Rhtrz) was determined using fluorescence resonance energy transfer (FRET). The thermodynamic properties and relative stabilities of the Rhtrz complex were examined, constructing the two model equation by DFT calculations (B3LYP(CPCM)/LANL2DZp). In vitro cytotoxicity and redox status on the human epithelial colorectal cancer cell line (HCT-116) and healthy human fibroblast cell line (MRC-5) were also investigated.

Two gold(III) complexes, square-planar [Au(DPP)Cl₂]⁺(1) and distorted square-pyramidal [Au(DMP)Cl₃] (2) (where DMP = 2,9-dimethyl-1,10-phenanthroline and DPP = 4,7-diphenyl-1,10-phenanthroline), were studied by different experimental methods. Their stability in water and in buffer solution (25 mM Hepes, 30 mM NaCl, pH = 7.2) was investigated by UV-Vis spectroscopy while their redox stability is confirmed by CV. Substitution reactions between complexes 1 and 2, and biologically relevant ligands, such as thiourea (Tu), guanosine-5′-monophosphate (5′-GMP), glutathione (GSH) and L-methionine (L-Met), were studied by a stopped-flow technique, under the pseudo-first order conditions as a function of ligand concentration and temperature. According to the values of the activation parameters, all studied reactions followed an associative substitution mechanism. DNA binding studies of complexes 1 and 2 were performed by UV-Vis and fluorescence spectroscopy and viscosity measurements, as well as interactions with bovine serum albumin (BSA). Density functional theory (DFT) was implemented in order to analyse the wave function of the optimized structures to get better insight into the binding interactions between the inert ligands and gold(III) center. The experimental results of binding studies with DNA and BSA were simulated and compared by performing a molecular docking study. All results demonstrate the strong connection between the reactivity of the complexes toward biologically important targets and their structural and electronic characteristics. The cytotoxic activity of complexes 1 and 2 against different cell lines (MDA-MB-231, HCT-116, and HaCaT) was evaluated 24 and 72 h after treatments. The results indicate reduced viability of cell lines in a time- and dose-dependent manner.