Biocompatible Porous Scaffolds of Chitosan/Poly(EG-ran-PG) Blends with Tailored Pore Size and Nontoxic to Mesenchymal Stem Cells: Preparation by Controlled Evaporation from Aqueous Acetic Acid Solution

The preparation of porous films (average size variation from 1 to 32 μm) of a 1:1 blend of chitosan with poly­(EG-ran-PG) by the controlled evaporation of water from a 2 wt % aqueous acetic acid solution is reported. Interestingly, the blend exhibited porosity that could be tailored from 1 to 32 μm with the temperature of preparation of the blend film. The powder X-ray diffraction, Fourier transform infrared, and differential scanning calorimetry analyses of the films suggested the formation of partially miscible blends. Temperature-induced phase separation of the blend appears to be the mechanism of pore formation. The tensile strength, cytotoxicity, and biocompatibility of the blend films for the growth of mesenchymal stem cells were assessed vis-a-vis chitosan. The 1:1 blend film was observed to lack cytotoxicity and was also viable for the growth of mesenchymal stem cells. The tensile properties of the 1:1 blend were superior to those of the chitosan film. The simple preparation of porous, nontoxic, and biocompatible films could find use as a scaffold in the growth of tissue, and especially bone tissue, in wound dressing, and in filtration if a better control over pore size is achieved

Mixed-ligand copper(II) complex of quercetin regulate osteogenesis and angiogenesis

Copper(II) complex of quercetin Cu + Q, mixed ligand complexes, quercetin-Cu(II)-phenanthroline [Cu + Q(PHt)] and quercetin-Cu(II)-neocuproine [Cu + Q(Neo)] have been synthesized and characterized. From the FT-IR spectroscopic studies, it was evident that C-ring of quercetin is involved in the metal chelation in all the three copper complexes. C-ring chelation was further proven by UV–Visible spectra and the presence of Cu(II) from EPR spectroscopic investigations. These complexes were found to have osteogenic and angiogenic properties, observed through in vitro osteoblast differentiation and chick embryo angiogenesis assay. In osteoblast differentiation, quercetin-Cu(II) complexes treatment increased calcium deposition and alkaline phosphatase activity (ALP) activity at the cellular level and stimulated Runx2 mRNA and protein, ALP mRNA and type 1 collagen mRNA expression at the molecular level. Among the complexes, Q + Cu(PHt) showed more effects on osteoblast differentiation when compared to that of other two copper complexes. Additionally, Q + Cu(Neo) showed more effect compared to Q + Cu. Furthermore, the effect of these complexes on osteoblast differentiation was confirmed by the expression of osteoblast specific microRNA, pre-mir-15b. The chick embryo angiogenesis assay showed that angiogenic parameters such as blood vessel length, size and junctions were stimulated by these complexes. Thus, the present study demonstrated that quercetin copper(II) complexes exhibit as a pharmacological agent for the orthopedic application

Investigation of nuclease, proteolytic and antiproliferative effects of copper(II) complexes of thiophenylmethanamine derivatives

Four coordinate copper(II) complexes 1, 2 and 3 of ligands based on thiophenemethylamine containing imidazole, benzimidazole and pyridine moiety have been synthesized and characterized. Complex 1 has also been crystallographically characterized. The three complexes bind to DNA non-intercalatively, though partial intercalation in the case of complex 2 cannot be ruled out. All the three complexes bring about hydroxyl radical mediated DNA cleavage in the presence of H2O2. Binding of the three copper(II) complexes to BSA lead to changes in the helicity of the protein. Among the three complexes, 2 and 3 are more effective in inhibiting the growth of cancerous MG63 cells than normal NIH3T3 cells. These two complexes promote apoptosis in MG 63 cells

Polyphenols-loaded electrospun nanofibers in bone tissue engineering and regeneration

Abstract Bone is a complex structure with unique cellular and molecular process in its formation. Bone tissue regeneration is a well-organized and routine process at the cellular and molecular level in humans through the activation of biochemical pathways and protein expression. Though many forms of biomaterials have been applied for bone tissue regeneration, electrospun nanofibrous scaffolds have attracted more attention among researchers with their physicochemical properties such as tensile strength, porosity, and biocompatibility. When drugs, antibiotics, or functional nanoparticles are taken as additives to the nanofiber, its efficacy towards the application gets increased. Polyphenol is a versatile green/phytochemical small molecule playing a vital role in several biomedical applications, including bone tissue regeneration. When polyphenols are incorporated as additives to the nanofibrous scaffold, their combined properties enhance cell attachment, proliferation, and differentiation in bone tissue defect. The present review describes bone biology encompassing the composition and function of bone tissue cells and exemplifies the series of biological processes associated with bone tissue regeneration. We have highlighted the molecular mechanism of bioactive polyphenols involved in bone tissue regeneration and specified the advantage of electrospun nanofiber as a wound healing scaffold. As the polyphenols contribute to wound healing with their antioxidant and antimicrobial properties, we have compiled a list of polyphenols studied, thus far, for bone tissue regeneration along with their in vitro and in vivo experimental biological results and salient observations. Finally, we have elaborated on the importance of polyphenol-loaded electrospun nanofiber in bone tissue regeneration and discussed the possible challenges and future directions in this field

DNA binding and cleavage activity of a structurally characterized oxobridged diiron(III) complex

1576-1583The synthesis, crystal structure and variable temperature magnetic measurement of an oxobridged dinuclear Fe(III) complex [Fe2O(phen)4Cl2](NO3)2 (1) [phen =1,10-phenanthroline] is reported. From X-ray diffractometry, it is shown that each Fe(III) in the compound is in distorted octahedral environment. Variable temperature magnetic study reveals strong antiferromagnetic behaviour of (<b style="mso-bidi-font-weight: normal">1) with = –104±2 cm-1, p = 0.8% and TIP = 280×10-6 cm-1, fixing g = 2.00. The binding property of the complex with calf thymus DNA has been investigated using absorption and emission studies, circular dichroism spectral investigations, thermal melting and viscosity experiments. The binding constant and the linear Stern-Volmer quenching constant of the complex have been determined to be 1.49×103 M-1 (<i style="mso-bidi-font-style: normal">R = 0.99922 for five points) and 2.02×103 (<i style="mso-bidi-font-style: normal">R = 0.99917 for five points), respectively. Spectroscopic and hydrodynamic investigations reveal a mixed mode involving groove binding along with partial intercalative interaction of (1) with CT-DNA. (1)<b style="mso-bidi-font-weight: normal"> is found to induce oxidative cleavage of the DNA from its supercoiled to both nicked circular and linear forms in a concentration-dependent manner