Morphological modification of silver nanoparticles against multi-drug resistant gram-negative bacteria and cytotoxicity effect in A549 lung cancer cells through in vitro approaches.

In the present study, the individual cultures of Proteus mirabilis (P. mirabilis) and Klebsiella pneumoniae (K. pneumoniae) were treated with morphologically modified silver nanoparticles (Ag NPs) and were found to display zones of inhibition of ~ 8 mm, 16 mm, 20 mm, and 22 mm (P. mirabilis) and 6 mm, 14 mm, 20 mm, and 24 mm (K. pneumoniae) at concentrations of 25 µg/ml, 50 µg/mL, 75 µg/mL, and 100 µg/mL, respectively. In addition, turbidity tests were performed based on O. D. values, which exhibited 92% and 90% growth inhibitions at 100 µg/mL concentration for P. mirabilis and K. pneumoniae, respectively. Furthermore, the IC50 concentration of Ag NPs was established for A549 lung cancer cells and found to be at 500 µg/mL. Evidently, the morphological variation of Ag NPs treated A549 lung cancer cells was exhibited with differential morphology studied by phase-contrast microscopy. The results demonstrated that the synthesized Ag NPs was not only efficient against gram-positive bacteria but also against gram-negative bacteria and A549 cancer cells, suggesting that the potential of these biosynthesized Ag NPs is a future drug discovery source for inhibiting bacteria and cancer cells.

Enhanced anti-cancer activity of chitosan loaded Morinda citrifolia essential oil against A549 human lung cancer cells.

In the present study, the chemical composition of Morinda citrifolia essential oils was determined by gas chromatography-mass spectrometry and was found to contain several anti-cancer compounds including L-scopoletin, nordamnacanthal, ß-morindone, α-copaene, 9-H-pyrido[3,4-b]indole, ß-thujene and terpinolene. The physico-chemical characterization of chitosan, chitosan nanoparticles and Morinda citrifolia essential oils loaded chitosan nanoparticles combination was carried out by Fourier transform infrared spectroscopy, powder X-ray diffraction and dynamic light scattering coupled with zeta potential. The morphological observation obtained by scanning electron microscopy and transmission electron microscopy provided clear indication that the immobile chitosan polymer formed a coating onto the Morinda citrifolia essential oils surface. The cytotoxic effect of Morinda citrifolia essential oils loaded chitosan nanoparticles against A549 cells were investigated, resulting in 54% inhibition at 40 µg/ml-1. Information about in vitro morphological modification, nucleus damages, ROS generation and cell cycle arrest was obtained by fluorescence microscopy and flow cytometer analysis. The toxicity evaluation against human red blood cells suggested that the Morinda citrifolia essential oils loaded chitosan nanoparticles possess minimum cytotoxicity. Altogether, the present study suggests that these Morinda citrifolia essential oils loaded chitosan nanoparticles are valuable biomaterials owing to their ability to fight against A549 cancer cells.

Cold-adaptation of a methacrylamide gelatin towards the expansion of the biomaterial toolbox for specialized functionalities in tissue engineering.

Tissue regeneration is witnessing a significant surge in advanced medicine. It requires the interaction of scaffolds with different cell types for efficient tissue formation post-implantation. The presence of tissue subtypes in more complex organs demands the co-existence of different biomaterials showing different hydrolysis rate for specialized cell-dependent remodeling. To expand the available toolbox of biomaterials with sufficient mechanical strength and variable rate of enzymatic degradation, a cold-adapted methacrylamide gelatin was developed from salmon skin. Compared with mammalian methacrylamide gelatin (GelMA), hydrogels derived from salmon GelMA displayed similar mechanical properties than the former. Nevertheless, salmon gelatin and salmon GelMA-derived hydrogels presented characteristics common of cold-adaptation, such as reduced activation energy for collagenase, increased enzymatic hydrolysis turnover of hydrogels, increased interconnected polypeptides molecular mobility and lower physical gelation capability. These properties resulted in increased cell-remodeling rate in vitro and in vivo, proving the potential and biological tolerance of this mechanically adequate cold-adapted biomaterial as alternative scaffold subtypes with improved cell invasion and tissue fusion capacity.

Graphene/nickel oxide nanocomposites against isolated ESBL producing bacteria and A549 cancer cells.

The synthesis of nickel oxide nanoparticles (NiO NPs) and graphene/nickel oxide nanocomposites (Gr/NiO NCs) was performed using a simple chemical reduction method. Powder X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were used to examine the crystalline nature and thermal stability of the synthesized NiO NPs and Gr/NiO NCs, respectively. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were utilized to observe the morphology of NiO NPs and Gr/NiO NCs and estimate their size range. TEM suggested that the NiO NPs were speared onto the surface of Gr nanosheet. The efficiency of NiO NPs and Gr/NiO NCs against extended spectrum ß-lacamase (ESBL) producing bacteria, which was confirmed by specific HEXA disc Hexa G-minus 24 (HX-096) and MIC strip methods (CLSI); namely Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) was investigated using the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) methods. MIC results suggested that the NiO NPs and Gr/NiO NCs possess maximum growth inhibition of 86%, 82% and 94%, 92% at 50 and 30 µg/mL concentrations, respectively. Similarly, both nanomaterials were found to inhibit the ß-lacamase enzyme at concentrations of 60 µg/mL and 40 µg/mL, respectively. The cytotoxicity of NiO NPs and Gr/NiO NCs was quantified against A549 human lung cancer cells. Cell death percentage values of 52% at 50 µg/mL against NiO NPs and 54% at 20 µg/mL against Gr/NiO NCs were obtained, respectively. The NCs were found to reduce cell viability, increase the level of reactive oxygen species (ROS) and modify both the mitochondrial membrane permeability and cell cycle arrest.