Photo-induced antibacterial activity of four graphene based nanomaterials on a wide range of bacteria

Due to controversial reports concerning antibacterial activity of different graphene based materials it is very important to investigate their antibacterial action on a wide range of Gram-positive and Gram-negative bacteria. In this paper we have investigated the structure induced phototoxic antibacterial activity of four types of graphene based materials: graphene oxide (GO), graphene quantum dots (GQDs), carbon quantum dots (CQDs) and nitrogen doped carbon quantum dots (N-CQDs). Antibacterial activity was tested on 19 types of bacteria. It is found that nanometer-size CQDs and N-CQDs are the most potent agents whereas micrometer-size GO has very poor antibacterial activity. Electron paramagnetic resonance measurements confirmed photodynamic production of singlet oxygen for all types of used quantum dots. Detailed analysis has shown that N-CQDs are an excellent photodynamic antibacterial agent for treatment of bacterial infections induced by Enterobacter aerogenes (E. aerogenes), Proteus mirabilis (P. mirabilis), Staphylococcus saprophyticus (S. saprophyticus), Listeria monocytogenes (L. monocytogenes), Salmonella typhimurium (S. typhimurium) and Klebsiella pneumoniae

Encapsulation of cobalt nanoparticles in cross-linked-polymer cages

10.1016/j.jmmm.2009.01.014Journal of Magnetism and Magnetic Materials321142135-2138JMMM

Colorimetric Disposable Paper Coated with ZnO@ZnS Core-Shell Nanoparticles for Detection of Copper Ions in Aqueous Solutions

In this study, we have proposed a new nanoparticle-containing test paper sensor that could be used as an inexpensive, easy-to-use, portable, and highly selective sensor to detect Cu2+ ions in aqueous solutions. This disposable paper sensor is based on ZnO@ZnS core-shell nanoparticles. The core-shell nanoparticles were synthesized using a chemical method and then they were used for coating the paper. The synthesis of the ZnO@ZnS core-shell nanoparticles was performed at a temperature as low as 60 degrees C, and so far this is the lowest temperature for the synthesis of such core-shell nanoparticles. The sensitivity of the paper sensor was investigated for different Cu2+ ion concentrations in aqueous solutions and the results show a direct linear relation between the Cu2+ ions concentration and the color intensity of the paper sensor with a visual detection limit as low as 15 mu M (similar to 0.96 ppm). Testing the present paper sensor on real river turbulent water shows a maximum 5% relative error for determining the Cu2+ ions concentration, which confirms that the presented paper sensor can successfully be used efficiently for detection in complex solutions with high selectivity. Photographs of the paper sensor taken using a regular digital camera were transferred to a computer and analyzed by ImageJ Photoshop software. This finding demonstrates the potential of the present disposable paper sensor for the development of a portable, accurate, and selective heavy metal detection technology.Funding Agencies|Shahid Chamran University; Linkoping University</p

Fabrication of graphene-silver/polyurethane nanofibrous scaffolds for cardiac tissue engineering

The graphene-based nanocomposites are considered as great candidates for enhancing electrical and mechanical properties of nonconductive scaffolds in cardiac tissue engineering. In this study, reduced graphene oxide-silver (rGO-Ag) nanocomposites (1 and 2 wt) were synthesized and incorporated into polyurethane (PU) nanofibers via electrospinning technique. Next, the human cardiac progenitor cells (hCPCs) were seed on these scaffolds for in vitro studies. The rGO-Ag nanocomposites were studied by X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscope (TEM). After incorporation of rGO-Ag into PU nanofibers, the related characterizations were carried out including scanning electron microscope (SEM), TEM, water contact angle, and mechanical properties. Furthermore, PU and PU/nanocomposites scaffolds were used for in vitro studies, wherein hCPCs showed good cytocompatibility via 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and considerable attachment on the scaffold using SEM studies. Real-time polymerase chain reaction (PCR) and immunostaining studies confirmed the upregulation of cardiac specific genes including GATA-4, T-box 18 (TBX 18), cardiac troponin T (cTnT), and alpha-myosin heavy chain (α-MHC) in the PU/rGO-Ag scaffolds in comparison with neat PU ones. Therefore, these nanofibrous rGO-Ag�reinforced PU scaffolds can be considered as suitable candidates in cardiac tissue engineering. © 2019 John Wiley & Sons, Ltd

Fabrication of graphene-silver/polyurethane nanofibrous scaffolds for cardiac tissue engineering

© 2019 John Wiley & Sons, Ltd. The graphene-based nanocomposites are considered as great candidates for enhancing electrical and mechanical properties of nonconductive scaffolds in cardiac tissue engineering. In this study, reduced graphene oxide-silver (rGO-Ag) nanocomposites (1 and 2 wt%) were synthesized and incorporated into polyurethane (PU) nanofibers via electrospinning technique. Next, the human cardiac progenitor cells (hCPCs) were seed on these scaffolds for in vitro studies. The rGO-Ag nanocomposites were studied by X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscope (TEM). After incorporation of rGO-Ag into PU nanofibers, the related characterizations were carried out including scanning electron microscope (SEM), TEM, water contact angle, and mechanical properties. Furthermore, PU and PU/nanocomposites scaffolds were used for in vitro studies, wherein hCPCs showed good cytocompatibility via 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and considerable attachment on the scaffold using SEM studies. Real-time polymerase chain reaction (PCR) and immunostaining studies confirmed the upregulation of cardiac specific genes including GATA-4, T-box 18 (TBX 18), cardiac troponin T (cTnT), and alpha-myosin heavy chain (α-MHC) in the PU/rGO-Ag scaffolds in comparison with neat PU ones. Therefore, these nanofibrous rGO-Ag–reinforced PU scaffolds can be considered as suitable candidates in cardiac tissue engineering