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Graphene bacteria

Massimiliano Papi, Valentina Palmieri, Francesca Bugli, Marco De Spirito, Maurizio Sanguinetti, Carlotta Ciancico, Maria Chiara Braidotti, Silvia Gentilini, Luca Angelani, Claudio Conti
Antibacterial surfaces have an enormous economic and social impact on the worldwide technological fight against diseases. However, bacteria develop resistance and coatings are often not uniform and not stable in time. The challenge is finding an antibacterial coating that is biocompatible, cost-effective, not toxic, and spreadable over large and irregular surfaces. Here we demonstrate an antibacterial cloak by laser printing of graphene oxide hydrogels mimicking the Cancer Pagurus carapace. We observe up to 90% reduction of bacteria cells...
December 2016: Scientific Reports
Ruoyu Zhang, Xiaolei Cai, Guangxue Feng, Bin Liu
Toxins and bacteria in water or food pose a threat to human life and could potentially be exploited for bioterrorism. Real-time naked-eye detection of these contaminants is highly desirable to provide a direct and simple analytical method and address the challenges of the existing strategies. Using the detection of ricin and B. subtilis as an example, a naked-eye multiplex detection model is established. In this work, a green fluorogen with aggregation-induced emission (AIE) characteristics was encapsulated in silica nanoshells...
December 5, 2016: Faraday Discussions
Feike J Leij, Scott A Bradford, Antonella Sciortino
Elucidating and quantifying the transport of industrial nanoparticles (e.g. silver, carbon nanotubes, and graphene oxide) and other colloid-size particles such as viruses and bacteria is important to safeguard and manage the quality of the subsurface environment. Analytic solutions were derived for aqueous and solid phase colloid concentrations in a porous medium where colloids were subject to advective transport and reversible time and/or depth-dependent retention. Time-dependent blocking and ripening retention were described using a Langmuir-type equation with a rate coefficient that respectively decreased and increased linearly with the retained concentration...
November 1, 2016: Journal of Contaminant Hydrology
Donglei Jiang, Dongdong Feng, Hui Jiang, Limin Yuan, Yin Yongqi, Xin Xu, Weiming Fang
This paper reports the a novel and simple mast cell-based electrochemical method for detecting of bacterial quorum signaling molecules, N-acylhomoserine lactones (AHLs), which can be utilized to preliminarily evaluate the toxicity of food-borne pathogenic bacteria. Rat basophilic leukemia (RBL-2H3) mast cells encapsulated in alginate/graphene oxide hydrogel were immobilized on a gold electrode, while mast cells as recognition elements were cultured in a 3D cell culture system. Electrochemical impedance spectroscopy (EIS) was utilized to record the cell impedance signal as-influenced by Pseudomonas aeruginosa quorum-sensing molecule, N-3-oxododecanoyl homoserine lactone (3OC12-HSL)...
September 28, 2016: Biosensors & Bioelectronics
Can-Hui Deng, Ji-Lai Gong, Peng Zhang, Guang-Ming Zeng, Biao Song, Hong-Yu Liu
This paper reports the fabrication of melamine sponge decorated with silver nanoparticles-modified graphene (G/AgNPs-MS) for water disinfection. The G/AgNPs-MS composites with the high porosity and elasticity were used in an antibacterial process in which the composite was first immersed in bacterial suspension, and subsequently squeezed via hand compression. G/AgNPs-MS exhibited more excellent bactericidal activity against Escherichia coli and Staphylococcus aureus bacteria compared with melamine sponge (MS), melamine sponge decorated with graphene (G-MS), and melamine sponge decorated with silver nanoparticles (AgNPs-MS)...
February 15, 2017: Journal of Colloid and Interface Science
Wen-Shuo Kuo, Chia-Yuan Chang, Hua-Han Chen, Chih-Li Lilian Hsu, Jiu-Yao Wang, Hui-Fang Kao, Lawrence Chao-Shan Chou, Yi-Chun Chen, Shean-Jen Chen, Wen-Tsan Chang, Shih-Wen Tseng, Ping-Ching Wu, Ying-Chih Pu
A graphene quantum dot (GQD) used as the photosensitizer with high two-photon absorption in the near-infrared region, a large absolute cross section of two-photon excitation (TPE), strong two-photon luminescence and impressive two-photon stability could be used for dual modality two-photon photodynamic therapy (PDT) and two-photon bioimaging with an ultrashot pulse laser (or defined as TPE). In this study, a GQD efficiently generated reactive oxygen species coupled with TPE, which highly increased the effective PDT ability of both gram-positive and -negative bacteria, with ultra-low energy and an extremely short photoexcitation time generated by TPE...
October 18, 2016: ACS Applied Materials & Interfaces
H Enis Karahan, Li Wei, Kunli Goh, Zhe Liu, Özgür Birer, Fariba Dehghani, Chenjie Xu, Jun Wei, Yuan Chen
Carbon-based nanomaterials have a great potential as novel antibacterial agents; however, their interactions with bacteria are not fully understood. This study demonstrates that the antibacterial activity of graphene oxide (GO) depends on the physiological state of cells for both Gram-negative and -positive bacteria. GO susceptibility of bacteria is the highest in the exponential growth phase, which are in growing physiology, and stationary-phase (non-growing) cells are quite resistant against GO. Importantly, the order of GO susceptibility of E...
October 6, 2016: Nanoscale
Chien-Lin Pan, Ming-Hong Chen, Fu-I Tung, Tse-Ying Liu
: Many non-antibiotic strategies, such as photocatalysis and photodynamic therapy, have been proposed to inhibit and/or kill bacteria. However, these approaches still have drawbacks such as insufficient bacterial specificity and the limited penetration depth of ultraviolet and near-infrared light. To overcome these limitations, we developed a bacteria-specific anti-bacterial technique via using low-dose X-ray. Graphene oxide quantum dots (GQDs, a multifunctional vehicle) conjugated with vancomycin (Van, a bacteria-targeting ligand) were assembled with Protoporphyrin IX (PpIX, a photo/radiation sensitizer) to yield a novel Van-GQDs/PpIX complex that specifically attached to Escherichia coli and efficiently generated intracellular reactive oxygen species following X-ray activation...
October 3, 2016: Acta Biomaterialia
Valentina Palmieri, Massimiliano Papi, Claudio Conti, Gabriele Ciasca, Giuseppe Maulucci, Marco De Spirito
The clinical challenge that research on antibacterial coatings faces nowadays is the need of reduction of resistant bacterial infections, major source of implant rejection and repeated surgery. In order to avoid microorganisms attachment and biofilm formation, coating materials on medical devices have been developed with shortcomings represented by short-term durability and induction of new mechanisms of bacterial resistance. Graphene-based films and hydrogel could represent the next generation protective coatings due to their excellent mechanical, chemical and thermal properties, high nanoparticle adsorption and antibacterial action...
October 6, 2016: Expert Review of Medical Devices
Jiawei Liu, Yue Zheng, Zilan Hong, Kai Cai, Feng Zhao, Heyou Han
Biosynthesis based on the reducing capacity of electrochemically active bacteria is frequently used in the reduction of metal ions into nanoparticles as an eco-friendly way to recycle metal resources. However, those bionanoparticles cannot be used directly as electrocatalysts because of the poor conductivity of cell substrates. This problem was solved by a hydrothermal reaction, which also contributes to the heteroatom doping and alloying between Pd and Au. With the protection of graphene, the aggregation of nanoparticles was successfully avoided, and the porous structure was maintained, resulting in better electrocatalytic activity and durability than commercial Pd/C under both alkaline (CH3CH2OH, 6...
September 2016: Science Advances
Haiwei Ji, Kai Dong, Zhengqin Yan, Chao Ding, Zhaowei Chen, Jinsong Ren, Xiaogang Qu
A novel platform for targeted on-demand prodrug ascorbic acid (AA) delivery is fabricated using a bacterial hyaluronidase sensitive graphene-mesoporous silica nanosheet@hyaluronic acid-magnetic nanoparticles as the nanocarrier to treat bacterial infections. The released AA can be converted to detrimental •OH in situ on the surface of bacteria. With the chemo-photothermal synergistic effect, the designed antibacterial system can effectively inactivate bacteria and disperse stubborn biofilm.
December 2016: Small
Jessica Campos-Delgado, Kelly L S Castro, Jose G Munguia-Lopez, Ana K González, Martin E Mendoza, Benjamin Fragneaud, Raphael Verdan, Joyce R Araujo, Francisco J González, Hugo Navarro-Contreras, Ivan N Pérez-Maldonado, Antonio de León-Rodríguez, Carlos A Achete
BACKGROUND: Driven by the potential biological applications of graphene, many groups have studied the response of cells exposed to graphene oxide (GO). In particular, investigations of bacteria indicate that there are 2 crucial parameters, which so far have only been investigated separately: GO size and exposure methodology. Our study took into account both parameters. We carefully characterized the samples to catalog sizes and structural properties, and tested different exposure methodologies: exposure in saline solution and in the presence of growth media...
September 7, 2016: Journal of Applied Biomaterials & Functional Materials
Saravanan Govindaraju, Monica Samal, Kyusik Yun
A complete bacterialysis analysis of glucosamine-gold nanoparticle-graphene oxide (GlcN-AuNP-GO) and UV-irradiated GlcN-AuNP-GO was conducted. Analytical characterization of GlcN-AuNPs, GO and GlcN-AuNP-GO revealed UV-Vis absorbance peak at around 230 and 500nm. Microscopic characterization of prepared nanomaterials was performed by scanning electron microscope, atomic force microscopy, and high-resolution transmission microscopy. The results confirmed that the GlcN-AuNPs were uniformly decorated on the surface and edges of graphene sheets...
December 1, 2016: Materials Science & Engineering. C, Materials for Biological Applications
Donghao Xie, Xue-Qing Feng, Xi-Le Hu, Lin Liu, Zhihong Ye, Jun Cao, Guo-Rong Chen, Xiao-Peng He, Yi-Tao Long
This paper describes the development of a "diffusion-to-surface" ratiometric graphene electrosensor for the selective detection of live cells and pathogens that highly express mannose-binding proteins (MBPs). MBPs have been implicated in many pathological processes and are identified on specific types of bacteria. Consequently, MBPs are a promising biomarker for targeted disease diagnosis and therapy. Here, we develop a unique electrosensor that features a ratiometric voltammetric signal for the selective probing of MBPs...
September 28, 2016: ACS Applied Materials & Interfaces
Juanni Chen, Long Sun, Yuan Cheng, Zhicheng Lu, Kang Shao, Tingting Li, Chao Hu, Heyou Han
Nanoparticle-based antibacterial agents have emerged as an interdisciplinary field involving medicine, material science, biology, and chemistry because of their size-dependent qualities, high surface-to-volume ratio, and unique physiochemical properties. Some of them have shown great promise for their application in plant protection and nutrition. Here, GO-AgNPs nanocomposite was fabricated through interfacial electrostatic self-assembly and its antifungal activity against phytopathogen Fusarium graminearum was investigated in vitro and in vivo for the first time...
September 14, 2016: ACS Applied Materials & Interfaces
Yan Wang, Qin Shi, Hui Wang, Zhao-yong Bian
The Pd-Fe/graphene multi-functional catalytic cathode was prepared by UV-assisted photocatalytic reduction. The catalytic cathode and a Ti/IrO₂/RuO₂ anode consisting of both three-electrode system (two cathodes) and two-electrode system (one cathode) were designed for the degradation of 4-chlorophenol in aid of olectrochemical reducing and oxidizing processes. The concentrations of the intermediates and products were monitored by high performance liquid chromatography (HPLC), total organic carbon (TOC), and ion chromatography (IC)...
April 15, 2016: Huan Jing Ke Xue= Huanjing Kexue
Safaa N Saud, Raheleh Hosseinian S, H R Bakhsheshi-Rad, F Yaghoubidoust, N Iqbal, E Hamzah, C H Raymond Ooi
In the present work, the microstructure, corrosion, and bioactivity of graphene oxide (GO) coating on the laser-modified and -unmodified surfaces of TiNb shape memory alloys (SMAs) were investigated. The surface morphology and chemical composition was examined using field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). The surface modification was carried out via a femtosecond laser with the aim to increase the surface roughness, and thus increase the adhesion property. FE-SEM analysis of the laser-treated Ti-30at...
November 1, 2016: Materials Science & Engineering. C, Materials for Biological Applications
Shikai Deng, Enlai Gao, Yanlei Wang, Soumyo Sen, Sreeprasad Theruvakkattil Sreenivasan, Sanjay Behura, Petr Král, Zhiping Xu, Vikas Berry
Curvature-induced dipole moment and orbital rehybridization in graphene wrinkles modify its electrical properties and induces transport anisotropy. Current wrinkling processes are based on contraction of the entire substrate and do not produce confined or directed wrinkles. Here we show that selective desiccation of a bacterium under impermeable and flexible graphene via a flap-valve operation produces axially aligned graphene wrinkles of wavelength 32.4-34.3 nm, consistent with modified Föppl-von Kármán mechanics (confinement ∼0...
September 27, 2016: ACS Nano
Ana M Díez-Pascual, Angel L Díez-Vicente
Poly(propylene fumarate) (PPF)-based nanocomposites incorporating different amounts of polyethylene glycol-functionalized graphene oxide (PEG-GO) have been prepared via sonication and thermal curing, and their surface morphology, structure, thermal stability, hydrophilicity, water absorption, biodegradation, cytotoxicity, mechanical, viscoelastic and antibacterial properties have been investigated. SEM and TEM images corroborated that the noncovalent functionalization with PEG caused the exfoliation of GO into thinner flakes...
July 20, 2016: ACS Applied Materials & Interfaces
Suela Kellici, John Acord, Arni Vaughn, Nicholas P Power, David J Morgan, Tobias Heil, Sébastien P Facq, Giulio I Lampronti
Demonstrated herein is a single rapid approach employed for synthesis of Ag-graphene nanocomposites, with excellent antibacterial properties and low cytotoxicity, by utilizing a continuous hydrothermal flow synthesis (CHFS) process in combination with p-hexasulfonic acid calix[6]arene (SCX6) as an effective particle stabilizer. The nanocomposites showed high activity against E. coli (Gram-negative) and S. aureus (Gram-positive) bacteria. The materials were characterized using a range of techniques including transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, UV-vis spectrophotometry, FT-IR, and X-ray powder diffraction (XRD)...
July 27, 2016: ACS Applied Materials & Interfaces
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