ABSTRACT
Detection is the first step to efficient treatment, therefore early detection of biofilm gains paramount importance for the initiation of mitigation protocols. A systematic study was conducted to detect the biofilm formation (1h to 2month period) on aluminium, titanium surfaces and their corresponding oxide film surfaces. The limit of detection (LOD) in case of traditional MALDI-MS was limited to a 6h old biofilm. Whereas, in case of the Graphene nanosheet mediated MALDI-MS (GN-MALDI-MS) approach, early detection of the biofilm was demonstrated to be 1h on titanium surfaces and 3h for Al surfaces.
Subject(s)
Biofilms , Graphite/chemistry , Nanostructures/chemistry , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Aluminum/chemistry , Biofilms/growth & development , Microscopy, Confocal , Microscopy, Electron, Scanning , Staphylococcus aureus/physiology , Titanium/chemistry , Vibrio alginolyticus/physiologyABSTRACT
Graphene oxide-zinc oxide hybrid nanostructures were synthesized and they demonstrated significant and promising antimicrobial activity on pathogenic bacteria. The combination of graphene oxide with zinc oxide nanorods showed an impressive antibacterial effect under intense scrutiny as compared with individual graphene oxide or zinc oxide nanomaterials. The characterization and investigation of GO-ZnO nanorod hybrid nanostructures were conducted using UV, FTIR, XRD, SEM, EDX and TEM measurements. The antimicrobial activity of the above hybrid material was evaluated by various methods including MALDI-MS analysis, a disk diffusion assay and optical density measurements.
Subject(s)
Anti-Infective Agents/chemical synthesis , Anti-Infective Agents/pharmacology , Graphite/chemistry , Graphite/pharmacology , Nanostructures/chemistry , Nanotubes/chemistry , Zinc Oxide/chemical synthesis , Zinc Oxide/pharmacology , Anti-Infective Agents/chemistry , Diffusion , Microbial Sensitivity Tests , Microscopy, Electron, Scanning , Nanotechnology , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Spectroscopy, Fourier Transform Infrared , X-Ray Diffraction , Zinc Oxide/chemistryABSTRACT
The integration of nanotechnology with mass spectrometry for sensitive and selective detection of molecules is a hot/important field of research. Synthesis of graphene (G) coated with mesoporous silica (SiO2, G@SiO2) for mass spectrometric application has been demonstrated. For the first time, we proposed the significant role of surfactant that used during the synthesis of mesorporous silicate (SiO2) in mass spectrometry. It was noticed that G could initiate SiO2 via surfactants which work as initiators for further ionization. The porosity of SiO2 trapped the analytes that was released and ionized with the surfactant fragments. Undoubtedly, strong background interferences were present in the case of organic matrix, which greatly obscured the detection of low molecular weight compounds. G@SiO2 nanocomposite affords several advantages, such as the ability to detect small molecules (<500Da), high sample localization through silica mesoporosity, and high ionization efficiency over than G or conventional matrices. The high performance of G@SiO2 is not only due to the large surface area but also due to high desorption/ionization efficiency of inevitably surfactant (cetyltrimethylammonium chloride, CATB). Unlike the conventional MALDI-MS, the G@SiO2-MS is capable of generating multiply charged polysaccharides. The present method was validated to detect surfactants with low limits of detection.
Subject(s)
Graphite/chemistry , Nanocomposites/chemistry , Silicon Dioxide/chemistry , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Environmental Pollutants/analysis , Environmental Pollutants/chemistry , Gramicidin/analysis , Gramicidin/chemistry , Microscopy, Electron, Transmission , Molecular Structure , Nanocomposites/ultrastructure , Particle Size , Porosity , Reproducibility of Results , Spectinomycin/analysis , Spectinomycin/chemistry , Spectrophotometry, Ultraviolet , Surface-Active Agents/analysis , Surface-Active Agents/chemistry , Tobramycin/analysis , Tobramycin/chemistry , beta-Cyclodextrins/analysis , beta-Cyclodextrins/chemistryABSTRACT
A novel method for pathogenic bacteria identification directly from blood samples using cationic ionic liquid-modified magnetic nanoparticles (CILMS) is reported. The magnetic nanoparticles were prepared by co-precipitation and the core-shell Fe3O4@SiO2 nanoparticles were prepared by the sol-gel process, followed by the grafting of 3-chloropropyltrimethoxysilane that was reacted further with N-methylimidazole to form cationic ionic liquid-modified Fe3O4@SiO2 magnetic nanoparticles (CILMS). The pathogenic bacteria were separated mainly based on the electrostatic interactions among the negative charges of the cell membranes and the positive charges of the CILMS particles. CILMS are used directly without the need for any further apparatus and auxiliary chemicals. The separated cells were detected using matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS). The lowest detectable number of bacteria was 3.4 × 103, 3.2 × 103, and 4.2 × 103 cfu mL-1 for Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, respectively. The bacterial affinity toward CILMS was investigated using transmission electron microscopy which revealed immobilization of the CILMS on the outer cell membranes. The present approach offers a highly sensitive, fast, and simple method for the cell capture of the pathogenic bacteria. The current approach could be adapted to separate and identify the pathogenic bacteria from septicemic patients or contaminated blood before blood transfusion.
