This thesis introduces various applications of organic and nanomaterials for detection/biosensing the biomolecules and pathogenic bacteria and their antibacterial activities. The main target of the present thesis is to apply new materials in analytical and nanobiomedicine fields. These new materials may be solving the main drawbacks of conventional matrixces of matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) in order to improve their sensitivety, detection capability and for better ionization. It was also applied for biosensing application for pathogenic bacteria and different biomolecules. In order to understand the physiological behavior and separation/biosensiong application; non-covalent interactions have been investigated among metals-drug, metallodrug-bacteria, metallodrug-protein, pathogenic bacteria-nanoparticles. Finally, some of new materials have been tested as antibacterial agents. The thesis was classified into four different parts as below:
First part introduces novel applications of organic and nanomaterials which can as matrices for matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS). This part introduces new materials in order to solve limitations of conventional organic matrices such as acidity, interferences and weak ionisability. First application introduces two novel organic matrices which called �焝efenamic and Furoic acids�� to work as powerful matrices for low molecular weight (0-3000Da) of various biomolecules. The new matrices show low interferences, less fragmentation and good resolution. Second application introduces new ionic liquid matrices (ILMs) for bacteria analysis. Due to the weak acidity of conventional matrices �㈣HB and sinapinic acid��, new series of ionic liquid matrices (ILMs) were applied to improve pathogenic bacteria signals of MALDI analysis. Third application show high and new ionization protocol based on graphene coated with porous silicates (SiO2). Analyte was ionized and desorbed from porous materials (SiO2) and was initiated by surfactant and graphene nanosheet. Data indicated high ionizability and better resolution of various analytes. The new organic materials (furoic acid, mefenamic acids, and ionic liquid) and graphene coated silica showed better ionization, low interference, and potential applicability for various biomolecules classes.
Second part characterizes the non-covalent bond among metals, drugs, proteins, quantum dots and bacteria. First application discusses the non-covalent interaction between metals and non-steroidal anti-inflammatory drug (NSAIDs) called flufenamic acid. Because conventional organic matrix destroys the non-covalent interaction in metallodrug and show interference at low molecular weight, a new method based on graphene was proposed. Metallodrug structures were proposed using graphene assisted laser desorption/ionization and confirmed using multiple analytical tools such as UV, fluorescence spectroscopy. Metallodrug-bacteria interaction was investigated using MALDI, thus was proposed for fluorescence biosensing applications. Second application monitors the non-covalent interactions between metallodrug and bovine serum albumin (BSA) using MALDI, FTIR, and fluorescence spectroscopy. Data reveal strong interaction between the protein and metallodrugs. Third application investigates the non-covalent interaction between bacteria cell membranes and chitosan which modified with quantum dots. Thermodynamic results indicate that there are hydrophobic interaction between bacteria cell membranes and chitosan backbone and it was drive entropically. Probe interaction among metals, drugs, bacteria and proteins are useful for develop drug without side effect and for biosensors applications.
Third part introduces several of nanomaterials such as graphene magnetic nanoparticles, polymer dots, and nanoceria (CeO2) for biosensing and separation purposes. First application showed multifunctional application of graphene magnetic nanoparticles modified chitosan (GMCS) based the combination between fluorescence properties of graphene and magnetic property of magnetic nanoparticles for biosensing applications. GMCS was prepared and characterized using transmission electron microscopy (TEM), Raman, UV, Fourier transform infrared (FTIR), and X-ray diffraction (XRD). GMCS was proposed for fluorescence and MALDI analysis of pathogenic bacteria (Pseudomonas aeruginosa and Staphylococcus aureus) in blood samples. Second application quantified the hydrophobic cellular biomolecules of pathogenic bacteria using polythiophene dispersed in organic solvent (choloroform, CHCl3). Third application proposes nanoceria (CeO2) modified surfactant for effective separation of pathogenic bacteria from blood samples using ultrasound enhanced surfactant-assisted dispersive liquid�濯iquid microextraction (UESA-DLLME). Nanomaterials (graphene magnetic nanoparticles, polymer dots, and nanoceria) showed effective separation/biosensing application for pathogenic bacteria.
Fourth part proposes metallodrug and nanomaterials for effect pathogenic bacteria treatments. Firstly, metallodrug based on metals (Cu+2, Fe+3) interact with ponstel drug were characterized using electrospray and quantum dots assisted laser desorption/ionization mass spectrometry. Data were confirmed using UV and fluorescence spectroscopy. Antibacterial activities were evaluated using plate counting and MALDI-MS. The metallodrug display antibacterial activity toward bacteria. Second application introduces graphene oxide (GO) as a nanocarrier for insoluble antibacterial called gramicidin (GD). Graphene oxide modified gramicidin (GOGD) was prepared an characterized using TEM, XRD, UV, FTIR and MALDI-MS. Antibacterial activity was measured using various analytical tools such as optical counting, optical density, fluorescence spectroscopy (2D, 3D), MALDI and transmission electron microscopy. Data revealed high antibacterial activity of GOGD over than GD and GO.
In conclusion, we successfully applied various organic materials and nanomaterials for detection/biosensing and for antibacterial activities.We introduce new organic and nanomaterials which can serve for energy receptor in order to ionize the different analytes. A new ionization method has been evaluated which consider matrix-free, cheap, high ionization efficiency, and have no interefences. Non-covalent interactions not only provide information about the side effect of the drug/metallodrg, but also important for biosensing/separation application. Various separation approaches have been used for separation and biosensing. Novel antibacterial classes were investigated based on graphene and metallodrug.