Spectrophotometric Determination of Arginine by Aggregation of Spherical Gold Nanoparticles

, M.Sc. Thesis Sharif University of Technology Pezeshkian, Zahra (Author) ; Hormozinezhad, Mohammad Reza (Supervisor)

Abstract

Spectrophotometric determination of arginine by aggregation of spherical Au nanoparticles Arginine has been classified as a ‘semi-essential’ or ‘conditionally-essential’ amino acid. This amino acid plays a crucial role in many biological path ways. Hence, its determination in biological body fluids such as blood plasma and urine is important for clinical diagnosis of various diseases. Herein we report the development of a sensitive colorimetric method for the determination of arginine based on aggregation of the citrate capped gold nanoparticles (Au NPs). Reaction contains replacement of citrate ions with guanidinium groups of arginine followed by establishing a chemical bond between amino...

Selective Colorimetric Detection of Pentaerythritol Tetranitrate (PETN) Using Arginine-mediated Aggregation of Gold Nanoparticles

, M.Sc. Thesis Sharif University of Technology Taefi, Zahra (Author) ; Hormozinezhad, Mohammad Reza (Supervisor)

Abstract

Detection of pentaerythritol tetranitrate (PETN) as an explosive has been of great interest because of public safety and military concerns. Here, we have presented a simple, selective and sensitive colorimetric method for direct detection of PETN. The gold nanoparticles (AuNPs) were first exposed to arginine which has primary amines in its structure. Primary amines from arginine as electron donors could strongly interact with electron deficient –NO2 group of PETN. Also, hydrogen bonding could happen between the –NO2 group of PETN and –NH2 group of arginine molecules. Therefore, selective aggregation of AuNPs happened because of the donor-acceptor and hydrogen bonding interactions. Due to the...

Synthesis and Characterization of Dextran Based Magnetic Nanogels as a Gene Delivery Vector and Investigating its Gene Therapy Efficiency

, M.Sc. Thesis Sharif University of Technology Azadpour, Behnam (Author) ; Madaah Hosseini, Hamid Reza (Supervisor) ; Arefian, Ehsan (Supervisor)

Abstract

The use of magnetic nanoparticles modified with proper surface agent and the ability of controlling by magnetic field, that can induce colloidal stability, is considered as a vector to transfer DNA plasmid, or pDNA in short, in the field of gene therapy. In thiss research, pH-responsive dextran-based magnetic nanogels (dextMNGs) were synthesized via inverse mini-emulsion method. Fourier transformation infrared spectroscopy (FTIR) showed that magnetite nanoparticles (MNPs) were successfully modified with arginine and had amine terminals. FTIR, also, proved that aldehyded dextran was crosslinked by arginine modified magnetite nanoparticles (RMNPs) via pH sensitive imine bonds. X-ray...

Design of Optical Sensor Arrays Using Plasmonic and Fluorescent Nanoprobes for the Detection of Antidepressants, Biothiols, and Discrimination of the Enantiomers of Tryptophan, Histidine, and Arginine

, Ph.D. Dissertation Sharif University of Technology Jafarnezhad Ivrigh, Zahra (Author) ; Hormozinezhad, Mohammad Reza (Supervisor)

Abstract

In the first part of this research, a single-component colorimetric sensor array based on the aggregation of AuNPs has been designed for the quantification and classification of antidepressant drugs (fluvoxamine (Flu), nortriptyline (Nor), citalopram (Cit), alprazolam (Alp), diazpam (Dia), sertraline (Ser), zolpidem (Zol), and imipramine (Imi)). Tuning the pH and ionic strength enabled the single-component probe to interact with the target analytes through different binding modes, providing the required cross-reactivity. To generate the array, a single AuNP was embedded into six experimental conditions: three different buffers (acidic, neutral and basic) each at two concentration levels (1mM...