Sharif Digital Repository

Surface-Enhanced Raman Spectroscopy (SERS) is a sensitive vibration spectroscopy method applied to analyze a variety of analytes, including toxins and pesticides. The SERS method is an accurate method for detecting significantly low concentrations of biomaterials and chemicals. In the present study, in order to detect atrazine pesticide, the glass fiber substrates coated with silver nanoparticles have been used as SERS plasmonic nanosensors. First, silver nanoparticles were prepared by applying a chemical approach named the Tollens' method, and the SERS plasmonic substrates (SPS) were fabricated by depositing the colloidal silver solution on a glass fiber substrate. The SERS plasmonic... 

Surface-enhanced Raman spectroscopy is a highly sensitive phenomenon and a powerful fingerprint detection tool that reflects the small changes in polarizability on the pattern and intensity of Raman signals. The SERS enhancement signals elucidate with the surface-selection rules. In this regard, molecular configuration and adsorption orientation on the surface, in addition to the direction of external electric field, can lead to different patterns of SERS spectra. To evaluate how the variation of these features influences the pattern and reproducibility of the spectra, the chemical charge-transfer SERS spectra for pyridine on silver clusters are calculated for different field directions,... 

We have investigated the surface-enhanced resonance Raman spectroscopy (SERRS) for 4,4′-diaminotolane absorbed on silver experimentally and theoretically. Experimental observation shows greatly enhanced bg symmetric modes ν26 and ν27, which are silent in normal Raman spectroscopy and SERS on gold. The dependence of the surface-enhanced Raman spectroscopy (SERS) spectra on five excitation lines has also been registered and classified for single bands into three profiles referring to the different contributions of resonant transitions. Theoretical calculations based on the time-dependent path integral formalism by including the Herzberg-Teller correction reproduce the experimental spectra with... 

This work presents the synthesis of nanostructured hollow polyaniline (PANI) capsules and their application for encapsulation of corrosion inhibitor 2-Mercaptobenzothiazole (MBT). The pH-triggered release of MBT from the capsules was evidenced using UV–vis and Surface Enhanced Raman Spectroscopy (SERS). Incorporation of MBT loaded PANI capsules into epoxy ester coating on AA2024-T3 resulted in a protective system with self-healing ability confirmed by Electrochemical Impedance Spectroscopy (EIS) and Scanning Vibrating Electrode Technique (SVET). The results showed that the incorporation of MBT-loaded PANI capsules into the coating has significantly improved its corrosion protection... 

The novel coronavirus pandemic has rapidly spread around the world since December 2019. Various techniques have been applied in identification of SARS-CoV-2 or COVID-19 infection including computed tomography imaging, whole genome sequencing, and molecular methods such as reverse transcription polymerase chain reaction (RT-PCR). This review article discusses the diagnostic methods currently being deployed for the SARS-CoV-2 identification including optical biosensors and point-of-care diagnostics that are on the horizon. These innovative technologies may provide a more accurate, sensitive and rapid diagnosis of SARS-CoV-2 to manage the present novel coronavirus outbreak, and could be... 

The novel coronavirus pandemic has rapidly spread around the world since December 2019. Various techniques have been applied in identification of SARS-CoV-2 or COVID-19 infection including computed tomography imaging, whole genome sequencing, and molecular methods such as reverse transcription polymerase chain reaction (RT-PCR). This review article discusses the diagnostic methods currently being deployed for the SARS-CoV-2 identification including optical biosensors and point-of-care diagnostics that are on the horizon. These innovative technologies may provide a more accurate, sensitive and rapid diagnosis of SARS-CoV-2 to manage the present novel coronavirus outbreak, and could be...