Azam Samadi

The potent antiviral action of metal silver (Ag) and silver nanoparticles (AgNPs) against viral infections has been demonstrated. The anti-viral activities of AgNP on Respiratory syncytial virus, Influenza virus, Norovirus, Hepatitis B virus, Human immunodeficiency virus and recently SARS-CoV-2 have been studied. Here, in this mini review, we summarize the anti-viral activity of AgNPs and further highlight their potential against SARS-CoV-2, which is expected to contribute to the control of COVID-19 epidemic.

Bisphenol A (BPA, 4,4'-dihydroxy-2,2-diphenylpropane) which has carcinogenic effects in breast and ovarian cancers can be released from cans and polycarbonate plastic products in dependence of temperature and pH. The present paper reports a simple spectrophotometric method for BPA detection in baby bottles and compact disks in the presence of Triton X-100. The proposed method is based on the formation of silver nanoparticles (AgNPs) in a medium containing ammonia and sodium hydroxide. The yellow color of AgNPs resulting from the localized surface plasmon resonance of AgNPs at 425 nm makes it possible to quantify BPA. Under the optimized conditions, the calibration curve of the proposed method was linear in the concentration range of 0.06–4 mg/L with the detection limit of 20 µg/L. The proposed method was successfully applied to determine BPA in some common products including baby bottles and compact disks after extraction in alkaline media.

Aptasensors are amazing among many currently formed procedures due to their excellent particularity, selectivity and responsiveness. These biosensors get more popular in combination with gold nanop...

In this paper, we report herein for the first time that a stop solution should be used to terminate the metal nanoparticles (MNPs) aggregation reactions especially salt-induced ones to increase the repeatability of the assays. It was found that hydrophobic surfactants have the ability to slow down the aggregation process of MNPs and can be applied as stop solution for aggregation-based colorimetric assays. This trick provides accurate and well-repeatable signals since the aggregation of the nanoparticles is a dynamic process and capturing signal in a predetermined time is difficult.

We report herein for the first time that a stop solution should be used to terminate the metal nanoparticles aggregation reactions especially salt-induced ones to increase the repeatability of the assays. It was found that hydrophobic surfactants have the ability to slow down the aggregation process of MNPs and can be applied as stop solution for aggregation based colorimetric assays. This trick provides accurate and well-repeatable signals since the aggregation of the nanoparticles is a dynamic process and capturing signal in a predetermined time is difficult.

Background: Tramadol, (±)-trans-2-[(dimethylamino) methyl]-1-(3-methoxyphenyl) cyclohexanol, is a synthetic centrally acting analgesic used in the treatment of moderate to chronic pain. Tramadol, like other narcotic drugs, is used for the treatment of pain and may also be abused. Its overdose can cause adverse effects such as dizziness, vomiting, and nausea. The aim of this paper is to develop a sample preparation method for the determination of tramadol in human plasma samples, followed by CE analysis. Methods: Ultrasound assisted-dispersive liquid-liquid microextraction using binary mixed extractant solvent (chloroform and ethyl acetate) was used for the extraction of one hundred microliters of tramadol spiked human plasma samples and in real human plasma samples obtained from the patients with abuse of tramadol. After evaporation of the extractant solvent, the residue was reconstituted in 100 μL deionized water and subsequently analyzed by CE-UV. Results: The developed method has remarkable characteristics, including simplicity, good repeatability and appreciable accuracy. Under the best extraction conditions, a low limit of detection at 7.0 μg per liter level with good linearity in the range of 0.02-10 μg mL^-1 was obtained. Conclusion: UA-DLLME, using a binary mixed extraction solvent, was established for the determination of tramadol in human plasma samples via the CE method with UV-detection. In addition, the analysis of tramadol in some plasma samples of patients with abuse of tramadol indicated that the method has acceptable performance for the determination of tramadol in plasma samples, which indicates that the method is suitable for clinical applications.

Background: Uremia is the outcome of the remaining of nitrogenous waste products that are normally removed by the kidneys. Para-cresol (4-methylphenol) can be regarded as a proteinbound uremic toxin. The p-cresol determination in sera is necessary since it is a marker of cardiovascular risk and overall mortality in hemodialysis patients. Among the reported methods, chromatographic ones especially HPLC techniques due to the high sensitivity, selectivity and reproducibility have been extensively exploited in analysis of p-cresol in complex mixtures. However, an appropriate sample preparation prior to analysis is necessary for obtaining accurate and precise results.Methods: In this study, the appropriate precipitating agent for p-cresol determination in plasma samples was investigated. Then, in situ surfactant-based solid phase microextraction followed by HPLCFL detection was developed and validated for the quantification of p-cresol in plasma samples.Results: According to the results, HCl/heat precipitation method was used for p-cresol microextraction from from plasma samples. In situ surfactant-based solid phase microextraction using cetyltrimethylammonium bromide as extraction medium was proposed for pretreatment of plasma samples prior to analysis. The separation was achieved by isocratic elution with sodium acetate buffer (pH 3.8) and acetonitrile (20:80, v/v). Linearity was found to be acceptable over the concentration ranges of 0.5 to 8 μg mL-1 with the limit of detection and quantification of 0.324 and 0.422 μg mL-1, respectively. The variations for intra-day and inter-day precisions were both less than 8.2% and the extraction recoveries were more than 97%.Conclusion: A validated ISS-SPME followed by HPLC-FL detection reported to determine the total p-cresol concentration of human plasma samples. The traditional liquid-liquid extraction techniques are normally time consuming and require the use of large amounts of toxic organic solvents. In addition, the evaporation of extraction solvent and dissolving the analyte in the mobile phase is commonly used before HPLC analysis. Such a requirement makes the sample preparation process even more tedious and time consuming. ISS-SPME that is the developed ISS-SPE in micro scale, is a simple, rapid and effective sample preparation technique that is appropriate for HPLC-FL analysis.

We present a new and sensitive fluorescent nanosensor for the direct determination of methimazole (MML) in human plasma samples. The strategy is based on fluorescence resonance energy transfer between amlodipine, an inexpensive pharmaceutical compound, as an energy donor and gold nanoparticles as an energy acceptor. The recovered fluorescence intensity in the presence of MML allows a direct and rapid quantitation of MML in human plasma samples with a detection limit of 0.15 ng/mL.

Background: Quantitative analyses of antiepileptic drugs are required in clinic and to rational dosage adjustment, the clinician needs the blood levels of these drugs. A high-performance liquid chromatography with spectrophotometric detection has been developed and validated for simultaneous determination of some antiepileptic drugs in plasma of patients with epilepsy. Methods: A simple procedure based on deproteinization by acetonitrile was used for pre-treatment of plasma samples. Liquid chromatographic analysis was carried out on a Nova-Pak® C18 analytical column, using a ternary mixture of potassium dihydrogen phosphate buffer (pH 6.0)-acetonitrile-2-propanol (63:22:15, v/v/v) as the mobile phase, at a flow rate of 1.0 mL min-1. Results: Calibration curves were linear over a range of 1–40 µg mL-1 for phenobarbital, 1–30 µg mL-1 for phenytoin, 0.3–15 µg mL-1 for carbamazepine and 0.5–6 µg mL-1 for carbamazepine epoxide. Conclusion: The simple sample pre-treatment, combined with the fast chromatographic run was used for the determination of antiepileptic drugs for a large number of patient samples.