Effects of chemical structure, solvent and solution pH on the visible spectra of some new methine cyanine dyes

Some new dimethine and bis-dimethine, cyanine dyes derived from benzo[2,3-b; 2`,3`-b`]bis-pyrazolo[4,5-b]-l,4-(oxa-, thia-, and pyra-)-zine-6,12-dione were synthesized. Effect of chemical structure on the electronic visible absorption spectra of all the synthesized cyanine dyes was investigated in 95% ethanol solution. Effects of solvent and/or solution pH on the electronic visible absorption spectra of some selected synthesized cyanine dyes were also examined in pure solvents having different polarities and/or in aqueous universal buffer solutions, respectively. Structural confirmations were carried out through elemental analysis, mass spectroscopy, IR and 1H NMR spectra

Novel styryl and aza-styryl cyanine dyes: Synthesis and spectral sensitization evaluation

Novel styryl cyanine dyes and aza-styryl cyanine dyes having the nucleus of furo[(3,2-d)pyrazole;(3',2'-d)oxazole] iodide salt were prepared. Spectral sensitization evaluation for all the synthesized styryl and aza-styryl cyanine dyes was carried out through investigating their electronic visible absorption spectra in 95% ethanol solution. The dyes were thought to be better spectral sensitizers when they absorb light at longer wavelength bands (bathochromic shifted and/or red shifted dyes). Consequently the spectral sensitization of the dyes decreased when they absorb light at shorter wavelength bands (hypsochromic shifted and/or blue shifted dyes). The results discussed in this study revealed that the spectral sensitization properties of the examined dyes is highly effected by the type of the X substituted in the phenyl ring system for the styryl cyanine dyes and by the type of the phenyl and/or the naphthyl ring system for the aza-styryl cyanine dyes. Structural confirmations were identified by elemental analysis, visible spectra, IR and 1H NMR spectroscopic data

Preliminary Step towards COVID-19 Inactivated Vaccine Development in Egypt.

International audienceThe current worldwide COVID-19 pandemic is causing severe human health problems, with high mortality rates and huge economic burdens requiring the urgent development of a safe and effective vaccine. Here, preclinical evaluation of an inactivated SARS-CoV-2 vaccine candidate (EgySerVac-20) is reported. Oropharyngeal swabs and nasopharyngeal aspirates obtained from Egyptian patients with laboratory-confirmed SARS-CoV-2 infection were isolated using Vero cells and were then genetically characterized. Vaccine inactivation was performed using diluted formaldehyde, followed by safety testing for the inactivated vaccine. To determine the high humoral immune responses against SARSCOV-2 infection, the safety and capacity of the vaccine prepared with alum adjuvant were tested. The immunogenicity and efficacy of the vaccine candidate was tested in vitro by a neutralization assay and in vivo using mouse models. Our results revealed a cytopathic effect which was observed 48 hours post infection and the viral particles were identified by rRT-PCR as SARS-CoV-2. Propagation of the isolated virus in ten serial passages on the Vero cells yielded a virus titer 7.5 log10 TCID50/ml. Complete inactivation of SARS-CoV-2 was observed at 37°C in 24 hours post treatment by diluted formaldehyde. Inactivated SARS-CoV-2 infected fluid safety was determined by absence of cytopathic effect by repeated passage in Vero cell line, indicating loss of virus infectivity. Virus inactivated by diluted formaldehyde showed no deaths or clinical symptoms in mice groups post intraperitoneal inoculation (0.5ml/mouse). EgySerVac-20 inactivated vaccine has safely induced high levels of neutralizing antibodies titers in mice, where 0.1 ml immunization dose showed protective efficacy against SARS-CoV-2 challenge in mice. This finding will support the future preclinical and clinical trials evaluation for our SARS-CoV-2 vaccine candidate in primates and human, respectively