Optical Biosensor for the Detection of Infectious Diseases Using the Copolymer F8T2 with Application to COVID-19

Ultrafast electron dynamics in excited states of conjugated thiophene-fluorene organic polymer (pF8T2) thin films

The electronic states of poly(9,9-dioctylfluorenyl-alt-bithiophene) pF8T2 on H/Si(100) substrates, prototypical for organic photovoltaics, were investigated by ultrafast photoelectron spectroscopy and by time-resolved fluorescence studies. Occupied and unoccupied electronic states were analysed by ultraviolet photoelectron spectroscopy (UPS), static and dynamic femtosecond two-photon photoemission (2PPE), and time-correlated single photon counting (TCSPC). Time-resolved measurements allow assessment of population lifetimes of intermediate states. The combination of time-resolved photoelectron spectroscopy and fluorescence excitation allows following the electronic dynamics in excited states from the femtosecond to the nanosecond time scale. For this prototypical material the electron kinetic energy resolved lifetimes range from about a few tens of femtoseconds up to hundreds of picoseconds. After annealing these types of organic thin films the efficiency of organic solar cells usually increases. We show that annealing does not influence the initial ultrafast charge generation processes, but the long-lived states. However, the nanosecond scale fluorescence lifetimes measured by TCSPC are prolonged after annealing, which therefore is identified as the cause of a greater exciton diffusion range and thus is beneficial for charge carrier extraction.

Epidemic history and evolution of an emerging threat of international concern, the severe acute respiratory syndrome coronavirus 2

This comprehensive review focuses on the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its impact as the cause of the COVID-19 pandemic. Its objective is to provide a cohesive overview of the epidemic history and evolutionary aspects of the virus, with a particular emphasis on its emergence, global spread, and implications for public health. The review delves into the timelines and key milestones of SARS-CoV-2's epidemiological progression, shedding light on the challenges encountered during early containment efforts and subsequent waves of transmission. Understanding the evolutionary dynamics of the virus is crucial in monitoring its potential for adaptation and future outbreaks. Genetic characterization of SARS-CoV-2 is discussed, with a focus on the emergence of new variants and their implications for transmissibility, severity, and immune evasion. The review highlights the important role of genomic surveillance in tracking viral mutations linked to establishing public health interventions. By analyzing the origins, global spread, and genetic evolution of SARS-CoV-2, valuable insights can be gained for the development of effective control measures, improvement of pandemic preparedness, and addressing future emerging infectious diseases of international concern.

SARS-CoV-2 detection methods: A comprehensive review

The ongoing novel COVID-19 has remained the center of attention, since its declaration as a pandemic in March 2020, due to its rapid and uncontrollable worldwide spread. Diagnostic tests are the first line of defense against the transmission of this infectious disease among individuals, with reverse-transcription quantitative polymerase chain reaction (RT-qPCR) being the approved gold standard for showing high sensitivity and specificity in detecting SARS-CoV-2. However, alternative tests are being invested due to the global demand for facilities, reagents, and healthcare workers needed for rapid population-based testing. Also, the rapid evolution of the viral genome and the emergence of new variants necessitates updating the existing methods. Scientists are aiming to improve tests to be affordable, simple, fast, and at the same time accurate, and efficient, as well as friendly user testing. The current diagnostic methods are either molecular-based that detect nucleic acids abundance, like RT-qPCR and reverse-transcription loop-mediated isothermal amplification (RT-LAMP); or immunologically based that detect the presence of antigens or antibodies in patients’ specimens, like enzyme-linked immunosorbent assay (ELISA), lateral flow assay (LFA), chemiluminescent immunoassay (CLIA), and neutralization assay. In addition to these strategies, sensor-based or CRISPR applications are promising tools for the rapid detection of SARS-CoV-2. This review summarizes the most recent updates on the SARS-CoV-2 detection methods with their limitations. It will guide researchers, epidemiologists, and clinicians in identifying a more rapid, reliable, and sensitive method of diagnosing SARS-CoV-2 including the most recent variant of concern Omicron.