Session: Analytical Division Poster:

An unexpected outbreak of coronavirus disease 2019 (COVID-19) has collapsed many health care systems and crashed numerous economies. A crucial shortcoming of the healthcare systems across the globe has been the ability to rapidly and accurately diagnose the disease. The shortcomings also lie when it comes to track the progress of the disease in patients and especially image the infected organs. Therefore, there is an urgent unmet need for a selective diagnostic probe for COVID-19 that can image the infected tissues without any difficulty. NIR-II responsive probes will be of high demand in this regard for fast and accurate determination of infection. The methodology, described herein, utilizes NIR-II responsive quantum dots (QDs) covalently functionalized with SARS-CoV-2 selective antisense oligonucleotide. These ASO capped QDs found to be agglomerated only in presence of its target N gene of SARS-CoV-2 RNA. The agglomeration of ASO capped QDs in the presence of SARS-CoV-2 RNA was studied by UV-Visible absorbance spectroscopy, TEM and hyperspectral imaging (HSI) techniques. Further, it was observed that the QDs after functionalization with ASO loses its NIR-II responsiveness and blue shifted in hyperspectral scattering plot. However, only in presence of SARS-CoV-2, its NIR-II fluorescence regained leading to red shift in hyperspectral scattering. The phenomena have been substantially studied with density functional theoretical calculations. Overall, a unique, selective NIR-II responsive diagnostic probe has been developed for the current COVID-19 causative virus, SARS-CoV-2, which can efficiently be utilized to diagnose the infection at the tissue level.

Figure. (a) Schematic representation of the antisense oligonucleotide capped lead sulfide quantum dots; (b) hyperspectral scattering of the agglomerated ASO tagged QDs in presence of SARS-CoV-2. (c) Bright-field and (d) NIR-II fluorescence imaging (emission 850-1300 nm) of lung tissue infected with SARS-CoV-2 with the newly developed diagnostic probe.

Figure. (a) Schematic representation of the antisense oligonucleotide capped lead sulfide quantum dots; (b) hyperspectral scattering of the agglomerated ASO tagged QDs in presence of SARS-CoV-2. (c) Bright-field and (d) NIR-II fluorescence imaging (emission 850-1300 nm) of lung tissue infected with SARS-CoV-2 with the newly developed diagnostic probe.

Dipendra Dahal

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