Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is the etiologic agent of the current pandemic of coronavirus disease 2019 (COVID-19) that has inflicted the loss of thousands of lives worldwide. The coronavirus surface spike (S) glycoprotein is a class I fusion with a S1 domain which is attached to the human angiotensin converting enzyme 2 (ACE2) receptor, and a S2 domain which enables fusion with the host cell membrane and internalization of the virus. Curcumin has been suggested as a potential drug to control inflammation and as a potential inhibitor of S protein, but its therapeutic effects are hampered by poor bioavailability. We performed a molecular docking and dynamic study using 94 curcumin analogues designed to have improved metabolic stability against the SARS-CoV-2 spike protein and compared their affinity with curcumin and other potential inhibitors. The docking analysis suggested that the S2 domain is the main target of these compounds and compound 2606 displayed a higher binding affinity (-9.6 kcal mol-1) than curcumin (-6.8 kcal mol-1) and the Food and Drug Administration (FDA) approved drug hydroxychloroquine (-6.3 kcal mol-1). Further additional validation in vitro and in vivo of these compounds against SARS-CoV-2 may provide insights into the development of a drug that prevents virus entry into host cells.

TiO2 has been used as a white pigment and studied since the first decades of the XX century for the undesirable chalking of outdoor paintings exposed to sunlight. Since the first report of Honda and Fujishima (1972) of the water splitting by the harvesting of sunlight on a n-type single crystal TiO2 electrode, the engagement of researchers with the field has grown steadily. TiO2-photocatalysis has joined the group of advanced oxidation processes for potential new water and wastewater treatments but, despite of its high chemical and photochemical stability and the great oxidizing power of its photogenerated holes, photons in UVA spectral region are needed to accomplish the high band gap, limiting the yield of sun-driven environmental applications. Nevertheless, this shortcoming has not restricted benchtop research and small and medium scale applications also relying on artificial UV sources, especially nowadays that highly-efficient UVA-LEDs are available. Herein, we review the fundamental aspects and the practical attributions of the trapping model in the charge transfer kinetics of photogenerated holes in nanoparticulate TiO2. Regarding to new practical uses, we focus our attention on some ingenious applications of this photocatalyst in the field of analytical chemistry, covering also subjects never reviewed before.