Dynamic spatial control of MOF position is obtained by incorporating carbon‐coated cobalt nanoparticles within metal organic framework (MOF)‐5 crystals. The cobalt framework composite obtained responds efficiently to magnetic stimuli. A luminescent functionality is added, showing that multifunctional MOF devices can be prepared. This new generation of adaptive material is tested as a position‐controlled molecular sensor.

Coronavirus disease 2019 (COVID‐19) is an infectious disease caused by the severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) that has quickly and deeply affected the world, with over 60 million confirmed cases. There has been a great effort worldwide to contain the virus and to search for an effective treatment for patients who become critically ill with COVID‐19. A promising therapeutic compound currently undergoing clinical trials for COVID‐19 is nitric oxide (NO), which is a free radical that has been previously reported to inhibit the replication of several DNA and RNA viruses, including coronaviruses. Although NO has potent antiviral activity, it has a complex role in the immunological host responses to viral infections, i.e., it can be essential for pathogen control or detrimental for the host, depending on its concentration and the type of virus. In this Essay, the antiviral role of NO against SARS‐CoV, SARS‐CoV‐2, and other human viruses is highlighted, current development of NO‐based therapies used in the clinic is summarized, existing challenges are discussed and possible further developments of NO to fight viral infections are suggested.

The use of ZnO particles as efficient agents for seeding, growing, and precisely positioning metal−organic frameworks (MOFs) is described. Ceramic seeds have been successfully used for the preparation of Zn-based MOFs with a number of different carboxylic acids: terephthalic acid, 2-aminoterephthalic acid, 1,3,5-benzenetricarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 4,4′-biphenyldicarboxylic acid. In situ synchrotron small-angle X-ray scattering and electron microscopy experiments were employed to determine the effect of the concentration of ZnO nanoparticles, temperature, and time on MOF growth. Under optimized conditions, MOF crystals were found to form in several minutes. This unprecedented capacity to seed MOF formation was used to control the growth of crystals in precise locations. Accordingly, we employed this seeding technique to position porous MOF crystals on paper strips (lateral flow), or within glass and PDMS microchannels (120 μm width and 100 μm height). These data demonstrate that ZnO nanoparticles are versatile seeding agents for the growth of porous crystals in a number of different microfluidic platforms.

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