Cre/loxP technology is an important tool for studying cell type‐specific gene functions. Cre recombinase mouse lines, including Agc1‐CreERT2, Col2a1‐Cre; Col2a1‐CreERT2, Shh‐Cre, Shh‐CreERT2, and Osx‐Cre, have been proven to be valuable tools to elucidate the biology of long bones, yet the information for their activity in postnatal intervertebral disc (IVD) tissues was very limited. In this study, we used R26‐mTmG fluorescent reporter to systematically analyze cell specificity and targeting efficiency of these six mouse lines in IVD tissues at postnatal growing and adult stages. We found that Agc1‐CreERT2 is effective to direct recombination in all components of IVDs, including annulus fibrosus (AF), nucleus pulposus (NP), and cartilaginous endplate (CEP), upon tamoxifen induction at either 2 weeks or 2 months of ages. Moreover, Col2a1‐Cre targets most of the cells in IVDs, except for some cells in the outer AF (OAF) and NP. In contrast, the activity of Col2a1‐CreERT2 is mainly limited to the IAF of IVD tissues at either stage of tamoxifen injection. Similarly, Shh‐Cre directs recombination specifically in all NP cells, whereas Shh‐CreERT2 is active only in a few NP cells when tamoxifen is administered at either stage. Finally, Osx‐Cre targets cells in the CEP, but not in the NP or AF of IVDs tissues at these two stages. Thus, our data demonstrated that all these Cre lines can direct recombination in IVD tissues at postnatal stages with different cell type specificity and/or targeting efficiency, and can, therefore, serve as valuable tools to dissect cell type‐specific gene functions in IVD development and homeostasis.

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The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causative agent of the COVID-19, which is a global pandemic, has infected more than 552 million people, and killed more than 6.3 million people. SARS-CoV-2 can be transmitted through airborne route in addition to direct contact and droplet modes, the development of disinfectants that can be applied in working spaces without evacuating people is urgently needed. TiO2 is well known with some features of the purification, antibacterial/sterilization, making it could be developed disinfectants that can be applied in working spaces without evacuating people. Facing the severe epidemic, we expect to fully expand the application of our proposed effective approach of mechanical coating technique (MCT), which can be prepared on a large-scale fabrication of an easy-to-use TiO2/Ti photocatalyst coating, with hope to curb the epidemic. The photocatalytic inactivation of SARS-CoV-2 and influenza virus, and the photocatalytic degradation of acetaldehyde (C2H4O) and formaldehyde (CH2O) has been investigated. XRD and SEM results show that anatase TiO2 successfully coats on the surface of Ti coatings, while the crystal structure of anatase TiO2 can be increased during the following oxidation in air. The catalytic activity towards methylene blue of TiO2/Ti coating balls has been significantly enhanced by the followed oxidation in air, showing a very satisfying photocatalytic degradation of C2H4O and CH2O. Notably, the TiO2/Ti photocatalyst coating balls demonstrate a significant antiviral activity, with a decrease rate of virus reached 99.96% for influenza virus and 99.99% for SARS-CoV-2.

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