Recently, it has been reported that SiO2-NPs can efficiently deliver active miR-34a into breast cancer cells leading to the reduction in mammosphere formation (Panebianco et al., 2019) and the downregulation of Notch-1, a well-established miR-34a target with an important role in regulating stem cell functions and autophagy process (Bouras et al., 2008; Marcel and Sarin, 2016). Here, NOTCH1 is linked to breast cancer.