Most present nanodrug delivery systems have been developed to target cancer cells but rarely nuclei. However, nuclear-targeted drug delivery is expected to kill cancer cells more directly and efficiently. In this work, TAT peptide has been employed to conjugate onto mesoporous silica nanoparticles (MSNs-TAT) with high payload for nuclear-targeted drug delivery for the first time. Monodispersed MSNs-TAT of varied particle sizes have been synthesized to investigate the effects of particle size and TAT conjugation on the nuclear membrane penetrability of MSNs. MSNs-TAT with a diameter of 50 nm or smaller can efficiently target the nucleus and deliver the active anticancer drug doxorubicin (DOX) into the targeted nucleus, killing these cancer cells with much enhanced efficiencies. This study may provide an effective strategy for the design and development of cell-nuclear-targeted drug delivery.

Photomediated drug release: Silica‐coated upconverting nanoparticles with mesopores modified by azobenzene molecules were synthesized. The azobenzene molecules make possible the release of the anticancer drug doxorubicin from the pore network of the mesoporous silica outer layer by irradiation with near‐infrared (NIR) laser light. The release is regulated by the trans–cis photoisomerization of the azobenzene molecules (see picture).

Hypoxia development in tumor is closely associated with its increased aggressiveness and strong resistance to therapy, leading to the poor prognosis in several cancer types. Clinically, invasive oxygen microelectrode and high dosage radiotherapy are often utilized to accurately detect and effectively fight hypoxia. Recently, however, there has been a surge of interdisciplinary research aiming at developing functional molecules and nanomaterials that can be used to noninvasively image and efficiently treat hypoxic tumors. In this review, we will provide an overview of the reports published to date on the imaging and therapy of hypoxic tumors. First, we will present the design concepts and engineering of various hypoxia-responsive probes that can be applied to image hypoxia noninvasively, in an order of fluorescent imaging, positron emission tomography, magnetic resonance imaging, and photoacoustic imaging. Then, we will summarize the up-to-date functional nanomaterials which can be used for the effective treatments of tumor hypoxia. The well-established chemical functions of these elaborately designed nanostructures will enable clinicians to adopt specific treatment concepts by overcoming or even utilizing hypoxia. Finally, challenges and future perspectives facing the researchers in the field will be discussed.