The nucleus is one of the most important cellular organelles and molecular anticancer drugs, such as cisplatin and doxorubicin, that target DNA inside the nucleus, are proving to be more effective at killing cancer cells than those targeting at cytoplasm. Nucleus‐targeting nanomaterials are very rare. It is a grand challenge to design highly efficient nucleus‐targeting multifunctional nanomaterials that are able to perform simultaneous bioimaging and therapy for the destruction of cancer cells. Here, unique nucleus‐targeting gold nanoclusters (TAT peptide–Au NCs) are designed to perform simultaneous in vitro and in vivo fluorescence imaging, gene delivery, and near‐infrared (NIR) light activated photodynamic therapy for effective cancer cell killing. Confocal laser scanning microscopy observations reveal that TAT peptide–Au NCs are distributed throughout the cytoplasm region with a significant fraction entering into the nucleus. The TAT peptide–Au NCs can also act as DNA nanocargoes to achieve very high gene transfection efficiencies (≈81%) in HeLa cells and in zebrafish. Furthermore, TAT peptide–Au NCs are also able to sensitize formation of singlet oxygen (1O2) without the co‐presence of organic photosensitizers for the destruction of cancer cells upon NIR light photoexcitation.

Conventional treatments fail to completely eradicate tumor or bacterial infections due to their inherent shortcomings. In recent years, photothermal therapy (PTT) has emerged as an attractive treatment modality that relies on the absorption of photothermal agents (PTAs) at a specific wavelength, thereby transforming the excitation light energy into heat. The advantages of PTT are its high efficacy, specificity, and minimal damage to normal tissues. To this end, various inorganic nanomaterials such as gold nanostructures, carbon nanostructures, and transition metal dichalcogenides have been extensively explored for PTT applications. Subsequently, the focus has shifted to the development of polymeric PTAs, owing to their unique properties such as biodegradability, biocompatibility, non-immunogenicity, and low toxicity when compared to inorganic PTAs. Among various organic PTAs, polyaniline (PANI) is one of the best-known and earliest-reported organic PTAs. Hence, in this review, we cover the recent advances and progress of PANI-based biomaterials for PTT application in tumors and bacterial infections. The future prospects in this exciting area are also addressed.

Development of simple, robust, and noninvasive therapeutic approaches to treat cancers and improve survival rates is a grand challenge in clinical biomedicine. In particular, the sizes and shape of the nanomaterials play a vital role in dictating their biodistribution and clearance pathways. It remains elusive how the size and shape of a nanomaterial affect its therapeutic efficacy in cancer diagnosis and treatments. To tackle the above problem, the effects of size and shape of Cu2(OH)PO4 nanostructures (nanosheets and quantum dots) on the photodynamic therapy (PDT) in destroying malignant drug‐resistant lung tumors and on combating the tumor hypoxia problem are investigated and compared. The photocatalytic mechanism of Cu2(OH)PO4 nanostructures mainly involves the generation of reactive oxygen species (ROS), such as hydroxyl radical (·OH) and singlet oxygen (1O2). Under an oxygen deprivation condition, Cu2(OH)PO4 nanosheets still can generate OH radicals to kill cancer cells upon near‐infrared (NIR) light irradiation. Overall, in vitro and in vivo experiments show that Cu2(OH)PO4 nanosheets can overcome tumor hypoxia problems and effectively mediate dual modal PDT and photothermal therapeutic (PTT) effects on destruction of NCI‐H23 lung tumors in mice using ultralow doses (350 mW cm−2) of NIR (915 nm) light.

Nucleus‐targeting gold nanoclusters (TAT peptide‐Au NCs) can act as intrinsic fluorescence probe for bioimaging, as shown by K. C. Hwang and co‐workers on page 5934. The nanoclusters also sensitize formation of singlet oxygen upon NIR light activation, to exert effective photodynamic therapeutic effects in killing cancer cells via subsequent DNA damage inside the nucleus, without using any additional photosensitizers.