Here, dual-modal bioprobes for combined optical and magnetic resonance (MR) imaging are reported. Gadolinium orthophosphate (GdPO₄) nanorods co-doped with light-emitting lanthanide ions have been successfully prepared through a hydrothermal method. An efficient downconversion luminescence from Ce/Tb or Eu doped GdPO₄ nanorods and upconversion luminescence from Yb/Er co-doped GdPO₄ nanorods are observed, respectively, which offers the optical modality for the nanoprobes. Notably, we first report the upconversion phenomenon based on the GdPO₄ matrix under 980 nm near infrared irradiation. The possibility of using these nanoprobes with downconversion and upconversion luminescent emissions for optical cell imaging is also demonstrated. Furthermore, these Gd³⁺-containing nanophosphors show good positive signal-enhancement ability when performed under a 4.7 T MR imaging scanner, indicating they have potential as T₁ MR imaging contrast agents. Thus, nanoprobes based on GdPO₄ nanophosphors are shown to provide the dual modality of optical and MR imaging.

Upconversion nanoparticles (UCNPs) have drawn much attention in biomedicine, and the clinical translation of UCNPs is closely related to their toxicity and metabolism in vivo. In this study, we chose polyethyleneimine modified NaYF₄:Yb,Er upconversion nanoparticles (abbreviated as PEI@UCNPs) to systematically study the biodistribution in mice using intravenous (i.v.), intraperitoneal (i.p.), and intragastric (i.g.) administration. The i.p. injected PEI@UCNPs exhibited obvious accumulation in the spleen within 30 days. Comparably, PEI@UCNPs via i.g. administration exhibited an accumulation that decreased with time in various body tissues and were found mainly in the ileum and cecum but were rather low in concentration in the other examined organs. For the i.v. injected group, the UCNPs exhibited an obvious clearance from the body within 30 days and the accumulation in the spleen gradually decreased. Furthermore, ⁶⁴Cu labeled PEI@UCNPs were i.v. injected for real-time photon emission computed tomography (PET) imaging to further confirm the biodistribution in mice. Afterward, the excretion routes of the PEI@UCNPs were evaluated. For i.p. injected groups, the UCNPs were slowly and partly excreted via feces and urine for 30 days, and a large number of the UCNPs were steadily excreted via feces for the i.v. group, suggesting that the UCNPs via i.v. injection can be potentially used for imaging and therapy studies in vivo. However, for the i.g. administrated group, most of the UCNPs were excreted through feces within 48 h. Hematology, body weight, and biochemical analysis were used to further quantify the potential toxicity of the UCNPs, and results indicated that there was no over toxicity of the UCNPs in mice at the tested period. This work suggests that the clearance and excretion capabilities of PEI@UCNPs are particularly dependent on their administration routes.

Nickel-based nanomaterials (NBNs) have seen a surge in usage across a variety of applications. However, the widespread use of NBNs has led to increased human exposure, raising questions about their associated health risks, both in the short and long term. Additionally, the spread of NBNs in the environment has attracted considerable attention, emerging as a vital focus for research and development. This review aims to provide an in-depth assessment of the current understanding of NBNs toxicity, the mechanisms underlying their toxicological effects, and the strategies for mitigating associated health risks. We begin by examining the physicochemical properties of NBNs, such as particle size, composition and surface functionalization, which are key determinants of their biological interactions and toxicity. Then, through an extensive analysis of in vitro and in vivo studies, we highlight the adverse effects of NBNs exposure, including the generation of reactive oxygen species (ROS), oxidative stress, inflammation, cytotoxicity, genotoxicity, and immunotoxicity. To address the potential health risks associated with NBNs, we propose future strategies for risk prevention, including the development of safer nanomaterial designs, implementation of stringent regulatory guidelines, and advancement of novel toxicity testing approaches. Graphical Abstract

Radiotherapy (RT), the most commonly used treatment method in clinics, shows unique advantages such as strong penetration, high energy intensity, and low systemic side effects. However, in vivo tumor hypoxia seriously hinders the therapeutic effect of RT. Hypoxia is a common characteristic of locally advanced solid tumor microenvironments, which leads to the proliferation, invasion and metastasis of tumor cells. In addition, oxygen consumption during RT will further aggravate tumor hypoxia, causing a variety of adverse side effects. In recent years, various biocatalytic nanomaterials (BCNs) have been explored to regulate and reverse tumor hypoxia microenvironments during RT. In this review, the most recent efforts toward developing oxygen-generating BCNs in relieving tumor hypoxia in RT are focused upon. The classification, engineering nanocatalytical activity of oxygen-generating BCNs and combined therapy based on these BCNs are systematically introduced and discussed. The challenges and prospects of these oxygen-generating BCNs in RT applications are also summarized.

A photoactivated MoO _x @MB-hy hydrogel was constructed with synergistic photothermal–photodynamic therapy properties for enhanced ROS accumulation on a bacterial surface to rapidly eradicate bacteria and accelerate the healing of wounds infected by drug-resistant bacteria.

With the rapid development of nanotechnology, nanomaterials have shown immense potential for antitumor applications. Nanosized calcium carbonate (CaCO₃) materials exhibit excellent biocompatibility and degradability, and have been utilized to develop platform technologies for cancer therapy. These materials can be engineered to carry anticancer drugs and functional groups that specifically target cancer cells and tissues, thereby enhancing therapeutic efficacy. Additionally, their physicochemical properties can be tailored to enable stimuli-responsive therapy and precision drug delivery. This Review consolidates recent literatures focusing on the synthesis, physicochemical properties, and multimodal antitumor therapies of CaCO₃-based nanoplatforms (CBN). We also explore the current challenges and potential breakthroughs in the development of CBN for antitumor applications, providing a valuable reference for researchers in the field.