Engineered nanoparticles have been used to provide diagnostic, therapeutic and prognostic information about the status of disease. Nanoparticles developed for these purposes are typically modified with targeting ligands (such as antibodies, peptides or small molecules) or contrast agents using complicated processes and expensive reagents. Moreover, this approach can lead to an excess of ligands on the nanoparticle surface, and this causes non-specific binding and aggregation of nanoparticles, which decreases detection sensitivity. Here, we show that magnetoferritin nanoparticles (M-HFn) can be used to target and visualize tumour tissues without the use of any targeting ligands or contrast agents. Iron oxide nanoparticles are encapsulated inside a recombinant human heavy-chain ferritin (HFn) protein shell, which binds to tumour cells that overexpress transferrin receptor 1 (TfR1). The iron oxide core catalyses the oxidation of peroxidase substrates in the presence of hydrogen peroxide to produce a colour reaction that is used to visualize tumour tissues. We examined 474 clinical specimens from patients with nine types of cancer and verified that these nanoparticles can distinguish cancerous cells from normal cells with a sensitivity of 98% and specificity of 95%.

No abstract

Editorial note: A potential breach of our editorial policies has emerged following the publication of this paper. Yongxin Pan and Changqian Cao, who are listed as contributing authors, have declared no knowledge of the submission of the paper, and their disagreement with its publication. They have pointed out several errors in the description of the synthesis and characterization of the magnetoferritin nanoparticles used in the study. We take breaches of editorial policies very seriously and have therefore informed the listed authors' institutions and the Chinese Academy of Sciences.

No abstract

The avascular microscopic breast and brain tumors (<1-2 mm diameter) can be noninvasively detected by designing human heavy-chain ferritin (HFn)-based nanoparticles as molecular probes for near-infrared fluorescence and magnetic resonance imaging. The intravenously injected HFn-based nano-particles (Cy5.5-HFn and M-HFn) can cross the endothelium, epithelium, and blood-brain barriers and be internalized into tumor cells.

Aims This study aimed to investigate the prevalence of anxiety, depression and PTSD symptoms, and associated risk factors among a large-scale sample of adolescents from China after the pandemic and lockdown. Method A total of 57,948 high school students took part in an online survey from July 13 to 29, 2020. The mental health outcomes included anxiety, depression and PTSD symptoms. Risk factors included negative family relationships, COVID-19 related exposure, and a lack of social support. Results The prevalence of anxiety, depression and PTSD symptoms was 7.1%, 12.8%, and 16.9%, respectively. COVID-19 related exposure significantly linked to the mental health outcomes (all p < .001). The most important predictors for the mental health outcomes were family relationship and social support (all p < .001). Conclusion The pandemic may have long-term adverse mental health consequences among adolescents. Adverse family relationships and lack of social support could be the major risk factors for the post-pandemic mental health outcomes of adolescents.

[1] Studying the magnetic properties of ultrafine nanometer-scale ferrimagnetic particles (<10 nm) is vital to our understanding of superparamagnetism and its applications to environmental magnetism, biogeomagnetism, iron biomineralization, and biomedical technology. However, magnetic properties of the ultrafine nanometer-sized ferrimagnetic grains are very poorly constrained because of ambiguities caused by particle magnetostatic interactions and unknown size distributions. To resolve these problems, we synthesized magnetoferritins using the recombinant human H chain ferritin (HFn). These ferrimagnetic HFn were further purified through size exclusion chromatography to obtain monodispersed ferrimagnetic HFn. Transmission electron microscopy revealed that the purified ferrimagnetic HFn are monodispersed and each consists of an iron oxide core (magnetite or maghemite) with an average core diameter of 3.9 ± 1.1 nm imbedded in an intact protein shell. The R value of the Wohlfarth-Cisowski test measured at 5 K is 0.5, indicating no magnetostatic interactions. The saturation isothermal remanent magnetization acquired at 5 K decreased rapidly with increasing temperature with a median unblocking temperature of 8.2 K. The preexponential frequency factor f 0 determined by AC susceptibility is (9.2 ± 7.9) × 10 10 Hz. The extrapolated M rs /M s and B cr /B c at 0 K are 0.5 and 1.12, respectively, suggesting that the ferrimagnetic HFn cores are dominated by uniaxial anisotropy. The calculated effective magnetic anisotropy energy constant K eff = 1.2 × 10 5 J/m 3 , which is larger than previously reported values for bulk magnetite and/or maghemite or magnetoferritin and is attributed to the effect of surface anisotropy. These data provide useful insights into superparamagnetism as well as biomineralization of ultrafine ferrimagnetic particles.

These findings provide novel insights into sex differential risk and features of youth's PTSD symptomatology. Sex differences reflected in the co-occurrence of PTSD symptoms may merit more consideration in research and clinical practice.