A fluorescent probe based on N-CDs was synthesized by a solvothermal method to detect ClO⁻ and HSO₃⁻ in cells through an “ON–OFF–ON” mode.

Lanthanide-based multimodal probes with high sensitivity, simple synthesis strategy, and good biocompatibility promise new applications for clinical diagnosis. However, today's challenge is not only to develop high-performance multimodal probes for more accurate and reliable diagnosis, but also to understand the fate of these probes in vivo. In this context, a novel PEGylated Dy-doped NaGdF₄ nanoprobe (PEG-NaGdF₄:Dy) was designed and fabricated as a T₁/T₂-weighted MRI/CT imaging agent. This nanoprobe has a distinct longitudinal relaxivity (r₁ = 5.17 mM⁻¹ s⁻¹), relatively high transverse relaxivity (r₂ = 10.64 mM⁻¹ s⁻¹), and exhibits strong X-ray attenuation properties (44.70 HU L g⁻¹) in vitro. Furthermore, T₁/T₂-weighted MRI/CT imaging in vivo confirmed that this PEG-NaGdF₄:Dy nanoprobe could lead to a significant contrast enhancement effect on liver, spleen and kidney at 24 h post injection. The MTT assay, histological analysis, and biodistribution investigation demonstrated that this multifunctional nanoprobe possessed relatively low cytotoxicity, negligible tissue damage and could be completely excreted out of the body of mice as time prolonged. Therefore, the present PEG-NaGdF₄:Dy nanoprobe has the potential for the development of multifunctional T₁/T₂-weighted MRI/CT imaging to provide more comprehensive and accurate diagnosis information.

A sensitive fluorescent probe based on carbon dots has been synthesized by a one-pot hydrothermal method for the rapid detection of intracellular Fe²⁺.

A tannic acid–Fe ³⁺ networks-functionalized polydopamine-based composite nanoparticle was constructed and demonstrated the promising application for T ₁ / T ₂ -weighted MR imaging-guided synergistic treatment of PTT and reductant/photothermal-enhanced CDT.