Manganese and dysprosium codoped carbon quantum dots as a potential fluorescent/T1/T2/CT quadri-modal imaging nanoprobe.

It has been challenging to integrate various medical imaging modalities into an ultra-small nanoparticle with good biocompatibility to build highly efficient multimodal imaging nanoprobes. A new manganese and dysprosium codoped carbon quantum dots (Mn,Dy-CQDs) with a mean diameter of 1.77 nm was synthesized for fluorescence imaging, T1/T2-weighted magnetic resonance imaging (T1/T2-weighted MRI), and X-ray computed tomography (CT) imaging using a simple one-step hydrothermal approach. The obtained Mn,Dy-CQDs showed good water solubility, long-term stability, strong stable fluorescence property (fluorescence quantum yield of 31.62%), and excellent biocompatibility. The cell imaging verified that the Mn,Dy-CQDs have high efficiency of fluorescence imaging. The Mn,Dy-CQDs, on the other hand, had a superior X-ray absorption performance (47.344 HU L g-1), a higher longitudinal relaxivity (r1=7.47 mM-1s-1), a higher transverse relaxivity (r2=42.686 mM-1s-1). In vitro T1/T2-weighted MRI and CT imaging showed that Mn,Dy-CQDs can produce a strong contrast enhancement impact. To summarise, the Mn,Dy-CQDs may be used as a T1/T2-weighted MRI/CT/fluorescent quadri-modal imaging nanoprobe, indicating that they have a lot of uses in biomedical multimode imaging and clinics.