Gd³⁺ doped CuInS₂/ZnS nanocrystals with high quantum yield for bimodal fluorescence/magnetic resonance imaging

Recently, CuInS₂/ZnS nanocrystals (CISZ NCs) have been widely used in many fields due to their excellent properties, such as tunable photoluminescence (PL) spectra, broad absorption, and non-toxicity. In order to expand the application of CISZ NCs, Gd³⁺ was introduced into the host serving as paramagnetic modules to achieve magnetic resonance imaging (MRI) enhancement. MRI probes could provide high-resolution anatomical information. The derived Gd-Cu-In-S/ZnS nanocrystals (GCISZNCs) exhibited the strong orange photoluminescence with a quantum yield of 57.6% and significantly high longitudinal relaxivity (r₁=20.4 mmol/s) in comparison with commercial Magnevist (Gd-DTPA, r₁=4.5 mmol/s). Effective enhancement of MRI and improved longitudinal relaxivity as well as lower cytotoxicity mode GCISZ NCs an ideal MRI probe, suggesting its potential and significance in practical biological and clinic applications in the future.