Constructing bimodal nanoprobe based on Gd:AgInS2/ZnS quantum dots for fluorometric/magnetic resonance imaging in mesenchymal stem cells

Mesenchymal stem cells (MSCs) hold great promise in regenerative medicine and received overwhelming concerns to promote their therapeutic effects. Owing to the shortage of MSCs-specific biomarkers, bimodal imaging nanoprobes with integrated complementary information are of great importance in ameliorating the efficacy of MSCs terminal tracking. In this study, a noninvasive dual-mode imaging nanoprobe with enhanced detection sensitivity and spatial resolution based on alloyed Gd:AgInS2/ZnS quantum dots (QDs) was first fabricated through a microwave-assisted heating method. The QDs with red emissive fluorescence exhibit excellent biocompatibility in MSCs under a confocal microscope. As for magnetic resonance imaging (MRI), the longitudinal relaxation rate of 11.1420 mM–1 S–1 of Gd:AgInS2/ZnS QDs was achieved, which was 1.7 times higher than that of commercial MRI contrast agent (6.4667 mM–1 S–1). Furthermore, the cellular internalization of Gd:AgInS2/ZnS QDs exerts no significant effect on the adipogenesis of MSCs and is conducive to the observation of further adipogenic differentiation. Our work helps to verify the promising prospect to develop a bimodal nanoprobe of fluorescence/MRI based on Gd:AgInS2/ZnS QDs, which could monitor the differentiation and migration of MSCs for further therapeutic approach.