Constructing bimodal nanoprobe based on Gd:AgInS_(2)/ZnS quantum dots for fluorometric/magnetic resonance imaging in mesenchymal stem cells

Mesenchymal stem cells(MSCs)hold great promise in regenerative medicine and received overwhelm-ing 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:AgInS_(2)/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:AgInS_(2)/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:AgInS_(2)/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:AgInS_(2)/ZnS QDs,which could monitor the differentiation and migration of MSCs for further therapeu-tic approach.