Quantum dots decorated single walled carbon nanotubes for multimodal cellular imaging

We present the quantum dots (QDs) decorated single walled carbon nanotubes (SWNT) nanohybrids (QD-SWNT) for multimodal cellular imaging via optical imaging and magnetic resonance imaging (MRI). The QD-SWNT has been synthesized by covalently linking QDs onto chitosan-functionalized SWNT. Incubating human embryonic kidney (HEK) cell line 293T cells with QD-SWNT demonstrates that the QD-SWNT shows highly intracellular labeling efficiency and enhanced T₂-weighted MRI signal. The higher intracellular labeling efficiency compared to pure QDs can be attributed to the ability of SWNT to readily penetrate into cells and the enhanced T₂-weighted MRI signal is the function of SWNT for lowering the transverse relaxation of water proton, which can acts as MRI contrast agent. Thus, QD-SWNT can serve as dual-modal MRI/optical imaging agent.