Self-assembled mPEG-PCL-g-PEI micelles for multifunctional nanoprobes of doxorubicin delivery and magnetic resonance imaging and optical imaging.

In this paper, a novel bifunctional nanoprobe based on polyethylene glycol(MPEG)-poly(ϵ-caprolactone)(ϵ-CL)-polyethylenimine(PEI) labeled with FITC (MPEG-PCL-PEI-FITC, PCIF) were prepared to provide tumor therapy and simultaneous diagnostic information via magnetic resonance imaging (MRI) and optical imaging. Superparamagnetic iron oxide (SPIO) and doxorubicin (DOX) loaded PCIF (PCIF/SPIO/DOX) nanoprobes were prepared by self-assembling into micelles, which had uniformly distributed particle size of 130 ± 5 nm and a zeta potential of +35 ± 2 mV. Transmission electronic microscopy(TEM) showed that SPIO NPs were loaded into PCIF micelles. The PCIF/SPIO/DOX nanoprobes were superparamagnetic at 300 K with saturated magnetization of 20.5 emu/g Fe by vibrating-sample-magnetomete (VSM). Studies on cellular uptake of PCIF/SPIO/DOX nanoprobes demonstrated that SPIO NPs, DOX and FITC labeled MPEG-PCL-PEI were simultaneously taken up by the breast cancer (4T1) cells. After intravenous injection of PCIF/SPIO/DOX nanoprobes in 4T1 tumor-bearing mice, SPIO NPs, DOX and FITC labeled MPEG-PCL-PEI micelles were simultaneously delivered into tumor tissue by histochemisty. This work is important for the applications to multimodal diagnostic and theragnosis as nanomedicine.