Novel Span-PEG Multifunctional Ultrasound Contrast Agent Based on CNTs as a Magnetic Targeting Factor and a Drug Carrier

Based on the targeting of ferroferric oxide (Fe 3 O 4 ) and the drug-loading property of carbon nanotubes (CNTs), a novel Span-PEG-composited Fe 3 O 4 -CNTs-DOX multifunctional ultrasound contrast agent was designed and applied to tumor lesions. In situ liquid phase synthesis was employed to prepare the Fe 3 O 4 -CNTs magnetic targeting complex, and the physical method was used to obtain the Fe 3 O 4 -CNTs-DOX complex by loading doxorubicin (DOX) onto Fe 3 O 4 -CNTs. The targeted drug-loading complex Fe 3 O 4 -CNTs-DOX was combined with the membrane material of Span-PEG by the acoustic vibration cavitation method. The maximum tolerance for Span-PEG-composited Fe 3 O 4 -CNTs-DOX microbubbles was 450 times higher, which has good safety. The loading rate of DOX in the obtained composite microbubbles was 17.02%. The proliferation inhibition rate of Span-PEG-composited Fe 3 O 4 -CNTs-DOX microbubbles on liver cancer SMMC-7721 cells reached 48.3%. Span-PEG-composited Fe 3 O 4 -CNTs-DOX microbubbles could significantly enhance ultrasonic imaging and enrich at a specific location under an external magnetic field, and the extended imaging time could ensure the effective observation and diagnosis of lesions.