New Span-PEG-composited Fe₃O₄-CNT as a multifunctional ultrasound contrast agent for inflammation and thrombotic...

By attaching ferroferric oxide (Fe₃O₄) to drug-carrying carbon nanotubes (CNTs), we generated a new Span-PEG composite with Fe₃O₄-CNT multifunctional microbubbles for inflammation and thrombus niduses. The Fe₃O₄-CNT magnetic targeting complex was prepared by in situ synthesis, and then acetylsalicylic acid (ASA) and gentamicin (GM) were loaded onto the Fe₃O₄-CNT complex by physical methods to produce Fe₃O₄-CNT-ASA and Fe₃O₄-CNT-GM complexes, respectively. Span-PEG-composited Fe₃O₄-CNT-ASA or Fe₃O₄-CNT-GM microbubbles were synthesized with Span and PEG as the membrane materials by the acoustic cavitation method. The obtained composite microbubbles were smooth, hollow spheres with an average particle size of 425 nm. The ASA and GM loading rates in Span-PEG-composited Fe₃O₄-CNT-ASA and Fe₃O₄-CNT-GM microbubbles were 1.12% and 19.05%, respectively. Span-PEG-composited Fe₃O₄-CNT-ASA microbubbles inhibited thrombosis and demonstrated an anticoagulation effect in vitro. Additionally, Span-PEG-composited Fe₃O₄-CNT-ASA microbubbles showed significantly enhanced ultrasound imaging of rabbit abdominal aorta and extended the signal time under the action of an external magnetic field. Thus, Span-PEG-composited Fe₃O₄-CNT-GM microbubbles inhibited Escherichia coli and Staphylococcus aureus, enhanced the ultrasound imaging of rabbit abdominal uterus and had better stability and fluidity.