Fe@Fe 3 O 4 Nanoparticles In The Study Of Apoptosis-targeted Magnetic Resonance Imaging And Photothermal Therapy

Apoptosis is a normal physiological process that occurs during embryonic development.Therefore,diagnosis of apoptosis is of great importance for the early determination of therapy efficiency and the evaluation of disease progression.In the early stage of apoptosis,phosphatidylserine?PS?is redistributed out to the cell surface.Annexin V protein binds to the negatively charged phospholipid PS with the high affinity.Considering the price and technical limitations of Annexin V protein,DPA-Zn probe has been designed as a mimic for monitoring PS activity both in vitro and in vivo.Magnetic resonance imaging?MRI?owns the high spatial resolution and deep penetration.Therefore,MRI can be acted as an attractive modality for soft tissue imaging in vivo.The use of MRI contrast agents helps to image tumor by enhancing difference between cancerous and normal tissues during the treatment of tumor,which offers information for restraining of cancer development.In this work,we developed a new MRI apoptosis imaging probe with Fe@ Fe₃O₄ nanoparticles?MNPs?.DPA-Zn was attached to MNPs surface through the ring strain promoted azide-alkyne cycloaddition reaction?SPAAC Reaction?.This surface modification with DPA-Zn conjugated DSPE-PEG₂₀₀₀ resulted in increased stability of MNPs in physiological condition.Our apoptosis imaging probe of MNPs-DPA-Zn was synthesized by a simple method with inexpensive reagent for noninvasive apoptosis imaging.On the base of apoptosis tumor model,the apoptosis targeting probe of MNPs-DPA-Zn achieved a high photothermal therapeutic efficacy in vivo with the guidance of MR imaging.