Keca JM, Valic MS, Cheng MHY, Jian W, Overchuk M, Chen J & Zheng G
Advanced Healthcare Materials, 2018
DOI: 10.1002/adhm.201800857

The discovery and synthesis of multifunctional organic building blocks for nanoparticles have remained challenging. Texaphyrin macrocycles are multifunctional, all‐organic compounds that possess versatile metal‐chelation capabilities and unique theranostics properties for biomedical applications. Unfortunately, there are significant difficulties associated with the synthesis of texaphyrin‐based subunits capable of forming nanoparticles. Herein, the detailed synthesis of a texaphyrin‐phospholipid building block is reported via a key 1,2‐dinitrophenyl‐phospholipid intermediate, along with stable chelation of two clinically relevant metal ions into texaphyrin‐lipid without compromising their self‐assembly into texaphyrin nanoparticles or nanotexaphyrin. A postinsertion methodology to quantitatively insert a variety of metal‐ions into preformed nanotexaphyrins is developed and employed to synthesize a structurally stable, mixed 111indium‐manganese‐nanotexaphyrin for dual modal single‐photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI). In vivo dual SPECT/MRI imaging of 111In‐Mn‐nanotexaphyrins in an orthotopic prostatic PC3 mouse model demonstrates complementary signal enhancement in the tumor with both modalities at 22 h post intravenous administration. This result highlights the utility of hybrid metallo‐nanotexaphyrins to achieve sensitive and accurate detection of tumors by accommodating multiple imaging modalities. The power of this mixed and matched metallo‐nanotexaphyrin strategy can be unleashed to allow a diverse range of multifunctional biomedical imaging.