Dragon fruit-like multifunctional probe for cancer precision theranostics
Along with the rapid rhythm of human lives, more and more fatal diseases have been surprisingly invading public health. Health is the greatest wealth, health is not equal to everything, but lose health will lose everything. Aside from maintaining a healthy lifestyle (scientific diet & exercise), it’s very significant to perform annual medical examination, because early diagnosis of many diseases (such as cancer) makes considerable roles in prognosis and treatment guidance.
So how to diagnose the disease? The research of molecular imaging techniques have presented promising potential to realize this goal. Especially, multimodal imaging provides comprehensive information and accomplishes synergistic advantages over any single modality alone, but it’s not easy to find such a multifunctional material. Thanks to the development of nanotechnology, it has offered numerous opportunity for preparing multifunctional nanomaterials with unique chemical and physical properties, however, it is usually tough to satisfy required demands and avoid intrinsic limitations at the same time. The typical case is that many synthetic nanoparticles can be made of controllable size and shape, but accompanies moderate biocompatibility and poor in vivo stability. On the contrary, materials from nature usually show amazing performance that perfectly matches human body, such like self-repairing, self-building and self-regulating.
Therefore, natural multifunctional nanomaterials are perfect candidates for multimodality imaging and therapeutic applications. Conventional methods of building multimodal imaging probes require either cross-linking to increase in vivo stability or covalently attach a target module to realize targeted imaging. In this study, we remedy these problems by utilizing two kinds of natural nanomaterials — melanin nanoparticle (MNP) and apoferrintin (APF). Melanin is natural biopolymer that is widely present in human body and has traditionally served as a biomarker for melanoma detection and therapy because of its intrinsic photoacoustic signals and the native strong chelating properties with metal ions. Ferritin is a natural iron storage protein. It shows cage-like structure with small size (around 10 nm), multi-channels (<1 nm) connecting the exterior with interior, and disassemble-reassemble characters upon pH changes. Moreover, it has targeting ability to transferrin receptor 1 (TfR1) which is over-expressed in numerous types of cancer cells.
Very interestingly, this efficient multimodal imaging nanoplatform (AMF) is constructed simply by pH tuning, without tedious assembling process (Fig. 1). APF cage significantly increased metal ions loading and therefore improved magnetic resonance imaging (MRI) sensitivity. In addition, synergistic use of Fe3+ and APF contributed to high photoacounstic imaging (PAI) sensitivity. AMF showed good bio-stability and presented excellent in vivo multimodality imaging (PET/MRI/PAI) properties in HT29 tumor because of its targeting property combined with the enhanced permeability and retention (EPR) effect. Overall, this nanoplatform is safe with complete utilization of natural materials, which is important for theranostics and translational nanomedicine in the future.
Dragon fruit-like biocage as an iron trapping nanoplatform for high efficiency targeted cancer multimodality imaging.
Yang M, Fan Q, Zhang R, Cheng K, Yan J, Pan D, Ma X, Lu A, Cheng Z
Biomaterials. 2015 Nov