With unique magnetic properties and feasible synthesis, magnetic nanoparticles (MNPs) have been widely used in cancer theranostics. Herein, we first introduce general protocle to produce monodisperse magnetic nanoparticles, and then highlight the synthetic process and theranostic applications of iron carbides, such as Fe5C2, Fe2C, even multifunctional Au-Fe2C nanoparticles (NPs). It’ worth noting that the presence of halides is critical to produce pure phase iron carbides, while the growth thermodynamic and kinetic processes also affect the final products. In addition, through modification of affinity proteins (ZHER2:342), Fe5C2 NPs can selectively bind to HER2 overexpressing cancer cells. T2-weighted MRI and PAT signals are readily observed, and tumors are effectively ablated by PTT under NIR irradiation. Likewise, the ZHER2:342-binding Au-Fe2C NPs are capable of MRI/multispectral photoacoustic tomography/computed tomography tri-modal imaging-guided PTT. To enhance cancer therapeutic efficiency, anticancer drug doxorubicin is loaded into bovine serum albumin coated Fe5C2 NPs, combining PTT with chemotherapy. Such nanoplatform can respond to NIR and acidic environments, and exhibit burst drug release. In summary, we will present their chemical synthesis and application potential of multimodal imaging-guided PTT for precise diagnosis and efficient cancer treatment of iron carbide NPs.
 R. Hao, R. Xing, Z. Xu, Y. Hou, S. Gao, S. Sun,, Advanced Materials, 22 (2010), 2729–2742.
 Z. Xu, C. Shen, Y. Hou, H. Gao, S. Sun. Chemistry of Materials, 21(2009), 1778-1780.
 C. Yang, J. Wu, Y. Hou, Chemical Communication, 47(2011), 5130-5141.
 C. Yang, H. Zhao, Y. Hou, D. Ma, Journal of the American Chemical Society, 134 (2012), 15814-15821.
 J. Yu, C. Yang, J. Li, Y. Ding, L. Zhang, M.Z. Yousaf, J. Lin, R. Pang, L. Wei, L. Xu, Advanced Materials, 26 (2014), 4114-4120.
 J. Yu, Y. Ju, L. Zhao, X. Chu, W. Yang, Y, Tian, F. Sheng, J. Lin, F. Liu, Y. Dong and Y. Hou, ACS Nano, 10(2016), 159−169.
 Y. Ju, H. Zhang, J. Yu, S. Tong, N. Tian, Z. Wang, X. Wang, X. Su, X. Chu, J. Lin, Y. Ding, G. Li, F. Sheng, Y. Hou, ACS Nano, 11, (2017), 9239-9248.