Dy2O3 nanoparticle nano-magnets
A previous study has explored the use of dextran coated Dy2O3 nanoparticles as an MRI contrast agent (Norek 2008). In another study, glucuronic acid was used to coat composite nanoparticles of Gd2O3 and Dy2O3 that served as a dual T1 and T2 relaxation agents (Tegafaw 2015).
Dy(III) loaded tobacco mosaic virus nanomagnets
T2 contrast agents such as superparamagnetic iron oxide nanoparticles (SIONPs) may have advantages in biomedical research and peclinical trials, ultrahigh magnetic fields may result in aggregation and movement (Hu 2017) Nicole Steinmetz’s group at Case Western Reserve University reported a clever way of loading tobacco mosaic virus particles with a Dy(III) compound.

Dy-DOTA was used to label glutamic acid residues on coat protein monomers within the cavity of the virus. Previous versions of this TMV nano-magnet used gadolinium-DOTA on the interior and VCAM-1 on the exterior to target atherosclerotic plaques (Buckman 2014). Labeling of glutamic acids involved propargylamine modification followed by reaction with Cy7.5 and Ds-DOTA azide derivatives.
If you wish to produce TMV nano-magnets
MSE Supplies sells a tissue homogenizer for grinding plant tissue used to grow the tobacco mosaic virus.

In both publications the authors coupled a near infrared Cy7.5 fluorescent probe for dual imaging. One could attach just about any targeting molecule to the exterior of the TMV particle for tissue targeted MRI applications.
Dysprosium binding to phosphate containing compounds
Takahashi (2012) used DNA hybrid filters to recover waste transition metals, one of which was dysprosium. Tesch (2017) used a nitrate salt of dysprosium to prepare magnetic hydroxy apatite crystals. Hydroxy apatite is a calcium phosphate polymer and a major component of bone.
References
Atabaev TS, Piao Z, Molkenova A. (2018) Carbon Dots Doped with Dysprosium: A Bimodal Nanoprobe for MRI and Fluorescence Imaging. J Funct Biomater. 2018 May 18;9(2). pii: E35.
Bruckman MA, Jiang K, Simpson EJ, Randolph LN, Luyt LG, Yu X, Steinmetz NF. (2014) Dual-modal magnetic resonance and fluorescence imaging of atherosclerotic plaques in vivo using VCAM-1 targeted tobacco mosaic virus. Nano Lett. 14(3):1551-8. Free Paper
Hu H, Zhang Y, Shukla S, Gu Y, Yu X, Steinmetz NF.(2017) Dysprosium-Modified Tobacco Mosaic Virus Nanoparticles for Ultra-High-Field Magnetic Resonance and Near-Infrared Fluorescence Imaging of Prostate Cancer. ACS Nano. 11(9):9249-9258 Free Paper
Norek M, Kampert E, Zeitler U, Peters JA. (2008) Tuning of the size of Dy2O3 nanoparticles for optimal performance as an MRI contrast agent. J Am Chem Soc. 2008 Apr 16;130(15):5335-40.
Takahashi Y, Kondo K, Miyaji A, Umeo M, Honma T, Asaoka S.(2012) Recovery and separation of rare earth elements using columns loaded with DNA-filter hybrid. Anal Sci. 28(10):985-92.
Tegafaw T, Xu W, Ahmad MW, Baeck JS, Chang Y, Bae JE, Chae KS, Kim TJ, Lee GH. (2015) Dual-mode T1 and T2 magnetic resonance imaging contrast agent based on ultrasmall mixed gadolinium-dysprosium oxide nanoparticles: synthesis, characterization, and in vivo application. Nanotechnology. 26(36):365102.
Tesch A, Wenisch C, Herrmann KH, Reichenbach JR, Warncke P, Fischer D, Müller FA.(2017)Luminomagnetic Eu3+- and Dy3+-doped hydroxyapatite for multimodal imaging. Mater Sci Eng C Mater Biol Appl. 81:422-431.