Dual-modal Imaging Agent Research Articles

Lymph node imaging using novel simultaneous PET/MRI and dual-modality imaging agent.

Lymph node (LN) imaging has clinical significance because the invasion status of the LN is crucial information for disease stratification, staging, and management. Compared with conventional method, simultaneous PET/MRI using the multi-modal imaging marker can offer synergistic advantages. Here, we present LN mapping using selfdeveloped PET/MRI and novel bimodal biomarker. The SiPM-based PET insert which has peak sensitivity of 3.4% and center volumetric resolution of 0.57 cubic mm was developed. The PET insert was placed between the RF and gradient coil of Bruker 7T MRI. For LN targeting, 64Cu-NOTA-ironoxide-mannose, a new LN targeted dualmodality probe yielding superior T2 contrast was used. The relaxivity of the probe was measured by phantom study. Before the simultaneous imaging, MRI of the left and right popliteal lymph node of an anaesthetized BALB/c mouse was acquired as the control. 10 μL of the tracer was then injected into the left hindpaw of same mouse. Simultaneous PET/MRI was acquired for 10 minutes after 10-min and 120-min uptake period. The r2 of the probe was 845.3 at 7T magnetic field. The simultaneous PET/MRI has sufficient resolution and sensitivity to imaging tiny organ like mouse LN. A left popliteal LN in the 120-min post-injection MRI resulted in a remarkable signal decrease compared to those in the pre-injection MRI and that was good agreement with PET. The 10-min post-injection PET also showed clear regional activity in the LN, but the 10-min uptake period was not sufficient to generate MR contrast. It is due to the large difference in the sensitivities of the two modality. The simultaneous PET/MRI is useful for in vivo imaging and bimodal imaging probe development particularly to generating negative T2 contrast.

Synthesis of heterodimer radionuclide nanoparticles for magnetic resonance and single-photon emission computed tomography dual-modality imaging.

We report a facile synthesis of bifunctional Fe3O4-Ag(125)I heterodimers for use as dual-modality imaging agents in magnetic resonance (MR) and single-photon emission computed tomography (SPECT). We introduced (125)I, which is a clinically used radioisotope, as a SPECT reporter, into Fe3O4-Ag heterodimer nanoparticles to provide a new type of bifunctional contrast agent for MRI and SPECT imaging.

(99m)Tc radiolabelling of Fe3O4-Au core-shell and Au-Fe3O4 dumbbell-like nanoparticles.

The development of nanoparticle-based dual-modality probes for magnetic resonance imaging (MRI) and positron emission tomography (PET) or single photon emission computed tomography (SPECT) is increasingly growing in importance. One of the most commonly used radionuclides for clinical SPECT imaging is (99m)Tc and the labelling of Fe3O4 nanoparticles with (99m)Tc was shown to be a successful strategy to obtain dual-modality imaging agents. In this work, we focus on gold containing magnetic nanomaterials. The radiolabelling of magnetic Fe3O4-Au core-shell and Fe3O4-Au dumbbell-like nanoparticles with the [(99m)Tc(CO)3](+) fragment is described. The key elements for this (99m)Tc labelling approach are novel coating ligands, consisting of an anchor for the Au surface, a polyethylene glycol linker and a strong chelator for the [(99m)Tc(CO)3](+) moiety.

Rare-Earth doped particles as dual-modality contrast agent for minimally-invasive luminescence and dual-wavelength photoacoustic imaging.

Multi-modal imaging is an emerging area that integrates multiple imaging modalities to simultaneously capture visual information over many spatial scales. Complementary contrast agents need to be co-developed in order to achieve high resolution and contrast. In this work, we demonstrated that rare-earth doped particles (REDPs) can be employed as dual-modal imaging agents for both luminescence and photoacoustic (PA) imaging to achieve intrinsic high contrast, temporal and spatial resolution, reaching deeper depth. REDPs synthesized with different surfactants (citric acid, polyacrylic acid, ethylenediaminetetraacetic acid and sodium citrate) exhibit tunable emission properties and PA signal amplitudes. Amongst these samples, sodium citrate-modified REDPs showed the strongest PA signals. Furthermore, since REDPs have multiple absorption peaks, they offer a unique opportunity for multi-wavelength PA imaging (e.g. PA signals were measured using 520 and 975 nm excitations). The in vivo PA images around the cortical superior sagittal sinus (SSS) blood vessel captured with enhanced signal arising from REDPs demonstrated that in addition to be excellent luminescent probes, REDPs can also be used as successful PA contrast agents. Anisotropic polyacrylic acid-modified REDPs were found to be the best candidates for dual-modal luminescence and PA imaging due to their strong luminescence and PA signal intensities.

DMAP-BODIPY alkynes: a convenient tool for labeling biomolecules for bimodal PET-optical imaging.

Several new boron dipyrromethene/N,N-dimethylaminopyridine (BODIPY-DMAP) assemblies were synthesized as precursors for bimodal imaging probes (optical imaging, OI/positron emission tomography, PET). The photophysical properties of the new compounds were also studied. The first proof-of-concept was obtained with the preparation of several new BODIPY-labeled bombesins and evaluation of the affinity for bombesin receptors by using a competition binding assay. Fluorination reactions were investigated on DMAP-BODIPY precursors as well as on DMAP-BODIPY-labeled bombesins. Chemical modifications on the BODIPY core were also performed to obtain luminescent dyes emitting in the therapeutic window (650-900 nm), suitable for in vivo imaging, making these compounds promising precursors for PET/optical dual-modality imaging agents.

T1 and T2 Dual-Mode MRI Contrast Agent for Enhancing Accuracy by Engineered Nanomaterials

One of the holy grails in biomedical imaging technology is to achieve accurate imaging of biological targets. The development of sophisticated instrumentation and the use of contrast agents have improved the accuracy of biomedical imaging. However, the issue of false imaging remains a problem. Here, we developed a dual-mode artifact filtering nanoparticle imaging agent (AFIA) that comprises a combination of paramagnetic and superparamagnetic nanomaterials. This AFIA has the ability to perform "AND logic gate" algorithm to eliminate false errors (artifacts) from the raw images to enhance accuracy of the MRI. We confirm the artifact filtering capability of AFIA in MRI phantoms and further demonstrate that artifact-free imaging of stem cell migration is possible in vivo.

Regulation of multifunctional mesoporous core-shell nanoparticles with luminescence and magnetic properties for biomedical applications.

Gd3+-based/mesoporous silica-coated multifunctional core-shell (Y,Gd)2O3:Eu3+@nSiO2@mSiO2 nanoparticles (YGO-Bmnc NPs) with red luminescence, paramagnetic and mesoporous properties are developed as a novel nanomedical platform for combined multimodal diagnosis and therapy. 40 nm sized (Y,Gd)2O3:Eu3+ (YGO-Ac) nanocore is synthesized by a labor-saving solvothermal method, 20 nm sized perpendicularly aligned mesoporous silica shell is then successfully coated onto the nanocore through two-step sol-gel process and a highly efficient surfactant removal method (NH4NO3-EtOH). The surface area of nanocore can be increased from 24 m2 g-1 to 562 m2 g-1 after coating mesoporous silica shell without any core-free silica NPs. Light-emitting Eu3+ ion is chosen as a model to study the solvothermal mechanism and downconversion/upconversion luminescence properties of nanocore; Y3+ is doped into matrix to enhance energy transfer from Gd3+ to the doped Eu3+. Further investigation of luminescence property of YGO-Bmnc NPs shows that they are good red phosphors with millisecond-lever fluorescence lifetime (τ = 2.54 ms, 612 nm, 5D0-7F2). MTT assay reveals low cytotoxicity of the system with IC50 ([Gd]) > 1000 µg mL-1 (6.36 mM). The possibility of using YGO-Bmnc NPs for optical imaging in vitro has been demonstrated. Magnetic resonance imaging (MRI) in vitro exhibits a high r1 relaxivity of 5.05 mM-1 s-1 and low r2/r1 ratio of 1.216 (3.0 T) which is much lower than other existing Gd3+-based nanoscale contrast agents, manifesting that YGO-Bmnc NPs can be efficient T1 contrast agents. In light of their good performance in optical-MR imaging and highly ordered mesoporous structure, it is anticipated that they are suitable for combined multimodal diagnosis and therapy, they can load other imaging agents or drugs to provide complementary information from each imaging modality and guide individual treatment. What's more, the mesoporous silica shell can provide a large venue for the effective modification of various functional groups and biotargets with selectivity and specificity.

Lanthanide(III) complexes of rhodamine-DO3A conjugates as agents for dual-modal imaging.

Two novel dual-modal MRI/optical probes based on a rhodamine–DO3A conjugate have been prepared. The bis(aqua)gadolinium(III) complex Gd.L1 and mono(aqua)gadolinium(III) complex Gd.L2 behave as dual-modal imaging probes (r1 = 8.5 and 3.8 mM–1 s–1 for Gd.L1 and Gd.L2, respectively; λex = 560 nm and λem = 580 nm for both complexes). The rhodamine fragment is pH-sensitive, and upon lowering of the pH, an increase in fluorescence intensity is observed as the spirolactam ring opens to give the highly fluorescent form of the molecule. The ligands are bimodal when coordinated to Tb(III) ions, inducing fluorescence from both the lanthanide center and the rhodamine fluorophore, on two independent time frames. Confocal imaging experiments were carried out to establish the localization of Gd.L2 in HEK293 cells and primary mouse islet cells (∼70% insulin-containing β cells). Colocalization with MitoTracker Green demonstrated Gd.L2’s ability to distinguish between tumor and healthy cells, with compartmentalization believed to be in the mitochondria. Gd.L2 was also evaluated as an MRI probe for imaging of tumors in BALB/c nude mice bearing M21 xenografts. A 36.5% decrease in T1 within the tumor was observed 30 min post injection, showing that Gd.L2 is preferentially up taken in the tumor. Gd.L2 is the first small-molecule MR/fluorescent dual-modal imaging agent to display an off–on pH switch upon its preferential uptake within the more acidic microenvironment of tumor cells.

Synthesis and Evaluation of a Targeted Nanoglobular Dual-Modal Imaging Agent for MR Imaging and Image-Guided Surgery of Prostate Cancer

To synthesize and evaluate a peptide targeted nanoglobular dual modal imaging agent specific to a cancer biomarker in tumor stroma for MRI and fluorescence visualization of prostate tumor in image-guided surgery. A peptide (CGLIIQKNEC, CLT1) targeted generation 2 nanoglobular (polylysine dendrimer with a silsesquioxane core) dual modal imaging agent, CLT1-G2-(Gd-DOTA-MA)-Cy5, was synthesized by stepwise conjugation of Gd-DOTA-MA, Cy5 and peptide to the dendrimer. Contrast enhanced MR imaging of the targeted dual imaging agent was evaluated on a Bruker 7T animal scanner with male athymic nude mice bearing orthotopic PC3-GFP prostate tumor. Fluorescence tumor imaging of the agent was carried out on a Maestro fluorescence imaging system. The targeted agent CLT1-G2-(Gd-DOTA-MA)-Cy5 produced greater contrast enhancement in the tumor tissue than the control agent KAREC-G2-(Gd-DOTA-MA)-Cy5 at a dose of 30 μmol-Gd/kg in the MR images of the tumor bearing mice. Signal-to-noise ratio (SNR) of CLT1-G2-(Gd-DOTA-MA)-Cy5 in the tumor tissue was approximately 2 fold of that of the control agent in the first 15 min post-injection. The targeted agent also resulted in bright fluorescence signals in the tumor tissue. The CLT1 peptide targeted nanoglobular dual-imaging agent CLT1-G2-(Gd-DOTA-MA)-Cy5 has a potential for MRI and fluorescence visualization of prostate tumor.

Preparation and characterization of QDs-loaded PLGA microbubbles as fluorescent-ultrasonic dual-modality imaging agent

Objective To prepare the quantum dots(QDs) (CdTe-MPA)-loaded polymer(lactic-coglycolic acid,PLGA) microbubbles(MBQDs@PLGA) as dual-modality imaging agent for both fluorescent and ultrasonic imaging ability.Methods The MBQDs@PLGA were generated by the double emulsion technique,then filling in C3F8 after freeze-drying.Confocal laser scanning microscope(CLSM) and transmission electron microscope(TEM) were used to confirm the load of quantum dots in the MBs.Fluorospectro photometer spectra of the MBQDs@PLGA were analyzed to demonstrate the fluorescent imaging ability and determine the encapsulation efficiency by using the regression equation.Imaging experiments was applied to validate the fluorescent and ultrasonic imaging ability of the MBQDs@PLGA both by imaging of the model in vitro and by imaging of ovarian tumor blood vessels of tumor-bearing nude mouse in vivo.Results At excitation 272 nm the MBQDs@PLGA peak of the emission spectrum was 549 nm,and the encapsulation efficiency was 54％.The average diameter of MBQDs@PLGA was (1.7 ±0.2)μm,CLSM and TEM results confirmed the QDs-loaded in MBQDs-PLGA.The imaging results of MBQDs@PLGA showed a dual-modality imaging ability both fluorescent and ultrasonic imaging.Conclusions MBQDs@PLGA present fluorescence-ultrasound dual mode imaging performance by the QDs embedding in polymer microbubbles,and explore a new development train of thought of multi-mode imaging agent. Key words: Ultrasonography; Microbubbles; Lactic-co-glycolic acid; Quantum dots; Dual modality imaging

Lewis Acid-Assisted Isotopic 18F-19F Exchange in BODIPY Dyes: Facile Generation of Positron Emission Tomography/Fluorescence Dual Modality Agents for Tumor Imaging

Positron emission tomography (PET) is a powerful technique for imaging biological pathways in vivo, particularly those that are key targets in disease processes. In contrast, fluorescence imaging has demonstrated to be a superior method for image-guided surgery, such as tumor removal. Although the integration of PET and optical imaging could provide an attractive strategy for patient management, there is a significant shortage of established platforms/methods for PET/optical probe construction. In this study, various reaction conditions were explored to develop a simple and fast method allowing for the introduction of [18F]-fluoride into BODIPY dyes. Through a systematic optimization of the reaction conditions, we found that BODIPY dyes, including commercial amine-reactive BODIPY succinimidyl esters, may be converted into their radioactive analogues in the matter of minutes via a 18F-19F isotopic exchange reaction promoted by a Lewis acid such as SnCl4. An integrin-targeting RGD peptide was also conjugated with [18F]BODIPY® R6G , derived from the commercially available BODIPY® R6G fluorescent tag, to provide a [18F]-RGD conjugate in 82% yield. In vivo evaluation of this imaging probe showed a discernible tumor uptake in the U87MG xenograft model. The dual modality imaging properties of the probe was confirmed by ex vivo fluorescence and microPET imaging experiments. In summary, in the matter of minutes, BODIPY dyes were converted into their “hot” radioactive analogues via a 18F-19F isotopic exchange reaction promoted by a Lewis acid. This approach, which can be applied to commercial BODIPY dyes, provides easy access to positron emission tomography/fluorescence dual modality imaging agents.

The ubiquitous DOTA and its derivatives: the impact of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid on biomedical imaging

Over the last twenty-five years 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) has made a significant impact on the field of diagnostic imaging. DOTA is not the only metal chelate in use in medical diagnostics, but it is the only one to significantly impact on all of the major imaging modalities Magnetic Resonance (MR), Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT), and Fluorescence imaging. This crossover of modalities has been possible due to the versatility of DOTA firstly, to complex a variety of metal ions and secondly, the ease with which it can be modified for different disease states. This has driven research over the last two decades into the chemistry of DOTA and the modification of the substituent pendant arms of this macrocycle to create functional, targeted and dual-modal imaging agents. The primary use of DOTA has been with the lanthanide series of metals, gadolinium for MRI, europium and terbium for fluorescence and neodymium for near infra-red imaging. There are now many research groups dedicated to the use of lanthanides with DOTA although other chelates such as DTPA and NOTA are being increasingly employed. The ease with which DOTA can be conjugated to peptides has given rise to targeted imaging agents seen in the PET, SPECT and radiotherapy fields. These modalities use a variety of radiometals that complex with DOTA, e.g.(64)Cu and (68)Ga which are used in clinical PET scans, (111)In, and (90)Y for SPECT and radiotherapy. In this article, we will demonstrate the remarkable versatility of DOTA, how it has crossed the imaging modality boundaries and how it has been successfully transferred into the clinic.

Rapid Transformation of Protein-Caged Nanomaterials into Microbubbles As Bimodal Imaging Agents

We present a general method for converting colloidal nanomaterials into microbubbles as ultrasound contrast agents. Protein-caged nanomaterials, made either by self-assembled nanoparticles' protein corona or by fluorescent gold nanoclusters, can be rapidly transformed into microbubbles via a sonochemical route, which promote disulfide cross-linking of cysteine residues between protein-caged nanomaterials and free albumin during acoustic cavitation. The proposed methods yielded microbubbles with multiple functions by adjusting the original nanoparticle/protein mixture. We also showed a new dual-modal imaging agent of fluorescent gold microbubbles in vitro and in vivo, which can hold many potential applications in medical diagnostics and therapy.

Europium-doped gadolinium sulfide nanoparticles as a dual-mode imaging agent for T1-weighted MR and photoluminescence imaging

We present a facile synthesis of europium-doped gadolinium sulfide (GdS:Eu3+) opto-magnetic nanoparticles (NPs) via sonochemistry. Their photoluminescence and strong paramagnetic properties enable these NPs to be utilized as an in vitro cell imaging and in vivo T1-weighted MR imaging probe. The GdS:Eu3+ NPs have a prominent longitudinal (r1) relaxivity value, which is a critical parameter for T1-weighted MR imaging. Here, we showed not only their strong positive contrast effect to blood vessels and organs of mice, but also blood half-life and biodistribution including clearance from organs, in order to assess the GdS:Eu3+ NPs as a competent nanocrystal-based T1 contrast agent. We further showed confocal images of breast cancer cells containing GdS:Eu3+ NPs to evaluate as a photoluminescence probe. Dual-mode imaging capability obtained from the GdS:Eu3+ NPs will allow target-oriented cellular imaging as well as the resulting disease-specific MR imaging.

A Dual PET/MR Imaging Nanoprobe: 124I Labeled Gd3N@C80

The current report describes the development of a dual modality tomographic agent for both positron emission tomography and magnetic resonance imaging (PET/MRI). The dual-modality agent in this study was based on a 124I (PET) radiolabeled tri-gadolinium endohedral metallofullerene Gd3N@C80 (MRI) nanoprobe platform. The outer surface of the fullerene cage of the Gd3N@C80 metallofullerenes was surface functionalized with carboxyl and hydroxyl groups (f-Gd3N@C80) using previously developed procedures and subsequently iodinated with 124I to produce 124I-f-Gd3N@C80 nanoprobe. Orthotopic tumor-bearing rats were infused intratumorally by convection-enhanced delivery (CED) with the 124I-f-Gd3N@C80 agent and imaged by MRI or micro PET. The anatomical positioning and distribution of the 124I-f-Gd3N@C80 agent were comparable between the MRI and PET scans. The 124I-f-Gd3N@C80­ dual-agent distribution and infusion site within the tumor was clearly evident in both T1- and T2-weighted MR images. The results demonstrate the successful preparation of a dual-modality imaging agent, 124I-f-Gd3N@C80, which could ultimately be used for simultaneous PET/MR imaging.

Nanogel Star Polymer Architectures: A Nanoparticle Platform for Modular Programmable Macromolecular Self‐Assembly, Intercellular Transport, and Dual‐Mode Cargo Delivery

There is a growing demand for the simultaneous, site-localized delivery and expression of tandem functionality within the human body. [1–7] The benefits of dual delivery of functional cargos such as two (synergistic) therapeutics, [8,9] a therapeutic and an imaging agent, [4,10] or dual-mode imaging agents [11,12] have all been recently reported. For many medical applications requiring such in vivo expression of exogenous functional materials, the use of polymeric nanoparticle delivery vehicles of increasingly complex design is envisioned. Currently, organic nanoparticle platforms under development for these purposes include liposomes, [13] dendrimers,[14] and micelles. [15] Alternatively, star polymers (unimolecular, globular, polymer architectures) are an increasingly attractive class of organic nanoparticles for biomedical research purposes. [16–18] Although topographically similar to dendrimers (i.e., a high local density of polymeric arms, surface functionality, and interstitial regions), they lack the synthetic and structural limitations of dendrimers [19,20] and the dynamic instability of micelles [21] and liposomes. [22] Nanogel star polymers, i.e., those with polymer “arms” emanating from a cross-linked polymer core, [23,24] in particular, offer a potential for variation in nanoparticle structure and surface functional, i.e., arm density but are among the most synthetically demanding of polymeric nanostructures to develop. [25–29]

Metal Complex Mediated Conjugation of Peptides to Nucleus Targeting Acridine Orange: A Modular Concept for Dual-Modality Imaging Agents

To target the nucleus of specific cells, trifunctional radiopharmaceuticals are required. We have synthesized acridine orange derivatives which comprise an imidazole-2-carbaldehyde function for coordination to the [Re(CO)₃](+) or [(99m)Tc(CO)₃](+) core. Upon coordination, this aldehyde is activated and rapidly forms imines with amines from biological molecules. This metal-mediated imine formation allows for the conjugation of a nuclear targeting portion with a specific cell receptor binding function directly on the metal. With this concept, we have conjugated the acridine orange part to a bombesin peptide directly on the (99m)Tc core and in one step. In addition, a linker containing an integrated disulfide has been coupled to bombesin. LC/MS study showed that the disulfide was reductively cleaved with a 60 min half-life time. This concept enables the combination of a nucleus targeting agent with a specific cell receptor molecule directly on the metal without the need of separate conjugation prior to labeling, thus, a modular approach. High uptake of the BBN conjugate into PC-3 cells was detected by fluorescence microscopy, whereas uptake into B16BL6 cells was negligible.

99mTc-Bisphosphonate-Iron Oxide Nanoparticle Conjugates for Dual-Modality Biomedical Imaging

The combination of radionuclide-based imaging modalities such as single photon emission computed tomography (SPECT) and positron emission tomography (PET) with magnetic resonance imaging (MRI) is likely to become the next generation of clinical scanners. Hence, there is a growing interest in the development of SPECT- and PET-MRI agents. To this end, we report a new class of dual-modality imaging agents based on the conjugation of radiolabeled bisphosphonates (BP) directly to the surface of superparamagnetic iron oxide (SPIO) nanoparticles. We demonstrate the high potential of BP-iron oxide conjugation using (⁹⁹m)Tc-dipicolylamine(DPA)-alendronate, a BP-SPECT agent, and Endorem/Feridex, a liver MRI contrast agent based on SPIO. The labeling of SPIOs with (⁹⁹m)Tc-DPA-alendronate can be performed in one step at room temperature if the SPIO is not coated with an organic polymer. Heating is needed if the nanoparticles are coated, as long as the coating is weakly bound as in the case of dextran in Endorem. The size of the radiolabeled Endorem (⁹⁹m)Tc-DPA-ale-Endorem) was characterized by TEM (5 nm, Fe₃O₄ core) and DLS (106 ± 60 nm, Fe₃O₄ core + dextran). EDX, Dittmer-Lester, and radiolabeling studies demonstrate that the BP is bound to the nanoparticles and that it binds to the Fe₃O₄ cores of Endorem, and not its dextran coating. The bimodal imaging capabilities and excellent stability of these nanoparticles were confirmed using MRI and nanoSPECT-CT imaging, showing that (⁹⁹m)Tc and Endorem co-localize in the liver and spleen In Vivo, as expected for particles of the composition and size of (⁹⁹m)Tc-DPA-ale-Endorem. To the best of our knowledge, this is the first example of radiolabeling SPIOs with BP conjugates and the first example of radiolabeling SPIO nanoparticles directly onto the surface of the iron oxide core, and not its coating. This work lays down the basis for a new generation of SPECT/PET-MR imaging agents in which the BP group could be used to attach functionality to provide targeting, stealth/stability, and radionuclides to Fe₃O₄ nanoparticles using very simple methodology readily amenable to GMP.

Rapid aqueous [18F]-labeling of a bodipy dye for positron emission tomography/fluorescence dual modality imaging

We report the rapid nucleophilic [(18)F]-radiolabeling of a bodipy dye in aqueous solutions. This radiolabeled dye, whose biodistribution and clearance has been studied in mice, is stable in vivo and can be used as a positron emission tomography/fluorescence dual modality imaging agent.

Synthesis and characterization of fluorescent magneto polymeric nanoparticles (FMPNs) for bimodal imaging probes

Novel bifunctional fluorescent magneto polymeric nanoprobes (FMPNs) were synthesized to provide simultaneous diagnostic information via magnetic resonance imaging (MRI) and optical imaging. FMPNs consist of ultra-sensitive magnetic nanocrystals that function as MR probes combined with Nile Red, which functions as a fluorescent probe. FMPNs were encapsulated by a nano-emulsion method in polyvinyl alcohol (PVA, 87–89% hydrolyzed) through a matrix of polymethyl methacrylate (PMMA). FMPNs exhibited excellent colloidal stability and monodispersity. The production of MR and optical images demonstrated that FMPNs have potential as dual-mode imaging agents.