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Various luminescent hybrid nanoparticles with a paramagnetic gadolinium oxide core, which are encapsulated within a polysiloxane shell, are applied and used as multimodal contrast agents for in vivo fluorescence, as well as magnetic resonance imaging. The analysis reveals that all these particles are suited for dual modality imaging and hence can be freely circulated in the blood vessels without being accumulated in the lungs and liver.

A new ligand, 8[O.sub.2] 1,4,7,10-tetraazadodecane tetraacetic acid (DOTAM), is synthesized and its lanthanide complexes are examined as potential chemical exchange saturation transfer (CEST) agents. The analysis reveals that the increasing ionic radius of the lanthanide ion leads to an increase in the extent of the distortion, thereby leading to a complete loss of symmetry in the complex.

We describe a family of calcium indicators for magnetic resonance imaging (MRI), formed by combining a powerful iron oxide nanoparticle-based contrast mechanism with the versatile calcium-sensing protein calmodulin and its targets. Calcium-dependent protein--protein interactions drive particle clustering and produce up to 5-fold changes in T2 relaxivity, an indication of the sensors' potency. A variant based on conjugates of wild-type calmodulin and the peptide M13 reports concentration changes near 1 [micro]M [Ca.sup.2+], suitable for detection of elevated intracellular calcium levels. The midpoint and cooperativity of the response can be tuned by mutating the protein domains that actuate the sensor. Robust MRI signal changes are achieved even at nanomolar particle concentrations ( magnetic resonance | T2 relaxation | signal transduction | molecular imaging | neuroimaging

The aggregation behavior of the water-soluble gadofullerene magnetic resonance imaging contrast agent, [Gd(at the rate of)C82O6(OH)16(NHCH2CH2COOH)8].sub. x] is studied in detail by dynamic light scattering, scanning electron microscopy, and atomic force microscopy. It is revealed that this agent aggregation in aqueous solution is pH dependent and at pH 2, it first self-assembles to form a ca. 30 nm small clusters, and then dozens of the small clusters further aggregate to form large grapelike particles.

A synthesis to improve the water proton relativity for MRI application using a tetranuclear gadolonium(III) complex, [Gd(sub 4)(4)(H(sub 2)O)(sub 8)] of DO3A appended onto the pentaerythrityl framework was made. The utility of multimetal gadolonium(III) chelates in accelerating water proton relaxitivity and the relaxivity is based on 'molecular' relaxitivity of the tetramer.

The article explains a newly devised core-shell design concept, which can be used for the fabrication of the dual mode nanoparticle contrast agents (DMCAs). These agents are shown to be extremely beneficial for the enhancement of the accuracy of MR imaging.

The anionic framework of the crystal is preserved even during the replacement of cationic sublattice with a different metal ion via reversible place exchange in ionic nanocrystals. This method has ensured that compositional interfaces within the heterostructure are conserved throughout the transformation when it is applied to nanoheterostructures.

The synthesis and characterization of a reversible T2 contrast agent consisting of cross-linked anionic dextran coated iron oxide nanoparticles covalently coupled to a light-sensitive spiropyran (SP)/merocyanine (MC) motif is described. The smart T2 agent has provided the advantage of reversibility that has enabled dynamic monitoring with MRI and the light responsiveness of the agent has indicated the potential to use them as MRI gene reporters for the luciferase expression system.

A method is described for visualizing submicrometer-scale patterns of monolayers terminated with C[F.sub.3] and C[H.sub.3] groups by using an ionic liquid (IL). The nonvolatile bis(hydroxyethyl)dimethylammonium methanesulfonate (BHDAMS) has sufficient contrast to image submicrometer-scale patterns of monolayers over large areas.

The design and synthesis of hyperbranched molecules are described that can be imaged in vivo by using [super 19]F magnetic resonance imaging (MRI). The polymers are cytocompatible following chain extension with PEGMA and the functionalization of these macromolecules is achieved with accessible and correct ligand presentation.

Hyperpolarization by dissolution dynamic nuclear polarization (DNP) has enhanced [super 89]Y spin magnetization and has provided a way to monitor yttrium-ligand complexation on the fly by means of [super 89]Y NMR. The studies have shown an example of free yttrium [Y.sup.3+] being complexed with 1,4,7,10-tetrakis(acetamido)-1,4,7,10-tetraazacyclododecane (DOTAM) to form [[Y(DOTAM)([H.sub.2]O)].sup.3+] as a model for gadolinium in contrast agents.

An effective new optical contrast agents is developed by describing the synthesis of porphyrazines (pzs) of the form [H.sub.2][pz([A.sub.4-n];[C.sub.n])] (A = peripheral heteroatom (S- and O-) R-groups and C is a fused, [bta],[bta]'-diisopropyloxynaphtho group). Emission from the oxygen-atom appended naphtho-pzs is observed within carcinoma cells, which has confirmed the cellular uptake and their potential use as optical agents.

The frequency-labeled exchange (FLEX) transfer principle is used for detecting the invisible protons of some nucleic acids and peptides as well as rapidly exchanging protons in chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) contrast agents. The alternative method of labeling and detecting exchangeable protons has benefited the development of new exchange-based MRI contrast agents, providing a method for multifrequency detection using frequency transfer instead of saturation transfer.

The article explains the formation, as well as the evaluation of a new supramolecular lanthanide complex, which is shown to act as luminescent contract agent for various purposes. The Eu(III) emission of the complex is shown to be independent of the pH value and hence can be used for the imaging of the damaged bone structure.

Nanoassembled capsules (NACs) formed by using the MRI contrast agent GdDOT[P.sup.5-] in the internal polymer aggregate are described, the smaller of which has shown promise as potential MRI contrast agents. The greatest gains in relaxivity are observed for smaller NACs, for which water accessibility has remained high but molecular rotation of the [Gd.sup.3+] chelate is restricted.

The synthesis and characterization of Fe(III)-carboxylate nanoscale metal-organic frameworks (NMOFs) with the MIL-101 structure is reported. The potential use of the newly obtained NMOF-based nanodelivery vehicles for optical imaging and anticancer therapy is also demonstrated in vitro by using HT-29 human colon adenocarcinoma cells.

The synthesis and analysis of a new class of cationic iodinated contrast agents for the imaging of cartilage using computed tomography (CT) is described. The cationic contrast agents have produced higher equilibrium concentrations in the articular cartilage of ex vivo rabbit femurs and greater imaging sensitivity and the studies have represented the first step in developing sensitive, nondestructive CT-based methods to study the biochemical properties of cartilage.

Eu[(S-THP).sup.3+] is the first PARACEST agent that has functioned through exchange of hydroxyl protons with water protons in aqueous solution and the CEST spectrum of this complex is strongly pH dependent. The sensitivity of the alcohol proton environment to interactions with the anions has shown that the complex has potential as a responsive PARACEST MRI contrast agent.

The increase of the hydration number of hydroxypyridonate-based Gd(super III) complexes by substituting the TAM podand with a moiety capable of hydrogen bonding a third water molecule close to the metal center is described. The resulting nine-coordinate Gd(super III) complex is the first displaying three inner sphere water molecules and high stability.

A new class of pyrone-derived tripodal chelators that form stable and soluble Gd(super 3+) complexes with high relaxivity for use as magnetic resonance imaging contrast agents (MRI-CAs) is described. The compounds are among the most soluble with a q=2 value, and one of them can be readily and economically synthesized from the food additive maltol.