Near infrared-fluorescent and magnetic resonance imaging molecular probe with high T1 relaxivity for in vivo multimodal imaging.
Ontology highlight
ABSTRACT:
SUBMITTER: Guo K
PROVIDER: S-EPMC2975539 | biostudies-literature | 2010 Jun
REPOSITORIES: biostudies-literature
Publications
Near infrared-fluorescent and magnetic resonance imaging molecular probe with high T1 relaxivity for in vivo multimodal imaging.
Guo Kevin K Berezin Mikhail Y MY Zheng Jie J Akers Walter W Lin Franck F Teng Bao B Vasalatiy Olga O Gandjbakhche Amir A Griffiths Gary L GL Achilefu Samuel S
Chemical communications (Cambridge, England) 20100413 21
A new gadolinium chelating NIR fluorescent molecular probe increases T(1) relaxivity of water protons, facilitating combined optical and magnetic resonance imaging. ...[more]
Similar Datasets
Project description:Gold nanostars functionalized with Gd(III) have shown significant promise as contrast agents for magnetic resonance imaging (MRI) because of their anisotropic, branched shape. However, the size and shape polydispersity of as-synthesized gold nanostars have precluded efforts to develop a rigorous relationship between the gold nanostar structure (e.g., number of branches) and relaxivity of surface-bound Gd(III). This paper describes the use of a centrifugal separation method that can produce structurally refined populations of gold nanostars and is compatible with Gd(III) functionalization. Combined transmission electron microscopy and relaxivity analyses revealed that the increased number of nanostar branches was correlated with enhanced relaxivity. By identifying the underlying relaxivity mechanisms for Gd(III)-functionalized gold nanostars, we can inform the design of high-performance MRI contrast agents.
| S-EPMC5172589 | biostudies-literature
Project description:The ability to image and ultimately quantitate beta-cell mass in vivo will likely have far reaching implications in the study of diabetes biology, in the monitoring of disease progression or response to treatment, and for drug development. Here, using animal models, we report on the synthesis, characterization, and intravital microscopic imaging properties of a near-infrared fluorescent exendin-4 analogue with specificity for the GLP-1 receptor on beta cells (E4(K12)-Fl). The agent demonstrated subnanomolar EC(50) binding concentrations, with high specificity and binding that could be inhibited by GLP-1R agonists. Following intravenous administration to mice, pancreatic islets were readily distinguishable from exocrine pancreas, achieving target-to-background ratios within the pancreas of 6:1, as measured by intravital microscopy. Serial imaging revealed rapid accumulation kinetics (with initial signal within the islets detectable within 3 min and peak fluorescence within 20 min of injection), making this an ideal agent for in vivo imaging.
| S-EPMC2912453 | biostudies-literature
Project description:Imaging agents with affinity for bone can enable early detection of changes to bone mineral density, which is a hallmark of many bone-associated pathologies such as Paget's disease and osteoporosis. Here, we report the development of a polymer nanoparticle (NP)-based multimodal imaging probe that enables visualization of bone mineral phase in near-infrared (NIR) optical tomography and detection in T2-weighted magnetic resonance imaging (MRI). Ultrasmall superparamagnetic iron oxide was first encapsulated in NPs derived by blending poly(dl-lactic-co-glycolic acid)-poly(ethylene glycol) (PLGA-PEG) with N-hydroxysuccinimide functionalized-PLGA (NHS-PLGA). Postmodification of NHS surface functionality on the NPs with alendronic acid (Aln), a bone-targeting ligand, yielded stable ultrasmall superparamagnetic iron oxide nanoparticles (USPIONs) containing NPs that exhibit good serum stability and favorable cytocompatibility. These post-Aln-modified NPs exhibit 8- to 10-fold higher affinity for synthetic and biogenic hydroxyapatite in comparison to NPs where Aln was introduced before NP formation and shorten the T2 relaxation times in both agarose phantoms and fresh spongy bone, thus enabling the interrogation of bone mineral phase in T2-MRI. Finally, by introducing an NIR-dye-modified PLGA during the NP formation step, NP probes that enable the visualization of bone mineral phase in both NIR optical tomography and MRI have been realized. The system presented herein meets many of the criteria for clinical translation and therefore opens new opportunities for bone imaging and targeted therapeutics.
| S-EPMC6044643 | biostudies-literature
Project description:We report the preparation and characterization of gadolinium (Gd)- or manganese (Mn)-loaded dendrimers and Gd-loaded dendrimer-entrapped gold nanoparticles (Gd-Au DENPs) to examine the relationship between the number of metal ion chelators and r1 relaxivity. In this study, amine-terminated fifth-generation poly(amidoamine) dendrimers (G5.NH2) modified with different numbers of DOTA-NHS chelators were used to chelate Gd and Mn ions. The remaining amine groups were then acetylated completely, followed by the use of materials with better r1 relaxivities and T1-weighted imaging performances as templates to synthesize Gd-Au DENPs. The Gd and Mn chelators as well as Gd-Au DENPs were characterized via different techniques. We show that the r1 relaxivity and T1 imaging performance increase with loading of greater numbers of Gd and Mn ions on the G5.NH2 and that the acetylation process affects the relaxivity and imaging properties to a certain extent. After entrapment with Au NPs, the r1 relaxivity and T1-weighted imaging performance of Gd-Au DENPs decrease with greater loading of Au NPs. This systematic study of the relaxivities and T1-weighted imaging performances of Gd, Mn, and Gd-Au DENP chelators are expected to be a theoretical basis for developing multifunctional dual-mode contrast agents.
| S-EPMC9589045 | biostudies-literature
Project description:Magnetic nanoparticles (MNPs) have been extensively explored as magnetic resonance imaging (MRI) contrast agents. With the increasing complexity in the structure of modern MNPs, the classical Solomon-Bloembergen-Morgan and the outer-sphere quantum mechanical theories established on simplistic models have encountered limitations for defining the emergent phenomena of relaxation enhancement in MRI. Recent progress in probing MRI relaxivity of MNPs based on structural features at the molecular and atomic scales is reviewed, namely, the structure-relaxivity relationships, including size, shape, crystal structure, surface modification, and assembled structure. A special emphasis is placed on bridging the gaps between classical simplistic models and modern MNPs with elegant structural complexity. In the pursuit of novel MRI contrast agents, it is hoped that this review will spur the critical thinking for design and engineering of novel MNPs for MRI applications across a broad spectrum of research fields.
| S-EPMC6392011 | biostudies-literature
Project description:Epilepsy is a chronic neurodegenerative disease, and accumulating evidence suggests its pathological progression is closely associated with peroxynitrite (ONOO-). However, understanding the function remains challenging due to a lack of in vivo imaging probes for ONOO- determination in epileptic brains. Here, the first near-infrared imaging probe (named ONP) is presented for tracking endogenous ONOO- in brains of kainate-induced epileptic seizures with high sensitivity and selectivity. Using this probe, the dynamic changes of endogenous ONOO- fluxes in epileptic brains are effectively monitored with excellent temporal and spatial resolution. In vivo visualization and in situ imaging of hippocampal regions clearly reveal that a higher concentration of ONOO- in the epileptic brains associates with severe neuronal damage and epileptogenesis; curcumin administration can eliminate excessively increased ONOO-, further effectively protecting neuronal cells. Moreover, by combining high-content analysis and ONP, a high-throughput screening method for antiepileptic inhibitors is constructed, which provides a rapid imaging/screening approach for understanding epilepsy pathology and accelerating antiseizure therapeutic discovery.
| S-EPMC6685465 | biostudies-literature
Project description:The development of fluorescence dyes for near-infrared (NIR) fluorescence imaging has been a significant interest for deep tissue imaging. Among many imaging fluoroprobes, indocyanine green (ICG) and its analogues have been used in oncology and other medical applications. However, these imaging agents still experience poor imaging capabilities due to low tumor targetability, photostability, and sensitivity in the biological milieu. Thus, developing a biocompatible NIR imaging dye from natural resources holds the potential of facilitating cancer cell/tissue imaging. Chlorophyll (Chl) has been demonstrated to be a potential candidate for imaging purposes due to its natural NIR absorption qualities and its wide availability in plants and green vegetables. Therefore, it was our aim to assess the fluorescence characteristics of twelve dietary leaves as well as the fluorescence of their Chl extractions. Bay leaf extract, a high-fluorescence agent that showed the highest levels of fluorescence, was further evaluated for its tissue contrast and cellular imaging properties. Overall, this study confirms bay-leaf-associated dye as a NIR fluorescence imaging agent that may have important implications for cellular imaging and image-guided cancer surgery.
| S-EPMC8705868 | biostudies-literature
Project description:An optical imaging probe was synthesized by attaching a near-infrared carbocyanine fluorophore to an affinity group containing two zinc(II) dipicolylamine (Zn-DPA) units. The probe has a strong and selective affinity for the surfaces of bacteria, and it was used to image infections of Gram-positive S. aureus and Gram-negative E. coli bacteria in living nude mice. After intravenous injection, the probe selectively accumulates at the sites of localized bacterial infections in the thigh muscles of the mice.
| S-EPMC2531239 | biostudies-literature
Project description:Epithelial ovarian cancer (EOC) is the seventh most common cancer among women worldwide. The 5-year survival rate for women with EOC is only 30%-50%, which is largely due to the typically late diagnosis of this condition. EOC is difficult to detect in its early stage because of its asymptomatic nature. Recently, near-infrared fluorescent (NIRF) imaging has been developed as a potential tool for detecting EOC at the molecular level. In this study, a NIRF-sensitive probe was designed to detect matrix metalloproteinase (MMP) activity in ovarian cancer cells. A cyanine fluorochrome was conjugated to the amino terminus of a peptide substrate with enzymatic specificity for MMP-3. To analyze the novel MMP-3 probe, an in vivo EOC model was established by subcutaneously implanting SKOV3 cells, a serous-type EOC cell line, in mice. This novel MMP-3-sensitive probe specifically reacted with only the active MMP-3 enzyme, resulting in a significantly enhanced NIRF emission intensity. Histological analysis demonstrated that MMP-3 expression and activity were enhanced in the stromal cells surrounding the ovarian cancer cells. These studies establish a molecular imaging reporter for diagnosing early-stage EOC. Additional studies are required to confirm the early-stage activity of MMP-3 in EOC and its diagnostic and prognostic significance.
| S-EPMC5794152 | biostudies-literature
Project description:Herein, we report on near-infrared (NIR) fluorescent nanoparticles generated from an emergent class of materials we refer to as a Group of Uniform Materials Based on Organic Salts (GUMBOS). GUMBOS are largely frozen ionic liquids, although the concept is more general and is also easily applied to solid ionic materials with melting points in excess of 100 degrees C. Nanoparticles based on GUMBOS (nanoGUMBOS) derived from a NIR fluorophore are prepared using a reprecipitation method and evaluated for in vivo fluorescence imaging. Due to their uniformity, single-step preparation, and composite nature, nanoGUMBOS help to resolve issues with dye leakage problems innate to alternate cellular stains and unlock a myriad of applications for these materials, highlighting exciting possibilities for multifunctional nanoGUMBOS.
| S-EPMC2818537 | biostudies-literature