Combined magnetic resonance and optical imaging of head and neck tumor xenografts using Gadolinium-labelled phosphorescent polymeric nanomicelles.
ABSTRACT The overall objective of this study was to develop a nanoparticle formulation for dual modality imaging of head and neck cancer. Here, we report the synthesis and characterization of polymeric phospholipid-based nanomicelles encapsulating near-infrared (NIR) phosphorescent molecules of Pt(II)-tetraphenyltetranaphthoporphyrin [Pt(TPNP)] and surface functionalized with gadolinium [Pt(TPNP)-Gd] for combined magnetic resonance imaging (MRI) and NIR optical imaging applications.
Dynamic light scattering, electron microscopy, optical spectroscopy and MR relaxometric measurements were performed to characterize the optical and magnetic properties of nanoparticles in vitro. Subsequently, in vivo imaging experiments were carried out using nude mice bearing primary patient tumor-derived human head and neck squamous cell carcinoma xenografts.
The nanomicelles were ~100 nm in size and stable in aqueous suspension. T1-weighted MRI and relaxation rate (R1 = 1/T1) measurements carried out at 4.7 T revealed enhancement in the tumor immediately post injection with nanomicelles, particularly in the tumor periphery which persisted up to 24 hours post administration. Maximum intensity projections (MIPs) generated from 3D T1-weighted images also demonstrated visible enhancement in contrast within the tumor, liver and blood vessels. NIR optical imaging performed (in vivo and ex vivo) following completion of MRI at the 24 h time point confirmed tumor localization of the nanoparticles. The large spectral separation between the Pt(TPNP) absorption (~700 nm) and phosphorescence emission (~900 nm) provided a dramatic decrease in the level of background, resulting in high contrast optical (NIR phosphorescence) imaging.
In conclusion, Pt(TPNP)-Gd nanomicelles exhibit a high degree of tumor-avidity and favorable imaging properties that allow for combined MR and optical imaging of head and neck tumors. Further investigation into the potential of Pt(TPNP)-Gd nanomicelles for combined imaging and therapy of cancer is currently underway.
Full-textDOI: · Available from: Tymish Y Ohulchanskyy, May 29, 2015
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ABSTRACT: Atherosclerotic plaques are the main cause of life threatening clinical endpoints like myocardial infarction and stroke. To prevent these endpoints, the improved early diagnosis and treatment of vulnerable atherosclerotic vascular lesions is essential. Although originally applied for anticancer treatment, recent advances have also showed the considerable potential of nanotechnology for atherosclerosis. Otherwise, one domain of laboratory medicine is the investigation of new biomarkers. Recent research activities have identified the usability of biomarker-targeted nanoparticles for molecular imaging and pharmacologic modification of vulnerable atherosclerotic lesions leading to myocardial infarction or stroke. These investigations have established a new research interface between laboratory medicine, nanotechnology, cardiology/neurology, and radiology. In this review, we discuss inflammatory pathophysiologic mechanisms and biomarkers associated with a vulnerable atherosclerotic plaque phenotype. Further, we will emphasize cardiovascular relevant functionalized nanoparticle biomarker constructs which were developed within the cooperation interface between Laboratory Medicine (anti-inflammatory biomarkers), Nano-Medicine (nanoparticle development), and Radiology (molecular imaging).Clinica Chimica Acta 07/2014; 437. DOI:10.1016/j.cca.2014.06.029 · 2.76 Impact Factor
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ABSTRACT: Introduction Iron-oxide nanoparticles can act as contrast agents in magnetic resonance imaging (MRI), while radiolabeling the same platform with nuclear medicine isotopes allows imaging with positron emission tomography (PET) or single-photon emission computed tomography (SPECT), modalities that offer better quantification. For successful translation of these multifunctional imaging platforms to clinical use, it is imperative to evaluate the degree to which the association between radioactive label and iron oxide core remains intact in vivo. Methods We prepared iron oxide nanoparticles stabilized by oleic acid and phospholipids which were further radiolabelled with 59Fe, 14C-oleic acid, and 111In. Results Mouse biodistributions showed 111In preferentially localized in reticuloendothelial organs, liver, spleen and bone. However, there were greater levels of 59Fe than 111In in liver and spleen, but lower levels of 14C. Conclusions While there is some degree of dissociation between the 111In labeled component of the nanoparticle and the iron oxide core, there is extensive dissociation of the oleic acid component.Nuclear Medicine and Biology 09/2014; DOI:10.1016/j.nucmedbio.2014.08.014 · 2.41 Impact Factor
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ABSTRACT: Bimodal imaging agents that combine magnetic resonance imaging (MRI) and nearinfrared (NIR) imaging formulated as nanoemulsions became increasingly popular for imaging inflammation in vivo. Quality of in vivo imaging using nanoemulsions is directly dependent on their integrity and stability. Here we report the design of nanoemulsions for bimodal imaging, where both photostability and colloidal stability are equally addressed. A highly chemically and photo stable quaterrylenediimide dye was introduced into perfluoro-15-crown-5 ether (PCE) nanoemulsions. The nanoemulsions were prepared with PCE and Miglyol 812N mixed at 1:1 v/v ratio as internal phase stabilized by non-ionic surfactants. Data shows exceptional colloidal stability demonstrated as unchanged droplet size (∼130 nm) and polydispersity (<0.15) after 182 days follow up at both 4 and 25 °C. Nanoemulsions also sustained the exposure to mechanical and temperature stress, and prolonged exposure to light without changes in droplet size, (19)F signal or fluorescence signal. No toxicity was observed in vitro in model inflammatory cells upon 24 h exposure while confocal microscopy showed that nanoemulsions droplets accumulated in the cytoplasm. Overall, our data demonstrates that design of bimodal imaging agents requires consideration of stability of each imaging component and that of the nanosystem as a whole to achieve excellent imaging performance.Biomaterials 03/2014; DOI:10.1016/j.biomaterials.2014.03.006 · 8.31 Impact Factor