Optical imaging: Current applications and future directions
ABSTRACT Optical techniques, such as bioluminescence and fluorescence, are emerging as powerful new modalities for molecular imaging in disease and therapy. Combining innovative molecular biology and chemistry, researchers have developed optical methods for imaging a variety of cellular and molecular processes in vivo, including protein interactions, protein degradation, and protease activity. Whereas optical imaging has been used primarily for research in small-animal models, there are several areas in which optical molecular imaging will translate to clinical medicine. In this review, we summarize recent advances in optical techniques for molecular imaging and the potential impact for clinical medicine.
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ABSTRACT: The therapeutic efficacy of radioiodine (131I) therapy has been reported to be variable among cancer patients and even between metastatic regions in the same patients. Because the expression level of sodium iodide symporter (NIS) cannot reflect the efficacy of therapy, other strategies are required to predict the precise therapeutic effect of 131I therapy. In this research, we investigated the correlation between iodine (I) uptake, apoptosis imaging, and therapeutic efficacy. Two HT29 cell lines, cytomegalovirus (CMV)-NIS (or NIS+++) and TERT-NIS (or NIS+), were established by retroviral transfection. I uptake was estimated by I-uptake assay and gamma camera imaging. Apoptosis was evaluated by confocal microscopy and a Maestro fluorescence imaging system (CRi Inc., Woburn, MA) using ApoFlamma (BioACTs, Seoul, Korea), a fluorescent dye-conjugated apoptosis-targeting peptide 1 (ApoPep-1). Therapeutic efficacy was determined by tumor size. The CMV-NIS showed higher I uptake and ApoFlamma signals than TERT-NIS. In xenograft models, CMV-NIS also showed high 99m technetium signals and ApoFlamma signals. Tumor reduction had a stronger correlation with apoptosis imaging signals than with gamma camera imaging signals, which reflect I uptake. Higher NIS-expressing tumors showed increased apoptosis and I uptake, resulting in a significant tumor reduction. Moreover, tumor reduction showed a strong correlation with ApoFlamma imaging compared to I-uptake imaging.Molecular Imaging 11/2014; 13:1-9. · 2.19 Impact Factor
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ABSTRACT: The luciferase fragment complementation assay (LFCA) enables molecular events to be non-invasively imaged in live cells in vitro and in vivo in a comparatively cheap and safe manner. It is a development of previous enzyme complementation assays in which reporter genes are split into two, individually enzymatically inactive, fragments that are able to complement one another upon interaction. This complementation can be used to externally visualize cellular activities. In recent years, the number of studies which have used LFCAs to probe questions relevant to cancer have increased, and this review summarizes the most significant and interesting of these. In particular, it focuses on work conducted on the epidermal growth factor, nuclear and chemokine receptor families, and intracellular signaling pathways, including IP3, cAMP, Akt, cMyc, NRF2 and Rho GTPases. LFCAs which have been developed to image DNA methylation and detect RNA transcripts are also discussed.
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ABSTRACT: We report a new surface modification approach of upconversion nanoparticles (UCNPs) structured as an inorganic host NaYF4 codoped with Yb3+ and Er3+ based on their encapsulation at a two-stage process of precipitation polymerization of acrolein under alkaline conditions in the presence of UCNPs. The use of tetramethylammonium hydroxide both as an initiator of the acrolein polymerization and agent for the UCNP hydrophilization made it possible to increase the polyacrolein yield up to 90%. This approach enabled facile, lossless embedment of UCNPs into the polymer particles suitable for bioassay. These particles are readily dispersible in aqueous and physiological buffers, exhibiting excellent photoluminescent properties, chemical stability, and allowed control of the particle diameters. The feasibility of as-produced photoluminescent polymer particles mean-sized 260 nm for in vivo optical whole-animal imaging was also demonstrated using a home-built epi-luminescence imaging system.Nanoscale 12/2014; 7(5). DOI:10.1039/C4NR05908E · 6.74 Impact Factor