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Optical Nanoprobes for Diagnosis
Published in D. Sakthi Kumar, Aswathy Ravindran Girija, Bionanotechnology in Cancer, 2023
R. G. Aswathy, D. Sakthi Kumar
Recently, in vivo imaging with UCNPs has been receiving great attention. The study of UCNPs for imaging live animal has been demonstrated [239]. Y2O3:Yb/Er NPs of 50–150 nm in size were administrated in live Caenorhabditis elegans (C. elegans) worms and the digestive system was imaged upon excitation at 980 nm. In vivo wholebody imaging of a Balb-c mouse with NIR-to-NIR UCNPs has been demonstrated [240]. The outstanding advantage of the study was the excitation and emission in NIR range, permitting deep tissue imaging. In another study, in vivo vascular imaging of nude mice was reported [241] using Y2O3:Yb/Er NPs coated with PEG polymer. The multi-channel label was injected to mice for the examination of their effectiveness in vascular imaging under clinically significant low power density laser excitation. The colocalization of the UC and cyanine fluorescence suggested the polymer coating was intact in vivo (Figure 7.13). Emission instigating from UC was bright to support real-time imaging stipulating a nanoplatform for in vivo imaging. The feasibility of UCNPs in transillumination imaging has been reported [242]. Images acquired by the transillumination technique were compared with NIR cyanine dyes and the results propose the better-quality and contrast of UCNP-based imaging moieties.
Routine and Special Techniques in Toxicologic Pathology
Published in Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page R. Bouchard, Toxicologic Pathology, 2018
Daniel J. Patrick, Matthew L. Renninger, Peter C. Mann
Traditional fluorochromes that are commonly used include fluorescein isothiocyanate (FITC, green color), 4′,6-diamidino-2-phenylindole (DAPI, blue color, binds to DNA in nuclei), and Texas Red (red color). Today, there are hundreds of fluorochromes available with various excitation peak and emission wavelengths. Desirable features of fluorochromes include a large extinction coefficient (likelihood of absorption of the excitation light), high quantum yield (ratio of light emitted to light absorbed, higher = brighter fluorescence), narrow emission spectrum (to minimize overlapping emissions when using multiple fluorochromes in a specimen), and good resistance to photobleaching (the irreversible decomposition of the fluorochrome by light excitation). Newer fluorochromes that possess more of these desirable features include cyanine dyes, Alexa Fluor dyes, DyLight fluorescent dyes, and Oyster fluorescent dyes.
Optical Techniques for Imaging of Cell Trafficking
Published in Martin G. Pomper, Juri G. Gelovani, Benjamin Tsui, Kathleen Gabrielson, Richard Wahl, S. Sam Gambhir, Jeff Bulte, Raymond Gibson, William C. Eckelman, Molecular Imaging in Oncology, 2008
The first fluorescent in vivo optical probes were based on fluorophores, such as the Alexa dyes and the cyanine dyes Cy5.5 and Cy7 (8). A large group of optical probes that consist of a fluorophore conjugated to a targeting moiety are represented by conjugates of a fluorophore with the ligand of αVβ3 integrin (9,10) for tumor detection and annexin V and Cy5.5 (11) probe for apoptosis detection. A modification to these probes is the activatable “smart” probes (12–14), which have a low signal-to-noise ratio and can be activated by upreglated proteins. The large number of fluorophores in such close proximity results in the fluorescence quenching. Enzymatic cleavage of the backbone by selective proteases (PR) releases the fluorophore molecules from the quenched state in the polymer complex, permitting fluorescence for detection of the protease. Quantum dots (QDs) are emerging as a new class of fluorescent probe for in vivo biomolecular and cellular imaging. QD are based on semiconductor nanocrystals with a broad absorption spectrum, high extinction coefficient, extremely long fluorescence lifetime and a narrow symmetrical emission spectrum and practically negligible photobleaching (15). Recent advances have led to the development of multifunctional nanoparticle probes that are very bright and stable under complex in vivo conditions. Bioconjugated QDs have raised new possibilities for ultrasensitive and multiplexed imaging of molecular targets in living cells, animal models, and possibly in humans. The use of QDs for sensitive and multicolor cellular imaging has seen major recent advances, owing to significant improvements in QD synthesis, surface chemistry, and conjugation.
Apoferritin: a potential nanocarrier for cancer imaging and drug delivery
Published in Expert Review of Anticancer Therapy, 2021
Hanitrarimalala Veroniaina, Xiuhua Pan, Zhenghong Wu, Xiaole Qi
In another report, water-soluble CuS nanoparticles have been used as an effective photothermal agent due to their strong near-infrared (NIR) photothermal conversion efficiency. CuS loaded apoferritin was prepared via the biomineralization synthesis method [87]. Then, a NIR dye (MBA) was added to enhance the photothermal efficiency of the CuS-apoferritin. CuS-apoferritin-MBA showed high tumor uptake due to the enhanced permeability, retention effect and the active targeting of apoferritin (Figure 5). Both in vitro and in vivo CuS-apoferritin-MBA anti-cancer evaluations have validated that this photothermal agent is highly effective for PTT. Similarly, Huang et al. successfully loaded a NIR cyanine dye within the apoferritin nanocage in the presence of IR820 molecules [40]. The IR820-loaded apoferritin can not only be excited with a high quantum yield at 550 nm for fluorescence imaging but also generate a distinct photothermal effect for photoacoustic imaging and PTT under 808 nm light irradiation. Moreover, Sozmen et al. modified the surface of apoferritin with Verteporfin (Visudyne®) and ultra-small CuS nanoparticles for dual cancer therapy [88]. The synergistic effect of PDT and PTT was achieved with 808 nm laser light and 690 nm LED light, respectively. This study not only provides a new horizon for multifunctional nanostructures for biological applications but also shows a new way of designing the novel PDT and PTT agents.
In vivo near-infrared fluorescent optical imaging for CNS drug discovery
Published in Expert Opinion on Drug Discovery, 2020
Maria J. Moreno, Binbing Ling, Danica B. Stanimirovic
Unconjugated Cy5.5 or Cy.7 dyes can have nonspecific binding to tumors due to high lipophilicity of the cyanine dyes [78]. Therefore, a new generation of NIR-I dyes with better physicochemical properties, including water solubility, dispersibility, and red-shifted peaks in the ~800 nm band, were developed. For instance, IRDye 800CW (Ex/Em: 774/805 nm) has deeper tissue penetration and higher signal-to-background ratio than Cy5.5 [79]. IRDye 800CW conjugated to the RGD sequence (argine-glycine-aspartic acid) that recognizes integrins, cell surface receptors highly expressed in the tumor vasculature and tumor cells, successfully identified the tumor and tumor margins in syngeneic and xenograft orthotopic glioblastoma tumors. Currently, there are 14 clinical trials using NIR-1 fluorescent contrast agents (ICG and IRDye800CW) for imaging brain pathologies (Table 1).
NAG-PEGylated multilamellar liposomes for BBB-GLUT transporter targeting
Published in Cogent Medicine, 2019
Nahid S. Kamal, Muhammad J. Habib, Ahmed S. Zidan, Pradeep K. Karla
Cytotoxicity assay was performed with the CellTox GreenTM dye Cytoxicity test kit (Promega Corporation, WI, USA). The assay protocol provided by the test kit manufacturer was adapted with no further modifications. The kit employed proprietary asymmetric cyanine dye that favorably stained the DNA of dead cells compared to viable cells. The fluorescence measured from the stain of dead cells was proportional to cell toxicity. The cells were seeded in Polystyrene nonpyrogenic 96-well plate at a density of 104 cells/well and were incubated at 37°C, 5% CO2, 95% relative humidity, and allowed 24 h to attach. Test formulations were added to the wells (n = 4) at four concentrations (0.312, 0.625, 1.25, 2.5 mg/ml). For positive control wells (lysis solution provided by the manufacturer), negative control (untreated cells) and blank (cultured medium) were employed. After treatment with liposomal formulations, the cells were incubated for 24 h and the fluorescence was measured at excitation (485–500 nm) and an emission (520-530nm) wavelengths utilizing CytoFluor Series 4000 Fluorescence Multi-Well Plate Reader (Applied Biosystems, Ca, USA). The cytotoxicity analysis was determined by plotting the percentage of cell viability vs. fluorescence.