Category Archives: Fluorescence

New NIR fluorescent dyes available for in-vivo imaging applications

PolySciTech division of Akina, Inc (www.polyscitech.com) provides a wide array of research products including Flamma Fluor dyes. Recently, 3 new dyes have been added to our local inventory available for 1 business-day shipping to anywhere in USA. These include FKI-749, a non-reactive hydrophobic near-IR (abs/em 746 nm/773 nm), FKI-749 dichlorotirazine, an amine and hydroxyl reactive near-IR dye (abs/em 749 nm/774 nm), and D-0013 (abs/em 739 nm/768 nm). Because of their near-IR fluorescence spectra, these dyes have the capability to operate in a region of light which passes easily through bodily tissues. The benefit to this is that these can be applied to in-vivo imaging, which is imaging of a structure or dyed component in an animal model while the animal is alive. This is particularly useful for research and other applications. Read more about in-vivo imaging here: Gibbs, Summer L. “Near infrared fluorescence for image-guided surgery.” Quantitative imaging in medicine and surgery 2, no. 3 (2012): 177-187. Full-Text: http://www.amepc.org/qims/article/view/1078/1373

“Abstract: Near infrared (NIR) image-guided surgery holds great promise for improved surgical outcomes. A number of NIR image-guided surgical systems are currently in preclinical and clinical development with a few approved for limited clinical use. In order to wield the full power of NIR image-guided surgery, clinically available tissue and disease specific NIR fluorophores with high signal to background ratio are necessary. In the current review, the status of NIR image-guided surgery is discussed along with the desired chemical and biological properties of NIR fluorophores. Lastly, tissue and disease targeting strategies for NIR fluorophores are reviewed. Key words: Near infrared (NIR); image-guided surgery”

Fluorescently conjugated chitosan from Akina, Inc used for microcapsule formation

PolySciTech division of Akina, Inc. provides a variety of modified chitosan products (https://akinainc.com/polyscitech/products/Kitopure/index.php) as well as other polymers and research products. Chitosan has a net positive charge due to amine units along the chain. When chitosan interacts with a negatively charged polymer the two bind together due to ionic attraction between the polymer chains forming what is called a polyelectrolyte complex. Recently, researchers at Yale University and the Université Paris Diderot, used fluorescently conjugated chitosan (a cationic polymer) from Akina, Inc. along with sulfonated styrene (an anionic polymer) to generate microcapsules held together by the polyelectrolyte complex formed between these two polymers. Read more: Kaufman, Gilad, Rostislav Boltyanskiy, Siamak Nejati, Abdou R. Thiam, Michael Loewenberg, Eric R. Dufresne, and Chinedum O. Osuji. “Single-step microfluidic fabrication of soft monodisperse polyelectrolyte microcapsules by interfacial complexation.” Lab Chip 14, no. 18 (2014): 3494-3497. http://pubs.rsc.org/en/content/articlepdf/2014/lc/c4lc00482e Full-Text: http://www.researchgate.net/profile/Siamak_Nejati/publication/263933420_Single-step_microfluidic_fabrication_of_soft_monodisperse_polyelectrolyte_microcapsules_by_interfacial_complexation/links/5419c56c0cf2218008bf9faa.pdf

“Abstract: Common methods for fabrication of polyelectrolyte microcapsules rely on a multi-step process. We propose a single-step approach to generate polyelectrolyte microcapsules with 1–2 μm shells based on polyelectrolyte complexation across a water/oil droplet interface and study the effect of parameters controlling the polyelectrolyte complexation on shell thickness.”

Image: http://3.bp.blogspot.com/-HRj6EdCatac/Vjzww3jWNtI/AAAAAAAAB7I/mHKXxylN09E/s1600/Kaufman%252C%2B2014%2Bmicrocapsules.png

New fluorescently conjugated mPEG-PLGA now available (AV18) for nanoparticle tracking

PolySciTech (www.polyscitech.com) provides a wide array of biodegradable block copolymers and related products. A new product is now available which is mPEG-PLGA (3000-36,000)-conjugated to FKR-560 dye. The FKR-560 dye has a maximum absorbance of 562 +/- 3nm and a maximum emission of 584 +/- 4 nm. The extinction coefficient of the dye in dimethylformamide is 50,000 +/- 5000 cm-1M-1. This dye has been chemically conjugated onto the PLGA terminus of the diblock copolymer rendering the polymer reddish in color and giving it the same fluorescent spectra as the dye. This is valuable for nanoparticle tracking and microscopy applications related to cellular uptake and flow of the formed nanoparticles. The spectral properties are such that this material has fluorescence similar to PE-Texas Red, R-phycoerythrin, and other related dyes and the same filter sets (TRITC region) can also be used for this dye so that you can use the same set-up for imaging that you have now to be able to track nanoparticles.  You can see this product in our online catalog here (https://akinainc.com/polyscitech/products/polyvivo/catalogue.php?highlight=AV18#h).

http://3.bp.blogspot.com/-6v14BrM3WpA/VcocC49D_wI/AAAAAAAABvA/VMqrT5N5TmI/s1600/AV18%2Badvertisement.jpg

New PEG-PLA-FKR648 from PolySciTech for NIR tracking of micelles

PolySciTech (www.polyscitech.com) provides a wide variety of fluorescently conjugated polyesters such as PLGA-FITC and others. We are proud to announce the development of our first fluorescently conjugated block copolymer. The block copolymer, PolyVivo AV17, is same size and configuration as our popular AK09 (mPEG-P(DL)La 2000-2200 Da) but has a NIR fluorescent dye (Flamma Fluor FKR-648) conjugated to the P(DL)La alcohol terminus via a dichlorotriazine linkage.  Read more about appropriate NIR imaging conditions for this type of dye here. Full-Text: Hollis, Christin P., Heidi L. Weiss, B. Mark Evers, Richard A. Gemeinhart, and Tonglei Li. “In Vivo Investigation of Hybrid Paclitaxel Nanocrystals with Dual Fluorescent Probes for Cancer Theranostics.” Pharmaceutical research 31, no. 6 (2014): 1450-1459. http://www.uic.edu/labs/bpslab/PDF/PharmRes_31_1450_2014.pdf

“Abstract: To develop novel hybrid paclitaxel (PTX) nanocrystals, in which bioactivatable (MMPSense® 750 FAST) and near infrared (Flamma Fluor® FPR-648) fluorophores are physically incorporated, and to evaluate their anticancer efficacy and diagnostic properties in breast cancer xenograft murine model. The pure and hybrid paclitaxel nanocrystals were prepared by an anti-solvent method, and their physical properties were characterized. The tumor volume change and body weight change were evaluated to assess the treatment efficacy and toxicity. Bioimaging of treated mice was obtained non-invasively in vivo.The released MMPSense molecules from the hybrid nanocrystals were activated by matrix metalloproteinases (MMPs) in vivo, similarly to the free MMPSense, demonstrating its ability to monitor cancer progression. Concurrently, the entrapped FPR-648 was imaged at a different wavelength. Furthermore, when administered at 20 mg/kg, the nanocrystal formulations exerted comparable efficacy as Taxol®, but with decreased toxicity. Hybrid nanocrystals that physically integrated two fluorophores were successfully prepared from solution. Hybrid nanocrystals were shown not only exerting antitumor activity, but also demonstrating the potential of multi-modular bioimaging for diagnostics.”

PolySciTech AV17

Use of FPR648 for tracking PTX nanoparticles

A recent article published in Pharmaceutical Research relates the usage of FPR648 to track uptake in-vivo of nanoparticles into tumor cells.  Full text available here (http://www.uic.edu/labs/bpslab/PDF/PharmRes_x_y_2013.pdf)

Image from:

Hollis, Christin P., et al. “In Vivo Investigation of Hybrid Paclitaxel Nanocrystals with Dual Fluorescent Probes for Cancer Theranostics.” Pharmaceutical research (2013): 1-10.

—abstract—-

To develop novel hybrid paclitaxel (PTX) nanocrystals, in which bioactivatable (MMPSense® 750 FAST) and near infrared (Flamma Fluor® FPR-648) fluorophores are physically incorporated, and to evaluate their anticancer efficacy and diagnostic properties in breast cancer xenograft murine model. The pure and hybrid paclitaxel nanocrystals were prepared by an anti-solvent method, and their physical properties were characterized. The tumor volume change and body weight change were evaluated to assess the treatment efficacy and toxicity. Bioimaging of treated mice was obtained non-invasively in vivo.The released MMPSense molecules from the hybrid nanocrystals were activated by matrix metalloproteinases (MMPs) in vivo, similarly to the free MMPSense, demonstrating its ability to monitor cancer progression. Concurrently, the entrapped FPR-648 was imaged at a different wavelength. Furthermore, when administered at 20 mg/kg, the nanocrystal formulations exerted comparable efficacy as Taxol®, but with decreased toxicity. Hybrid nanocrystals that physically integrated two fluorophores were successfully prepared from solution. Hybrid nanocrystals were shown not only exerting antitumor activity, but also demonstrating the potential of multi-modular bioimaging for diagnostics.

———–

AV06 and FPI749 usage in-vivo imaging

I often get questions about the use of FPI749 as well as conjugates such as AV06 and here’s some helpful info on these.

 

FAQ: Is the dye stable enough to use in-vivo?

“Our experience has been the dye is extremely stable and usable in-vivo. It was used previously by Dr. Li’s group at University of Kentucky to track PTX nanoparticles (full-text articles at http://tigger.uic.edu/labs/bpslab/PDF/MolPharmaceutics_8_1985_2011.pdf and http://www.uic.edu/labs/bpslab/PDF/PharmRes_x_y_2013.pdf for similar FPR648). Additionally we uses the AV06 conjugate here to make 50um PLGA microparticles which we injected SubQ and IM in a mouse model and tracked for up to 22 days until euthanasia (results not published but images shown at bottom of website here https://akinainc.com/polyscitech/products/imaging/elvis.php). ”

 

FAQ: What’s the detection limit/Best ratio for imaging?

“It depends on quantity of material, depth of tissue, and quality of imager.  FPR749 has a quantum yield of 0.04 but it operates in a very long-wave near-infrared region so there is limited noise from other sources. In Dr. Li’s research he used 0.79% w/w FPR749/PTX and was able to track in rat model to specific organs/tumors in an IVIS system.  In our research we utilized the ELVIS system which has less depth of permeation than an IVIS system.  We used 100% AV06 to make the microparticles for this one and were able to track but this was only SubQ/IM so only a depth of 5-10mm or so.