Super-Photostable Near Infrared Dye PREX710-NHS

PREX710 is a super-photostable near infrared (NIR) fluorescent dye with high chemical stability. PREX710 is more suitable for biological imaging, especially in vivo and deep imaging, than conventional cyanine dyes such as indocyanine green (ICG). Our format is PREX710-NHS (N-hydroxysuccinimide) which enables to label amino group-containing molecules such as proteins, antibodies, peptides, amino-nucleotides and any other small compounds.

   Photostability of PREX710-conjugated antibody under Xe lamp irradiation
   Normalized absorbance of PREX710-, competitive NIR dye "A"- and "C" -conjugated antibodies under irradiation with high power (300 W) Xe lamp    was monitored at each maximum wavelength.

In vivo deep imaging of blood vessels in live mouse brain
PREX710-dextran conjugate was injected into bloodstream via a tail vein of young adult ICR mouse. The brain tissue was monitored by “openslull” method with confocal microscopy (Ex./Em. = 638 nm/ 667-733 nm).
PREX710 was highly stable in blood and could be excited by near-infrared light which has little effect on hemoglobin.

Single molecule imaging
Avidin protein was labeled with PREX710-NHS or cyanine-type NIR dye "A" and subsequently immobilized on a glass slide via biotin conjugated linker. Single molecule images of PREX710 and NIR dye "A" were acquired continuously at 10 frames per second for 120 sec with excitation light at 640 nm (60 W/cm2) in PBS (pH 7.4).
PREX710 showed high photostability under the single molecule level compared with NIR dye “ A ””. PREX710 has a great potential to apply into single molecular imaging.

Plant imaging
Physcomitrella patens was stained with PREX710-conjugated octaarginine (R8) and fluorescent signal was observed by fluorescent microscopy. PREX710 (Ex./Em. = 703-717 nm/ 754-816 nm), chloroplast (Ex./Em. = 300-400 nm/ >420 nm).
As fluorescent signal of PREX710 (cyan) was clearly separated from chloroplast’s autofluorescence (red), PREX710 is a good fluorescent dye for plant imaging.

Fluorescent spectrum
UV-Vis and normalized fluorescence spectra of free-PREX710 dye in 10 mM PBS buffer (pH 7.4). Blue; Absorption spectra. Red; Excitation spectra.

Effect of pH on the stability of PREX710 dye
Normalized absorbance of free-PREX710 dye measured at maximum 712 nm for 10 hours using three different pH buffers in vitro. PREX710 is highly stable from pH 4 to 10.

Chemical stability of PREX710 in blood serum
Free-PREX710 in PBS buffer (pH 7.4) were irradiated with high power (300 W) Xe lamp using continuous range of visible light 385-740 nm. The change of absorption spectra over time was monitored.

Photostability of PREX710 dye under Xe lamp irradiation
Normalized absorbance of free-PREX710 dye in 100% fetal bovine serum (FBS) was monit ored at maximum 712 nm in 10 min intervals for 10 hours in vitro.

Formulation: C40H43ClN3O7P as chloride salt

Grzybowski M et al., Angew. Chem. Int. Ed., 57, 10137～10141 (2018) A Highly Photostable Near-Infrared Labeling Agent Based on a Phospha-rhodamine for Long-Term and Deep Imaging.