XPack CMV-XP-RFP-EF1α-Puro Expression Lentivector

Label exosomes with RFP and track uptake into target cells with XPack CMV-XP-RFP-EF1α-Puro Expression Lentivector.

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XPack CMV-XP-RFP-EF1α-Puro Expression Lentivector

10 µg
$ 714
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Label exosomes with RFP using XPack™

Easily create stable cell lines that produce RFP-labeled exosomes with the XPack CMV-XP-RFP-EF1α-Puro Expression Lentivector. Take advantage of SBI’s well-proven lentivector technology to express RFP from the strong CMV promoter (also available with an MSCV promoter for expression in hematopoietic and stem cells) and the optimized XPack exosome targeting tag to package RFP into exosomes.

The XPack System at a glance:

  • Powerful—enables a wealth of applications, including
    • Exosome labeling
    • Exosome cargo tracking
    • Exosomes as cargo delivery vehicles
    • Exosomes as biotherapeutics
    • Exosome-generating stable cell lines with protein cargo-of-interest
  • Optimized—SBI developed the XPack peptide tag for robust exosome targeting
  • Reliable—based on SBI’s highly-cited, well-proven lentivector technology
  • Versatile
    • Two promoter options for expression in a wide range of cells
    • Comes as pre-built reporters (GFP, RFP, luciferase) or ready-to-customize cloning lentivectors

Choose the XPack Lentivector that’s right for you

  CMV Promoter

For most cell lines

MSCV Promoter

For hematopoietic and stem cell lines

Customize with our cloning vector
  XPAK510PA-1 XPack CMV-XP-MCS-EF1α-Puro XPAK710PA-1 XPack MSCV-XP-MCS-EF1α-Puro
Label exosomes with pre-built reporters



XPack CMV-XP-GFP-EF1α-Puro XPAK730PA-1


Luciferase XPAK532CL-1



XPack CMV-XP-Luciferase-EF1α-Puro XPAK732PA-1


XPack MSCV-XP-Luciferase-EF1α-Puro

How It Works

Optimized for success

With XPack, SBI has developed an optimized N-terminal peptide sequence that targets the peptide—and any protein fused to it—to the inner surface of the exosome membrane. Our pre-built XPack-reporter constructs come in GFP, RFP, and luciferase options to cover a wide range of labeling needs.

Supporting Data

XPack efficiently packages GFP into exosomes which can be used to deliver GFP to target cells

Part 1: Packaging GFP into exosomes with XPack

The XPack-GFP fusion protein is efficiently packaged as exosome cargo and delivered to target cells. HEK-293 cells were transfected with a plasmid encoding an N-terminal XPack-GFP fusion protein (Cat.# XPAK530PA-1). Twenty-four hours later, GFP localization patterns were visualized on a Leica DMI300B fluorescent microscope (Figure 1, upper panel). GFP expression patterns within transfected cells demonstrate a localization pattern characteristic of exosomal loading, with punctate spots along the cell periphery indicating budding vesicles and a brightly fluorescent spot in the cell interior corresponding to the multivesicular body (MVB), the site of exosome assembly and maturation prior to secretion.

After 48 hours, exosomes were isolated using ExoQuick-TC® and analyzed for GFP via Western blot (Figure 1, lower panel). Equal amounts of exosomal lysates (15 µg) were separated on gradient SDS PAGE gels and detected for GFP protein expression. The control for exosome loading was an anti-CETP antibody. XPack-GFP exosomes had very high amounts of GFP protein loaded as cargo.

XPack efficiently packages GFP into exosomes

Figure 1. XPack efficiently packages GFP into exosomes. (Upper panel) XPack-GFP localization during packaging. (Lower panel) Western blot showing robust loading of GFP into the isolated exosomes.

Part 2: XPack-GFP Exosome Delivery to Target Cells

The XPack-GFP exosomes isolated as described above were then added to recipient HEK-293 cells to test for GFP delivery. Cells exposed to XPack-GFP exosomes were imaged by fluorescent microscopy, which showed subcellular GFP localization consistent with endocytosis of the XPack-GFP exosomes and delivery of the XPack-GFP protein cargo into the cell (Figure 2, left panels). Subsequently, these recipient cells were washed twice with PBS and cellular lysates were prepared for Western blot analysis using anti-GFP antibodies. Anti-GAPDH was used as a cellular protein loading control. The Western blot data further verified the successful delivery of GFP proteins to recipient cells via the XPack exosome engineering technology (Figure 2, right panel).XPack-GFP exosomes deliver GFP to target cells

Figure 2. XPack-GFP exosomes deliver GFP to target cells. (Left panel) XPack-GFP localization during packaging. (Right panel) Western blot showing robust GFP delivery to target cells.