Exosome targeting technology: XStamp

The XStamp™ exosome targeting technology from System Biosciences is a patented exosome surface display technology which can be used to place cellular "addresses" on exosomes in order to send them to specific destinations for cargo delivery. Based on a C-terminal fusion of the C1C2 domain from MFG-E8, protein sequences fused to the XStamp tag will display the protein ligand fusion on the surfaces of secreted exosomes, enabling specific delivery.

NCAM-XStamp construct (cat no. XSTP721PA-1) and BHP1-XStamp construct (cat no. XSTP722PA-1) were transfected separately into mouse MSCs with SBI's XPack-GFP construct (cat no. XPAK530PA-1) for fluorescent tracking. After 48 h, the exosomes were collected. Equal amounts (100 ug) of control (No XStamp), NCAM-XStamp or BHP1-XStamp MSC exosomes were added to Neuro2a neuroblastoma cells in culture. Neurons were imaged for phase and GFP signals after 24 h incubation with the various exosomes to monitor GFP delivery mediated by the XStamp ligand coats.

XStamp with motilin specifically targets exosomes to GI cells

Motilin is a 22-amino acid polypeptide hormone that binds to the motilin receptor, which is exclusively expressed in the intestine. XStamp with motilin can be used to target exosomes to GI cells. METHODS: The XStamp-Motilin construct (Cat.# XSTP720PA-1) was transfected into HEK293 cells and after 48 hours, the exosomes were isoalated using ExoQuick-TC. The next day, the XStamp-Motilin exosomes were Exo-Fected with a Texas-Red-labeled siRNA to monitor exosome docking and delivery. The transfected XStamp-Motilin exosomes were then added to MDA-MB-231 Breast Cancer Cells (motilin receptor negative) and to HT-29 Colon Cancer Cells (motilin receptor positive). The cells were imaged after 24 hours for uptake of the Texas-Red-labeled siRNA delivery from the XStamped exosomes. The HT-29 colon cancer cells that are motilin receptor positive took up the XStamp-Motilin exosomes at a much higher rate than the MDA-MB-231 Breast Cancer (motilin receptor negative) cells.

Material available for download
XStamp exosome targeting technology datasheet
XStamp exosome targeting technology manual