To this end, we tested if the EV-immobilized antibodies still retained their binding affinity and specificity using two models of surface antigen targeting: EGFR targeting in EGFR-positive MCF10CA1a (CA1a) breast cancer cells or 4T1-tdTomato-hEGFR mouse breast cancer cells using an anti-human EGFR biparatopic camelid-derived single domain antibody (VHH), and EpCAM targeting in EpCAM-positive NCI-H358 lung cancer cells using a commercially obtained anti-human EpCAM monoclonal antibody (Figure S6B-G). Here, EGFR is linked to breast cancer.