Engineered Stem Cell-Derived Exosomes for Dual siRNA and Chemotherapy Delivery via Rolling Circle Transcription

Exosomes (EVs) are promising drug carriers, with efficiency dependent on membrane proteins and drug loading capacity. Preserving EVs integrity and enabling efficient drug loading is crucial. We developed a nondestructive system using stem cell-derived EVs for tumor treatment by functionalizing the EVs surface with a cholesterol-modified T7 primer, enabling robust siRNA production via rolling circle transcription (RCT) for potent gene silencing. Results show RCT-engineered EVs with high-density siRNA enhance antitumor activity, improve serum stability, and extend tumor tissue retention. To boost efficacy, we encapsulated peptide-doxorubicin into EVs via stem cell coculture, releasing it in response to elevated matrix metalloproteinase levels. Additionally, EVs-RCT loaded with doxorubicin prolong drug blood half-life and improve chemotherapeutic outcomes. Combining intracellular drug loading via coculture with external surface engineering enhances drug payload, preserves EVs integrity, and enables more effective tumor treatment.