A new review examines how bacterial extracellular vesicles (BEVs) could be engineered for cancer drug delivery, immunotherapy, and biomarker detection.
Bacteria naturally shed microscopic, membrane-enclosed particles filled with proteins, lipids, DNA, RNA, and metabolites. These particles, known as bacterial extracellular vesicles (BEVs), are now being explored as possible tools for cancer diagnosis and treatment, according to a new review published in the journal Biomedical Technology.
The review surveys recent progress in BEV research, tracing the process from vesicle formation and purification through molecular analysis, engineering, and early testing in cancer models. It also considers how BEVs could be adapted for precision cancer medicine — carrying drugs, activating immune responses, limiting metastasis, and identifying cancer biomarkers — while examining the practical obstacles still standing in the way, including inconsistent production, safety risks, contamination, and the lack of shared manufacturing and quality standards.
Why Bacterial Vesicles Are Drawing Interest
“Part of their appeal lies in how they are made,” said Duanrui Liu, senior and co-corresponding author of the review. “Scientists can grow bacteria in controlled conditions, alter the bacteria genetically, and then modify the released vesicles chemically. This gives researchers several ways to adjust where the vesicles travel and what they carry.”
BEVs could, for example, be fitted with molecules that help them recognize tumors. “Drugs or therapeutic nucleic acids may be packed inside them,” Liu said. “Their bacterial origin also means they can alert the immune system, which may help trigger an anticancer response. The same molecular cargo could provide clues for liquid biopsy or the discovery of new cancer biomarkers.”
What makes bacterial vesicles particularly notable, according to the review, is their dual function: they can act as both a delivery vehicle and an immune signal at the same time. “That combination creates exciting possibilities for precision oncology, but only if the field can make these vesicles consistently and prove that they are safe,” Liu added.
The Reproducibility Problem
The review’s authors also compared BEVs with mammalian extracellular vesicles and conventional nanocarriers, noting that new methods in synthetic biology, microfluidic isolation, multiomics analysis, and surface modification are giving researchers finer control over vesicle design. Reproducibility, however, remains a persistent challenge.
“A change in bacterial strain, culture conditions, or purification method can alter the final product,” explained Xue Gao, the review’s first author. “Yields may be low. Harmful bacterial material can remain after purification, and an immune response intended to fight cancer could instead produce damaging inflammation.”
Before BEVs move closer to clinical use, the authors say researchers will need more reliable manufacturing processes, strict testing of each production batch, and safer methods for reducing unwanted bacterial components. “Their place alongside chemotherapy, radiotherapy, and immune checkpoint inhibitors must also be worked out,” Gao said. “If those questions can be answered, these small vesicles may offer a single platform for drug delivery, cancer vaccines, immunotherapy, and tumor monitoring.”