Aptamer-Proximity Ligation Coupled with Rolling Circle Amplification Strategy for an Ultrasensitive Analysis of Tumor-Derived Extracellular Vesicles PD-L1

Tumor-derived extracellular vesicles (T-EVs) PD-L1 are an important biomarker for predicting immunotherapy response and can help us understand the mechanism of resistance to immunotherapy. However, this is due to the interference from a large proportion of nontumor-derived EVs. It is still challenging to accurately analyze T-EVs PD-L1 in complex human fluids. Herein, a simple and ultrasensitive method based on the dual-aptamer-proximity ligation assay (PLA)-guided rolling circle amplification (RCA) for the analysis of T-EVs PD-L1 was developed. First, dual aptamers with strong binding affinity were utilized for the recognition of EpCAM and PD-L1 on EVs, and then the aptamer-based PLA occurred. With the aid of the high signal amplification ability of RCA guided by the dual-aptamer-based PLA and efficient magnetic separation, the biosensor could realize highly sensitive quantification of EpCAM and PD-L1 dual-positive EVs with a low detection limit of 7.5 particles/μL. In addition, this method based on the aptamer-PLA-guided RCA was used to discriminate cancer patients from healthy donors with 100% accuracy without additional purification. Overall, this strategy might provide a practical tool for the analysis of multiple proteins on EVs, exhibiting great potential in early cancer diagnosis and treatment.

M. Ye, L. Mou, J. Feng, L. Wu, D. Jin, X. Hu, Q. Xu, Y. Shu. Aptamer-Proximity Ligation Coupled with Rolling Circle Amplification Strategy for an Ultrasensitive Analysis of Tumor-Derived Extracellular Vesicles PD-L1[J]. Analytical Chemistry, 2025, 97: 2343–2350. DOI: 10.1021/acs.analchem.4c05700.

@article{ye2025192,
  author  = {M. Ye and L. Mou and J. Feng and L. Wu and D. Jin and X. Hu and Q. Xu and Y. Shu},
  title   = {Aptamer-Proximity Ligation Coupled with Rolling Circle Amplification Strategy for an Ultrasensitive Analysis of Tumor-Derived Extracellular Vesicles PD-L1},
  journal = {Analytical Chemistry},
  year    = {2025},
  volume  = {97},
  pages   = {2343–2350},
  doi     = {10.1021/acs.analchem.4c05700},
}