posted on 2022-12-17, 14:04authored byJiacheng Wu, Zhun Lin, Zhengyu Zou, Siping Liang, Minhao Wu, Tony Y. Hu, Yuanqing Zhang
Tumor-derived
extracellular vesicle (tEV) biomarkers can reflect
cancer cell phenotypes and have great potential for cancer diagnosis
and treatment. However, tEVs display high heterogeneity, and rapid
and sensitive identification of EV biomarkers remains challenging
due to their low expression. Spectral overlap also significantly limits
the multiplex analysis of EV biomarkers by fluorescent probes. Herein,
we developed a method for highly sensitive tEV phenotyping that uses
size-coded microbeads that carry hairpin probes that can bind to aptamers
targeting distinct tEV biomarkers. We also designed a microfluidic
chip containing spacer arrays that segregate these microbeads in distinct
chip regions according to their size to generate location-specific
signals indicating the level of different EV biomarkers. The EV biomarker
signal on these microbeads was amplified by in situ rolling cyclic amplification (RCA). This strategy permits the simultaneous
detection of multiple tEV phenotypes by fluorescence spectroscopy
without the limitations of spectral overlap. This study demonstrates
that this tEV phenotyping method can rapidly and simultaneously detect
six different tEV phenotypes with high sensitivity. Due to the programmability
of the sensing platform, this method can be rapidly adapted to detect
different tEV phenotype substitutions of the detected biomarkers.
Notably, clinical cohort studies show that this strategy may provide
new ideas for the precise diagnosis and personalized treatment of
cancer patients.