Abstract
Plasma circulating extracellular vesicle (EV) has emerged as a promising biomarker for diagnosis and prognosis of various epithelial tumors. However, fast and efficient capture of EVs with microfluidic chip in sarcoma remains to be established. Herein, we reported a ZnO-nanorods integrated (ZNI) microfluidic chip, where EV capture antibody was uniformly grafted to the surface of the ZnO-nanorods of the chip to enhance the plasma turbulence formation and the capture efficiency at the micro-scale. Based on osteosarcoma (OS) cell line, we demonstrated that a combination of CD81 and CD63 antibody on ZNI chip yielded the greatest amount of total EVs, with an extra sensitive limit of detection (LOD) of ~104 particles mL-1. Furthermore, the addition of fluorescent labeling of Vimentin (VIM), a previously reported sarcoma cell surface biomarker, could enabled the dual visualization of total plasma EVs and VIM-positive EVs from OS patients’ plasma. Based on our ZNI chip, we found that the amount of plasma total EVs was significantly different between OS and healthy donors (1562 a.u. versus 639 a.u., p< 0.05), but not between metastatic and nonmetastatic OS (p> 0.05). Interestingly, patients with metastatic disease had a significantly greater amount of VIM-positive EVs (1411 a.u. versus 231 a.u.., p< 0.05) and increased VIM-positive/total EVs ratio (0.943 versus 0.211, p< 0.05) in comparison with the nonmetastatic counterpart. Therefore, our ZNI microfluidic chip has great potential for the fast quantification of plasma EVs, and the microfluidic-based quantification of total and VIM-positive EVs might serve as a promising biomarker for the diagnosis and surveillance in OS patients.
Highlights
Liquid biopsy of circulating extracellular vesicle (EV) has nowadays gained an increasing popularity as a promising source of prognostic and therapeutic biomarkers for several common types of epithelial cancer [1,2,3]
We found that our device had an extremely low limit of detection (LOD) of ~104 particles/mL, which was drastically below the EV concentration in plasma
The ZnO growth chip consisted of 4 channels with a width of 200 mm and a height of 75 mm, and the ZnO-nanorods integrated (ZNI) chip consisted of the main microfluidic channel and the HB structure (Figure 2B)
Summary
Liquid biopsy of circulating extracellular vesicle (EV) has nowadays gained an increasing popularity as a promising source of prognostic and therapeutic biomarkers for several common types of epithelial cancer [1,2,3]. The isolation of EVs mainly relies on ultracentrifugation (UC), which is limited by large sample consumption, low sample recovery rate and complicated procedures [11,12,13,14]. Other methods such as ultra-filtration and precipitation-based commercial kits suffer from poor standardization and the contamination of non-vesicular particles [15,16,17,18]. Our microfluidic-based EV quantification could distinguish osteosarcoma patients from healthy donors, and the metastatic diseases from the non-metastatic counterparts
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