A Biomimetic Microfluidic Strategy for Efficient Tumor Cell Isolation Using Electrospun Membranes

Metastasis, the leading cause of cancer-related mortality, is driven by the spread of tumor cells through the bloodstream [1]. Circulating tumor cells (CTCs), shed from primary or metastatic sites, offer a minimally invasive means to monitor cancer progression and treatment response. However, isolating viable CTCs remains difficult due to their rarity—just a few among millions of blood cells per milliliter—and biological heterogeneity [2,3]. Recent advances in micro- and nano-technologies, especially microfluidic systems, have shown promise for sensitive, specific, and viable CTC capture and downstream analysis [4].

In this context, we present a multilayer microfluidic device integrating a removable electrospun polycaprolactone (PCL) membrane designed to enhance tumor cell capture and post-isolation culture. The ONCO-CTC chip, fabricated from bonded PDMS layers, features a central chamber housing the membrane, which was manufactured using controlled electrospinning parameters [5]. Scanning electron microscopy (SEM) and micro-computed tomography (microCT) confirmed a porous, highly interconnected membrane structure (porosity: 13.1 ± 0.9%; interconnectivity: 88.5 ± 1.1%) optimized for cell retention and nutrient exchange.

When challenged with HCT-116 colorectal cancer cells, the system achieved a cell capture efficiency of 94±2.6%—significantly higher than the commercial ScreenCell® system, which reached only 82±10.9%. Retained cells were identified via EpCAM-FITC and DAPI staining. After 72 hours of culture on retrieved membranes, cells showed significantly higher viability as compared to those cultured on commercial membranes (613.4 ± 126 vs. 15.4 ± 0.5; p < 0.01), as measured by PrestoBlue® assay and observed by Calcein-AM/PI staining.

This bioengineered platform enables modular, biologically compatible tumor cell capture and culture, overcoming the limitations of traditional rigid filters. Its gentle flow dynamics and ease of membrane retrieval support downstream analyses for various diagnostic or research applications. The reproducibility and adaptability of the ONCO-CTC highlight its strong potential as a next-generation tool in liquid biopsy for cancer diagnostics and personalized treatment planning.

Acknowledgments: This research was supported by the UID/50026:3B's-Biomaterials, Biodegradables and Biomimetics Research Group, University of Minho (3B's Res. Group/UMinho) and the EU-EC through the ONCOSCREEN (ID: 101097036) and EngVIPO (ID: 101183041) projects.

 References:

[1] Ring, A. et al., Nat. Rev. Cancer, 2023. doi: 10.1038/s41568-022-00536-4;

[2] van den Puttelaar, R. et al., Cancer Epidemiol Biomarkers Prev, 2023. doi:10.1158/10559965.EPI-22-0544

[3] Gu, X. et al., Signal Transduct Target Ther, 2024. doi:10.1038/s41392-024-01938-6

[4] Mishra, A. et al., Nat Commun, 2025. doi:10.1038/s41467-024-55140-x

[5] Casanova, M.R. et al., Provisional Patent Application No. 119865 (2024)