Immunomagnetic separation in a novel cavity-added serpentine microchannel structure for the selective isolation of lung adenocarcinoma cells

Enhancing the efficiency of lung cancer cell capture using microfluidic dielectrophoresis and aptamer-based surface modification

Metastasis remains a significant cause to cancer-related mortality, underscoring the critical need for early detection and analysis of circulating tumor cells (CTCs). This study presents a novel microfluidic chip designed to efficiently capture A549 lung cancer cells by combining dielectrophoresis (DEP) and aptamer-based binding, thereby enhancing capture efficiency and specificity. The microchip features interdigitated electrodes made of indium-tin-oxide that generate a nonuniform electric field to manipulate CTCs. Following three chip design, scenarios were investigated: (A) bare glass surface, (B) glass modified with gold nanoparticles (AuNPs) only, and (C) glass modified with both AuNPs and aptamers. Experimental results demonstrate that AuNPs significantly enhance capture efficiency under DEP, with scenarios (B) and (C) exhibiting similar performance. Notably, scenario (C) stands out as aptamer-functionalized surfaces resisting fluid shear forces, achieving CTCs retention even after electric field deactivation. Additionally, an innovative reverse pumping method mitigates inlet clogging, enhancing experimental efficiency. This research offers valuable insights into optimizing surface modifications and understanding key factors influencing cell capture, contributing to the development of efficient cell manipulation techniques with potential applications in cancer research and personalized treatment options.

The effect of magnetic bead size on the isolation efficiency of lung cancer cells in a serpentine microchannel with added cavities

An investigation was conducted to examine the effect of magnetic bead (MB) size on the effectiveness of isolating lung cancer cells using the immunomagnetic separation (IMS) method in a serpentine microchannel with added cavities (SMAC) structure. Carboxylated magnetic beads were specifically conjugated to target cells through a modification procedure using aptamer materials. Cells immobilized with different sizes (in micrometers) of MBs were captured and isolated in the proposed device for comparison and analysis. The study yields significance regarding the clarification of device working principles by using a computational model. Furthermore, an accurate evaluation of the MB size impact on capture efficiency was achieved, including the issue of MB-cell accumulation at the inlet-channel interface, despite it being overlooked in many previous studies. As a result, our findings demonstrated an increasing trend in binding efficiency as the MB size decreased, evidenced by coverages of 50.5%, 60.1%, and 73.4% for sizes of 1.36 μm, 3.00 μm, and 4.50 μm, respectively. Additionally, the overall capture efficiency (without considering the inlet accumulation) was also higher for smaller MBs. However, when accounting for the actual number of cells entering the channel (i.e., the effective capture), larger MBs showed higher capture efficiency. The highest effective capture achieved was 88.4% for the size of 4.50 μm. This research provides an extensive insight into the impact of MB size on the performance of IMS-based devices and holds promise for the efficient separation of circulating cancer cells (CTCs) in practical applications.