Analysing circulating tumour cells (CTCs) in the blood could help scientists detect cancer in the body. But separating CTCs from blood is a difficult, laborious process and requires large sample volumes.
Researchers at the K N Toosi University of Technology (KNTU) in Tehran, Iran believe that ultrasonic waves could separate CTCs from red blood cells accurately, in an energy efficient way and in real time. They publish their study in the journal Physics of Fluids.
“In a broader sense, we asked: ‘How can we design a microfluidic, lab-on-a-chip device powered by SAWs [standing acoustic waves] that remains simple enough for medical experts to use easily, while still delivering precise and efficient cell separation?’,” says senior author Naser Naserifar, an assistant professor in mechanical engineering at KNTU. “We became interested in acoustofluidics because it offers strong, biocompatible forces that effectively handle cells with minimal damage.”
Acoustic waves can deliver enough force to move cells over small distances without damaging them. The researchers used dual pressure acoustic fields at critical positions in a microchannel to separate CTCs from other cells. The CTCs are gathered at an outlet for further analyses, cultures and laboratory procedures.
In the process of designing the chip, the researchers integrated computational modelling, experimental analysis and artificial intelligence (AI) algorithms to analyse acoustofluidic phenomena and generate datasets that predict CTC migration in the body.
“We introduced an acoustofluidic microchannel with two optimized acoustic zones, enabling fast, accurate separation of CTCs from RBCs [red blood cells],” explains Afshin Kouhkord, who performed the work while a master’s student in the Advance Research in Micro And Nano Systems Lab at KNTU. “Despite the added complexity under the hood, the resulting chip is designed for simple operation in a clinical environment.”
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So far, the researchers have evaluated the device with numerical simulations and tested it using a physical prototype. Simulations modelled fluid flow, acoustic pressure fields and particle trajectories. The physical prototype was made of lithium niobate, with polystyrene microspheres used as surrogates for red blood cells and CTCs. Results from the prototype agreed with numerical simulations to within 3.5%.
“This innovative approach in laboratory-on-chip technology paves the way for personalized medicine, real-time molecular analysis and point-of-care diagnostics,” Kouhkord and Naserifar write.
The researchers are now refining their design, aiming for a portable device that could be operated with a small battery pack in resource-limited and remote environments.
