A spiral microfluidic chip endows high efficiency single cell alignment at extremely low flow for ICP-MS analysis

Abstract

A spiral microfluidic chip integrating periodic micro pillars was designed to achieve focusing and sorting of cells at ultra-low flow rate. It enables high efficiency single cell analysis by combining with time resolved inductively coupled plasma mass spectrometry (TRA-ICP-MS). The spiral chip facilitates focusing of particles or cells through the action of secondary flow and inertial induced lift force. The simulation illustrated that the periodic micro-pillars enhanced the influence of secondary flow and resulted in a superb focusing of cells. The focusing capability of the chip was demonstrated by using fluorescent particles of 9.77 μm in diameter and MCF-7 cells stained with DiI, wherein excellent focusing/alignment was achieved at flow rates of as low as 5 μL min−1 for fluorescent particles and 10 μL min−1 for MCF-7 cells, respectively. Furthermore, the spiral microfluidic chip was used for focusing/alignment of MCF-7 and LoVo cells after incubating with anticancer metal prodrug (cobalt curcumin complex [Co(tpa)(cur)](ClO4)2). The uptake of this prodrug in individual MCF-7 and LoVo cell was investigated with detection by TRA-ICP-MS in single cell resolution. The two types of cancer cells exhibit different uptake behaviors of the complex, and differences among individual cells of each type were also identified. A single cell detection efficiency of 67.5 ± 4.6% was obtained at the flow rate of 50 μL min−1.