An integrated plastic microchip for enhancing electrophoretic separation using tunable pressure‐driven backflows

Abstract

Microfluidic CE (MCE) is an effective solution for rapid and sensitive determination of multiple analytes. Herein, a dynamic coated cyclic olefin copolymer microchip was developed having an on‐chip micropump for fluid velocity adjusting in electrophoretic separations. This micropump was fabricated by constructing a polyacrylamide gel membrane at one channel terminal. Once applying electric field across the membrane, a pressure‐driven flow generated automatically to balance the electroosmotic flow (EOF) mismatch at the channel‐membrane interface. The influence of gel precursor concentration and operating voltages on the fluid velocity was carefully evaluated. Moreover, the highly integration of injection, separation, and pumping units of the MCE system minimized the dead volume and provides satisfied column efficiency. Experiments showed that by adjusting of pumping voltage reduced the fluid velocity by a factor of 6, resulting six‐ and threefold resolving power enhancements of rhodamine dye mixture and amino acid mixture, respectively. Furthermore, the developed MCE method was applied for rhodamines and amino acids quantitation in food and cosmetics, with standard addition recoveries of 87.3–106.9% and 89.9–117.4%, respectively. These results were also confirmed by standard HPLC method, revealing the application potential in fast and onsite analysis of complex samples.

Recent advances in microchip electrophoresis for analysis of pathogenic bacteria and viruses

“…Such applications involve forensic genotyping [66, 67], analysis of illicit drugs [68], separation of explosive residues [69], and forensic screening of adulterations in beverages [70–72]. It was also applied to the analysis of small molecules such as pharmaceutical compounds [73–78], amino acids [75, 79, 80], environmental contaminants [81–83], and specific biomarkers [84–87]. Its use in the analysis of microbial contaminations of water, air, and foodstuffs has witnessed a great interest in the last decade [88–90].…”

Size‐resolved counting of circulating tumor cells on pinched flow‐based microfluidic cytometry

“…In this work, a simple cross-channel layout microchip in cyclic olefin copolymer (COC) was developed for microspheres and cells focusing through sheath fluids. Then this microchip device was coupled to a laser-induced fluorescence detector used for microfluidic capillary electrophoresis in our laboratory previously [23,24] to perform size-resolved fluorescence microspheres and cell counting as a microflow cytometer. After performance evaluation, the proposed COC microflow cytometer device was applied to CTCs detecting and counting, including an MDA-MB-231 (human breast cell line) spiked red blood cells (RBCs) sample and a mixture of MDA-MB-231 and MCF-7 (human breast cell line) sample.…”