(567d) Multistage Enrichment of Particles Using Temperature-Responsive Polymers

Enrichment of cells is an important process for sample preparations, which are the foundations for effective technology validation as well as for meaningful biological and clinical research. A conventional method for cell enrichment is magnetic particle separation technology, which allows for the simple, rapid and efficient enrichment of cells. A well known problem that prevents the magnetic particle separation technology from achieving high enrichment factors is the non-specific interactions between target species and the magnetic particles. To circumvent this problem we develop an enrichment technology by reversibly capturing and releasing target species with poly (N-isopropylacrylamide) (PNIPAM) coupled magnetic particles. This is realized by manipulating hydrophobic interactions between the temperature-responsive PNIPAM molecules covalently grafted both on the magnetic particles and the target species. At 37 °C, the PNIPAMs exhibit a hydrophobic conformation, and the target species are captured by the magnetic particles through hydrophobic interactions. While at 4 °C, the PNIPAMs are trigged to their hydrophilic state, and the target species are released from the magnetic particles. We design a multistage enrichment process by introducing multiple capture-and-release cycles to the magnetic separation procedure. Experiments demonstrated the multistage enrichment of modeled particles, an analogy to target cells and showed that the cumulative enrichment factor increases as the number of stage increases.