PT  - JOURNAL ARTICLE
AU  - Nicolas Castaño
AU  - Sungu Kim
AU  - Adrian M. Martin
AU  - Stephen J. Galli
AU  - Kari C. Nadeau
AU  - Sindy K.Y. Tang
TI  - Exponential magnetophoretic gradient for the direct isolation of basophils from whole blood in a microfluidic system
AID  - 10.1101/2022.02.11.480005
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2022.02.11.480005
4099  - http://biorxiv.org/content/early/2022/02/11/2022.02.11.480005.short
4100  - http://biorxiv.org/content/early/2022/02/11/2022.02.11.480005.full
AB  - Despite their rarity in peripheral blood, basophils play important roles in allergic disorders and other diseases including sepsis and COVID-19. Existing basophil isolation methods require many manual steps and suffer from significant variability in purity and recovery. We report an integrated basophil isolation device (i-BID) in microfluidics for negative immunomagnetic selection of basophils directly from 100 μL of whole blood within 10 minutes. We use a simulation-driven pipeline to design a magnetic separation module to apply an exponentially increasing magnetic force to capture magnetically tagged non-basophils flowing through a microtubing sandwiched between magnetic flux concentrators sweeping across a Halbach array. The exponential profile captures non-basophils effectively while preventing their excessive initial buildup causing clogging. The i-BID isolates basophils with a mean purity of 93.9%±3.6% and recovery of 95.6%±3.4% without causing basophil degradation or unintentional activation. Our i-BID has the potential to enable basophil-based point-of-care diagnostics such as rapid allergy assessment.Competing Interest StatementN.C. and S.K.Y.T. are inventors on a provisional patent application related to this work filed by Stanford University (number 63246069, filed on September 20, 2021). The authors declare that they have no other competing interests, and all other authors declare they have no competing interests.