Selective digestion of Ba2+/Ca2+ alginate gel microdroplets for single-cell handling

• Published in: Japanese Journal of Applied Physics 2018-05, Vol.57 (6S1)
• Main Authors: Odaka, Masao, Hattori, Akihiro, Matsuura, Kenji, Yasuda, Kenji
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.7567/JJAP.57.06HH02

Cells encapsuled by polymer microdroplets are an effective platform for the identification and separation of individual cells for single-cell-based analysis. However, a key challenge is to maintain and release the captured cells in the microdroplets selectively, nondestructively, and noninvasively. We developed a simple method of encapsulating cells in alginate microdroplets having different digestion characteristics. Cells were diluted with an alginate polymer of sol state and encapsulated into microdroplets with Ba2+ and Ca2+ by a spray method. When a chelating buffer was applied, alginate gel microdroplets were digested according to the difference in chelating efficiency of linkage-divalent cations; hence, two types of alginate microdroplets were formed. Moreover, we examined the capability of the alginate gel to exchange linkage-divalent cations and found that both Ca2+ exchange in Ba-alginate microdroplets and Ba2+ exchange in Ca-alginate microdroplets occurred. These results indicate that the potential applications of a mixture of alginate microdroplets with different divalent cations control the selective digestion of microdroplets to improve the high-throughput, high-content microdroplet-based separation, analysis, or storage of single cells.