Exceeding 80% Efficiency of Single-Bead Encapsulation in Microdroplets through Hydrogel Coating-Assisted Close-Packed Ordering
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作者
Chen, Long; Zhao, Yi; Li, Jie; Xiong, Chenwei; Xu, Yi; Tang, Chengren; Zhang, Rong; Zhang, Jingwei; Mi, Xianqiang; Liu, Yifan
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刊物名称
ANALYTICAL CHEMISTRY
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年、卷、文献号
2023, 95, 1520-6882
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关键词
Chen, Long; Zhao, Yi; Li, Jie; Xiong, Chenwei; Xu, Yi; Tang, Chengren; Zhang, Rong; Zhang, Jingwei; Mi, Xianqiang; Liu, Yifan
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摘要
High-efficiencyencapsulation of single microbeads inmicrodropletsis essential for droplet-based high-throughput analysis such as single-cellgenomics and digital immunoassays. However, the demand has been hinderedby the Poisson statistics of beads arbitrarily distributed in thedroplet partitions. Although techniques such as inertial orderinghave been proven useful to improve bead-loading efficiency, a generalmethod that requires no advanced microfluidics and owns compatibilitywith diverse bead types is still highly desired. In this paper, wepresent hydrogel coating-assisted close-packed ordering, a simplestrategy that improves the bead-loading efficiency to over 80%. Inthe strategy, the raw beads are coated with a thin layer of hydrogelto become slightly compressible and lubricious, so that they can beclose-packed in a microfluidic device and loaded into droplets ina synchronized manner. We first show that the thin hydrogel coatingcan be realized conveniently through jetting microfluidics or vortexemulsification. When loading single 30-mu m polystyrene beads,we experimentally determine an overall efficiency of 81% with theproposed hydrogel coating strategy. Of note, the strategy is not sensitiveto the selection of raw beads and can tolerate their polydispersity.Using the strategy, we achieve a cell capture rate of 68.8% when co-encapsulatingHEK293T cells and polydispersed barcoded beads for single-cell transcriptomics.Further sequencing results verify that the reversible hydrogel coatingdoes not affect the RNA capture behavior of the encapsulated barcodedbeads. Given its convenience and broad compatibility, we anticipatethat our strategy can be applied to various droplet-based high-throughputassays to improve their efficiency drastically.
