Fine-tuning cell-mimicking polyacrylamide microgels: Sensitivity to microscale reaction conditions in droplet microfluidics

Goswami R, Kim K, Boccaccini AR, Guck J, Girardo S (2026)

Publication Type: Journal article

Publication year: 2026

Journal

Materials and Design Elsevier

Book Volume: 262

Article Number: 115450

DOI: 10.1016/j.matdes.2026.115450

Abstract

Shaping polyacrylamide (PAAm) hydrogels via droplet microfluidics enables production of microgels that mimic cellular physical properties, advancing mechanobiology research. Controlling microgel size and elasticity is essential but challenging, as multiple factors influence polymerization and network formation. Although chemical reactions in microdroplets are generally faster and more uniform than in bulk, these microreactors are highly sensitive: small changes in chemical or physical conditions can cause significant variations in microgel properties. Our study identifies flow conditions as a crucial factor affecting both microgel elasticity and size by modulating interfacial transport during gelation. Using a flow-focusing microfluidic chip, we generated pre-gel droplets with the same composition in an oil phase, systematically varying the PAAm-to-oil flow rate ratio while maintaining a constant total flow rate. This method produced droplets with minimal size variation ('1 µm), but beads exhibited distinct Young’s moduli despite identical monomer concentrations. Further analysis showed that catalyst transport across the oil–water interface strongly impacts polymerization efficiency and network structure. These findings demonstrate that while droplet polymerization offers advantages, reproducible microgel properties demand precise flow control. This work emphasizes the critical role of microfluidic parameter tuning in advancing PAAm microgel applications in biophysics.

Authors with CRIS profile

Aldo Boccaccini Lehrstuhl für Werkstoffwissenschaften (Biomaterialien) Jochen Guck

Involved external institutions

Max-Planck-Institut für die Physik des Lichts (MPL) / Max Planck Institute for the Science of Light DE Germany (DE)

How to cite

APA:

Goswami, R., Kim, K., Boccaccini, A.R., Guck, J., & Girardo, S. (2026). Fine-tuning cell-mimicking polyacrylamide microgels: Sensitivity to microscale reaction conditions in droplet microfluidics. Materials and Design, 262. https://doi.org/10.1016/j.matdes.2026.115450

MLA:

Goswami, Ruchi, et al. "Fine-tuning cell-mimicking polyacrylamide microgels: Sensitivity to microscale reaction conditions in droplet microfluidics." Materials and Design 262 (2026).

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