Microfluidic System for Controlled Gelation of a Thermally Reversible Hydrogel

The integration of cell culture and characterization onto a miniaturized platform promises to benefit many applications such as tissue engineering, drug screening, and those involving small, precious cell populations. This paper presents the controlled on-chip gelation of a thermally-reversible hydrogel. Channel design and flowrate control are crucial in determining hydrogel geometry, while integrated temperature control triggers reversible gel formation. Formation of hydrogel droplets through shearing of immiscible flows is demonstrated with subsequent on-chip gelation. The temperature of phase transition occurs between 32 degrees C-34 degrees C well within the range for mammalian cell encapsulation and culture.