Spontaneous Formation of Uniform Cell‐Sized Microgels through Water/Water Phase Separation

Abstract

In this study, a one‐step method is discussed for producing uniform cell‐sized microgels using glass capillaries filled with a binary polymer blend of polyethylene glycol (PEG) and gelatin. Upon decreasing temperature, phase separation of the PEG/gelatin blends and gelation of gelatin occur, and then the polymer blend forms linearly aligned, uniformly sized gelatin microgels in the glass capillary. When DNA is added to the polymer solution, gelatin microgels entrapping DNA are spontaneously formed, and the DNA prevents the coalescence of the microdroplets even at temperatures above the melting point. This novel method to form uniform cell‐sized microgels may be applicable to other biopolymers. This method is expected to contribute to diverse materials science via biopolymer microgels and biophysics and synthetic biology through cellular models containing biopolymer gels.

Periodic Alignment of Binary Droplets via a Microphase Separation of a Tripolymer Solution under Tubular Confinement

“…This pattern, emerging from the phase separation of two types of hydrophilic polymers in water within a capillary, organizes itself. 31 , 32 In this present study, we demonstrate that a periodic alignment of binary microdroplets, each surrounded by a different polymer solution, arises from the phase separation of an aqueous tripolymer solution in a capillary. Recently, in the studies concerning coacervate formation, generation of various specific spatial patterns with polydispersity have been reported.…”

“…Conversely, our recent findings reveal the spontaneous alignment of uniformly sized microdroplets within a quasi-one-dimensional confinement (quasi-1D). This pattern, emerging from the phase separation of two types of hydrophilic polymers in water within a capillary, organizes itself. , In this present study, we demonstrate that a periodic alignment of binary microdroplets, each surrounded by a different polymer solution, arises from the phase separation of an aqueous tripolymer solution in a capillary. Recently, in the studies concerning coacervate formation, generation of various specific spatial patterns with polydispersity have been reported. ,− It is particularly notable that the periodic pattern formation of our study occurs in a thermodynamically closed system, which is in contrast to the pattern formation observed in thermodynamically open systems, such as the reaction-diffusion system responsible for Turing patterns. − In essence, the spatial periodic pattern in our system is kinetically stable, persisting without the need for a continuous input of energy or materials, distinguishing it from the dynamics of patterning in reaction-diffusion systems.…”

“…A glass capillary (Microcaps; Drummond, U.S.A.) with an inner diameter of 140 or 280 μm and 32 mm in the long axis was used. For PEG-coating of the inner wall of the capillary, poly- l -lysine­(20) graft­[3,5] PEG(2) (PLL(20)-g­[3,5]-PEG(2); SuSoS AG, Switzerland) was used according to the reported method …”

“…For PEG-coating of the inner wall of the capillary, poly- l -lysine(20) graft[3,5] PEG(2) (PLL(20)-g[3,5]-PEG(2); SuSoS AG, Switzerland) was used according to the reported method. 32 …”