Phase separation in binary polymer solution: Gelatin/Poly(ethylene glycol) system

Yanagisawa, Miho; Yamashita, Yutaro; Mukai, Satoru; Annaka, Masahiko; Tokita, Masayuki

doi:10.1016/j.molliq.2013.12.035

Cited by 31 publications

(42 citation statements)

References 35 publications

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“…A fast quench with a smaller t delays the phase separation by the gelation and produces spherical microgels or a porous gel according to their volume fractions, as previously reported (Fig. S1) (19,20).…”

Section: Significancesupporting

confidence: 75%

“…To prepare the gelatin/PEG solution, PEG is first dissolved in distilled water, and subsequently gelatin was added at 65°C, thus forming a homogeneous phase. With a decrease in temperature, the gelatin/ PEG system undergoes phase separation into two liquid phases (18,19). Under the present experimental conditions, the polymer composition was fixed to PEG 1.7 wt% and gelatin 5.0 or 7.0 wt%.…”

Section: Methodsmentioning

confidence: 99%

“…Under this condition, these transition points (T p and T g ) are plotted against the gelatin concentration in Fig. 1B (19). With a decrease in the temperature, the PEG/gelatin blend first separates into two liquid phases at T p (L-L phase), and then the gelatin-rich phase turns into a gel below T g (< T p ) (L-G phase).…”

Section: Significancementioning

confidence: 97%

“…phase separation has been well characterized (18,19). Here, we used 1.7 wt% PEG20000 to set the phase separation point, T p , slightly above the gelation point, T g .…”

Section: Significancementioning

confidence: 99%

“…The gelatin/ PEG solution was confined in water-in-oil (W/O) microdroplets coated by a lipid layer, wherein the phase separation and sol-gel transition of the gelatin occur with a decrease in the temperature (18)(19)(20). This process led to gelation after and during the phase separation in the presence of the interactions between the polymers and lipid membranes.…”

mentioning

confidence: 99%

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Multiple patterns of polymer gels in microspheres due to the interplay among phase separation, wetting, and gelation

Yanagisawa

Nigorikawa

Sakaue

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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We report the spontaneous patterning of polymer microgels by confining a polymer blend within microspheres. A poly(ethylene glycol) (PEG) and gelatin solution was confined inside water-in-oil (W/O) microdroplets coated with a layer of zwitterionic lipids: dioleoylphosphatidylethanolamine (PE) and dioleoylphosphatidylcholine (PC). The droplet confinement affected the kinetics of the phase separation, wetting, and gelation after a temperature quench, which determined the final microgel pattern. The gelatin-rich phase completely wetted to the PE membrane and formed a hollow microcapsule as a stable state in the PE droplets. Gelation during phase separation varied the relation between the droplet size and thickness of the capsule wall. In the case of the PC droplets, phase separation was completed only for the smaller droplets, wherein the microgel partially wetted the PC membrane and had a hemisphere shape. In addition, the temperature decrease below the gelation point increased the interfacial tension between the PEG/ gelatin phases and triggered a dewetting transition. Interestingly, the accompanying shape deformation to minimize the interfacial area was only observed for the smaller PC droplets. The critical size decreased as the gelatin concentration increased, indicating the role of the gel elasticity as an inhibitor of the deformation. Furthermore, variously patterned microgels with spherically asymmetric shapes, such as discs and stars, were produced as kinetically trapped states by regulating the incubation time, polymer composition, and droplet size. These findings demonstrate a way to regulate the complex shapes of microgels using the interplay among phase separation, wetting, and gelation of confined polymer blends in microdroplets. microgels | aqueous two-phase systems | sol-gel phase separation | hydrogels | emulsions T he regulation of the 3D shapes of biopolymer gels at the mesoscale has numerous applications in the biomedical, cosmetic, and food materials industries, among others (1). Recently, top-down and bottom-up approaches have been reported to control the mesoscopic patterns of polymer gels. For example, photolithography and two-photon polymerization allow the regulation of gel patterns at the mesoscale (2-4). The advanced design of the molecules enables polymerization with a self-assembly and produces nonspherical microgels: spherical particles with a cavity, capsules, and cubic particles (5-7). However, these methods require highly specialized equipment and are generally difficult to adapt for biopolymer gels.Dynamical coupling between phase separation and sol-gel transition in polymer blends has also been investigated for the spontaneous formation of spherical microgels and a porous gel (8, 9). Ma et al. (10) and Choi et al. (11) confined aqueous two-phase systems (ATPSs) in microdroplets and fabricated microgels by selective polymerization. In such a confined space, phase separation accompanies wetting of a polymer to the substrate (12-15). Although the selective polymerization of phase-se...

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Section: Significancesupporting

confidence: 75%

Section: Methodsmentioning

confidence: 99%

Section: Significancementioning

confidence: 97%

“…phase separation has been well characterized (18,19). Here, we used 1.7 wt% PEG20000 to set the phase separation point, T p , slightly above the gelation point, T g .…”

Section: Significancementioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Multiple patterns of polymer gels in microspheres due to the interplay among phase separation, wetting, and gelation

Yanagisawa

Nigorikawa

Sakaue

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Flexible Allyl‐Modified Gelatin Photoclick Resin Tailored for Volumetric Bioprinting of Matrices for Soft Tissue Engineering

Cianciosi,

Stecher,

Löffler

et al. 2023

Adv Healthcare Materials

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Volumetric bioprinting (VBP) is a light‐based 3D printing platform, which recently prompted a paradigm shift for additive manufacturing (AM) techniques considering its capability to enable the fabrication of complex cell‐laden geometries in tens of seconds with high spatiotemporal control and pattern accuracy. A flexible allyl‐modified gelatin (gelAGE)‐based photoclick resin is developed in this study to fabricate matrices with exceptionally soft polymer networks (0.2–1.0 kPa). The gelAGE‐based resin formulations are designed to exploit the fast thiol‐ene crosslinking in combination with a four‐arm thiolated polyethylene glycol (PEG4SH) in the presence of a photoinitiator. The flexibility of the gelAGE biomaterial platform allows one to tailor its concentration spanning from 2.75% to 6% and to vary the allyl to thiol ratio without hampering the photocrosslinking efficiency. The thiol‐ene crosslinking enables the production of viable cell‐material constructs with a high throughput in tens of seconds. The suitability of the gelAGE‐based resins is demonstrated by adipogenic differentiation of adipose‐derived stromal cells (ASC) after VBP and by the printing of more fragile adipocytes as a proof‐of‐concept. Taken together, this study introduces a soft photoclick resin which paves the way for volumetric printing applications toward soft tissue engineering.

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Aqueous Two‐Phase Emulsion Bioink‐Enabled 3D Bioprinting of Porous Hydrogels

et al. 2018

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The three-dimensional (3D) bioprinting technology provides programmable and customizable platforms to engineer cell-laden constructs mimicing human tissues for a wide range of biomedical applications. However, the encapsulated cells are often restricted in spreading and proliferation by dense biomaterial networks from gelation of bioinks. Herein, we report a novel cell-benign approach to directly bioprint porous-structured hydrogel constructs by using an aqueous two-phase emulsion bioink. The bioink, which contains two immiscible aqueous phases of cell/gelatin methacryloyl (GelMA) mixture and poly(ethylene oxide) (PEO), is photocrosslinked to fabricate predesigned cell-laden hydrogel constructs by extrusion bioprinting or digital micromirror device-based stereolithographic bioprinting. Porous structure of the 3D-bioprinted hydrogel construct is formed by subsequently removing the PEO phase from the photocrosslinked GelMA hydrogel. Three different cells (human hepatocellular carcinoma cells, human umbilical endothelial cells, and NIH/3T3 mouse embryonic fibroblasts) within the 3D-bioprinted porous cell-laden hydrogel patterns showed enhanced cell viability, spreading, and proliferation compared to the standard (i.e. non-porous) hydrogel constructs. The new 3D bioprinting strategy is believed to provide a robust and versatile platform to engineer porous-structured tissue constructs and their models for a variety of applications in tissue engineering, regenerative medicine, and personalized therapeutics.

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Phase separation in binary polymer solution: Gelatin/Poly(ethylene glycol) system

Cited by 31 publications

References 35 publications

Multiple patterns of polymer gels in microspheres due to the interplay among phase separation, wetting, and gelation

Multiple patterns of polymer gels in microspheres due to the interplay among phase separation, wetting, and gelation

Flexible Allyl‐Modified Gelatin Photoclick Resin Tailored for Volumetric Bioprinting of Matrices for Soft Tissue Engineering

Aqueous Two‐Phase Emulsion Bioink‐Enabled 3D Bioprinting of Porous Hydrogels

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