Formation of liquid-core capsules having a thin hydrogel membrane: liquid pearls

We report an experimental investigation on the formation of liquid-core capsules having a thin hydrogel elastic membrane, named ‘liquid pearls’. These fish-egg-like structures are initially made of a millimetric liquid drop, aqueous or not, coated with an aqueous liquid film containing sodium alginate that gels once the double drop enters a calcium chloride bath. The creation of such pearls with a micrometer-thick membrane requires the suppression of mixing until gelling takes place. Here, we show that superimposing a two-dimensional surfactant precipitation at the interface confers a transient rigidity that can damp the shear-induced instability at impact. Based on this, pearls containing almost any type of liquid can be created. This opens the possibility to use such structures as a new tool for screening microorganism survival and growth in various three-dimensional environments.

[1]  S. Chandrasekhar.  Hydrodynamic and Hydromagnetic Stability , 1961 .

[2]  R. K. Shah,et al.  Fabrication of Monodisperse Thermosensitive Microgels and Gel Capsules in Microfluidic Devices Highlight Www.rsc.org/softmatter | Soft Matter , 2022 .

[3]  Pascal Martin,et al.  Liquid/liquid dewetting , 1993 .

[4]  D. Weitz,et al.  Monodisperse Double Emulsions Generated from a Microcapillary Device , 2005, Science.

[5]  Gorka Orive,et al.  History, challenges and perspectives of cell microencapsulation. , 2004, Trends in biotechnology.

[6]  T. A. Carpenter,et al.  The gelation of sodium alginate with calcium ions studied by magnetic resonance imaging (MRI) , 1994 .

[7]  P. Gennes.  The Physics Of Foams , 1999 .

[8]  H. Chang,et al.  Microencapsulation of microbial cells. , 2000, Biotechnology advances.

[9]  Fernando Leal-Calderon,et al.  Emulsion Science: Basic Principles , 2003 .

[10]  and Alexey Kabalnov,et al.  Macroemulsion Stability: The Oriented Wedge Theory Revisited , 1996 .

[11]  Lorenz Sigurdson,et al.  The three-dimensional vortex structure of an impacting water drop , 1994 .

[12]  C. Béguin,et al.  Maximal deformation of an impacting drop , 2004, Journal of Fluid Mechanics.

[13]  Ethan Tumarkin,et al.  Microfluidic production of biopolymer microcapsules with controlled morphology. , 2006, Journal of the American Chemical Society.

[14]  David J Mooney,et al.  Alginate hydrogels as biomaterials. , 2006, Macromolecular bioscience.

[15]  R. Craster,et al.  On compound liquid threads with large viscosity contrasts , 2005, Journal of Fluid Mechanics.

[16]  Emmanuel Villermaux,et al.  Mixing and Spray Formation in Coaxial Jets , 1998 .

[17]  O. Basaran,et al.  Nonlinear dynamics and breakup of compound jets , 2006 .

[18]  A. Mata,et al.  Self-Assembly of Large and Small Molecules into Hierarchically Ordered Sacs and Membranes , 2008, Science.

[19]  D. Hartl,et al.  Selection in chemostats. , 1983, Microbiological reviews.

[20]  Urs von Stockar,et al.  Formation of microcapsules from polyelectrolyte and covalent interactions. , 2005, Langmuir : the ACS journal of surfaces and colloids.