Self-assembly of abiotic & biotic mineralized forms
We explore the theoretical principles for the growth and form of biominerals and dynamical sculpting of analogous synthetic systems.
Structures with intricate 3D shapes are increasingly essential for next-generation materials, such as in optics or catalysis. A promising candidate for their bottom-up fabrication is biomineralization-inspired growth, which takes full advantage of the physico-chemical processes that arise in natural systems. Biomineralization couples transport and reaction of species and their solidification at the growth front. Inorganic model systems, such as carbonate-silica precipitates and chemical gardens, exhibit analogous dynamics. The theoretical challenge lies at determining the physical laws that enable steering the gradients to guide the position, direction, local ordering of assembly. A theoretical understanding paves the way for the synthesis of complex brittle morphologies and understanding bone formation.
Carbone-silica composites. Experimental patterns (top left). Waveguiding helix (top right). Comparison of theory with experiment (bottom) (Science 2017).
C. N. Kaplan*, W. L. Noorduin*, L. Li, R. Sadza, L. Folkertsma, J. Aizenberg, L. Mahadevan, “Controlled growth and form of precipitating microsculptures.” Science 355, 1395 (2017). (*equal contribution) [link]
Soft bioinspired & biological systems
Our research in this area builds the theoretical infrastructure of soft biomimetic platforms that selectively translate environmental input into local mechanical, optical or chemical output.
Living organisms store and differentiate information or exhibit self-regulated motion by processing dynamical cues from their environment. Our goal is to quantify how multiphase soft biological and synthetic materials interact with external signals. This will advance engineered systems where complex signal processing is critical, ranging from tissue engineering to drug delivery to soft robotics.
Signal integration in gels. A PAA hydrogel patterned with a microplate array for deformation readout. The gel is initially blue due to copper complexation. Acid enters from left and replaces copper (a receding blue color front) and at the same time creates a localized swelling front, visualized by the plates standing upright (in revision 2019).
P. A. Korevaar, C. N. Kaplan, A. Grinthal, R. M. Rust, J. Aizenberg, “Non-equilibrium signal integration in hydrogels.” Nature Communications 11, 386 (2020). [link]
T. Gibaud, C. N. Kaplan, P. Sharma, A. Ward, M. J. Zakhary, R. Oldenbourg, R. B. Meyer, R. D. Kamien, T. R. Powers, Z. Dogic, “Achiral symmetry breaking and positive Gaussian modulus lead to scalloped colloidal membranes.”
PNAS 114, E3376 (2017). [link]
M. J. Zakhary, T. Gibaud, C. N. Kaplan, E. Barry, R. Oldenbourg, R. B. Meyer, Z. Dogic, “Imprintable membranes from incomplete chiral coalescence.” Nature Communications 5, 3063 (2014). [link]
C. N. Kaplan, R. B. Meyer, “Colloidal membranes of hard rods: unified theory of free edge structure and twist walls.”
Soft Matter 10, 4700 (2014). [link]
C. N. Kaplan, T. Gibaud, R. B. Meyer, “Intrinsic curvature determines the crinkled edges of crenellated disks.”
Soft Matter 9, 8210 (2013). [link]
C. N. Kaplan, H. Tu, R. A. Pelcovits, R. B. Meyer, “Theory of depletion induced phase transition from chiral smectic A twisted ribbons to semi–infinite flat membranes” Physical Review E 82, 021701 (2010). [link]
Fluid dynamics of physical & biological suspensions
We develop continuum formulations of passive and active multiphase flows that unify mass & momentum transfer, as well as mechanical properties of constituent phases with well-defined microscopic limits.
Evaporative patterning (left). Multiphase flow mechanics within thin films of drying colloidal mixtures lead to a plethora of residual patterns, from bands to uniform solid deposits composed of particles (Physics of Fluids 2015).
Our recent work is focused on the multiphase flow dynamics of biological suspensions, as in the case of bacteria spreading over water-permeable surfaces. Our approach integrates the activity and biomass production of bacteria to the multiphase flow picture of passive colloidal suspensions, which we developed previously to elucidate the formation of a range of residual patterns in drying liquids.
S. Srinivasan, C. N. Kaplan, L. Mahadevan, “A multiphase theory for spreading microbial swarms and films.”
eLife 8, e42697 (2019). [link]
C. N. Kaplan, L. Mahadevan, “Evaporation-driven ring and film deposition from colloidal droplets.”
Journal of Fluid Mechanics 781, R2 (2015). [link]
C. N. Kaplan, N. Wu, S. Mandre, J. Aizenberg, L. Mahadevan, “Dynamics of evaporative colloidal patterning.”
Physics of Fluids 27, 092105 (2015). [link]