Self-organized gels in DNA/F-actin mixtures without crosslinkers: networks of induced nematic domains with tunable density.
We examine mixtures of DNA and filamentous actin (F-actin) as a model system of like-charged rigid rods and flexible chains. Confocal microscopy reveals the formation of elongated nematic F-actin domains reticulated via defect-free vertices into a network embedded in a mesh of random DNA. Synchrotron x-ray scattering results indicate that the DNA mesh squeezes the F-actin domains into a nematic state with an interactin spacing that decreases with increasing DNA concentration as d(actin) proportional, variantrho(DNA)(-1/2). Interestingly, the system changes from a counterion-controlled regime to a depletion-controlled regime with added salt, with drastic consequences for the osmotic pressure induced phase behavior.
Lai
Ghee Hwee
GH
Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Butler
John C
JC
Zribi
Olena V
OV
Smalyukh
Ivan I
II
Angelini
Thomas E
TE
Purdy
Kirstin R
KR
Golestanian
Ramin
R
Wong
Gerard C L
GC
D000199:Actins / Q000737:chemistry*; D000818:Animals; D004247:DNA / Q000737:chemistry*; D005782:Gels / Q000737:chemistry; D018260:Gelsolin / Q000737:chemistry; D006801:Humans; D018613:Microscopy, Confocal; D017434:Protein Structure, Tertiary; D011817:Rabbits; D053838:Scattering, Small Angle; D013816:Thermodynamics; D014961:X-Ray Diffraction
D000199:Actins; D005782:Gels; D018260:Gelsolin; D004247:DNA