Linker-Mediated Phase Behavior of DNA-Coated Colloids

Abstract

The possibility of prescribing local interactions between nano-and microscopic components that direct them to assemble in a predictable fashion is a central goal of nanotechnology research. In this article we advance a new paradigm in which self-assembly of DNA-functionalized colloidal particles is programmed using linker oligonucleotides dispersed in solution. We find a phase diagram that is surprisingly rich compared to phase diagrams typical of other DNA-functionalized colloidal particles that interact by direct hybridization, including a re-entrant melting transition upon increasing linker concentration, and show that multiple linker species can be combined together to prescribe many interactions simultaneously. A new theory predicts the observed phase behavior quantitatively without any fitting parameters. Taken together, these experiments and model lay the groundwork for future research in programmable self-assembly, enabling the possibility of programming the hundreds of specific interactions needed to assemble fully-addressable, mesoscopic structures, while also expanding our fundamental understanding of the unique phase behavior possible in colloidal suspensions.arXiv:1902.08883v2 [cond-mat.soft]

Linker-mediated self-assembly of mobile DNA-coated colloids

“…8 actually accounts for multiparticle systems, which already includes multibody effects. Similar re-entrant melting was also found in a recent work of linkermediated immobile DNACCs, in which the ssDNA receptors are grafted on the colloids instead of being mobile on the particle surface (31). A local chemical equilibrium approach was used in (31) to treat the linker-mediated interaction between colloids, and it is related to the statistical mechanical description used here (24).…”

Unfolding of the chromatin fiber driven by overexpression of noninteracting bridging factors

“…1b is somehow analogous to the resolubilization of virus crystals [18], proteins [19], or nucleic acids [20] at a concentration of multivalent ions (forming inter-molecular bridges) higher than some mMs. Similarly, aggregates of ligandpresenting colloids cross-linked by short DNA oligomers dispersed in solution melt when increasing the concentration of the bridging molecule beyond a threshold value (ranging between 10 −8 M and 10 −4 M) which depends on the number of ligands per particle [21]. The proposed method, along with other simulation strategies implementing reaction moves in systems of multivalent chains [22][23][24][25][26][27][28][29][30], are ideal for studying the unfolding transition given that the high free energy barriers between competing states are sidestepped by dedicated MC moves.…”

Programming Self-Assembled Materials With DNA-Coated Colloids

“…For example, they found that the phase behavior of DNA-coated colloids can be altered by adding free DNA strands for displacement reaction, as mentioned above [62]. Then, using free DNA strands as the linkers to bridge grafted DNA on colloids' surface, they reported a reentrant melting transition upon increasing concentration of linker as well as the possibility to encode multiple interactions spontaneously [63]. In addition, colloidal crystals are constructed using free linker DNA, depending on the concentration and the symmetry of the linker.…”

“…Rogers et al [62][63][64][65][66] further investigated the physical behavior of the assembly of DNA-coated colloids mediated by free DNA strands. They argued that encoding information into the sequence and concentration of the free strands instead of the grafted strands could overcome the problems conventional colloidal self-assembly suffers, including uncollaborative mutual interactions and a limited number of interactions.…”