Using DNA strand displacement to control interactions in DNA-grafted colloids

Abstract

Grafting DNA oligonucleotides to colloidal particles leads to specific, reversible interactions between those particles. However, the interaction strength varies steeply and monotonically with temperature, hindering the use of DNA-mediated interactions in self-assembly. We show how the dependence on temperature can be modified in a controlled way by incorporating DNA stranddisplacement reactions. The method allows us to make multicomponent systems that can selfassemble over a wide range of temperatures, invert the dependence on temperature to design colloidal systems that melt upon cooling, controllably transition between structures with different compositions, or design systems with multiple melting transitions. This wide range of behaviors can be realized simply by adding a small number of DNA strands to the solution, making the approach modular and straightforward to implement. We conclude with practical considerations for designing systems of DNA-mediated colloidal interactions.

Programming Self-Assembled Materials With DNA-Coated Colloids

“…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. 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].…”

“…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.…”

Programming configurational changes in systems of functionalised polymers using reversible intramolecular linkages

“…This observation will motivate studying new design principles not based solely on rules to fine-tune the parameters of the system, like the degree of functionalisation, rather on the selection of particular linking dynamics leading to a sought chain morphology. We observe that engineering of different bond dynamics is currently an active field in DNA functionalised materials [48][49][50][51] .…”

Control and optical mapping of mechanical transitions in polymer networks and DNA-based soft materials

“…In the last few years, two main advances in the design of DNA-coated colloids have been proposed, namely the use of strand exchange to tune the kinetics and the thermodynamics of interactions, and the introduction of DNA strands to emulsion droplets and lipid vesicles as mobile tethers. An example of the former strategy involves a binary mixture of complementary colloids and free single strands, partially complementary to one population [32,33]. Binding of the two populations hence proceeded via strand displacement reactions, resulting in a rich phase behaviour, with tunable width of the gas-solid coexistence region and re-entrant melting with fine temperature control.…”