Specific binding of different vesicle populations by the hybridization of membrane-anchored DNA.
We demonstrate a method of heterogeneous vesicle binding using membrane-anchored, single-stranded DNA that can be used over several orders of magnitude in vesicle size, as demonstrated for large 100 nm vesicles and giant vesicles several microns in diameter. The aggregation behavior is studied for a range of DNA surface concentrations and solution ionic strengths. Three analogous states of aggregation are observed on both vesicle size scales. We explain the existence of these three regimes by a combination of DNA binding favorability, vesicle collision kinetics, and lateral diffusion of the DNA within the fluid membrane. The reversibility of the DNA hybridization allows dissociation of the structures formed and can be achieved either thermally or by a reduction in the ionic strength of the external aqueous environment. Difficulty is found in fully unbinding giant vesicles by thermal dehybridization, possibly frustrated by the attractive van der Waals minimum in the intermembrane potential when brought into close contact by DNA binding. This obstacle can be overcome by the isothermal reduction of the ionic strength of the solution: this reduces the Debye screening length, coupling the effects of DNA dehybridization and intermembrane repulsion due to the increased electrostatic repulsion between the highly charged DNA backbones.
Beales
Paul A
PA
Department of Chemical Engineering, Princeton University, Princeton, New Jersey 08544, USA.
Vanderlick
T Kyle
TK
D004277:DNA, Single-Stranded / Q000737:chemistry*; D007700:Kinetics; D008567:Membranes, Artificial; D009693:Nucleic Acid Hybridization; D009994:Osmolar Concentration; D013056:Spectrophotometry, Ultraviolet; D055672:Static Electricity
D004277:DNA, Single-Stranded; D008567:Membranes, Artificial