A nanorobot is a popular term for molecules with a unique property that enables them to be programmed to carry out a specific task. In collaboration with colleagues in Italy and the USA, researchers at Aarhus University have now taken a major step towards building the first nanorobot of DNA molecules that can encapsulate and release active biomolecules.
In time, the nanorobot (also called a DNA nanocage) will no doubt be used to transport medications around in the body and thereby have a targeted effect on diseased cells.
Ref: Temperature-Controlled Encapsulation and Release of an Active Enzyme in the Cavity of a Self-Assembled DNA Nanocage. ACS Nano (29 October 2013) | DOI: 10.1021/nn4030543
We demonstrate temperature-controlled encapsulation and release of the enzyme horseradish peroxidase using a preassembled and covalently closed three-dimensional DNA cage structure as a controllable encapsulation device. The utilized cage structure was covalently closed and composed of 12 double-stranded B-DNA helices that constituted the edges of the structure. The double stranded helices were interrupted by short single-stranded thymidine linkers constituting the cage corners except for one, which was composed by four 32 nucleotide long stretches of DNA with a sequence that allowed them to fold into hairpin structures. As demonstrated by gel-electrophoretic and fluorophore-quenching experiments this design imposed a temperature-controlled conformational transition capability to the structure, which allowed entrance or release of an enzyme cargo at 37 °C while ensuring retainment of the cargo in the central cavity of the cage at 4 °C. The entrapped enzyme was catalytically active inside the DNA cage and was able to convert substrate molecules penetrating the apertures in the DNA lattice that surrounded the central cavity of the cage.