"Choo-choo" Nanotrain on the way

"Attention Please! All board the nanotrain asap" :D :) 

You may 'wonder' what I am talking about? Everyone have run their on train in their childhood. Holding the shirt one behind the other....mimicking the sound of train and running around. Quite fun.. isn't it? I really miss those days!!! :D 

Scientists at Oxford University and Warwick University have developed tiny self-assembling transport networks, powered by nano-scale motors and controlled by DNA. The system can construct its own network of tracks spanning tens of micrometers in length, transport cargo across network and even dismantle the tracks. 

The news came in Nature Nanotechnology and was supported by the Engineering and Physical Sciences Research Council and the Biotechnology and Biological Sciences Research Council. 

So, From where the researchers got such an inspiration? They were inspired by the 'Melanophore', used by fish cells to control their colour. Tracks in the network all come from a central point, like the spokes of a bicycle wheel. Motor proteins transport pigment around the network, either concentrating it in the centre or spreading it throughout the network. Concentrating pigment in the centre makes the cells lighter, as the surrounding space is left empty and transparent. 

Green dye-carrying shuttles sit idle on the tracks before refuelling

The system uses 'Kinesin', a motor protein, powered by ATP fuels. Kinesins move along the micro-tracks carrying control modules made from short strands of DNA. 'Assembler' nanobots are made with two kinesin proteins, allowing them to move tracks around to assemble the network, whereas the 'shuttles' only need one kinesin protein to travel along the tracks. 

'DNA' is an excellent building block for constructing synthetic molecular systems, as we can program it to do whatever we need,'said Adam Wollman, who conducted the research at Oxford University's Department of Physics. 'We design the chemical structures of the DNA strands to control how they interact with each other. The shuttles can be used to either carry cargo or deliver signals to tell other shuttles what to do. 

'We first use assemblers to arrange the tracks into 'spokes', triggered by the introduction of ATP. We then send in shuttles with fluorescent green cargo which spread out across the track, covering it evenly. When we add more ATP, the shuttles all cluster in the center of the track where the spokes meet. Next, we send signal shuttles along the tracks to tell the cargo-carrying shuttles to release the fluorescent cargo into the environment, where it disperse. We can also send shuttles programmed with 'dismantle' signals to the central hub, telling the tracks to break up.' 

Their demonstration used fluorescent green as cargo, but the same methods could be applied to to other compounds. As well as colour changes, spoke-like track systems could be used to speed up chemical reactions by bringing the necessary compounds together at the central hub. More broadly, using DNA to control motor proteins could enable the development of more sophisticated self-assembling systems for a variety of applications. 

A lot to come on our way and we might see some unimaginable applications on the way. For the moment... keep guessing...!!! :D :) 

Notes:

Melanophores: Fishes and amphibians possess specialized cells called Melanophores which contains hundreds of melanin-filled pigment granules termed melanosomes. The sole function of these cells is pigment aggregation in the center of the cell or dispersion throughout the cytoplasm. This alternative transport of pigment allows the animal to effect colour changes important for their camouflage and social interactions. They also transport their pigment in response to extracellular cues: neurotransmitters in the case of fish and hormonal stimuli in the case of frogs. In both cases, melanosome dispersion is induced by elevation of intracellular cAMP (Cyclic adenosine monophophate) levels, while aggregation is triggered by depression of cAMP. 

Kinesin: It is a protein belonging to a class of motor proteins found in eukaryotic cells. Kinesins move along microtubule filaments, and are powered by thr hydrolysis of ATP. The active movement of kinesins supports several cellular functions including mitosis, meiosis and transport of cellular cargo such as axonal transport. 

Animation of Kinesin walking on a microtubule

Kinesin dimer attaches to, and moves along, microtubules