BBC Knowledge Asia Edition 3

PHOTOS: SCIENCE PHOTO LIBRARY X3, GETTY X4

nanomachines can even puncture a hole in cell membranes,

much like how a virus injects its DNA to infect a host cell.

By putting these elements together – payload delivery,

molecular recognition and pore puncturing – scientists can

create vessels capable of travelling to the site of a tumour,

for example, and treating it directly.

ON TRIAL

Only around a dozen nanomedicines are licensed for use at

the moment, but hundreds more are in development or

undergoing clinical trials.

Imagine, for example, being able to release drugs into

your body by shining a torch onto your arm rather than

having an injection. Well, researchers at the University of

California, San Diego might just have made that a reality.

They’ve developed ball-shaped nanoparticles made from a

polymer that falls apart when UV light is shone on it. This

simple system means the nanoparticles release their

medical payload wherever light is shone into the

TOP: A single

human cell rests

on a bed of

nanoneedles

ABOVE:

Quantum

dots can be

engineered

to emit light

at specific

wavelengths

POLYMERS

Polymers are materials that form hollow balls that

can then be filled with tiny amounts of other

useful chemicals.

GRAPHENE

A type of carbon that forms sheets just

one atom thick. The material is strong and highly

unreactive, so can be used to create a range

of tiny objects.

CARBON NANOTUBES

Sheets of graphene rolled up into tiny

tubes (‘nanotubes’) have been a key component in

nanotechnology for years. These tubes could be used on the

ends of ‘nanoneedles’, allowing them to inject substances into

specific areas of individual cells.

QUANTUM DOTS

Quantum dots are tiny spheres that are small

enough to pass freely through cells. They have a

metal inner core and an outer casing. Some emit light,

which can be used signal the presence of disease.

DNA

DNA’s ability to self-assemble into complex shapes

makes it an ideal material for making devices on a

tiny scale. Scientists have already created DNA-based shapes

that can act like tiny motors or boxes.

PROTEINS

Like DNA, proteins are capable of assembling

themselves into large, complex, and highly

predictable shapes. New shapes and functions can be

designed by altering the sequence of subunits from which

the proteins are made.

VIRUSES

Viruses are nature’s own nanomachines. Barely

considered living organisms, they are often made

of just a few proteins and strands of DNA. Yet they can still

infect host cells to make copies of themselves. Bolting

useful medical functions onto existing viruses is a

promising area of nanomedicine under development.

THE NANO TOOLKIT

HOW DO YOU MAKE A MACHINE

THAT’S SMALL AND SMART ENOUGH TO

TRAVEL INTO THE BODY AND BLAST A

TUMOUR?