The president of the Royal Academy of Engineering has added his voice to the debate about nanotechnology
An artist's concept of a nano-engineered material used to make springy running shoes
In the fourth of his BBC Reith lectures, Lord Broers debunks the myth that nanomachines could turn the planet into grey goo.
The idea that nano-robots could run amok is "speculative and unproven", he says.
Nanotechnology is an umbrella discipline concerned with engineering of matter from individual atoms.
While some aspects of nanotech may need careful monitoring, other parts have been unfairly demonised, says Lord Broers.
SOME CURRENT NANO USES
Disk drives with nanometre layers to increase data storage
Lipid (fat) globules for anti-cancer drug delivery
Stain repellent/waterproof textiles
Anti-fungal sprays and fabrics
Novel coatings, paints and pigments
Source: Inst of Nanotechnology
The idea of tiny machines self-replicating and breaking down biological material was first mooted by Dr Eric Drexler, regarded by some as a "father of nanotechnology". He has since refuted these claims.
Lord Broers has added his voice to general scepticism that such machines could even be built let alone replicate.
"Our experience with chemistry and physics teaches us that we do not have any idea how to make an autonomous self-replicating machine at any scale," he says.
Nanotechnology is the manipulation of atoms and molecules at the "nanoscale". One nanometre is about a million times smaller than the diameter of a pinhead. A human hair is about 80,000 nanometres wide.
It is a subject close to the heart of Lord Broers, who is in his own right a world-renowned nanotech pioneer.
He is delighted that the science of the small has caught up with the large in terms of practical significance to people's lives.
In past centuries, it has been gigantic structures such as the Colossus of Rhodes, the Pyramids or the engineering feats of Brunel that have won praise and held the public's imagination, he says.
Nanotech can be as awe-inspiring as the pyramids
"It would have been difficult to persuade Brunel that the ability to design and fabricate at the nanometre scale was going to have as much impact upon people as the ability to build bridges and railways, but I believe that is now the case," he says.
"We had to wait for the age of electronics for miniaturisation to become an important achievement in its own right - until the same kind of awe could be inspired by the very small," he says.
The current fascination with nanotech has led to it embracing many different scientific disciplines, something Lord Broers thinks could be confusing for people.
"Those that take on the title gain the glamour of the most successful, and more importantly make themselves eligible for any funding that is allocated by government and private sources," he says.
But they also risk being linked to the concerns surrounding the more controversial branches of nanoscience.
In his lecture, he lays out what he sees as some of the most important strands of nanotech, charting their evolution and the way many innovations in nanotechnologies have provided a bridge between science and technology.
He marvels at the developments in the 20th Century which have made nanotech a reality, the most important of which has been the miniaturisation of electronics.
"It has now reached the point where microelectronics has become nanoelectronics, and electronic chips are now without doubt amongst the most useful of the nanotechnologies," he says.
SOME POTENTIAL USES OF NANOTECHNOLOGIES
1 - Organic Light Emitting Diodes (OLEDs) for displays
2 - Photovoltaic film that converts light into electricity
3 - Scratch-proof coated windows that clean themselves with UV
4 - Fabrics coated to resist stains and control temperature
5 - Intelligent clothing measures pulse and respiration
6 - Bucky-tubeframe is light but very strong
7 - Hip-joint made from biocompatible materials
8 - Nano-particle paint to prevent corrosion
9 - Thermo-chromic glass to regulate light
10 - Magnetic layers for compact data memory
11 - Carbon nanotube fuel cells to power electronics and vehicles
12 - Nano-engineered cochlear implant
The fourth of this year's Reith Lectures airs on Radio Four at 2000 BST on Wednesday 27 April