How SPERM could protect your home from fire: Scientists use DNA from herring to develop new flame retardants
comments
DNA molecules extracted from fish sperm is being used to develop new types of flame retardant materials.
Scientists recently discovered that DNA is highly resistant to fire.
And in a series of experiments, the researchers coated cloth in the DNA from herring sperm cells and found it converts to a ceramic-like material when exposed to extreme heat.
Cotton layered with DNA molecules resists burning as the genetic material forms a ceramic-like coating over the fabric, shown in the bottom image in the photograph above, while untreated cotton will burn readily (top)
This char-like foam then helps to prevent the flames from catching alight on the material.
Researchers behind the work believe DNA could provide a natural and environmentally-friendly way of protecting fabrics from fire.
Currently many materials including furniture, such as sofas, are coated in chemical flame retardants that have been found to be accumulating in the environment and have been linked to infertility, cancers and birth defects.
Professor Giulio Malucelli, a materials scientist at the Polytechnic University of Turin, Italy, has been leading the research.
Writing in the journal Polymer, he and his colleagues said: 'We have explored its flame retardant activity by applying as a surface coating on cotton fabrics and observed that on exposure to heat, the DNA was able to form a foamed char on the surface of the fabric.
'DNA has proven to be an efficient renewable, natural flame suppressant and retardant, due to its intrinsic intumescent features.'
Biologists have known for some time that DNA is extremely sensitive to heat as it the helical structure can deform out of shape when it is heated even gently.
Professor Malucelli and his colleagues, however, found that when it is exposed to temperatures above 200°C (392°F), its properties change causing it to form a foam.
Their findings were highlighted by io9.com.
The researchers found that layers of DNA applied to cotton could reduce the amount of heat released by fire by 40 per cent and limits the availability of oxygen to the flames.
And in a more recent paper, published in the journal Polymer Degradation and Stability, they found that DNA changes chemically to have this effect.
Researchers behind the work believe DNA could provide a natural and environmentally-friendly way of protecting fabrics from fire. For the study they used DNA extracted from the sperm of herring (pictured above) to protect pieces of cotton
The images above show cotton coated with DNA before burning (b and c) and after it has burned (d and e). So-called deoxyribose groups in DNA release water when they are set alight and form a gel that chars and acts as a protective shield to the rest of the material. This process is known as an 'itnumescent effect'
The deoxyribose groups in the DNA release water when they are set alight and form a foaming gel that chars and acts as a protective shield to the rest of the material. This process is known as an 'itnumescent effect'.
The water also combines with phosphoric acid created from the phosphate groups that form part of the backbone of the DNA molecule to create a flame retardant residue.
Nitrogen in each of the DNA bases also form ammonia when heated - another flame retardant.
Dr Jenny Alongi, a researcher also at the Polytechnic University of Turin who has been working on the study with Professor Malucelli, said DNA appeared to become intumescent at relatively low temperatures compared to other fire retardant materials.
Sperm cells, shown above approaching an egg, could provide DNA for use in future flame retardant materials
In cells DNA binds itself together to form chromosomes (shown above) but when heated it rapidly denatures
She said: 'This may be the reason for the DNA high fire retardant effectiveness particularly when DNA is layered onto polymer surface.
'The intumescent fire protection screen is thus formed at a lower temperature than that at which thermal decomposition of organic polymers occurs.
'Furthermore, the chemical composition of the intumescent residue on heat exposure is converted into a highly thermally stable ceramic-like material which is resistant to thermal oxidation.
'Thus, the fire protection built by DNA decomposition can withstand fire exposure for longer time than traditional intumescent fire retardants.'
The researchers also recently found that some proteins found in biological cells have similar fire resistant properties - raising the prospect of a new generation of biological flame retardants.
Put the internet to work for you.
0 comments:
Post a Comment