An international team of researchers has created a mix of collagen and single wall carbon nanotubes (SWCNT) to repair the skin of burn victims, aid in cosmetic surgery patients and toughen leather made from animal skins. They also created a SWCNT separation process using proteins.
The method of separating carbon nanotubes with collagen developed by National Physical Laboratory Chemist Debdulal Roy (Twickenham, GB), Research Associate at National Centre for Scientific Research (CNRS) scientists Sanjib Bhattacharyya (Orleans, FR), Marie-Louise Saboungi (Orleans, FR) and Jean-Paul Salvetat (Marcilly-en-Villete, FR) is detailed in U.S. Patent Application 20100022438.
Their method of separating carbon nanotubes with substantially the same diameter includes the steps of: providing a sample of carbon nanotubes; separating individual nanotubes within the sample, and mixing with a solution comprising fibrous protein fibrils so that at least some individual nanotubes form a complex with the protein fibrils, and separating out those nanotubules which have formed a complex. Preferably the protein is collagen. The separated nanotubes can be used in the fields of electronics, medical and materials science.
Instead of collagen it would be possible to use a similar interaction mechanism and choose different molecules to select the tubes of other diameters. It can also be used to deliver SWCNTs into the body which would be otherwise difficult due to their likely antigenicity.
Since the SWCNT is wrapped in collagen, the SWCNT can be introduced into the body preventing it being attacked as a foreign body. Furthermore, material can be inserted inside the SWCNT before introduction. Biosensors for example can be loaded into SWCNTs and introduced into the body. Other materials can be loaded into SWCNTs, for example colored material for use in cosmetics.
The SWCNTs can be used to toughen skin, for example around scar tissue in order to prevent shrinkage of the skin. This is particularly useful in burns patients and following cosmetic surgery. Introducing SWCNTs into animal skin permits the skin to be toughened, improving the strength of the resulting leather.
Separating SWCNT starts with mixing a solution comprising protein fibrils so that at least some individual carbon nano tubules form a complex with the fibrils; and separating out those nano tubules which have formed a complex.
To separate individual nanotubes within the sample, the tubes can be treated with acid and dispersed in water. Additionally or alternatively, surfactant can be added to the solution. In this case, the tubes do not need to be acid treated. Typically the surfactant is SDS (sodium dodecyl sulphate), although other surfactants may be used.
In a preferred embodiment, the collagen is Type 1 collagen. The collagen may be obtained from calf skin. Other types of collagen may be used such as Types II, III, and/or VI. A mixture of different types of collagen can also be used. Advantageously, the collagen is dissolved in water. However, other solvents may be used.
The step of separating out the tubules forming a complex may involve centrifugation and/or fractionation. The sample may be acid treated prior to mixing with the surfactant and the collagen solution. The diameter of the separated carbon nanotubules may be from about 0.8 to about 1.4 nm, preferably about 0.9 to about 1.3 nm, and more preferably about 1 to about 1.2 nm.