The scCO2 approach
Carbon dioxide is in its supercritical state when both the temperature and pressure equal or exceed the critical point of 31ºC and 73 atm. In its supercritical state, CO2 has both gas-like and liquid-like qualities and it is this dual characteristic of scCO2 that yields rather uncommon properties providing the ideal conditions for cleaning and sterilising allograft tissues.
One of scCO2’s most distinctive properties is that it can effuse through solids like a gas and dissolve materials like a liquid. By controlling or regulating pressure and temperature, the density or solvent strength of scCO2 can be altered to simulate a wide range of organic solvents. This dissolving power is applied to purify, extract and sterilise a wide variety of sensitive materials. The low temperature of the process and the stability of CO2 also allows compounds to be extracted with no damage or denaturation to the allograft tissue.
Because of these features, the process of scCO2 treatment is capable of substantially reducing the presence of microorganisms, whereby the tissues are not only thoroughly cleaned, but they also meet the sterility assurance level of 10-6 (SAL6) for all kinds of microorganism.