The supercritical CO₂ sterilization process
Why a low-temperature gas that’s neither liquid nor vapor has become a preferred method for sterilizing allograft tissue.
Last updated: July 2026
Supercritical CO₂ is carbon dioxide held above its critical point — about 31.1°C and 73.8 atm — where it behaves simultaneously like a liquid and a gas. That combination gives it liquid-like solvency with gas-like penetration, letting it move through tissue and carry away lipids, blood residues, and pathogens far more thoroughly than a purely liquid wash.
The 31.1°C critical temperature is the key clinical advantage: it’s well below the point at which heat begins to denature collagen and other structural proteins, so processing can clean and sterilize tissue without the thermal damage associated with heat-based methods, or the harsh residues left behind by some chemical sterilants. Published research on scCO₂-processed allografts has reported better-preserved elastic properties and strength compared to tissue treated with more traditional sterilization methods, and studies specific to bone and tendon allografts describe the process reliably reaching a sterility assurance level (SAL) of 10⁻⁶ — the recognized industry benchmark.
PASCO2® is Precision Allograft’s proprietary implementation of this methodology. We distribute allografts processed with it, built on the same scCO₂ science described in the peer-reviewed literature below.
Sources
NovaSterilis — Supercritical CO₂ Sterilization · Development of a sterilization process for amniotic membrane allograft tissue using supercritical CO₂ (PMC) · Safe and effective use of scCO₂-processed bone allografts (PMC)