Electro-elution, a novel method to remove transmissible spongiform encephalopathy-associated PrP Sc from stainless steel surgical instruments

Abstract

Iatrogenic transmission of transmissible spongiform encephalopathies (TSEs) has been demonstrated via surgical instruments and there is concern over the efficacy of conventional decontamination techniques used to reprocess reusable instruments. This paper describes the development of a novel cleaning method, 'electro-elution', to remove TSE disease-specific abnormal protein PrP(Sc) from the surface of stainless steel surgical instruments. The electro-elution process subjects the stainless steel instrument to an electrical current in the presence of an electrolytic buffer to remove protein deposits. Stainless steel discs were contaminated with infectious brain homogenate and subjected to a range of conditions to determine the ability of electro-elution to remove the deposits. To determine whether there was any residual PrP(Sc) remaining on the disc after electro-elution, a novel detection method, 'direct blotting', was also developed. Direct blotting utilizes a process of passive transfer of proteins directly from the surface of the instrument to a proteophilic membrane for detection. Our study shows that electro-elution has the ability to effectively remove, and possibly degrade, disease-associated PrP(Sc) from the surface of stainless steel surgical instruments.