Aims: To investigate the effectiveness of pulsed electric field (PEF) treatment as a new method for inactivation of micro-organisms in complex biomatrices and to assess this by quantifying the inactivation of Escherichia coli seeded in collagen gels.
Methods and results: PEF was applied to E. coli seeded collagen gels in static (nonflowing) chambers. The influence of electric field strength, pulse number and seeded cell densities were investigated. The highest level of inactivation was obtained at the maximum field strength of 45 kV cm(-1). For low levels of E. coli contamination (10(3) CFU ml(-1)), PEF treatment resulted in no viable E. coli being recovered from the gels. However, PEF treatment of gels containing higher cell densities (>or=10(4) CFU ml(-1)) did not achieve complete inactivation of E. coli.
Conclusions: PEF treatment successfully inactivated E. coli seeded in collagen gels by 3 log(10) CFU ml(-1). Complete inactivation was hindered at high cell densities by the tailing effect observed.
Significance and impact of the study: PEF shows potential as a novel, nondestructive method for decontamination of collagen-based matrices. Further investigation is required to ensure its compatibility with other proteins and therapeutic drugs for tissue engineering and drug delivery applications.