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Molecular-level removal of proteinaceous contamination from model surfaces and biomedical device materials by air
K K Banerjee1, S Kumar, K E Bremmell
1Ian Wark Research Institute, University of South Australia, Adelaide, Australia.
Abstract:
Established methods for cleaning and sterilising biomedical devices may achieve removal of bioburden only at the macroscopic level while leaving behind molecular levels of contamination (mainly proteinaceous). This is of particular concern if the residue might contain prions. We investigated at the molecular level the removal of model and real-life proteinaceous contamination from model and practical surfaces by air plasma (ionised air) treatment. The surface-sensitive technique of X-ray photoelectron spectroscopy (XPS) was used to assess the removal of proteinaceous contamination, with the nitrogen (N1s) photoelectron signal as its marker. Model proteinaceous contamination (bovine serum albumin) adsorbed on to a model surface (silicon wafer) and the residual proteinaceous contamination resulting from incubating surgical stainless steel (a practical biomaterial) in whole human blood exhibited strong N1s signals [16.8 and 18.5 atomic percent (at.%), respectively] after thorough washing. After 5min air plasma treatment, XPS detected no nitrogen on the sample surfaces, indicating complete removal of proteinaceous contamination, down to the estimated XPS detection limit 10ng/cm(2). Applying the same plasma treatment, the 7.7at.% nitrogen observed on a clinically cleaned dental bur was reduced to a level reflective of new, as-received burs. Contact angle measurements and atomic force microscopy also indicated complete molecular-level removal of the proteinaceous contamination upon air plasma treatment. This study demonstrates the effectiveness of air plasma treatment for removing proteinaceous contamination from both model and practical surfaces and offers a method for ensuring that no molecular residual contamination such as prions is transferred upon re-use of surgical and dental instruments.
Insights
Air plasma treatment effectively removes molecular-level proteinaceous contamination, including potential prions, from medical instruments. This advanced cleaning method ensures instruments are safe for reuse by eliminating even trace residues invisible to the naked eye.
Area of Science:
- Biomaterials Science
- Surface Chemistry
- Medical Device Sterilization
Background:
- Established sterilization methods often fail to remove molecular-level proteinaceous contamination from biomedical devices.
- Residual contamination, particularly prions, poses a significant risk for disease transmission during instrument reuse.
- There is a critical need for advanced cleaning techniques capable of molecular decontamination.
Purpose of the Study:
- To investigate the efficacy of air plasma treatment in removing proteinaceous contamination at the molecular level from various surfaces.
- To assess the potential of air plasma for eliminating prion contamination on surgical and dental instruments.
- To evaluate air plasma as a superior decontamination method compared to conventional cleaning.
Main Methods:
- Utilized X-ray photoelectron spectroscopy (XPS) with nitrogen (N1s) signal as a marker to quantify proteinaceous contamination.
- Applied air plasma (ionized air) treatment to model surfaces (silicon wafer with bovine serum albumin) and practical surfaces (surgical stainless steel, clinically cleaned dental bur).
- Employed contact angle measurements and atomic force microscopy to corroborate surface cleanliness.
Main Results:
- Air plasma treatment completely removed proteinaceous contamination, indicated by the absence of nitrogen signals detected by XPS (detection limit ~10 ng/cm²).
- Residual nitrogen on clinically cleaned dental burs was reduced to levels comparable to new instruments after plasma treatment.
- Surface analysis confirmed complete molecular-level removal of contaminants, evidenced by changes in surface properties.
Conclusions:
- Air plasma treatment is highly effective for removing proteinaceous contamination from both model and practical surfaces at the molecular level.
- This method offers a promising solution for ensuring the complete decontamination of surgical and dental instruments, preventing the transfer of infectious agents like prions.
- Air plasma represents a significant advancement in biomedical device reprocessing, enhancing patient safety.
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