At site quantification of fibrin residues on medical instruments
IGF 21936 N
Medical joint and hollow instruments place particularly high demands on cleaning during reprocessing. The most difficult soiling to remove is the protein fibrin, the removal of which can so far only be controlled by destructive testing.
The aim of the research project is an at-site quantification of fibrin for routine control of cleaning.
The quantification is based on the selective binding of fibrin by a hybrid molecule consisting of a carrier oligonucleotide coupled with the peptide CREKA, to which 10 thermally cleavable signal oligonucleotides are bound.
After removal of unbound hybrid molecules, the signal oligonucleotides are cleaved off by heating. After elution from the instrument, these can be quantified by means of a thermally regenerable flip-up fluorescence indicator to be developed: flip-up oligonucleotides functionalised with carbon quantum dots are covalently immobilised on a surface coated with graphene oxide, which straighten up after binding of eluted signal oligonucleotides (flip up).
After excitation with suitable light, a fluorescence signal is generated and quantified using a simple camera and image analysis software. The fluorescent indicator can be regenerated about a hundred times by heating.
The at site quantification is highly sensitive and enables the detection of a cleaning effect (≤ 3 µg fibrin/cm2) that meets the requirements, even with small instruments. The new method improves safety in instrument reprocessing and reduces the risk for patients.