Fluorimetric characterisation of metabolic activity of ex vivo perfused pig hearts.

Autofluorescence of tissues and organs is an indicator of the physiological state of cells. The aim of the study was to investigate whether fluorimetric determination of the redox state of the ex vivo perfused pig heart can provide fast online detection of progressive changes in heart muscle tissue. Measurements on six organs perfused in a four-chamber working heart model were performed using a spectroscopic method exploiting the specific and different fluorescence lifetimes of intrinsic fluorophores such as NADH and flavins and providing a means of internal signal referencing.

Improved routine bio-medical and bio-analytical online fluorescence measurements using fluorescence lifetime resolution.

Fluorescence techniques are widely used as sensitive detection methods in bio-analytics. The use of the bio-physical parameter fluorescence lifetime additional to the spectral characteristics of fluorescence has the potential to improve fluorescence-related detection methods in terms of selectivity in signal recognition, robustness against disturbing influences, and the accessibility of novel bio-chemical process parameters. This article describes the technical set up of a time-resolving instrument with either a fixed time-gated detection principle for improved evaluation of tissue metabolism by an online monitoring of the tissue autofluorescence or a direct fluorescence lifetime detection principle for lifetime-based fluorescent assays.