Discrimination of microorganisms and cells in tissue engineering by Raman spectroscopy

Sterility testing of cell or tissue cultures is an essential task in the fields of regenerative medicine and tissue engineering. Especially in case of Good manufacturing practice (GMP) of cell and tissue based transplants. We present a system based on a commercially available microscope equipped with a microfluidic cell that prepares the particles found in the solution for analysis. A Raman-spectrometer attachment optimized for non-destructive, rapid recording of Raman spectra, and a data acquisition and analysis tool for identification of the particles. Identification of critical particles like microorganisms via microscopic imaging and subsequent image analysis is carried out before micro-Raman analysis of those particles is then carried out with an excitation wavelength of 785 nm. Howev er an automated image analysis of small particles from supernatant of biopsies on a filter chip with tiny holes is a difficult task. Especially for the discrimination of small particles like cell debris and bacteria, which have a quite similar range of size. Because of that particles in the supernatant and microorganisms have to be discriminated by means of Raman spectroscopy. We present here a Raman based method to discriminate between cells, microorganisms and particles in cell culture.