The particle generation of medical implants and drug coated balloons (DCB) is evaluated by simulating the implantation process and collecting the released particle material. In addition to size and particle counts their material composition is of interest. Raman spectroscopy and micros-copy are established methods for chemical identification. For the manual analysis of the particles different filter or rather background materials are suitable because different require-ments in height and intensity of the spectra can be compen-sated by the user. The aim of this study was to find suitable background materials for automatic particle identification.
Raman analysis of background and spherical polystyrene standard particles on filters and plain surfaces was performed manually to receive evaluable spectra for automation. Auto-matic analysis was done by a) single-point spectrum meas-urement using the coordinate list of all particles, and b) scan-ning a large sample area pixel by pixel measuring back-ground and particles.
For automatic analysis with method a) the polycarbonate membrane provided best results. With method b) the polysty-rene spectrum of the particles could be found on both plain surfaces and the polycarbonate membrane. Influences from the background spectrum could be kept small by thoroughly defining the focal plane with a wavelength specific autofocus mode for method a) and manually for method b).