Simultaneous identification of amorphous calcium phosphate and S.epidermidis bacteria by photoacoustic spectroscopy

The incorporation of biomaterials in human tissue requires methods to study the interface of the implant with the biological setting. We set out to study whether Photoacoustic spectroscopy with a higher level of sensitivity from the cantilever detector could simultaneously detect amorphous calcium phosphate and the bacteria. The calcium phosphate was synthesized, pressed into tablets, and then immersed in a solution containing S.epidermidis bacteria. Spectra were recorded after 1, 2, 3, 4 and 5 days. Deconvolution of the spectra at different time periods was able to separate bands belonging to the bacteria and carbonate bands arising from the calcium phosphate. This allowed the simultaneous identification of the biomaterial and bacteria. It was found that the PAS spectra could not identify the bacterial adhesion process due to the low concentration, but the amide peaks at 3 days inferred colonization of bacteria. This was confirmed by SEM that shoed an increase in the bacteria concentration. This is the first step in showing the simultaneous detection of calcium phosphate and bacteria by Photoacoustic spectroscopy, a method that required more research to show changes on the surface of the implant.