Surface enhanced Raman spectroscopic monitor of P. acnes lipid hydrolysis in vitro

Surface enhanced Raman spectroscopy (SERS) at a silver microelectrode was used to monitor bacterial hydrolysis of triglycerides in lipid mixtures that model sebaceous gland secretions. Mixtures of wax esters, squalene, triolein, and triisostearin were used as model skin secretions. The transformation was followed in vitro as changes in the SERS caused by hydrolysis of triglyceride to fatty acid. The fatty acid was adsorbed as its carboxylate, which is readily identified by the characteristic band at ca. 1395 cm-1. Co-adsorption of propionate was also observed. The technique can also confirm the presence of bacteria by detection of short chain carboxylic acids released as products of fermentation during the growth of these cells.—Weldon, M. K., M. D. Morris, A. B. Harris, and J. K. Stoll. Surface enhanced Raman spectroscopic monitor of P. acnes lipid hydrolysis in vitro.