Isolation and Enrichment of Pathogens with a Surface-Modified Aluminium Chip for Raman Spectroscopic Applications

We developed a Raman‐compatible chip for isolating microorganisms from complex media. The isolation of bacteria is achieved by using antibodies as capture molecules. Due to the very specific interaction with the targets, this approach is promising for isolation of bacteria even from complex matrices such as body fluids. Our choice of capture molecules also enabled the investigation of samples containing yet unidentified bacteria, as the antibodies can capture a large variety of bacteria based on their analogue cell wall surface structures. The capability of our system is demonstrated for a broad range of different Gram‐positive and Gram‐negative germs. Subsequent identification is done by recording Raman spectra of the bacteria. Further, it is shown that classification with chemometric methods is possible. Casting for bacteria: A Raman‐compatible chip for isolating microorganisms from complex media is presented. The bacteria are enriched on the chip (see picture) by using antibodies against analogue cell wall surface structures of Gram‐negative and Gram‐positive bacteria as capture molecules. Raman measurements of single bacteria cells can be performed directly on the chip surface. Subsequent identification is achieved by comparing the single cell spectra to a database.