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

Abstract

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.

The application of Raman spectroscopy for the detection and identification of microorganisms

“…Thus, special attention should be paid to both the isolation procedures and the data evaluation steps. Especially the analysis of single bacterial cells from real sample matrices requires a destruction‐free isolation step prior to the Raman spectroscopic identification to ensure that the single organisms are put in the laser excitation focus in an unobstructed manner …”

Discrimination of clostridium species using a magnetic bead based hybridization assay

“…[13] Compared to chip-based methods [14][15][16][17][18][19][20][21][22] the use of magnetic particles benefits from improved hybridization kinetics. By employing biotin-labeled primers for the amplification of target DNA with polymerase chain reaction (PCR), the PCR products can bind directly onto the magnetic beads.…”

IR and Raman Spectroscopy for Pathogen Detection

“…For example, density gradient centrifugation [176] and isolation using antibody-modified substrates to catch bacteria [178] have been shown to be suitable and Raman-compatible approaches. Also, the combination of Raman microspectroscopy with microscopic images and fluorescence imaging allows the localization of bacteria and their differentiation from abiotic particles.…”