Synchrotron FTIR Light Reveals Signal Changes of Biofunctionalized Magnetic Nanoparticle Attachment on Salmonella sp.

The objective of this research was to develop new technology for possible noncontact, nondestructive, and culture-independent rapid detection of Salmonella using ferromagnetic nanoparticles. Light signal changes of particles, cells, and their reaction stages were investigated. Amino-functionalized ferromagnetic nanoparticles (amino-FMNs) were synthesized and modified by glutaraldehyde to crosslink the attachment of specific antibodies to the particles. The nanoparticle complex was used to capture, concentrate, and isolate Salmonella in a culture broth. Signal changes of the four stages of the nanoparticles-amino-glutaraldehyde-antibodies-Salmonella cell attachments were tracked with sensitive Synchrotron FTIR spectroscopy (SR-FTIR). The unique peaks from these four steps were identified. Results can be applied to develop a new test method or a new test/universal reader for rapid, nondestructive, and culture-independent detection of Salmonella in food products using IR spectroscopy at wave numbers 1454 cm-1, 1542 cm-1, and 1414 cm-1, respectively.