Time-Resolved Electrochemical Surface-Enhanced Resonance Raman Spectroscopy Double-Fingerprint for the Detection of Pseudomonas aeruginosa.

Bacterial detection constitutes a significant area of contemporary research. A particularly compelling strategy for unequivocal bacterial identification involves measuring specific biomarkers. In the context of bacteria responsible for infections, the development of rapid and highly sensitive analytical detection methods is crucial for timely application of necessary medical treatments. Time-resolved electrochemical surface-enhanced Raman scattering (TR-EC-SERS) has emerged as a promising technique for addressing these challenges. This work presents a TR-EC-SERS-based methodology for the detection of pyocyanin, a biomarker of Pseudomonas aeruginosa. TR-EC-SERS allows the detection of pyocyanin at picomolar concentrations in synthetic samples and nanomolar concentrations in complex media. In fact, pyocyanin exhibits pronounced surface-enhanced resonance Raman scattering (SERRS) characteristics, which enhance the sensitivity of the analytical method. Moreover, time-resolved electrochemical surface-enhanced resonance Raman scattering (TR-EC-SERRS) provides a double fingerprint response based on the Raman spectrum and the shape of the corresponding voltaRamangram, which depends on the electrochemical response of pyocyanin, showing a very high selectivity for pyocyanin and demonstrating the advantages of this technique for obtaining reliable information in the study of complex chemical systems. Furthermore, TR-EC-SERRS facilitates the monitoring of pyocyanin secretion during the growth of P. aeruginosa in a culture medium, providing significant insights into this process. A simple pretreatment of bacterial samples based on the use of ether is proposed, which inactivates P. aeruginosa and facilitates its subsequent analysis.