Inkjet Dispense Sers (Id-Sers) For Quantitative Analysis And Bacterial Detection

Surface-Enhanced Raman Scattering (SERS) has emerged as a powerful technique for sensitive detection of a wide variety of substances including drugs, pesticides, and biological molecules. Despite its potential as a broadly applicable detection strategy, quantitative studies using SERS have been hindered by substrate performance variability. We recently reported an in situ calibration method that merges inkjet dispense with SERS (ID-SERS), yielding quantitative measurements with Relative Standard Deviation (RSD) values below 2%. In this work, we provide a conceptual review of ID-SERS, highlighting the advantages of using inkjet to pattern microdroplets (28 pL) on the surface of a single SERS sensor and produce standard curves on a single SERS sensor. We subsequently explore the application potential of ID-SERS by producing ID-SERS response curves for adenine and pyocyanin, two well-known metabolites that are biomarkers for bacterial detection. We then report preliminary results that suggest that ID-SERS can be harnessed to detect time-dependent changes in the spectra of metabolites released by bacteria under nutrient-deprived conditions. The ability to use ID-SERS to monitor the time-evolution in the SERS spectra of nutrient-deprived bacteria has implications for developing a SERS-based method for antibiotic susceptibility testing. More generally, we believe that the benefits afforded by ID-SERS will facilitate the development of reproducible plasmonic sensing for real-world applications.