On-chip approach for traceable quantification of biomarkers based on isotope-dilution surface-enhanced Raman...

We present an on-chip approach for the quantification of biomarkers based on isotope-dilution surface-enhanced Raman scattering (IDSERS). The full procedure was realized on a few square millimetres of a SERS-active substrate, covered with either lithographically engineered gold nanotriangles or silver nanospheres generated by galvanic displacement deposition. The use of certified reference materials combined with the ID principle ensures traceability of the quantitation to SI units. A series of substance spots was deposited onto the SERS active area and measured one by one in fast sequence. The SERS spectra were used to generate and validate a PLS model and also to predict the creatinine concentration of an unknown serum sample.