Use of a porous silicon–gold plasmonic nanostructure to enhance serum peptide signals in MALDI-TOF analysis

•Porous silicon–gold nanoparticle (PSi–GNP) hybrid was used as new type of MALDI chip.•The PSi–GNP can greatly enhance MS signal intensity in serum peptide detection.•The plasmon and charge transfer effect of PSi–GNP lead to the MS signal enhancement.•Interference from large proteins can be eliminated with the PSi–GNP chip.•High quality serum peptide fingerprint can be acquired with the chip.

Small peptides in serum are potential biomarkers for the diagnosis of cancer and other diseases. The identification of peptide biomarkers in human plasma/serum has become an area of high interest in medical research. However, the direct analysis of peptides in serum samples using mass spectrometry is challenging due to the low concentration of peptides and the high abundance of high-molecular-weight proteins in serum, the latter of which causes severe signal suppression. Herein, we reported that porous semiconductor-noble metal hybrid nanostructures can both eliminate the interference from large proteins in serum samples and significantly enhance the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) yields of peptides captured on the nanostructure. Serum peptide fingerprints with high fidelity can be acquired rapidly, and successful discrimination of colorectal cancer patients based on peptide fingerprints is demonstrated.

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