Different ratios of 1 mM fetuin and 1 mM asialofetuin in 100 mM MES buffer (pH 5) were mixed at different ratios to prepare a titration curve ranging from 0% to 100% of 1 mM fetuin, with 20% intervals. The glycoprotein mixtures were spotted on the BA-coated nanopapers and incubated at room temperature for 1 hour. The nanopaper was then dried in an oven at 75℃ for 5 minutes and measured by Raman spectrometer using the same protocol as above.