Fig. 11. SERS spectra of AuNFs-4-MBA@CS colloids after adding different heparin concentrations: (A) (a–n; 0.01, 0.1, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, and 10.0 ppm); (C) a serial spectra after adding 1.0 ppm heparin from 12 random times on the colloidal SERS-tags; (D) (a–f; 30, 40, 50, 60, 80, and 100 ppm). (B) and (E) linear plots of Raman intensity at 1587 cm⁻¹ against different heparin concentrations. Serial SERS spectra of AuNFs-MBA-4-MBA@CS with heparin concentration of 30 ppm from different times, and (F) Raman vibrational intensities of 4-MBA at 1587 cm⁻¹ after adding 1.0 ppm of heparin.