Fig. 4

Verification of FITC labeled LDL peptides binding to PLA-coated MSNPs (only 1:0.25 showed) using EDC/NHS method. a No fluorescence observed from PMSNPs without the peptide. b MSNPs with PLA and fluorescent LDL peptide coating (1:0.25) shows strong fluorescence intensity, which is stable after multiple centrifugation washes. c The MSNPs with PLA coating passively adsorb LDL peptides in the absence of EDC/NHS and showed weak fluorescence intensity, and the fluorescent LDL peptides can be washed off by PBS (d). e Quantification of fluorescence intensity of PMSNPs in the absence or presence of FITC-LDL peptides with or without EDC/NHS. *p < 0.05 vs FITC-peptides + PMSNPs in presence of EDC/NHS; ^#p < 0.05 vs FITC-labeled peptides + PMSNPs in absence of EDC/NHS