Fig. 2

Optimization and characterization of AuNRs based on plasmonic immunoassay for Myo detection. a Optimization of HRP and CTAB concentration in AuNRs based on plasmonic immunoassay. Different color lines represent different concentrations of CTAB, among which 6.25 mM CTAB and 1.5 μM HRP were preferred. b Optimization of time for H₂O₂ etching AuNRs, for which 1.5 μM HRP, 6.25 mM CTAB, and 100 μM H₂O₂ contained in citrate buffer (20 mM, pH 4.0) for 30 min was preferred. c LSPR spectrum of AuNRs with the addition of 50 μL of varying concentrations of H₂O₂. d–f TEM images of AuNRs etched by different concentrations of H₂O₂ (0 μM, 10 μM, and 100 μM) for 30 min. g LSPR shift of AuNRs under different concentrations of GOx. h LSPR spectrum of AuNRs in the presence of GOx-Ab2 at different dilution ratios. i LSPR spectrum shift of AuNRs in the direct plasmonic immunoassay coated with different concentrations of Myo. Each value presents the mean from three replicates