Detection of Bacillus anthracis Spores Using Peptide Functionalized SERS-Active Substrates

Figure 4

(A) RS of 0.55 mg/mL DPA in 1 N KOH in a plain glass capillary (intensity multiplied by 3.5 to match SERS intensity of 1000 cm⁻¹ peak of (B)). Spectral conditions: 300 mW of 785 nm irradiation at the sample, 25 min acquisition time, 8 cm⁻¹ resolution. SERS of (B) B. anthracis-Sterne, (C) B. cereus, and (D) B. subtilis all at a concentration of 10⁹ spores/mL on the B. anthracis-Sterne peptide functionalized SERS-active substrate after a 15-min incubation period, a wash step, and the addition of acetic acid. Spectral conditions for (B)–(D) as in Figure 2.