Figure 4.

Dynamic range of peptide. Ratiometric signal (i.e., Abs₆₀₀/Abs₅₂₀ at 3 h readout time) recorded from DPPS-AuNPs (2.8 nM, 120 μL) incubated with various amount of D₃F₀C₁ intact (a), D₃F₁C₁ intact (b), D₃F₂C₁ intact (c), D₃F₄C₁ intact (d), D₃F₂C₀ intact (e), D₃Y₂C₁ intact (f), and their corresponding proteolytic fragments (red). The charged polar head, di-homo aromatic amino acid, and cysteine are indispensable modules for peptide amphiphiles to colorimetrically measure protease. The determined lower limit of dynamic range for D₃F₂C₁, D₃F₄C₁, and D₃Y₂C₁ SLP is 36.6, 16.5, and 31.1 μM, respectively. Error bars = standard deviations (n = 2).