Fig. 3.

Model-predicted behavior of synthetic biomarkers. Key parameters within the mathematical model were varied to explore how they affect urine signals. (A) Urine signals decrease as background protease activities in blood ($E_{n.s.}^{blood}$, $k_{cat}^{blood}$) are decreased (n = 3; error bars, s.d.). (B) Normalized urine signals (Tumor – control) increased as $k_{cat}^{blood}$ was decreased. Predicted response of the urine signal as circulation time $t_{1/2}$ (C), dose $N$ (D), scaffold transport into tumor $k_{tumor}^{NP}$ (E), concentration of enzymes $E_{MMP9}$ (F), and rate of catalysis $k_{cat}^{MMP9}$ (G) were increased. Except for dose of NPs, all increases in the parameters resulted in increased detection signals. Arrows show direction of trend.