Fig. 8.

Fluorescence change due to the action of penicillinase ($\mathrm{\beta }$-lactamase) on first and second generation probes. 10 μM first and second generation probes were incubated with penicillinase enzyme (final concentration $5\mathrm{U}/\mathrm{ml}$ in each reaction) or plain PBS, respectively. The fluorescence change over time was monitored for 60 min and is presented as bar graphs. The $y$-axis shows the measured fluorescence change rate in relative fluorescence units (RFU)/min, which reflects the probe cleavage in respective reactions.