Figure 3.
Accurate, calibration-free measurement for cocaine and doxorubicin. The use of iNR to normalize E-AB sensor outputs (eq 4) produces excellent accuracy and precision. (A and B) Shown are cocaine-detecting sensors interrogated in undiluted blood serum and whole blood, respectively. Under the former conditions, sensor-estimated concentrations are accurate to within ±10% (i.e., the estimated concentration is within 10% of the spiked concentration) over the concentration range 20 to 800 μM (dark blue) and ±20% over the range 8 to 800 μM (light blue). Under the latter conditions, we observe likewise excellent accuracy, achieving accuracy within ±10% over the range 60 μM to 1 mM (dark blue) and ±20% over the range 20 μM to 2 mM (light blue). The dashed lines in all four panels represent ±20% error bands. (C and D) Shown are doxorubicin-detecting sensors interrogated in undiluted blood serum and whole blood, respectively. Under the former conditions, we achieved excellent accuracy within ±10% over the range 2.5 to 6 μM (dark blue) and 20% over the range 2 to 40 μM (light blue). Under the latter conditions, once again, these sensors produced excellent accuracy, achieving accuracy within ±10% over the range 10 to 60 μM (dark blue) and within ±20% over the range 4 to 100 μM (light blue). Additional data for individual sensors (illustrating, for example, the good precision of these sensors) are presented in Figures S8 and S14.