Figure 3.

The sensors are selective and specific. For example, the T20 sensor shown here (A) exhibits little loss in signal when transferred from simple buffer solution to undiluted whole milk and (B, C) performs well when challenged in this complex sample matrix. Specifically, the signal gain observed in undiluted whole milk is within the error of that seen in simple buffer, when challenging the sensors with 1 mM melamine. The sensor is also specific, responding to melamine but not (<5% signal change, which is within normal sensor-to-sensor variation for these hand-fabricated devices) to its molecular analogue, cyanuric acid. Of note, sensors built from the other two T-rich sequences we have explored exhibit similar selectivity (Figure S1).