Chemoresponsive Nanofluidic Pump That Turns Off in the Presence of Lead Ion

There are many applications that require the integration of a pump and a chemical sensor so that the solution being pumped can be analyzed in real time for a specific chemical species and the flow adjusted according to the measured concentration of that species. We describe here an alternative strategy: a chemoresponsive pump where a single device acts as both the sensor and pump simultaneously. We demonstrate this concept with a nanofluidic Pb²⁺-responsive pump that uses electroosmotic flow as the pumping technology, and a Pb²⁺-binding ionophore that allows the device to selectively respond to Pb²⁺. The pump yields high flow rates at low Pb²⁺ concentrations (<1 μM), but flow rate decreases with concentrations above this threshold and ultimately goes to zero at concentrations above 100 μM.