A molecular-imprint nanosensor for ultrasensitive detection of proteins

Molecular imprinting is a technique for preparing polymer scaffolds that function as synthetic receptors 1 , 2 , 3 . Imprinted polymers that can selectively bind organic compounds have proven useful in sensor development 2 , 3 , 4 , 5 , 6 , 7 . Although creating synthetic molecular-imprinting polymers that recognize proteins remains challenging 8 , 9 , 10 , 11 , nanodevices and nanomaterials show promise in this area 12 , 13 , 14 . Here, we show that arrays of carbon-nanotube tips with an imprinted non-conducting polymer coating can recognize proteins with subpicogram per litre sensitivity using electrochemical impedance spectroscopy. We have developed molecular-imprinting sensors specific for human ferritin and human papillomavirus derived E7 protein. The molecular-imprinting-based nanosensor can also discriminate between Ca 2+ -induced conformational changes in calmodulin. This ultrasensitive, label-free electrochemical detection of proteins offers an alternative to biosensors based on biomolecule recognition. Carbon nanotube tips containing imprints within a non-conducting polymer coating can detect proteins with high sensitivity, offering a label-free alternative to sensors based on biomolecule recognition.