Single-walled carbon nanotube-based chemiresistive affinity biosensors for small molecules: ultrasensitive glucose detection.

We report for the first time single-walled carbon nanotube (SWNT)-based chemiresistive affinity sensors for highly sensitive and selective detection of small and/or weakly charged or uncharged molecules using a displacement format. The detection of glucose, a small, weakly charged molecule, by displacement of plant lectin (concavalin A) bound to a polysaccharide (dextran) immobilized on SWNTs with picomolar sensitivity and selectivity over other sugars and human serum proteins is demonstrated as a proof of concept.