A microfluidic aptasensor integrating specific enrichment with a graphene nanosensor for label-free detection of small biomolecules

We here present a microfluidic aptasensor that integrates aptamer-based selective analyte enrichment, isocratic elution and conductance-based graphene nanosensing, achieving sensitive and label-free detection of small biomolecules. An aptamer specific to a target analyte is immobilized on microbeads for selective enrichment and isocratic elution of the analyte. A conductance-based graphene nanosensor using a competitive assay format achieves label-free detection, with a high sensitivity due to surface binding-induced changes in carrier concentration in the bulk of graphene. Experimental results show that our integrated device is capable of detecting arginine vasopressin (AVP), a small peptide, at clinically relevant low concentrations (1-500 pM).