Fluorescent Single Wall Carbon Nanotube Microarray for Label-Free, Real-Time Biomolecular Detection and Binding Kinetic Analysis

A label-free, real-time, multiplexed detection method is desired for biomolecular sensing for their high sensitivity, the capacity for kinetic analysis and the short processing time. We present here an optical microarray platform based on fluorescent single wall carbon nanotubes that has integrated all these features. The microarray constructed are made of carbon nanotubes dispersed on the glass substrates and has a spot density of ~300 spots/cm². The nanotubes are non-covalently modified with a chelating group to immobilize Cu²⁺ ions and subsequently the histidine-tagged molecular recognition sites, in order to perform specific detection. As a proof-of-concept, a group of immunoglobulin-binding proteins is integrated as capture proteins and the sensor responses towards the antibody analytes are recorded in real-time. Not only does the microarray quantitatively respond to the analyte with various concentrations, it also provides rich binding kinetics of the analyte, using a few micro liter of sample. Moreover, when sensors modified with different capture proteins are integrated into the same microarray, they demonstrated specific recognition of the target analyte based on the interaction kinetics. We envision this platform will open a new path to examine multiple biomolecules with interaction kinetics, for bioanalytical applications such as pharmaceutical quality control and biomarker detections.