A high throughput nanohole-array based system to monitor multiple binding events in real time

ANYL 144

Jin Ji, jin_ji@hms.harvard.edu and Dale N. Larson. Technology and Engineering Center, Harvard Medical School, 240 longwood ave, BCMP SGM060, Boston, MA 02115
We have developed an integrated label-free biosensing system that is able to monitor multiple biomolecular binding events based on changes in the intensity of extraordinary optical transmission (EOT) through nanohole arrays. The core of the system is a sensing chip that consists of multiple nanohole arrays embedded in an optically thick gold film, where each array functions as an independent sensor. For demonstration purposes, sensing chips containing 25 nanohole array sensors were studied for their use in simultaneous detection, although the sensing chip could fit up to 10,000 sensors. The integrated system includes a flow cell to encase the sensing chip and maintain a stable temperature, a laser light source and a charge-coupled detector to allow real time monitoring, and a syringe pump and injector for sample injection. Using this system, we successfully monitored 25 separate binding events between glutathione S-transferase (GST) and anti-GST simultaneously in real time with high spatial resolution and sensitivity. The system responds to binding events in a concentration-dependant manner. The linear dynamic range of the system with good sensitivity is found to be from 13 nM to 290 nM anti-GST. The system offers high throughput and sensitivity, fully taking advantage of the sensitive optical response and easy integration of EOT intensity-based nanohole array sensors.