Non-Faradaic electrochemical detection of protein interactions by integrated neuromorphic CMOS sensors

• Published in: Biosensors & bioelectronics 2008-05, Vol.23 (10), p.1503-1511
• Main Authors: Jacquot, Blake C., Muñoz, Nini, Branch, Darren W., Kan, Edwin C.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biomimetic Materials; Biosensing Techniques - instrumentation; Biosensing Techniques - methods; Biosensor; Biosensors; Biotechnology; Equipment Design; Equipment Failure Analysis; FET; Fundamental and applied biological sciences. Psychology; Methods. Procedures. Technologies; Microfluidic Analytical Techniques - instrumentation; Microfluidic Analytical Techniques - methods; MOSFET; Neural Networks (Computer); Protein Interaction Mapping - instrumentation; Protein Interaction Mapping - methods; Protein microarray; Reproducibility of Results; Semiconductors; Sensitivity and Specificity; Systems Integration; Various methods and equipments
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2008.01.006

Electronic detection of the binding event between biotinylated bovine serum albumen (BSA) and streptavidin is demonstrated with the chemoreceptive neuron MOS (CνMOS) device. Differing from the ion-sensitive field-effect transistors (ISFET), CνMOS, with the potential of the extended floating gate determined by both the sensing and control gates in a neuromorphic style, can provide protein detection without requiring analyte reference electrodes. In comparison with the microelectrode arrays, measurements are gathered through purely capacitive, non-Faradaic interactions across insulating interfaces. By using a (3-glycidoxypropyl)trimethoxysilane (3-GPS) self-assembled monolayer (SAM) as a simple covalent link for attaching proteins to a silicon dioxide sensing surface, a fully integrated, electrochemical detection platform is realized for protein interactions through monotone large-signal measurements or small-signal impedance spectroscopy. Calibration curves were created to coordinate the sensor response with ellipsometric measurements taken on witness samples. By monitoring the film thickness of streptavidin capture, a sensitivity of 25ng/cm2 or 2Å of film thickness was demonstrated. With an improved noise floor the sensor can detect down to 2ng/(cm2mV) based on the calibration curve. AC measurements are shown to significantly reduce long-term sensor drift. Finally, a noise analysis of electrochemical data indicates 1/fα behavior with a noise floor beginning at approximately 1Hz.