AVS 53rd International Symposium
    Biomaterial Interfaces Tuesday Sessions
       Session BI2-TuM

Paper BI2-TuM3
Covalent Functionalization of Amorphous Carbon Thin Films: Materials Integration for Real-time Electromechanical Biosensing

Tuesday, November 14, 2006, 8:40 am, Room 2014

Session: Biodiagnostic Innovation
Presenter: B. Sun, University of Wisconsin at Madison
Authors: B. Sun, University of Wisconsin at Madison
P. Colavita, University of Wisconsin at Madison
H. Kim, University of Wisconsin at Madison
M. Marcus, University of Wisconsin at Madison
L.M. Smith, University of Wisconsin at Madison
R.J. Hamers, University of Wisconsin at Madison
Correspondent: Click to Email
One of the barriers to real-time biosensing is the need for development of interfaces that are compatible with microelectronics processing methods and that also provide the requisite selectivity and stability when exposed to biological environments. Previous studies have shown that diamond thin films exhibit excellent stability and selectivity. However, diamond deposition temperatures are typically high, limiting the ability to integrate with low-temperature materials. Amorphous carbon films can be deposited to form very thin coatings on a wide variety of materials. Here, we show that varpor-deposited amorphous carbon (a-C) can be covalently modified with functional organic layers in order to covalently tether biomolecules, yielding excellent interfaces with excellent selectivity and stability. We characterized functionalized films by X-ray Photoelectron Spectroscopy (XPS), Infrared Reflection-absorption Spectrocopy (IRRAS), and fluorescence techniques. Surfaces coated with amorphous carbon and covalently modified by single stranded DNA exhibit high biochemical selectivity when exposed to complementary vs. non-complementary sequences. Our results show that covalently modified amorphous carbon films display excellent chemical stability, superior to alternative substrates such as gold, glass, etc. We also demonstrate that the chemical treatments developed here are compatible with metal electrode structures, by integrating amorphous carbon thin films with Quartz Crystal Microbalance (QCM) sensor. We demonstrate real-time DNA detection on the carbon-coated QCM sensor. Moreover, the sensor surface can be regenerated multiple times with no detectable degradation of its performance. Our results demonstrate that amorphous carbon thin film forms a stable bio-interface with excellent microelectronic compatibility, that provides a suitable platform for integrated real-time bio-electrical sensing and existing microelectronic technology.