| AVS 57th International Symposium & Exhibition | |
| Biomaterial Interfaces | Friday Sessions |
| Session BI+MN-FrM |
| Session: | Sensors & Fluidics for Biomedical Applications |
| Presenter: | C.J. Stavis, University of Wisconsin-Madison |
| Authors: | R.J. Hamers, University of Wisconsin-Madison C.J. Stavis, University of Wisconsin-Madison A. Radadia, University of Illinois at Urbana-Champaign R. Brashir, University of Illinois at Urbana-Champaign J.A. Carlisle, Advanced Diamond Technologies W.P. King, University of Illinois at Urbana-Champaign H. Zeng, Advanced Diamond Technologies |
| Correspondent: | Click to Email |
The use proteins, such as antibodies, for the detection of target biological species in water supplies or with in situ medical diagnostics will require immobilization of these proteins on surfaces that resist non-specific adsorption and maintain the protein’s activity over time. Ultrananocrystalline diamond (UNCD) thin films are a promising material that may address several major challenges for the next generation of biosensors including detection of cellular mass loading, stability throughout multiple uses and regenerations of the sensor surface, and use at elevated temperatures.
We are currently investigating the chemical functionalization of diamond thin films with antibodies for selective recognition and detection of biological cells, using E. coli as a model system. Infrared spectroscopy and X-ray photoelectron spectroscopy measurements have been performed to characterize the covalent attachment of antibodies to the surface and to quantitatively characterize the antibody surface attachment via the N(1s) and S(2p) levels. To determine the factors controlling selectivity and stability, we have performed time-dependent cell capture studies and have correlated the time-dependent changes in cell capture efficiency with corresponding measurements of the surface composition. These measurements are used to establish whether long-term stability and selectivity for biomolecular recognition is limited by loss of the ligands directly linked to the diamond substrate, by removal of the biological layer, or by alteration of the antibody structure. Infrared measurements of the Amide I band is particularly useful in characterizing changes in the antibody secondary structures. These studies provide important fundamental insights into the chemical factors that control biological interactions at surfaces and provide guidance on efforts to make ultra-stable biological sensing platforms.