Issue 20, 2010

High efficiency amine functionalization of cycloolefinpolymer surfaces for biodiagnostics


Point-of-care (POC) diagnostics implementing microfluidic technology on single use disposable plastic chips has potential applications in personalized medicine, clinical diagnostics and global health. However, the challenges in commercializing POC devices must be addressed. Immobilization of biomolecules to plastic chips through appropriate surface functionalization is a key issue for the fabrication of new generation biomedical diagnostic devices. The most important requirements for a practicable surface functionalization process are speed, control and reliability. Plasma-based methods can meet these criteria. A single step, solventless, ecofriendly and high throughput nature of plasma processing makes them highly attractive. Here we demonstrate the efficient surface functionalization of a next-generation biosensor material, a chemically inert cycloolefin polymer (COP). The plasma formation of a surface-bound aminated siloxane network from mixed aminopropyltriethoxysilane and ethylenediamine precursors allowed us to form a well-adherent film with an exceptionally high degree of amine functionalization. We deduce that the siloxane was the critical component for radical insertion into the COP and for building a stable network to support the reactive amine functionalities. We present a full physical and chemical characterization of the films, including a detailed study of their swelling in water, using an array of surface analytical techniques: X-ray photoelectron spectroscopy, X-ray reflectivity, reflection infra-red spectroscopy, atomic force microscopy (AFM) and fluorophore binding reactions. We demonstrate an original approach for qualitatively analyzing the distribution of amine functionalities by counting surface-bound functionalized silica nanoparticles in the AFM. The relative contributions from covalent (specific) and non-covalent (non-specific) reaction chemistry assessed using 3′-fluorescein-labeled ssDNA attachment showed that the non-specific binding could be reduced significantly according to the particular feed gas mixture used to prepare the coating. A reaction mechanism has been proposed for the deposition of amine functionalities on COP plastic and also for enhancing the amine functionalities that affect the non-specific binding significantly.

Graphical abstract: High efficiency amine functionalization of cycloolefin polymer surfaces for biodiagnostics

Supplementary files

Article information

Article type
07 Dec 2009
04 Mar 2010
First published
13 Apr 2010

J. Mater. Chem., 2010,20, 4116-4127

High efficiency amine functionalization of cycloolefin polymer surfaces for biodiagnostics

R. P. Gandhiraman*, C. Volcke, V. Gubala, C. Doyle, L. Basabe-Desmonts, C. Dotzler, M. F. Toney, M. Iacono, R. I. Nooney, S. Daniels, B. James and D. E. Williams, J. Mater. Chem., 2010, 20, 4116 DOI: 10.1039/B925737C

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