AVS 53rd International Symposium
    Biomaterial Interfaces Tuesday Sessions
       Session BI+MN-TuA

Paper BI+MN-TuA8
Biomolecule Assembly and Functionality in Completely Packaged Microfluidic Devices

Tuesday, November 14, 2006, 4:20 pm, Room 2014

Session: Microfluidics, MEMS, Lab-on-Chip
Presenter: X. Luo, University of Maryland
Authors: X. Luo, University of Maryland
J.J. Park, University of Maryland
H. Yi, University of Maryland
R. Ghodssi, University of Maryland
G.W. Rubloff, University of Maryland
Correspondent: Click to Email
We demonstrate in situ biomolecule assembly at readily addressable sites in a completely packaged bioMEMS device. Chitosan's pH responsive properties for site-selective electrodeposition and its amine functionality for biomolecular conjugation allow this aminopolysaccharide to be employed as the platform for electric signal-guided assembly of biomolecules onto conductive inorganic surfaces from aqueous environment, preserving the activity of biomolecules being assembled. Our completely packaged microfluidic device features consistently leak-free sealing, fluidic inputs/outputs for solution transport, electrical ports to guide the assembly onto selective sites, and simple in situ and ex situ examination of the assembly procedures within the channel for 4 different cases. (1)We electrodeposited fluorescently labeled chitosan at specific electrodes to directly demonstrate the potential of biomolecule assembly inside a microfluidic channel. (2)We assembled fluorescent marker molecules (fluorescein and green fluorescent protein (GFP)) onto an electrodeposited chitosan scaffold to illustrate the in situ biomolecule assembly at readily addressible sites, with GFP's biofunctionality retained through the assembly process. (3)We covalently assembled probe single-stranded DNA onto an electrodeposited chitosan scaffold, then exposed the scaffold to mismatching and matching fluorescently labeled target DNA to show the ability to assemble probe species and to detect sequence-specific hybridization through sequences of reactions. (4)We compared fluorescence images to post-process profilometer measurements, confirming the relation between the active chitosan sites and the observed fluorescence. These results demonstrate the first signal-directed chitosan-mediated in situ biomolecule assembly in the microfluidic environment after complete packaging of the bioMEMS device, preserving the biological activities of assembled biomolecules.