AVS 51st International Symposium
    Nanometer-scale Science and Technology Tuesday Sessions
       Session NS-TuA

Paper NS-TuA3
Fabrication of Nano-Structured Polymeric Surfaces for Bio-Sensing Devices

Tuesday, November 16, 2004, 2:00 pm, Room 213D

Session: Nanostructures and Biology
Presenter: P. Colpo, EU-JRC-IHCP, Italy
Authors: A. Valsesia, EU-JRC-IHCP, Italy
P. Colpo, EU-JRC-IHCP, Italy
T. Meziani, EU-JRC-IHCP, Italy
M. Manso, EU-JRC-IHCP, Italy
D. Gilliland, EU-JRC-IHCP, Italy
G. Ceccone, EU-JRC-IHCP, Italy
F. Rossi, EU-JRC-IHCP, Italy
Correspondent: Click to Email
The interaction between material surfaces with specific chemical functionalities and bio-molecules has been widely investigated in order to modulate the performances of bio-sensors and medical devices. When the dimensions of the interacting surface structures are comparable with those of the single protein molecules or small clusters of proteins, the bio-molecules absorption is considerably influenced both from the morphological and chemical point of view. This can be exploited for the orientation of specific binding sites between antigens and antibodies. In this work we develop a reliable technique to produce chemical contrast at sub-micrometric level through the fabrication of nano-island from Poly Acrylic Acid (PAA) film deposited onto anti-fouling substrates. First, a thin layer of PAA is deposited on the substrate by PE-CVD. Then, a layer of polystyrene colloidal nano-particles (200-500 nm) is deposited by spin coating. The nano-particles are then partially removed by oxygen plasma etching of the surface. The etching process is stopped before the complete etching of the nano-particles and the residual ones are removed by ultrasonic bath. Whereas unmasked PAA film is completely etched, nano-domes of as deposited-PAA (located under the nano-mask) are created evenly on the surface. The shape and the 2-D geometry of the resulting PAA nano-domes (lateral distribution, surface density) is controlled by the parameters of the spin casting process and by the wetting characteristic of deposited PAA. The chemistry of the PAA films was characterized by XPS, whilst the resulting nano-structured surfaces have been studied using AFM, SEM, SPM and SIMS in imaging mode. Then protein absorption test have been performed on the nanostrucured surfaces: the SEM and AFM characterization revealed that nanometric proteins clusters are selectively bond on the top of the domes, and not between them where the anti-fouling matrix repels the biomolecules.