AVS 59th Annual International Symposium and Exhibition
    Nanometer-scale Science and Technology Tuesday Sessions
       Session NS+EN+GR-TuA

Paper NS+EN+GR-TuA2
Nanopatterning of SPRi Sensor Surfaces for Sub-Nanomolar Biomarker Detection

Tuesday, October 30, 2012, 2:20 pm, Room 12

Session: Nanomaterials in Two and Three Dimensions
Presenter: M.A. Parracino, Nanobiosciences Unit, JRC, Italy
Authors: M.A. Parracino, Nanobiosciences Unit, JRC, Italy
MJ. Perez Roldan, Nanobiosciences Unit, JRC, Italy
J. Hanus, Nanobiosciences Unit, JRC, Italy
V. Spampinato, Nanobiosciences Unit, JRC, Italy
G. Ceccone, Nanobiosciences Unit, JRC, Italy
P. Colpo, Nanobiosciences Unit, JRC, Italy
F. Rossi, Nanobiosciences Unit, JRC, Italy
Correspondent: Click to Email
In this work we report the detection of low-molecular weight biomarkers on two kinds of nanostructured surfaces by using a SPRi sensor. Nanopatterned surfaces are fabricated by combining functionalization and patterning techniques. Two different methods were used for the surface nanopatterning: electro-beam lithography (EBL) and colloidal lithography (CL). Maltose binding protein (MBP) and transthyretin (TTR) are respectively immobilized on the two types of nanopatterns and used as biological recognition elements.Chemical contrast adhesive/non adhesive at nanoscale has been created in order to control protein binding at nanoscale. Plasma deposited (PEO)-like film was used as passivation layer to prevent non-specific binding of protein in between the protein adhesives nano-areas. All the fabrication steps of both surfaces have been carefully controlled and analyzed using several techniques such as AFM, XPS, and SEM. The gold nanostructures were 185 nm width lines, for the patterned created with EBL, and holes of 250 nm in diameters for the pattern fabricated using CL.The gold grating surface made using EBL was functionalized with sugar via a thiol-linker. Maltose Binding Protein (MBP) was bound on sugar modified surface in order to develop a competitive assay for maltose detection. In this competitive assay, the protein binding on the sugar functionalized surface depends on the concentration of his free competitor in solution: by measuring the protein binding, it is possible to evaluate the concentration of the small molecule in solution.In the second methods, NTA functionalized nanoholes in PEO like background were fabricated and substequently activated with nickel (Ni II)for a selective immobilization of histidines tagged TTR, which underlies to a direct detection of Thyroxine 4 (T4).In both case, the biological intermediates, MBP and TTR, are selectively immobilized onto nanopatterned surfaces. The ligand protein binding on the nanostructure is higher than on the flat surface. The better ligand orientation and immobilization on the nanostructures results in analyte detection at sub-nanomolar concentration.The combination of nanopatterning features with the two different methods of detection presented in this work provides a description for a more generalized approach for the development of stable and reliable biosensor platforms for the detection of different small molecules having an high impact in environmental, and biomedical field.