title: Determination of surface concentrations of individual molecule-layers used in nanoscale biosensors by in situ ATR-FTIR spectroscopy.
abstract: For the development of nanowire sensors for chemical and medical detection purposes, the optimal functionalization of the surface is a mandatory component. Quantitative ATR-FTIR spectroscopy was used in situ to investigate the step-by-step layer formation of typical functionalization protocols and to determine the respective molecule surface concentrations. BSA, anti-TNF-α and anti-PSA antibodies were bound via 3-(trimethoxy)butylsilyl aldehyde linkers to silicon-oxide surfaces in order to investigate surface functionalization of nanowires. Maximum determined surface concentrations were 7.17 × 10(-13) mol cm(-2) for BSA, 1.7 × 10(-13) mol cm(-2) for anti-TNF-α antibody, 6.1 × 10(-13) mol cm(-2) for anti-PSA antibody, 3.88 × 10(-13) mol cm(-2) for TNF-α and 7.0 × 10(-13) mol cm(-2) for PSA. Furthermore we performed antibody-antigen binding experiments and determined the specific binding ratios. The maximum possible ratio of 2 was obtained at bulk concentrations of the antigen in the μg ml(-1) range for TNF-α and PSA.
authors.affiliation: Institute of Biophysical Chemistry, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.
authors.forename: Manuel
authors.initials: M
authors.lastname: Punzet
authors.forename: Dieter
authors.initials: D
authors.lastname: Baurecht
authors.forename: Franz
authors.initials: F
authors.lastname: Varga
authors.forename: Heidrun
authors.initials: H
authors.lastname: Karlic
authors.forename: Clemens
authors.initials: C
authors.lastname: Heitzinger
mesh_terms: D000327:Adsorption; D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D002417:Cattle; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D020099:Coated Materials, Biocompatible / Q000032:analysis / Q000737:chemistry; D006801:Humans; D008954:Models, Biological; D036103:Nanotechnology / Q000379:methods*; D053770:Nanowires / Q000737:chemistry*; D009994:Osmolar Concentration; D011506:Proteins / Q000032:analysis* / Q000493:pharmacokinetics; D012710:Serum Albumin, Bovine / Q000032:analysis / Q000493:pharmacokinetics; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013499:Surface Properties; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000493:pharmacokinetics
chemical_list: D020099:Coated Materials, Biocompatible; D011506:Proteins; D014409:Tumor Necrosis Factor-alpha; D012710:Serum Albumin, Bovine