title: Biorecognition layer engineering: overcoming screening limitations of nanowire-based FET devices.
abstract: Detection of biological species is of great importance to numerous areas of medical and life sciences from the diagnosis of diseases to the discovery of new drugs. Essential to the detection mechanism is the transduction of a signal associated with the specific recognition of biomolecules of interest. Nanowire-based electrical devices have been demonstrated as a powerful sensing platform for the highly sensitive detection of a wide-range of biological and chemical species. Yet, detecting biomolecules in complex biosamples of high ionic strength (>100 mM) is severely hampered by ionic screening effects. As a consequence, most of existing nanowire sensors operate under low ionic strength conditions, requiring ex situ biosample manipulation steps, that is, desalting processes. Here, we demonstrate an effective approach for the direct detection of biomolecules in untreated serum, based on the fragmentation of antibody-capturing units. Size-reduced antibody fragments permit the biorecognition event to occur in closer proximity to the nanowire surface, falling within the charge-sensitive Debye screening length. Furthermore, we explored the effect of antibody surface coverage on the resulting detection sensitivity limit under the high ionic strength conditions tested and found that lower antibody surface densities, in contrary to high antibody surface coverage, leads to devices of greater sensitivities. Thus, the direct and sensitive detection of proteins in untreated serum and blood samples was effectively performed down to the sub-pM concentration range without the requirement of biosamples manipulation.
authors.affiliation: School of Chemistry, the Raymond and Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, Tel Aviv 69978, Israel.
authors.forename: Roey
authors.initials: R
authors.lastname: Elnathan
authors.forename: Moria
authors.initials: M
authors.lastname: Kwiat
authors.forename: Alexander
authors.initials: A
authors.lastname: Pevzner
authors.forename: Yoni
authors.initials: Y
authors.lastname: Engel
authors.forename: Larisa
authors.initials: L
authors.lastname: Burstein
authors.forename: Artium
authors.initials: A
authors.lastname: Khatchtourints
authors.forename: Amir
authors.initials: A
authors.lastname: Lichtenstein
authors.forename: Raisa
authors.initials: R
authors.lastname: Kantaev
authors.forename: Fernando
authors.initials: F
authors.lastname: Patolsky
mesh_terms: D055910:Antibodies, Immobilized; D057005:Bioengineering; D015415:Biomarkers / Q000097:blood; D015374:Biosensing Techniques / Q000295:instrumentation*; D001774:Blood Chemical Analysis / Q000295:instrumentation; D001798:Blood Proteins / Q000032:analysis / Q000276:immunology; D006801:Humans; D007140:Immunoglobulin Fab Fragments; D018625:Microscopy, Atomic Force; D036103:Nanotechnology; D053770:Nanowires; D009994:Osmolar Concentration; D045663:Quantum Dots; D012822:Silicon Dioxide; D014173:Transistors, Electronic; D020107:Troponin T / Q000097:blood
chemical_list: D055910:Antibodies, Immobilized; D015415:Biomarkers; D001798:Blood Proteins; D007140:Immunoglobulin Fab Fragments; D020107:Troponin T; D012822:Silicon Dioxide