title: Mid-IR biosensor: detection and fingerprinting of pathogens on gold island functionalized chalcogenide films.
abstract: Antibody (human IgG, anti-E. coli O157:H7, and anti-Salmonella) complexes on the surface of IR-transparent Ge-containing chalcogenide glass films were formed via thiol chemistry on 20-nm-thick gold islands. As a first step, the protocol was validated by monitoring fluorescently tagged targets to validate binding. FT-IR spectroscopy confirmed that the coating of the films with 20-nm gold did not have a significant effect on the propagation and penetration of IR evanescent waves through the film. The films functionalized with anti-E. coli O157:H7 and anti-Salmonella antibodies were used to detect E. coli O157:H7 and S. enteriditis through label-free IR fingerprinting. Highly selective detection of bacterial targets was achieved at both the species (E. coli vs. S. enteriditis) and strain level (E. coli O157:H7 vs E. coli K12). A mid-infrared approach could thus be used as a biosensor as well as a molecular fingerprinting tool.
authors.affiliation: Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Chenxu
authors.initials: C
authors.lastname: Yu
authors.forename: Ashtosh
authors.initials: A
authors.lastname: Ganjoo
authors.forename: H
authors.initials: H
authors.lastname: Jain
authors.forename: C G
authors.initials: CG
authors.lastname: Pantano
authors.forename: Joseph
authors.initials: J
authors.lastname: Irudayaraj
mesh_terms: D000907:Antibodies, Bacterial / Q000032:analysis; D015373:Bacterial Typing Techniques / Q000379:methods; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D018011:Chalcogens / Q000737:chemistry*; D019453:Escherichia coli O157 / Q000254:growth & development / Q000302:isolation & purification*; D005516:Food Microbiology; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007136:Immunoglobulins / Q000737:chemistry / Q000276:immunology; D012680:Sensitivity and Specificity; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods
chemical_list: D000907:Antibodies, Bacterial; D018011:Chalcogens; D007136:Immunoglobulins; D006046:Gold