title: Acoustic wave biosensor for the detection of the breast and prostate cancer metastasis biomarker protein PTHrP.
abstract: There are currently no biosensors that are able to reliably detect the process of cancer metastasis. We describe the first label-free real-time ultra-high frequency acoustic wave biosensor prototype capable of detecting the breast and prostate cancer metastasis biomarker, parathyroid hormone-related peptide (PTHrP). Two different linkers - 11-trichlorosilyl-undecanoic acid pentafluorophenyl ester (PFP) and S-(11-trichlorosilyl-undecanyl)-benzothiosulfonate (TUBTS) - were used to immobilize whole anti-PTHrP antibodies and Fab' fragments to surfaces as biorecognition elements. The biosensor surfaces were optimized using X-ray photoelectron spectroscopy (XPS) and the ultra-high frequency electromagnetic piezoelectric acoustic sensor (EMPAS). One optimized whole antibody-based surface (PFP/protein G'/whole antibodies/ethanolamine) and one optimized Fab' fragment-based surface (TUBTS/Fab' fragments) were tested as biosensors. It was determined that an in-line injection of bovine serum albumin prior to analyte injection yielded the most minimally fouling surfaces. Each surface was tested with no mass amplification and with sandwich-type secondary antibody mass amplification. The whole antibody-based mass-amplified biosensor yielded the lowest limit of detection (61 ng/mL), highest sensitivity, and a linear range from 61 ng/mL to 100 μg/mL. However, the Fab' fragment-based biosensor displayed better regenerability as a loss of ~20% of the initial analyte signal intensity was observed with each subsequent injection. The whole antibody-based biosensor was only capable of producing an analyte signal in the first injection.
authors.affiliation: Department of Chemistry, University of Toronto, Toronto, ON, Canada M5S 3H6.
authors.forename: Victor
authors.initials: V
authors.lastname: Crivianu-Gaita
authors.affiliation: Department of Chemistry, University of Toronto, Toronto, ON, Canada M5S 3H6.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Aamer
authors.affiliation: Department of Chemistry, University of Toronto, Toronto, ON, Canada M5S 3H6.
authors.forename: Roy T
authors.initials: RT
authors.lastname: Posaratnanathan
authors.affiliation: Clinical Biochemistry, St. Michael's Hospital, Toronto, ON, Canada M5B 1W8.
authors.forename: Alexander
authors.initials: A
authors.lastname: Romaschin
authors.affiliation: Department of Chemistry, University of Toronto, Toronto, ON, Canada M5S 3H6. Electronic address: mikethom@chem.utoronto.ca.
authors.forename: Michael
authors.initials: M
authors.lastname: Thompson
mesh_terms: D000818:Animals; D055910:Antibodies, Immobilized / Q000737:chemistry / Q000276:immunology; D015374:Biosensing Techniques; D001943:Breast Neoplasms / Q000175:diagnosis*; D002417:Cattle; D005260:Female; D005464:Fluorobenzenes / Q000737:chemistry; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry / Q000276:immunology; D008297:Male; D009362:Neoplasm Metastasis; D044162:Parathyroid Hormone-Related Protein / Q000302:isolation & purification*; D010636:Phenols / Q000737:chemistry; D056951:Photoelectron Spectroscopy; D011471:Prostatic Neoplasms / Q000175:diagnosis*; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000276:immunology; D013016:Sound; D005466:Fluorocarbons
chemical_list: D055910:Antibodies, Immobilized; D005464:Fluorobenzenes; D007140:Immunoglobulin Fab Fragments; D044162:Parathyroid Hormone-Related Protein; D010636:Phenols; D012710:Serum Albumin, Bovine; C085539:2,3,4,5,6-pentafluorophenol; D005466:Fluorocarbons
keywords: Acoustic wave sensor; Antibodies; Biosensor; Cancer metastasis; Fab' fragments; Parathyroid hormone-related peptide