Acoustic wave biosensor for the detection of the breast and prostate cancer metastasis biomarker protein PTHrP

• Published in: Biosensors & bioelectronics 2016-04, Vol.78, p.92-99
• Main Authors: Crivianu-Gaita, Victor, Aamer, Mohamed, Posaratnanathan, Roy T., Romaschin, Alexander, Thompson, Michael
• Format: Article
• Language: English
• Subjects: Acoustic wave sensor; Acoustics; Amplification; Animals; Antibodies; Antibodies, Immobilized - chemistry; Antibodies, Immobilized - immunology; Biosensing Techniques; Biosensor; Biosensors; Breast; Breast Neoplasms - diagnosis; Cancer; Cancer metastasis; Cattle; Fab' fragments; Female; Fluorobenzenes - chemistry; Fragments; Humans; Immunoglobulin Fab Fragments - chemistry; Immunoglobulin Fab Fragments - immunology; Male; Neoplasm Metastasis; Parathyroid hormone-related peptide; Parathyroid Hormone-Related Protein - isolation & purification; Phenols - chemistry; Photoelectron Spectroscopy; Prostate; Prostatic Neoplasms - diagnosis; Serum Albumin, Bovine - chemistry; Serum Albumin, Bovine - immunology; Sound
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2015.11.031

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 (61ng/mL), highest sensitivity, and a linear range from 61ng/mL to 100μg/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. •Cancer metastasis is hard to detect to due to rare circulating tumor cells (CTCs).•Parathyroid hormone-related peptide (PTHrP) is a more reliable metastasis biomarker.•Biosensor surfaces were optimized using whole antibodies and Fab' fragments.•The whole antibody mass-amplified sensor showed the lowest CLoD of 61ng/mL.•First biosensor prototype for detecting breast and prostate cancer metastasis.