Investigation of molybdenum-crosslinker interfaces for affinity based electrochemical biosensing applications

• Published in: Applied surface science 2018-04, Vol.436, p.441-450
• Main Authors: Kamakoti, Vikramshankar, Shanmugam, Nandhinee Radha, Tanak, Ambalika Sanjeev, Jagannath, Badrinath, Prasad, Shalini
• Format: Article
• Language: English
• Subjects: C-reactive protein; Cross-linkers; Molybdenum electrode; Point of care biosensors; Urine dip stick
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2017.12.026

[Display omitted] •Surface analysis of Molybdenum (Mo) with thiol and carbodiimide crosslinkers has been investigated.•Microscopy and spectroscopy was utilized to understand surface interactions of the crosslinker molecules on Mo.•Electrochemical characterization of the Mo-crosslinker interface was achieved through AC and DC methods.•Affinity based electrochemical biosensing of the Mo-crosslinker interface has been demonstrated with C-reactive protein. Molybdenum (Mo) has been investigated for implementation as an electrode material for affinity based biosensing towards devloping flexibe electronic biosensors. Treatment of the native oxide of molybdenum was investigated through two surface treatment strategies namely thiol and carbodiimide crosslinking methods. The binding interaction between cross-linker molecules and Mo electrode surface has been characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and optical microscopy. The efficacy of treatment of Mo with its native oxide using carbodiimide cross linking methodology was established. The carbodiimide cross-linking chemistry was found to possess better surface coverage and binding affinity with Molybdenum electrode surface when compared to thiol cross-linking chemistry.Electrochemical characterization of Mo electrode using Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltametry (CV) techniques was performed to evaluate the effect of ionic properties of solution buffer on the Mo electrode’s performance. Affinity based biosensing of C-Reactive Protein (CRP) has been demonstrated on a flexible nanoporous polymeric substrate with detection threshold of 100pg/ml in synthetic urine buffer medium. The biosensor has been evaluated to be developed as a dipstick based point of care device for detection of biomarkers in urine.