Gold-coated carbon nanotube electrode arrays: Immunosensors for impedimetric detection of bone biomarkers

• Published in: Biosensors & bioelectronics 2016-03, Vol.77, p.580-588
• Main Authors: Ramanathan, Madhumati, Patil, Mitali, Epur, Rigved, Yun, Yeoheung, Shanov, Vasselin, Schulz, Mark, Heineman, William R., Datta, Moni K., Kumta, Prashant N.
• Format: Article
• Language: English
• Subjects: Animals; Biomarkers; Biomarkers - metabolism; Biosensors; Bone and Bones - metabolism; Bone marker; Bones; C-terminal telopeptide; Carbon nanotubes; CNT; Coated Materials, Biocompatible - chemical synthesis; Collagen Type I - metabolism; Conductometry - instrumentation; Electrochemical impedance spectroscopy; Electrodes; Equipment Design; Equipment Failure Analysis; Gold - chemistry; Gold nanoparticles; Humans; Immunosensor; Impedance; Metabolism; Microelectrodes; Nanotubes, Carbon - chemistry; Nanotubes, Carbon - ultrastructure; Peptides - metabolism; Reproducibility of Results; Sensitivity and Specificity; Sensors; Tissue Array Analysis - instrumentation
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2015.10.014

C-terminal telopeptide (cTx), a fragment generated during collagen degradation, is a key biomarker of bone resorption during the bone remodeling process. The presence of varying levels of cTx in the bloodstream can hence be indicative of abnormal bone metabolism. This study focuses on the development of an immunosensor utilizing carbon nanotube (CNT) electrodes coated with gold nanoparticles for the detection of cTx, which could ultimately lead to the development of an inexpensive and rapid point-of-care (POC) tool for bone metabolism detection and prognostics. Electrochemical impedance spectroscopy (EIS) was implemented to monitor and detect the antigen–antibody binding events occurring on the surface of the gold-deposited CNT electrode. Type I cTx was used as the model protein to test the developed sensor. The sensor was accordingly characterized at various stages of development for evaluation of the optimal sensor performance. The biosensor could detect cTx levels as low as 0.05ng/mL. The feasibility of the sensor for point-of-care (POC) applications was further demonstrated by determining the single frequency showing maximum changes in impedance, which was determined to be 18.75Hz. •Biosensor development on gold coated vertically aligned carbon nanotubes (CNT).•Impedance based detection of various c-terminal telopeptide concentrations.•Single frequency of 18.75Hz is used for successful and rapid analyte detection.•Biosensor sensitivity is also maintained with introduction of protein interference.