Enhancing surface functionality of reduced graphene oxide biosensors by oxygen plasma treatment for Alzheimer's disease diagnosis

• Published in: Biosensors & bioelectronics Vol. 92; pp. 610 - 617
• Main Authors: Chae, Myung-Sic, Kim, Jinsik, Jeong, Dahye, Kim, YoungSoo, Roh, Jee Hoon, Lee, Sung Min, Heo, Youhee, Kang, Ji Yoon, Lee, Jeong Hoon, Yoon, Dae Sung, Kim, Tae Geun, Chang, Suk Tai, Hwang, Kyo Seon
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15.06.2017
• Subjects: Alzheimer disease; Alzheimer Disease - diagnosis; Alzheimer's diseases; Amyloid beta-Peptides - analysis; antibodies; Antibodies, Immobilized - chemistry; Biosensing Techniques - instrumentation; Biosensor; biosensors; disease diagnosis; electrical properties; Equipment Design; Exosome; Exosomes - chemistry; graphene oxide; Graphite - chemistry; Humans; Immunoassay - instrumentation; nanomaterials; Nanostructures - chemistry; Oxidation-Reduction; Oxides - chemistry; oxygen; Oxygen - chemistry; Oxygen plasma treatment; patients; peptides; Plasma Gases - chemistry; Reduced graphene oxide; Sensitivity and Specificity; Surface Properties; topography; Reduced graphene oxide; Exosome; Biosensor; Alzheimer's diseases; Oxygen plasma treatment
• ISSN: 0956-5663; 1873-4235; 1873-4235
• DOI: 10.1016/j.bios.2016.10.049

We performed oxygen plasma treatment on reduced graphene oxide (rGO) to improve its surface reactivity with respect to biomolecular interactions. Oxygen-plasma-treated rGO surfaces were employed as reactive interfaces for the detection of amyloid-beta (Aβ) peptides, the pathological hallmarks of Alzheimer's disease (AD), as the target analytes. By measuring the changes in electrical characteristics and confirmation through topographic analysis, the oxygen-plasma-treated rGO sensors had enhanced surface functionality for better antibody immobilization and sensing performance, with a 3.33-fold steeper slope for the electrical responses versus analyte concentration curve (logarithmic scale) compared to the untreated. The elicited biomolecular reactivity of the rGO surfaces with the oxygen plasma treatment remained at 46–51% of the initial value even after aging for 6h in ambient conditions. This phenomenon was also confirmed by pretreating the rGO surfaces with a blocking agent and subsequently subjecting them to antibody immobilization. Finally, the feasibility of the oxygen-plasma-treated rGO sensors as a diagnostic tool was evaluated with clinical samples of neural-derived exosomal Aβ peptides extracted from apparent AD patients and normal controls (NC). In contrast to the untreated sensors (p=0.0460), the oxygen-plasma-treated rGO sensors showed a significant p-value in the identification of clinical samples of AD and NC subjects (p<0.001). These results suggest that oxygen plasma treatment improves sensor performance without complicated fabrication procedures and should aid in the development of novel diagnostic tools based on carbon nanomaterials. •Oxygen plasma treatment improved the biological functionality of reduced graphene oxide (rGO) biosensors.•The effects of oxygen plasma treatment on rGO biosensors were investigated.•Oxygen-plasma-treated rGO biosensors showed 3.33-fold greater responses in target specific recognition.•Identification of Alzheimer's disease patients and normal control was performed by use of exosomal samples.•The oxygen-plasma-treated rGO biosensors showed the feasibility of a diagnostic tool for Alzheimer's Disease.