Facile fabrication of flexible glutamate biosensor using direct writing of platinum nanoparticle-based nanocomposite ink

• Published in: Biosensors & bioelectronics Vol. 131; pp. 257 - 266
• Main Authors: Nguyen, Tran N.H., Nolan, James K., Park, Hyunsu, Lam, Stephanie, Fattah, Mara, Page, Jessica C., Joe, Hang-Eun, Jun, Martin B.G., Lee, Hyungwoo, Kim, Sang Joon, Shi, Riyi, Lee, Hyowon
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15-04-2019
• Subjects: Additive manufacturing; Biosensing Techniques; Biosensor; Direct ink writing; Electrochemical Techniques; Enzymes, Immobilized - chemistry; Glucose - chemistry; Glutamate; Glutamate Dehydrogenase - chemistry; Glutamic Acid - chemistry; Glutamic Acid - isolation & purification; Humans; Hydrogen Peroxide - chemistry; Implantable; Limit of Detection; Nanoparticles - chemistry; Nanotubes, Carbon - chemistry; Platinum - chemistry; Rapid prototyping; Spinal cord injury; Biosensor; Direct ink writing; Rapid prototyping; Additive manufacturing; Glutamate; Implantable; Spinal cord injury
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2019.01.051

Glutamate excitotoxicity is a pathology in which excessive glutamate can cause neuronal damage and degeneration. It has also been linked to secondary injury mechanisms in traumatic spinal cord injury. Conventional bioanalytical techniques used to characterize glutamate levels in vivo, such as microdialysis, have low spatiotemporal resolution, which has impeded our understanding of this dynamic event. In this study, we present an amperometric biosensor fabricated using a simple direct ink writing technique for the purpose of in vivo glutamate monitoring. The biosensor is fabricated by immobilizing glutamate oxidase on nanocomposite electrodes made of platinum nanoparticles, multi-walled carbon nanotubes, and a conductive polymer on a flexible substrate. The sensor is designed to measure extracellular dynamics of glutamate and other potential biomarkers during a traumatic spinal cord injury event. Here we demonstrate good sensitivity and selectivity of these rapidly prototyped implantable biosensors that can be inserted into a spinal cord and measure extracellular glutamate concentration. We show that our biosensors exhibit good flexibility, linear range, repeatability, and stability that are suitable for future in vivo evaluation.
•Commercially available nanomaterials mixed to create printable biosensor.•Implantable glutamate biosensors fabricated using direct writing.•Platinum nanoparticle-based devices performed as well as MEMS-fabricated biosensors.•Amperometry at low potential significantly improved the sensitivity and selectivity.•Ex vivo glutamate monitoring demonstrated using rat spinal cord sections.