A Sensitive and Fast Fiber Bragg Grating-Based Investigation of the Biomechanical Dynamics of In Vitro Spinal Cord Injuries

• Published in: Sensors (Basel, Switzerland) Vol. 21; no. 5; p. 1671
• Main Authors: Mishra, Satyendra Kumar, Mac-Thiong, Jean-Marc, Wagnac, Éric, Petit, Yvan, Ung, Bora
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01-03-2021; MDPI
• Subjects: Analyzers; Biomechanical Phenomena; Biomechanics; Bragg gratings; Communication; Compression tests; Contusions; fiber Bragg grating; Humans; Humidity; Occlusion; optical spectrum analyzer; photodiode; Pressure; Real time; Response time; Sensors; Soft tissues; Spectrum allocation; spinal cord; Spinal Cord Injuries; Spine; strain; United States > US; strain; fiber Bragg grating; photodiode; spinal cord; optical spectrum analyzer
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s21051671

To better understand the real-time biomechanics of soft tissues under sudden mechanical loads such as traumatic spinal cord injury (SCI), it is important to improve in vitro models. During a traumatic SCI, the spinal cord suffers high-velocity compression. The evaluation of spinal canal occlusion with a sensor is required in order to investigate the degree of spinal compression and the fast biomechanical processes involved. Unfortunately, available techniques suffer with drawbacks such as the inability to measure transverse compression and impractically large response times. In this work, an optical pressure sensing scheme based on a fiber Bragg grating and a narrow-band filter was designed to detect and demonstrate the transverse compression inside a spinal cord surrogate in real-time. The response time of the proposed scheme was 20 microseconds; a five orders of magnitude enhancement over comparable schemes that depend on costly and slower optical spectral analyzers. We further showed that this improvement in speed comes with a negligible loss in sensitivity. This study is another step towards better understanding the complex biomechanics involved during a traumatic SCI, using a method capable of probing the related internal strains with high-spatiotemporal resolution.