A Variable Height Microfluidic Device for Multiplexed Immunoassay Analysis of Traumatic Brain Injury Biomarkers

Area of Science:

• Biomedical Engineering
• Neuroscience
• Analytical Chemistry

Background:

• Traumatic brain injury (TBI) presents significant global health challenges due to limited diagnostic tools and treatments.
• Protein biomarkers are crucial for TBI diagnosis and monitoring, necessitating methods for simultaneous detection.
• Current methods for multiplexed biomarker analysis face limitations in sensitivity and throughput.

Purpose of the Study:

• To develop a novel microfluidic device for passive, multiplexed immunoassay of TBI protein biomarkers.
• To demonstrate the capability of the device to simultaneously detect key TBI biomarkers like IL-6, GFAP, and IL-8.
• To establish a scalable platform for future TBI biomarker discovery and validation.

Main Methods:

• A single-channel microfluidic device with variable height was designed to passively trap assay beads based on diameter.
• Bead-based quantum dot-linked immunosorbent assays (QLISAs) were developed for interleukin-6 (IL-6), glial fibrillary acidic protein (GFAP), and interleukin-8 (IL-8).
• Multiplexed assays were successfully performed using channels with varying height gradients, ranging from approximately 7.6 µm to 2.1 µm and 6.3 µm to 0.9 µm.

Main Results:

• The variable height microfluidic device successfully multiplexed IL-6 and GFAP QLISAs.
• Further multiplexing of IL-6, GFAP, and IL-8 QLISAs was achieved using a narrower channel height range.
• The system demonstrated passive trapping of beads with different diameters, enabling size-based multiplexing.

Conclusions:

• A novel variable height microfluidic device enables passive, multiplexed detection of TBI protein biomarkers.
• The developed QLISA platform is adaptable for simultaneous analysis of multiple biomarkers, supporting TBI research.
• This technology offers a scalable solution for accelerating TBI biomarker discovery and clinical application.