Fast cerebrospinal fluid detection using inexpensive modular packaging with disposable testing strips

This report details the use of a Si Metal Oxide Semiconductor Field Effect Transistor (MOSFET) with the gate connected to a disposable antibody-functionalized electrode for the detection of β-2-transferrin (β2T) as a marker of cerebral spinal fluid (CSF). Through the design of a Si based PCB the need for GaN High Electron Mobility Transistors has been mitigated and brings the cost of production for commercial application closer to realization. Through the use of a double pulse method to the test electrode and the drain of the Si MOSFET, ionicity of the test solution is no longer a concern as a double layer is produced and perturbed on the test electrode giving rise to current changes related to the concentration of the biomarker. Additionally, the PCB provides connections for an oscilloscope readout or an onboard display entirely removing the need for any expensive semiconductor parameter analyzers. Clinically, the cutoff for β2T as indicator of CSF leakage has traditionally been limited to ∼2 μg/mL and takes several hours; with this newly designed board, CSF was detected at levels from 0.1 ng/mL to 100 μg/mL within 5 minutes, greatly improving the detection limits and feedback time for medical professionals.