Neurofilament Light (NFL) Assay

Background of Neurofilament Light Chain

Neurofilament light chain (NFL) consists of neuronal cytoskeletal intermediate filament polypeptide encoded by the NEFL gene. NFL is the most abundant and soluble subunit of neurofilament. They are the primary constituents of the neuronal cytoskeleton, providing structural support for the axon and determining axon diameter. In a range of neurological disorders, including neuroinflammation, neurodegenerative, traumatic diseases, etc., levels of NFL in cerebrospinal fluid and blood increase according to the degree of axonal injury or degeneration. The sensitive and repeatable measurement of NFL in cerebrospinal fluid and blood at ultralow levels makes it possible to reflect the axonal damage. Thus, NFL may exert as a meaningful biomarker for diagnosis, prognosis, and monitoring of the neurodegenerative processes, especially the chronic neurodegenerative autoimmune disease multiple sclerosis (MS), which permits accurate anticipation of pharmacodynamic response to test compounds to screen promising drug candidates for MS.

Fig.1 Overview of the structure of neurofilaments and neurofilament light chain. (Gaetani, 2019)

Neurofilament Light (NFL) Assay

NFL in cerebrospinal fluid can be identified by sandwich-based immunoassay techniques, while the sensitivity of sandwich ELISA measuring NFL in the blood is insufficient. Electrochemiluminescence assay is another technology detecting the concentration of NFL in cerebrospinal fluid. However, the sensitivity is also inadequate to measure NFL in blood. A more accurate and sensitive assay, the single molecule array (Sioma) assay, has been performed to identify and quantify the biomarker NFL at lower levels in serum, plasma, and cerebrospinal fluid. Paramagnetic particles coupled with antibodies binding to a specific target are added to the sample. Antibodies capable of producing fluorescence are then added, forming an immunocomplex consisting of beads, bound proteins, and detection antibodies. At low concentrations, each bead contains a bound protein. The sample is then loaded into the array for reading. Single molecule array assay is orders of magnitude more sensitive than traditional sandwich ELISA as it can isolate and read single molecules in femtoliter-sized wells.

Reliable ex vivo NFL biomarker assays offered by Creative Biolabs enable accurate identification and quantification of axonal impairment and degeneration of MS through the measurement of biomarker NFL in blood and cerebrospinal fluid. NFL assay can be used to optimize the diagnostic and prognostic assessment. It also contributes to drug development as it can evaluate patients' responses to treatments. If you want to get more information about ex vivo NFL assay, please don't hesitate to contact us.

Reference

1. Gaetani, L.; et al. Neurofilament light chain as a biomarker in neurological disorders. Journal of Neurology, Neurosurgery & Psychiatry. 2019, 90(8): 870-881.