6 research outputs found
Single-step functionalization of poly-catecholamine nanofilms for ultra-sensitive immunosensing of ubiquitin carboxyl terminal hydrolase-L1 (UCHL-1) in spinal cord injury
Polyethylenimine Modified Graphene-Oxide Electrochemical Immunosensor for the Detection of Glial Fibrillary Acidic Protein in Central Nervous System Injury
Glial
fibrillary acidic protein (GFAP) is as an intermediate filament
protein expressed by certain cells in the central nervous system (CNS).
GFAP has been recognized as a reliable biomarker of CNS injury. However,
due to the absence of rapid and easy-to-use assays for the detection
of CNS injury biomarkers, measuring GFAP levels to identify CNS injury
has not attained widespread clinical implementation. In the present
work, we developed a polyethylenimine (PEI) coated graphene screen-printed
electrode and used it for highly sensitive immunosensing of GFAP.
Covalent binding of GFAP antibody to the PEI-modified electrode surface
along with electrochemical impedance spectroscopy was used for detecting
the change in the electrical conductivity of the electrodes. A highly
linear response was recorded for various GFAP concentrations. Quantitative,
selective, and label-free detection was achieved in the dynamic range
of 1 pg mL<sup>–1</sup> to 100 ng mL<sup>–1</sup> for
GFAP spiked in phosphate buffer saline, artificial cerebrospinal fluid,
and human blood serum. The performance of the immunosensor was further
validated and correlated by testing samples with the commercially
available enzyme-linked immunosorbent assay method. This functionalized electrode could be used clinically for rapid detection and monitoring of CNS injury
Nanoporous Carbon Immunosensor for Highly Accurate and Sensitive Clinical Detection of Glial Fibrillary Acidic Protein in Traumatic Brain Injury, Stroke, and Spinal Cord Injury
Elevated glial fibrillary acidic protein (GFAP) in the
blood serum
is one of the promising bodily fluid markers for the diagnosis of
central nervous system (CNS) injuries, including traumatic brain injury
(TBI), stroke, and spinal cord injury (SCI). However, accurate and
point-of-care (POC) quantification of GFAP in clinical blood samples
has been challenging and yet to be clinically validated against gold-standard
assays and outcome practices. This work engineered and characterized
a novel nanoporous carbon screen-printed electrode with significantly
increased surface area and conductivity, as well as preserved stability
and anti-fouling properties. This nano-decorated electrode was immobilized
with the target GFAP antibody to create an ultrasensitive GFAP immunosensor
and quantify GFAP levels in spiked samples and the serum of CNS injury
patients. The immunosensor presented a dynamic detection range of
100 fg/mL to 10 ng/mL, a limit of detection of 86.6 fg/mL, and a sensitivity
of 20.3 Ω mL/pg mm2 for detecting GFAP in the serum.
Its clinical utility was demonstrated by the consistent and selective
quantification of GFAP comparable to the ultrasensitive single-molecule
array technology in 107 serum samples collected from TBI, stroke,
and SCI patients. Comparing the diagnostic and prognostic performance
of the immunosensor with the existing clinical paradigms confirms
the immunosensor’s accuracy as a potential complement to the
existing imaging diagnostic modalities and presents a potential for
rapid, accurate, cost-effective, and near real-time POC diagnosis
and prognosis of CNS injuries