Palladium nanoclusters as a label to determine GFAP in human serum from donors with stroke by bimodal detection: inductively coupled plasma-mass spectrometry and linear sweep voltammetry.
Alejandro Rodríguez-PenedoEstefanía Costa-RamaBeatriz FernándezCarmen García-CaboLorena BenaventeSergio CallejaM Teresa Fernández-AbedulRosario PereiroPublished in: Mikrochimica acta (2023)
Water-soluble, stable, and monodisperse palladium nanoclusters (PdNCs) were synthesized using NaBH 4 as a reductant and lipoic acid as a ligand. PdNCs, measured by high-resolution transmission electron microscopy, showed a round shape and a diameter of 2.49 ± 0.02 nm. It was found that each PdNC contains 550 Pd atoms on average. These PdNCs offer high amplification as a label of biochemical reactions when inductively coupled plasma-mass spectrometry (ICP-MS) is used as a detector. In addition, PdNCs have catalytic activity on electrochemical reactions, allowing detection by linear sweep voltammetry (LSV). As a proof of applicability, a competitive immunoassay based on PdNC labels was developed for the determination of glial fibrillary acidic protein (GFAP) in human serum, comparing ICP-MS and LSV detection. GFAP is a biomarker for differentiating between patients with ischemic stroke (IS) and hemorrhagic stroke (HS). The limit of detection (LoD), corresponding to IC 10 (4-parameter logistic curve), was 0.03 pM of GFAP, both by ICP-MS and LSV, being lower than the 0.31 pM LoD provided by the ELISA commercial kit. Using the error profile method, 0.03 pM and 0.11 pM LoDs were obtained respectively by ICP-MS and LSV: LoD is lower by ICP-MS due to the better precision of the measurements. The analyses of human serum samples from IS, HS, and control (CT) donors using PdNC labels and detection by ICP-MS and LSV were validated with a commercial ELISA kit (for CT donors only ICP-MS provided enough sensitivity). Results point out toward the future use of PdNCs as a label in other immunoprobes for the determination of specific proteins requiring very low LoDs as well as the development of electrochemical decentralized methodologies.
Keyphrases
- mass spectrometry
- label free
- water soluble
- liquid chromatography
- high resolution
- capillary electrophoresis
- high performance liquid chromatography
- multiple sclerosis
- ms ms
- particulate matter
- gas chromatography
- loop mediated isothermal amplification
- air pollution
- real time pcr
- atrial fibrillation
- gold nanoparticles
- heavy metals
- sensitive detection
- computed tomography
- contrast enhanced
- magnetic resonance imaging
- molecularly imprinted
- polycyclic aromatic hydrocarbons
- image quality
- solid phase extraction
- dual energy
- positron emission tomography
- magnetic resonance
- blood brain barrier
- photodynamic therapy
- risk assessment
- spinal cord injury
- high speed