Magnetic Bead-Based Electrochemical Immunoassays On-Drop and On-Chip for Procalcitonin Determination: Disposable Tools for Clinical Sepsis Diagnosis

Abstract

Procalcitonin (PCT) is a known protein biomarker clinically used for the early stages of sepsis diagnosis and therapy guidance. For its reliable determination, sandwich format magnetic bead-based immunoassays with two different electrochemical detection approaches are described: (i) disposable screen-printed carbon electrodes (SPE-C, on-drop detection); (ii) electro-kinetically driven microfluidic chips with integrated Au electrodes (EMC-Au, on-chip detection). Both approaches exhibited enough sensitivity (limit of detection (LOD) of 0.1 and 0.04 ng mL−1 for SPE-C and EMC-Au, respectively; cutoff 0.5 ng mL−1), an adequate working range for the clinically relevant concentrations (0.5–1000 and 0.1–20 ng mL−1 for SPE-C and EMC-Au, respectively), and good precision (RSD < 9%), using low sample volumes (25 µL) with total assay times less than 20 min. The suitability of both approaches was successfully demonstrated by the analysis of human serum and plasma samples, for which good recoveries were obtained (89–120%). Furthermore, the EMC-Au approach enabled the easy automation of the process, constituting a reliable alternative diagnostic tool for on-site/bed-site clinical analysis.

Emerging Biosensors to Detect Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): A Review

“…The redox-active reaction could detect as low as 1 copy μL −1 of viral N or S genes in less than 2 hours. Moreover, the use of magnetic capture and separation of targets from non-targets reduces the chance of residual contamination and pipetting error, thereby reducing the risk of erroneous results and improving the assay precision [ 85 ]. The potentiostat is a key component for reading electrochemical signals, but the traditionally large and expensive bench-top versions limit its use in resource-limited environments.…”

Micro- and nanosensors for detecting blood pathogens and biomarkers at different points of sepsis care

“…They also exhibit excellent sensitivity and reproducibility. Their performance can be greatly improved by incorporating nanomaterials such as gold, copper [15], platinum [16,17], Prussian blue or zinc nanoparticles [18], carbon nanodots [19], quantum dots [20], magnetic beads [21][22][23][24], graphene [25,26], graphene oxide [27][28][29][30], and carbon nanotubes [15,27,31]. The large surface area afforded by nanomaterials facilitates the capture of the target at the electrode/solution interface and increases currents.…”

State-of-the-art colloidal particles and unique interfaces-based SARS-CoV-2 detection methods and COVID-19 diagnosis

“…The same group, this time, developed an electrochemical immunoassay based on magnetic beads in a sandwich format with two different approaches: The first approach consisted of disposable screen-printed carbon electrodes (SPE-C) and microfluidic chips (EMC-Au) with integrated Au electrodes. This approach offers good sensitivity with LOD of 0.1 and 0.04 ng mL -1 for SPE-C and EMC-Au, respectively, with a total test time of fewer than 20 minutes ( 48 ).…”