A photonic crystal biosensor assay for ferritin utilizing iron-oxide nanoparticles

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• Iron deficiency anemia is a global health issue affecting millions, primarily women and children.
• Accurate detection of serum ferritin is crucial for diagnosing iron deficiency.
• Existing diagnostic methods may have limitations in sensitivity or efficiency.

Purpose of the Study:

• To develop and evaluate a novel immunodiagnostic platform using iron-oxide nanoparticles (IONPs) and a photonic crystal (PC) optical biosensor.
• To assess the performance of this PC biosensor for detecting serum ferritin.
• To compare the sensitivity and accuracy of the PC biosensor with established ELISA tests.

Main Methods:

• Development of a PC optical biosensor assay incorporating IONPs.
• Evaluation using human liver ferritin, clinical serum controls, and commercially available ELISA kits.
• Assays performed included label-free, sandwich with secondary antibody (pAb), and pAb functionalized with IONPs (FpAb).
• Performance metrics included inter-/intra-assay variability, spike-recovery, limit of detection (LOD), and matrix effects.
• Bland-Altman analysis was used for agreement assessment.

Main Results:

• The PC biosensor exhibited low inter- and intra-assay variability (<10%).
• Spike-recovery percentages were high (94.3% and 96.9%).
• The FpAb-functionalized PC biosensor showed a two-order increase in sensitivity, achieving an LOD as low as 26 ng/mL.
• The PC biosensor demonstrated lower bias and a narrower limit of agreement compared to ELISA tests.

Conclusions:

• IONPs significantly enhance the sensitivity of PC biosensors for biomarker detection.
• The developed PC biosensor platform is a promising tool for sensitive and accurate determination of serum ferritin.
• This technology holds potential for improved diagnostics of nutritional status, particularly iron deficiency.