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Laser-printed paper ELISA and hydroxyapatite immobilization for colorimetric congenital anomalies screening in saliva
Hichem Moulahoum1, Faezeh Ghorbanizamani1, Suna Timur2
1Biochemistry Department, Faculty of Science, Ege University, 35100, Bornova, Izmir, Turkey.
Insights
We developed a novel laser-printed paper-based ELISA (LP-pELISA) for noninvasive detection of Alpha-fetoprotein (AFP) in saliva. This cost-effective, user-friendly assay offers sensitive results for congenital anomaly screening at the point-of-care.
Area of Science:
- Biomarker Detection
- Point-of-Care Diagnostics
- Biosensor Technology
Background:
- Alpha-fetoprotein (AFP) is a crucial biomarker for detecting congenital anomalies like Down syndrome.
- Current AFP detection methods are invasive and require complex laboratory equipment.
- Paper-based ELISA (p-ELISA) offers a promising alternative for resource-limited settings.
Purpose of the Study:
- To develop a novel laser-printed paper-based ELISA (LP-pELISA) for sensitive and noninvasive AFP detection.
- To utilize saliva as a sample matrix for improved patient accessibility.
- To establish a cost-effective and user-friendly diagnostic tool.
Main Methods:
- Fabrication of LP-pELISA by laser printing hydrophobic barriers on filter paper.
- Immobilization of antibodies onto hydroxyapatite (HAp) modified paper.
- Colorimetric detection using gold nanoparticles (AuNPs) and silver enhancement.
Main Results:
- The LP-pELISA demonstrated a linear response for AFP detection from 1.0-800 ng/mL in buffer and saliva.
- Achieved a limit of detection (LOD) of 1.0 ng/mL for AFP.
- Validated assay performance with spiked human saliva samples, showing good selectivity, repeatability, and stability.
Conclusions:
- The LP-pELISA is a simple, cost-effective, and user-friendly platform for noninvasive AFP detection.
- This technology has broad applicability for detecting other biomarkers, advancing paper-based biosensors.
- LP-pELISA shows significant potential as a transformative tool for point-of-care diagnostics.
Background:
Alpha-fetoprotein (AFP) is a fetal protein that can indicate congenital anomalies such as Down syndrome and spinal canal blockage when detected at abnormal levels in pregnant women. Current AFP detection methods rely on invasive blood or serum samples, which require sophisticated equipment. From the many solutions proposed, colorimetric paper-based assays excel in point-of-care settings. The concept of paper-based ELISA (p-ELISA) enhances traditional methods, aligning with the ASSURED criteria for diagnostics in resource-limited regions. Despite success in microfluidic paper-based assay devices, laser printing remains underexplored for p-ELISA. Additionally, modifying the paper surface provides an additional layer of sensitivity enhancement.
Results:
In this study, we developed a novel laser-printed paper-based ELISA (LP-pELISA) for rapid, sensitive, and noninvasive detection of AFP in saliva samples. The LP-pELISA platform was fabricated by printing hydrophobic barriers on filter paper using a laser printer, followed by depositing hydroxyapatite (HAp) as an immobilization material for the antibodies. The colorimetric detection was achieved using AuNPs functionalized with anti-AFP antibodies and silver nitrate enhancement. The LP-pELISA exhibited a linear response for AFP detection in both buffer and saliva samples over a range of 1.0-800 ng mL-1, with a limit of detection (LOD) reaching 1.0 ng mL-1. The assay also demonstrated good selectivity, repeatability, reproducibility, and stability. The LP-pELISA was further validated by testing spiked human saliva samples, showing its potential for point-of-care diagnosis of congenital disabilities.
Significance:
The LP-pELISA is a noninvasive platform showcasing simplicity, cost-effectiveness, and user-friendliness, utilizing laser printing, hydroxyapatite modification, and saliva samples to efficiently detect AFP. Beyond its application for AFP, this method's versatility extends to other biomarkers, positioning it as a catalyst for the evolution of paper-based biosensors. The LP-pELISA holds promise as a transformative tool for point-of-care diagnostics, fostering advancements in healthcare with its innovative technology.
