Cellulose-Based Colorimetric Test Strips for SARS-CoV-2 Antibody Detection

Area of Science:

• Biotechnology
• Immunology
• Materials Science

Background:

• The COVID-19 pandemic underscored the need for accessible diagnostic tools.
• Existing serological assays can be expensive and time-consuming.
• Rapid monitoring of immune response is crucial for public health.

Purpose of the Study:

• To develop novel, cost-effective paper-based colorimetric biosensors for detecting SARS-CoV-2 antibodies.
• To utilize glutaraldehyde as a novel protein dye for colorimetric detection.
• To assess the sensitivity, selectivity, and applicability of the developed biosensors.

Main Methods:

• Functionalization of Wathman filter paper with (3-aminopropyl)triethoxysilane (APTES).
• Immobilization of virus-like particles (VLPs) and nucleocapsid protein (N-protein) as biorecognition elements.
• Colorimetric detection using glutaraldehyde and RGB analysis via ImageJ software.

Main Results:

• Both biosensors demonstrated a linear correlation between antibody concentration and RGB values.
• The VLP sensor showed linear response from 1.0-20 µg/mL in diluted serum.
• The N-protein sensor showed linear response from 1.0-40 µg/mL in diluted serum.
• Good selectivity was observed, with minimal interference from glucose.

Conclusions:

• The developed paper-based biosensors offer a sensitive, user-friendly, and cost-effective method for semi-quantitative serological analysis.
• Glutaraldehyde serves as an effective protein dye in this novel biosensor application.
• The biosensor technology shows potential for broader applications beyond SARS-CoV-2 antibody detection.