Aptamer-Conjugated Multi-Quantum Dot-Embedded Silica Nanoparticles for Lateral Flow Immunoassay

Area of Science:

• Nanotechnology
• Biomedical Diagnostics
• Assay Development

Background:

• Lateral flow immunoassays (LFIA) offer rapid, cost-effective diagnostics but require improved reliability.
• Quantum dot silica core-shell nanoparticles (SiO2@QD@SiO2 or QD2) provide superior fluorescence intensity compared to single quantum dots (QDs).

Purpose of the Study:

• To develop and optimize a novel QD2-aptamer conjugate for sensitive detection of carbohydrate antigen (CA) 19-9 using LFIA.
• To enhance the fluorescence intensity and reliability of LFIA for CA 19-9 detection.

Main Methods:

• Synthesis of QD2@PEG@Aptamer conjugates using succinimidyl-[(N-maleimidopropionamido)-hexaethyleneglycol]ester.
• Optimization of LFIA conditions, including reagent ratios, developing solution, and nanoparticle concentration.
• Evaluation of assay selectivity, detection limit, and fluorescence stability for CA 19-9 detection.

Main Results:

• The QD2@PEG@Aptamer conjugate exhibited 130 times higher fluorescence intensity than single QDs.
• Optimized LFIA achieved a sensitive detection limit of 1.74 × 10^-2 mg·mL^-1 for CA 19-9.
• The assay demonstrated stable fluorescence signals for up to 10 days post-detection.

Conclusions:

• QD2 and aptamer conjugation technology offers a robust and sensitive platform for LFIA.
• This approach significantly enhances fluorescence intensity and reliability for diagnostic applications.
• The developed assay shows promise for improved CA 19-9 detection in clinical settings.