The 2023 Nobel Prize in Chemistry honors the groundbreaking
contributions
of Alexei Ekimov, Louis Brus, and Moungi Bawendi to the field of quantum
dots (QDs). In this spirit, we developed a direct competitive QD fluorescence
immunoassay (dc-QD-FLISA) to detect aristolochic acid type I (AAI),
a potent carcinogen found in herbal remedies. Unexpectedly, the dc-QD-FLISA
exhibited lower sensitivity than that of an indirect competitive enzyme-linked
immunosorbent assay (ic-ELISA), contrary to our initial expectations.
This discrepancy in the sensitivity prompted a comprehensive analysis
of the entire experimental process. We propose that steric hindrance
between QDs and antigen-binding sites on antibodies may significantly
diminish the binding efficiency, reducing sensitivity within the dc-QD-FLISA
method. Furthermore, issues such as buffer conditions, antibody handling,
and separation methods are also contributing factors. We recommend
site-directed QD modification and stringent consideration of the experimental
conditions. This study not only provides insights into QD-based immunoassays
but also highlights the need for future advancements in immunoassay
technology in terms of augmenting sensitivity and specificity, potentially
revolutionizing disease diagnosis, biomarker discovery, and biomedical
research.