Ratiometric fluorescent sensor based on biomass-derived carbon dots for on-site detection of pollen allergen

The increasing global prevalence of pollen-induced respiratory allergy highlights the need for precise and accessible methods of allergen identification. In this study, we developed a sensing platform based on carbon dots (CDs) for the detection of Art v1, the primary allergen in mugwort (Artemisia) pollen. Biomass-derived CDs were synthesized from Xanthii Fructus using a microwave-assisted hydrothermal method. The synthesis process was carefully designed to retain the specific bioactive components from the plant precursor, which endowed the CDs with inherent molecular recognition toward Art v1. The correlation between the retained component content and the recognition capability of the CDs was established through FTIR and XPS analyses. Subsequently, a ratiometric fluorescent probe was constructed by integrating the CDs with a Ru(bpy)₃Cl₂·6H₂O reference signal into a portable test strip sensor. This probe allows visual assessment through distinct color shifts under UV light. Furthermore, when coupled with a smartphone-based colorimetric readout system, the platform facilitates accurate and highly selective identification and quantification of Art v1 within 5 min. The detection range was 0.5–80 nM, with a limit of detection of 0.186 nM. The sensor demonstrated robust on-site detection capability in complex biological and environmental matrices, with recovery rates ranging from 90.5% to 104.5%. This work not only presents a cost-effective, user-friendly strategy for allergen detection but also illustrates a pathway to confer targeted molecular recognition to sensing materials through rational biomass precursor selection and process design.