Influence of excitation pulse duration on the efficiency of upconversion nanoparticle-based FRET
Accurate and reliable quantification of Förster Resonance Energy Transfer (FRET) is essential for the development of sensitive upconverting nanoparticle (UCNP)-based biosensors. While lifetime-based FRET measurements are generally considered robust, excitation conditions can significantly bias obser...
| Authors: | ; ; ; ; ; ; |
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| Format: | Article |
| Publication date: | 2025 |
| Country: | España |
| Institution: | Universidad Complutense de Madrid (UCM) |
| Repository: | Docta Complutense |
| Language: | English |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/131487 |
| Online Access: | https://hdl.handle.net/20.500.14352/131487 |
| Access Level: | Open access |
| Keyword: | Óptica Nanopartículas Óptica (Física) 2209 Óptica |
| Summary: | Accurate and reliable quantification of Förster Resonance Energy Transfer (FRET) is essential for the development of sensitive upconverting nanoparticle (UCNP)-based biosensors. While lifetime-based FRET measurements are generally considered robust, excitation conditions can significantly bias observed efficiencies. Here, we investigate how excitation pulse width and power influence lifetime-derived FRET efficiency in core–shell β-NaYF4:Yb0.2@NaYF4:Yb0.2,Er0.02 UCNPs functionalized with Cy3 dyes. Time-resolved upconversion luminescence (UCL) measurements reveal that apparent FRET efficiencies decrease with increasing excitation pulse duration and power. These variations stem from excitation-induced changes in the UCL lifetime, arising from the complex dynamics that accompany the upconversion emission process. A dynamic rate equation model reproduces the experimental trends, confirming that excitation parameters alter emissive state kinetics and thus bias lifetime-based FRET measurements. Our findings identify excitation conditions as a hidden variable in UCNP-FRET experiments and underscore the need for standardized measurement protocols. |
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