Nanoparticle Hybrid Materials Using Plasmonic-Enhanced Upconversion FRET for Multiplexed Sensing and Optical Barcoding

• Applicants: Professorin Dr. Christina Graf; Dr. Ute Resch-Genger, since 3/2019
• Subject Area: Synthesis and Properties of Functional Materials
• Term: from 2015 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 280181689

The development of photoluminescent nanomaterials (PNMs) with tailored photophysical properties is a dynamic area of materials science. Much effort has been devoted to high-order multiplexing in sensing as well as optical barcoding for security applications and quality control using PNMs by tuning of the photoluminescence (PL) color, intensity, and lifetime. NIR-excitable upconverting nanoparticles (UCNPs) are newly emerging PNMs, which provide higher penetration depths in water and biological tissues, strongly anti-Stokes shifted emission, high photostability and strongly reduced autofluorescence background. Although UCNPs are considered ideal candidates for the applications mentioned above, they face challenges regarding low PL quantum yields (QY), limited color and lifetime tunability, and low stability in aqueous solution.5 renowned research teams from 3 European countries form the nanohype concept-driven project consortium, which combines computational modeling, synthesis, and experimental validation to design novel metal-shelled UCNPs to obtain: - 50-fold PL QY enhancement- tunable PL lifetimes between 100 ns - 600 µs- tunable PL colors by multiplexed Förster Resonance Energy Transfer (FRET) to quantum dots (QDs) or dyesThe novel PNMs will consist of silica-embedded UCNPs with metal surface coatings for plasmonic PL enhancement, and lifetime tunability and different QD or dye FRET acceptors for PL color and lifetime tuning by UCNP to QD/dye distance arrangement. For this purpose, techniques of synthesizing fluorescent nanomaterials, metal nanoshells, and UCNPs will be further optimized based on predictive modeling and simulation. By precisely tuning the distance and material parameters by combined computational modeling, materials engineering and synthesis, targeted PL properties for optimal multiplexing capabilities with improved QY will be obtained.The predictive power of computational modeling of the variable PNM structures will provide a recipe for PNM synthesis with targeted PL properties. The modeled structural properties will be produced as follows. Defect-free UCNPs will be synthesized and coated with undoped lanthanides and silica shells with precisely controlled thickness, which will enable precise positioning of FRET acceptors in or on the shells. These PNMs will then be coated with complete or partly open metal shells to utilize plasmonic interactions for an enhancement in excitation and emission and to enable access of analytes to the FRET acceptors. The proposed modeling/synthesis approach will result in the development of design criteria for such UCNP-based PNMs. We will provide the experimental validation of the predicted target properties of the novel PNMs for sensing and optical barcoding and demonstrate their superiority resulting from tailored synthesis. The multidisciplinary consortium will significantly contribute to strengthen the European Integrated Computational Materials Engineering community.

• DFG Programme: Research Grants
• International Connection: France, Spain
• Cooperation Partners: Professor Dr. Javier Garcia De Abajo; Professor Dr. Niko Hildebrandt
• Ehemaliger Antragsteller: Professor Dr. Michael Schäferling, until 2/2019