Thin Amphiphilic Polymer-Capped Upconversion Nanoparticles: Enhanced Emission and Thermoresponsive Properties

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• 作者：Marta Liras ; Mar铆a Gonz谩lez-B茅jar ; Elena Peinado ; Laura Franc茅s-Soriano ; Julia P茅rez-Prieto ; Isabel Quijada-Garrido ; Olga Garc铆a
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：July 8, 2014
• 年：2014
• 卷：26
• 期：13
• 页码：4014-4022
• 全文大小：593K
• ISSN：1520-5002

文摘

Upconversion nanoparticles (尾-NaYF₄:Er³⁺, Yb³⁺, UCNPs) were capped with a thin polymer shell by replacing the oleate ligand of hydrophobic UCNPs by multidentate thiolate-grafting of P(MEO₂MA-co-SEMA) copolymers. The presence of the 2-(2-methoxyethoxy)ethyl side chains of MEO₂MA extending out of the nanohybrid made them water-dispersible. The UCNP@P(MEO₂MA-co-SEMA) nanohybrids exhibited an enhanced emission by up to a factor of 10, as compared with that of their hydrophobic precursor in dichloromethane and even in water (a factor of 2). Moreover, their thermoresponsiveness was modulated by the pH; this is consistent with the presence of some thiol groups at the nanohybrid periphery. Remarkably, the nanohybrid emission, as well as its stability, was almost independent of the aggregation state (in the basic-acid and temperature range studied here). The formation of stable water-dispersible UCNPs with enhanced emission, together with their amphiphilic and temperature-responsive polymer coating, is promising for building multifunctional nanostructures for intracellular imaging, therapy, and drug delivery.