Epelde-Elezcano Nerea, Prieto-Montero Ruth, Martínez-Martínez Virginia, Ortiz María J, Prieto-Castañeda Alejandro, Peña-Cabrera Eduardo, Belmonte-Vázquez José L, López-Arbeloa Iñigo, Brown Ross, Lacombe Sylvie
Departamento de Química Física, Universidad del País Vasco-EHU, Apartado 644, 48080, Bilbao, Spain.
Phys Chem Chem Phys. 2017 May 31;19(21):13746-13755. doi: 10.1039/c7cp01333g.
A modified Stöber method is used to synthesize spherical core-shell silica nanoparticles (NPs) with an external surface functionalized by amino groups and with an average size around 50 nm. Fluorescent dyes and photosensitizers of singlet oxygen were fixed, either separately or conjointly, respectively in the core or in the shell. Rhodamines were encapsulated in the core with relatively high fluorescence quantum yields (Φ ≥ 0.3), allowing fluorescence tracking of the particles. Various photosensitizers of singlet oxygen (PS) were covalenty coupled to the shell, allowing singlet oxygen production. The stability of NP suspensions strongly deteriorated upon grafting the PS, affecting their apparent singlet oxygen quantum yields. Agglomeration of NPs depends both on the type and on the amount of grafted photosensitizer. New, lab-made, halogenated 4,4-difluoro-4-bora-3a,4a-diaza-s-indacenes (BODIPY) grafted to the NPs achieved higher singlet oxygen quantum yields (Φ ∼ 0.35-0.40) than Rose Bengal (RB) grafted NPs (Φ ∼ 0.10-0.27). Finally, we combined both fluorescence and PS functions in the same NP, namely a rhodamine in the silica core and a BODIPY or RB grafted in the shell, achieving the performance Φ ∼ 0.10-0.20, Φ ∼ 0.16-0.25 with a single excitation wavelength. Thus, proper choice of the dyes, of their concentrations inside and on the NPs and the grafting method enables fine-tuning of singlet oxygen production and fluorescence emission.
采用改进的Stöber方法合成了平均尺寸约为50 nm的球形核壳二氧化硅纳米颗粒（NPs），其外表面由氨基官能化。荧光染料和单线态氧光敏剂分别或联合固定在核或壳中。罗丹明以相对较高的荧光量子产率（Φ≥0.3）封装在核中，可对颗粒进行荧光追踪。各种单线态氧光敏剂（PS）共价偶联到壳上，可产生单线态氧。接枝PS后，NP悬浮液的稳定性严重恶化，影响其表观单线态氧量子产率。NP的团聚既取决于接枝光敏剂的类型，也取决于其用量。新的实验室自制的卤代4,4-二氟-4-硼-3a,4a-二氮杂-s-茚（BODIPY）接枝到NP上，比接枝玫瑰红（RB）的NP具有更高的单线态氧量子产率（Φ0.35-0.40）（Φ0.10-0.27）。最后，我们在同一NP中结合了荧光和PS功能，即在二氧化硅核中加入罗丹明，在壳中接枝BODIPY或RB，在单一激发波长下实现了Φ0.10-0.20、Φ0.16-0.25的性能。因此，通过适当选择染料、其在NP内部和表面的浓度以及接枝方法，可以对单线态氧的产生和荧光发射进行微调。
