通过 Bodipy 标记的聚丙交酯纳米颗粒中聚集引起的猝灭和激发能量转移来微调光声产生效率,The Journal of Physical Chemistry C

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通过 Bodipy 标记的聚丙交酯纳米颗粒中聚集引起的猝灭和激发能量转移来微调光声产生效率
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2023-09-18 , DOI: 10.1021/acs.jpcc.3c03500
Jean-Baptiste Bodin _{1,

2} , Clément Linger _{2,

3} , Jérôme Gateau ₃ , Théo Beguin ₁ , Théotim Lucas _{3,

4} , Laurence Moine ₂ , David Chapron ₂ , Minh-Huong Ha-Thi ₁ , Anam Fatima ₁ , Gilles Clavier ₅ , Nicolas Tsapis ₂ , Rachel Méallet ₁

Affiliation

证明了聚丙交酯-Bodipy 纳米粒子（PLA-Bodipy NPs）中聚集引起的猝灭（ACQ）引起的荧光减少与光声产生效率之间的关系。使用校准的光声分光光度计研究了具有不同 PLA-Bodipy 负载量（按重量计 2.5% 至 50%）的 PLA NP。通过确定全局光声效率（GPAE），我们证明了两种光声发射机制的存在，它代表了整个研究波段（680-870 nm）的平均光声产生效率。在单体体系中，PLA-Bodipy 的重量低于 10%，Bodipy 单体的荧光发射限制了 GPAE。在 ACQ 体系中，超过 10% 的 PLA-Bodipy 时，聚集体的非辐射失活占主导地位，并且 GPAE 达到 93% 的高值。B _PA，作为 GPAE 与 NP 摩尔消光系数的乘积。当Bodipy聚集时，达到高纳米颗粒消光系数（NP-50%为2.4 × 10 ⁸ L·mol ^–1 ·cm ^–1）和高GPAE值，从而产生超亮的纳米颗粒（22 × 10 ⁷ L·mol ^–1 ·cm ^–1 )。最后，我们表明，高激光注量（1–3.5 mJ·cm ^–2）可以通过带最大激发处的基态减少来显着减少光声信号（NP-2.5 %为−20%））。ACQ 体系中的 NP 可以大大减少这种非线性效应。PLA-Bodipy 含量高于 10% 时，纳米粒子表现出强烈的光声亮度和非线性效应带来的低信号损失。吸收和光声激发光谱的数学拟合使我们能够引入带光声效率（BPAE），以在光谱上区分最大 BPAE 红色带和振动肩_BPAE蓝色带中的_平均光声效率。由于高基态减少，BPAE_{红色高度依赖于激光注量，而 BPAE}_蓝色由于激光注量饱和度较低，因此不随注量变化。

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Fine Tuning of the Photoacoustic Generation Efficiency by Aggregation-Caused Quenching and Excitation Energy Transfer in Bodipy-Labeled Polylactide Nanoparticles

The relationship between the fluorescence decrease by aggregation-caused quenching (ACQ) and the photoacoustic generation efficiency in polylactide-Bodipy nanoparticles (PLA-Bodipy NPs) is demonstrated. PLA NPs with different PLA-Bodipy loadings (from 2.5 to 50% by weight) were studied using a calibrated photoacoustic spectrophotometer. We demonstrate the presence of two photoacoustic emission regimes thanks to the determination of the global photoacoustic efficiency (GPAE), which represents the averaged photoacoustic generation efficiency over the whole studied band (680–870 nm). In the monomer regime, below 10% by weight of PLA-Bodipy, the fluorescence emission from the Bodipy monomer limits the GPAE. Above 10% of PLA-Bodipy, in the ACQ regime, nonradiative deactivations from the aggregates are predominant and GPAE reaches a high value of 93%. We also introduce the photoacoustic brightness B_PA, as the product of the GPAE by the molar extinction coefficient of NPs. When Bodipy is aggregated, high nanoparticle extinction coefficients (2.4 × 10⁸ L·mol^–1·cm^–1 for NP-50%) and high GPAE values are reached, leading to ultrabright NPs (22 × 10⁷ L·mol^–1·cm^–1). Finally, we show that high laser fluences (1–3.5 mJ·cm^–2) can significantly reduce the photoacoustic signal by ground state depopulation at the band maximum excitation (−20% for NP-2.5%). This nonlinear effect can be highly reduced with NPs in the ACQ regime. Above 10% PLA-Bodipy, NPs exhibit intense photoacoustic brightness and low signal loss by nonlinear effects. A mathematical fit of the absorption and photoacoustic excitation spectra allowed us to introduce the band photoacoustic efficiency (BPAE) to spectrally differentiate the averaged photoacoustic efficiency at the band maximum BPAE_red and in the vibrational shoulder BPAE_blue. The BPAE_red highly depends on the laser fluence due to high-ground state depopulation, whereas the BPAE_blue does not change with the fluence because of a lower laser fluence saturation.

更新日期：2023-09-18

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