J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , v.v.i., Dolejškova 3, 182 23 Prague 8, Czech Republic.
Faculty of Science, Charles University , 2030 Hlavova, 128 43 Prague 2, Czech Republic.
ACS Appl Mater Interfaces. 2017 Oct 18;9(41):36229-36238. doi: 10.1021/acsami.7b12009. Epub 2017 Oct 4.
We report the synthesis and characterization of sulfonated polystyrene nanoparticles (average diameter 30 ± 14 nm) with encapsulated 5,10,15,20-tetraphenylporphyrin or ionically entangled tetracationic 5,10,15,20-tetrakis(N-methylpyridinium-4-yl)porphyrin, their photooxidation properties, and the application of singlet oxygen-sensitized delayed fluorescence (SODF) in oxygen sensing. Both types of nanoparticles effectively photogenerated singlet oxygen, O(Δ). The O(Δ) phosphorescence, transient absorption of the porphyrin triplet states, and SODF signals were monitored using time-resolved spectroscopic techniques. The SODF intensity depended on the concentration of the porphyrin photosensitizer and dissolved oxygen and on the temperature. After an initial period (a few microseconds), the kinetics of the SODF process can be approximated as a monoexponential function, and the apparent SODF lifetimes can be correlated with the oxygen concentration. The oxygen sensing based on SODF allowed measurement of the dissolved oxygen in aqueous media in the broad range of oxygen concentrations (0.2-38 mg L). The ability of both types of nanoparticles to photooxidize external substrates was predicted by the SODF measurements and proven by chemical tests. The relative photooxidation efficacy was highest at a low porphyrin concentration, as indicated by the highest fluorescence quantum yield (Φ), and it corresponds with negligible inner filter and self-quenching effects. The photooxidation abilities were sensitive to the influence of temperature on the diffusion and solubility of oxygen in both polystyrene and water media and to the rate constant of the O(Δ) reaction with a substrate. Due to their efficient photogeneration of cytotoxic O(Δ) at physiological temperatures and their oxygen sensing via SODF, both types of nanoparticles are promising candidates for biomedical applications.
我们报告了磺化聚苯乙烯纳米粒子（平均直径 30 ± 14nm）的合成与表征，这些纳米粒子包裹有 5,10,15,20-四苯基卟啉或离子缠结的四阳离子 5,10,15,20-四（N-甲基吡啶-4-基）卟啉，以及它们的光氧化性质和单线态氧敏延迟荧光（SODF）在氧传感中的应用。这两种类型的纳米粒子都能有效地光生单线态氧，O(Δ)。通过时间分辨光谱技术监测卟啉三重态的磷光、瞬态吸收和 SODF 信号。SODF 强度取决于卟啉光敏剂和溶解氧的浓度以及温度。在初始阶段（几微秒）后，SODF 过程的动力学可以近似为单指数函数，并且表观 SODF 寿命可以与氧浓度相关。基于 SODF 的氧传感允许在宽浓度范围内（0.2-38mg/L）测量水介质中的溶解氧。SODF 测量预测了两种类型的纳米粒子都具有光氧化外部底物的能力，并通过化学测试得到证实。如荧光量子产率（Φ）最高所示，在低卟啉浓度下，相对光氧化功效最高，这与内滤和自猝灭效应可忽略不计相对应。光氧化能力对温度对聚苯乙烯和水介质中氧的扩散和溶解度的影响以及 O(Δ)与底物反应的速率常数敏感。由于它们在生理温度下有效地光生细胞毒性 O(Δ)，并且通过 SODF 进行氧传感，这两种类型的纳米粒子都有望成为生物医学应用的候选材料。
