Kou Meng, Qin Feng, Wang Yongda, Peng Lixin, Hu Zheng, Zhao Hua, Zhang Zhiguo
School of Physics, Harbin Institute of Technology, Harbin, 150001, China.
School of Instrumentation Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China.
Anal Chim Acta. 2024 Nov 15;1329:343222. doi: 10.1016/j.aca.2024.343222. Epub 2024 Sep 7.
Photodynamic therapy (PDT) is emerging as a promising cancer treatment. The PDT efficacy is primarily attributed to the generation of singlet oxygen (O), stemming from the integrated effects of the photosensitizer, oxygen, and light. The singlet oxygen quantum yield (Φ) serves as a bridge that links these parameters to the overall efficacy of PDT. The near-infrared luminescence of O provides a direct way for determining Φ, but suffers from a poor signal-to-noise ratio. While the chemical trap probe method is detection-friendly, but it has a strict requirement for the excitation wavelength. Therefore, the existing methods for Φ measurement are insufficient.
In this work, we developed an approach to determine Φ of a broader range of photosensitizers using only the commonly used solvent dimethyl sulfoxide (DMSO), which can be oxidized by O to dimethyl sulfone. This method establishes the relationship between O production and changes in DMSO absorption spectra, eliminating the need for additional chemical probes. This method was validated by measuring the Φ of rose bengal (RB) through systematic changes in absorption spectrum of DMSO under various RB concentrations and different excitation light power densities. Moreover, the Φ of hematoporphyrin monomethyl ether (HMME), as determined by this method, is consistent with measurements obtained using the 1,3-diphenylisobenzofuran (DPBF) trapping probe. This consistency further validates the reliability of this method.
This work presents a direct, probe-free method to determine Φ, reducing potential interference and expanding the range of useable excitation wavelengths. Its ability to measure Φ using only DMSO enhances the accuracy of photosensitizer measurement, and broadens the applicability of the method to a wide range of samples, thereby advancing research on the properties of photosensitizers and further promoting the development of PDT.
光动力疗法（PDT）正成为一种有前景的癌症治疗方法。PDT的疗效主要归因于单线态氧（O）的产生，这源于光敏剂、氧气和光的综合作用。单线态氧量子产率（Φ）是将这些参数与PDT的整体疗效联系起来的桥梁。O的近红外发光为确定Φ提供了一种直接方法，但信噪比很差。虽然化学捕获探针法对检测友好，但对激发波长有严格要求。因此，现有的Φ测量方法存在不足。
在这项工作中，我们开发了一种仅使用常用溶剂二甲基亚砜（DMSO）来测定更广泛范围光敏剂的Φ的方法，DMSO可被O氧化为二甲基砜。该方法建立了O产生与DMSO吸收光谱变化之间的关系，无需额外的化学探针。通过在不同玫瑰红（RB）浓度和不同激发光功率密度下，通过DMSO吸收光谱的系统变化来测量RB的Φ，验证了该方法。此外，用该方法测定的血卟啉单甲醚（HMME）的Φ与使用1,3 - 二苯基异苯并呋喃（DPBF）捕获探针获得的测量结果一致。这种一致性进一步验证了该方法的可靠性。
这项工作提出了一种直接的、无需探针的方法来测定Φ，减少了潜在干扰并扩大了可用激发波长的范围。仅使用DMSO测量Φ的能力提高了光敏剂测量的准确性，并将该方法的适用性扩展到广泛的样品，从而推动了对光敏剂性质的研究，并进一步促进了PDT的发展。
