Photodynamic therapy (PDT) is a therapeutic modality that has shown effectiveness in the inactivation of cancer cell lines and microorganisms. Treatment consists of activating the photosensitizer (PS) upon light irradiation of adequate wavelength. After reaching the excited state, the PS can handle the intersystem conversion through energy transfer to the molecular oxygen, generating reactive oxygen species. This especially applies to singlet oxygen (¹O₂), which is responsible for the selective destruction of the sick tissue. Photosensitizing compounds (chlorophylls and derivatives) existing in the spinach extract have applicability for PDT. This study aimed to develop and characterize the thermoresponsive bioadhesive system composed of Pluronic F127 20.0%- and Carbopol 934P 0.2% (w/w) (FC)-containing chlorophyll-based extract 0.5% (w/w) (FC-Chl). Mechanical and rheological properties, in vitro release, sol–gel transition temperature, and ex vivo permeability of the spinach extract PS components (through pig ear skin) were investigated. Furthermore, photodynamic activity of the system was accessed through uric acid and time-solved measurements. The sol–gel transition temperature obtained for the FC-Chl system was 28.8 ± 0.3 °C. Rheological and texture properties of the platform were suitable for use as a dermatological system, exhibiting easy application and good characteristics of retention in the place of administration. In vitro release studies showed the presence of two distinct mechanisms that reasonably obey the zero-order and first-order kinetics models. PS components presented skin permeability and reached a permeation depth of 830 μm (between the epidermis and dermis). The photodynamic evaluation of the FC-Chl system was effective in the degradation of uric acid. The quantum yield (Φ_Δ¹O₂) and life time (τ¹O₂) of singlet oxygen showed similar values for the spinach extract and the isolated chlorophyll a species in ethanol. These results allowed for the classification of the FC-Chl platform as potentially useful for the delivery of the chlorophyll-based extract in the topic PDT, suggesting that it is worthy for in vivo evaluation.

中文翻译：

---

基于叶绿素的提取物用于主题光动力疗法的生物医学平台开发：机械和光谱性质。

光动力疗法（PDT）是一种治疗方法，已显示出在癌细胞系和微生物失活方面的有效性。治疗包括在适当波长的光照射下激活光敏剂（PS）。达到激发态后，PS可以通过能量转移到分子氧来处理系统间转换，从而产生活性氧。特别是单线态氧（¹ O ₂），这是有选择地破坏患病组织的原因。菠菜提取物中存在的光敏化合物（叶绿素和衍生物）对PDT具有适用性。这项研究旨在开发和表征由Pluronic F127 20.0％和含0.2％（w / w）（FC）的Carbopol 934P（FC）含叶绿素的提取物0.5％（w / w）（FC-Chl）组成的热敏生物粘附系统。研究了菠菜提取物PS成分（通过猪耳皮肤）的机械和流变特性，体外释放，溶胶-凝胶转变温度和离体渗透性。此外，通过尿酸和时间溶解的测量值可以访问系统的光动力活性。FC-Chl系统获得的溶胶-凝胶转变温度为28.8±0.3°C。该平台的流变学和质地特性适合用作皮肤病学系统，具有易于施用和在给药部位具有良好保留特性的特点。体外释放研究表明存在两种不同的机制，可以合理地遵循零级和一级动力学模型。PS成分具有皮肤渗透性，渗透深度达到830μm（在表皮和真皮之间）。FC-Chl系统的光动力学评估有效地降解了尿酸。量子产率（Φ PS成分具有皮肤渗透性，渗透深度达到830μm（在表皮和真皮之间）。FC-Chl系统的光动力学评估有效地降解了尿酸。量子产率（Φ PS成分具有皮肤渗透性，渗透深度达到830μm（在表皮和真皮之间）。FC-Chl系统的光动力学评估有效地降解了尿酸。量子产率（Φ_Δ ¹ Ò ₂）和寿命（τ ¹ Ò ₂单线态氧的）显示出对菠菜提取物和分离的叶绿素类似的值一个在乙醇物种。这些结果允许将FC-Chl平台分类为可能在主题PDT中传递基于叶绿素的提取物，这表明它值得进行体内评估。