Core–shell polymeric nanoparticles (NPs) made of either di-block or tri-block poly-ε-caprolactone and polyethylene glycol copolymers, covalently integrating Rhodamine B in the core or the shell have been prepared and a green fluorescent NO photodonor entrapped therein. One- and two-photon fluorescence experiments demonstrate that effective Förster Resonance Energy Transfer (FRET) occurs exclusively in the di-block NPs having the Rhodamine in the core, accounting for a localization of the NO photoreleaser in the inner part of the polymeric nanocarrier. These di-block NPs are stable in the presence of human serum albumin and their cargo release NO under exclusive excitation with visible light. Two-photon imaging experiments carried out using 900 nm NIR light, demonstrate that the release of the NO photodonor can be monitored in biological tissue, herein human skin, and provide insights into the integrity and penetration depth of the NPs. Toxicity experiments performed on NCTC keratinocyte cell lines in the dark and upon visible light irradiation show good biocompatibility of the polymeric system that therefore has a great potential in light of the multifaceted therapeutic role of NO.

中文翻译：

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通过Förster共振能量转移和双光子荧光成像 监测聚合物纳米颗粒中NO光供体的释放†

制备了由二嵌段或三嵌段聚ε-己内酯和聚乙二醇共聚物制成的核壳聚合物纳米颗粒（NPs），将罗丹明B共价整合在核或壳中，并在其中捕获了绿色荧光NO供体。单光子和双光子荧光实验表明，有效的福斯特共振能量转移（FRET）仅发生在核心中具有罗丹明的二嵌段NP中，这说明了NO光释放剂在聚合物纳米载体内部的定位。这些二嵌段NP在人血清白蛋白的存在下是稳定的，并且它们的货物在可见光排他性激发下释放NO。使用900 nm近红外光进行的双光子成像实验表明，可以在生物组织中监测NO光供体的释放，在这里是人类的皮肤，并提供有关NP完整性和渗透深度的见解。在黑暗中和在可见光照射下对NCTC角质形成细胞系进行的毒性实验显示，聚合物系统具有良好的生物相容性，因此，鉴于NO的多方面治疗作用，它具有很大的潜力。