NanoDelivery Lab, Department of Molecular Medicine, "Sapienza" University, Viale Regina Elena 291, 00161, Rome, Italy.
Department of Anatomy, Histology, Forensic Medicine and Orthopaedics, Section of Histology and Medical Embryology, "Sapienza" University, Rome, Italy.
Environ Res. 2024 Mar 1;244:117936. doi: 10.1016/j.envres.2023.117936. Epub 2023 Dec 16.
The presence of plastic fragments in aquatic environments, particularly at the micro- and nano-scale, has become a significant global concern. However, current detection methods are limited in their ability to reveal the presence of such particles in liquid samples. In this study, we propose the use of a fluorescence lifetime analysis system for the detection of micro- and nanoplastics in water. This approach relies on the inherent endogenous fluorescence of plastic materials and involves the collection of single photons emitted by plastic fragments upon exposure to a pulsed laser beam. Briefly, a pulsed laser beam (repetition frequency = 40 MHz) shines onto a sample solution, and the emitted light is filtered, collected, and used to trace the time distributions of the photons with high temporal resolution. Finally, the fluorescence lifetime was measured using fitting procedures and a phasor analysis. Phasor analysis is a fit-free method that allows the measurement of the fluorescence lifetime of a sample without any assumptions or prior knowledge of the sample decay pattern. The developed instrument was tested using fluorescence references and validated using unlabelled micro- and nano-scale particles. Our system successfully detected polystyrene particles in water, achieving a remarkable sensitivity with a detection limit of 0.01 mg/mL, without the need for sample pre-treatment or visual inspection. Although further studies are necessary to enhance the detection limit of the technique and distinguish between different plastic materials, this proof-of-concept study suggests the potential of the fluorescence lifetime-based approach as a rapid, robust, and cost-effective method for early warning detection and identification of plastic contaminants in aquatic environments.
在水生环境中，尤其是在微观和纳米尺度下，存在塑料碎片已成为一个重大的全球性问题。然而，目前的检测方法在揭示液体样品中存在这些颗粒方面能力有限。在这项研究中，我们提出使用荧光寿命分析系统来检测水中的微塑料和纳米塑料。这种方法依赖于塑料材料的固有内源性荧光，并涉及收集塑料碎片在暴露于脉冲激光束时发射的单光子。简而言之，脉冲激光束（重复频率=40MHz）照射到样品溶液上，发射的光经过过滤、收集，并用于以高时间分辨率追踪光子的时间分布。最后，使用拟合程序和相图分析测量荧光寿命。相图分析是一种无拟合方法，无需对样品的衰减模式进行任何假设或预先了解，即可测量样品的荧光寿命。开发的仪器使用荧光参考物质进行了测试，并使用未标记的微塑料和纳米塑料进行了验证。我们的系统成功地检测到了水中的聚苯乙烯颗粒，其检测限达到了 0.01mg/mL，灵敏度非常高，无需样品预处理或目视检查。尽管需要进一步研究来提高该技术的检测限并区分不同的塑料材料，但这项概念验证研究表明，基于荧光寿命的方法具有成为快速、稳健且具有成本效益的水生环境中塑料污染物早期预警检测和识别方法的潜力。
