@article{LeiterWohlschlaegerVersenetal.2025, author = {Leiter, Nina and Wohlschl{\"a}ger, Maximilian and Versen, Martin and Harter, Sonja D. and Kießlich, Tina and Lederer, Franziska and Clauß, Stefanie and Schlosser, Dietmar and Armanu, Emanuel Gheorghita and Eberlein, Christian and Heipieper, Hermann J. and L{\"o}der, Martin G. J. and Laforsch, Christian}, title = {Effects of defined organic layers on the fluorescence lifetime of plastic materials}, series = {Analytical and Bioanalytical Chemistry}, volume = {417}, journal = {Analytical and Bioanalytical Chemistry}, number = {16}, doi = {10.1007/s00216-025-05888-y}, pages = {3651 -- 3663}, year = {2025}, abstract = {Plastics have become an integral part of modern life, and linked to that fact, the demand for and global production of plastics are still increasing. However, the environmental pollution caused by plastics has reached unprecedented levels. The accumulation of small plastic fragments—microplastics and nanoplastics—potentially threatens organisms, ecosystems, and human health. Researchers commonly employ non-destructive analytical methods to assess the presence and characteristics of microplastic particles in environmental samples. However, these techniques require extensive sample preparation, which represents a significant limitation and hinders a direct on-site analysis. In this context, previous investigations showed the potential of fluorescence lifetime imaging microscopy (FLIM) for fast and reliable identification of microplastics in an environmental matrix. However, since microplastics receive an environmental coating after entering nature, a challenge arises from organic contamination on the surface of microplastic particles. How this influences the fluorescence signal and the possibility of microplastic detection are unknown. To address this research gap, we exposed acrylonitrile butadiene styrene (ABS) and polyethylene terephthalate (PET) plastic samples to peptides, proteins, bacteria, and a filamentous fungus to induce organic contamination and mimic environmental conditions. We analyzed the fluorescence spectra and lifetimes of the samples using fluorescence spectroscopy and frequency-domain fluorescence lifetime imaging microscopy (FD-FLIM), respectively. Our results demonstrate that reliably identifying and differentiating ABS and PET was possible via FD-FLIM, even in the presence of these biological contaminations. These findings highlight the potential of this technique as a valuable tool for environmental monitoring and plastic characterization, offering a rapid and efficient alternative to currently used analytical methods.}, language = {en} } @inproceedings{LeiterWohlschlaegerAueretal.2021, author = {Leiter, Nina and Wohlschl{\"a}ger, Maximilian and Auer, Veronika and Versen, Martin and Laforsch, Christian}, title = {A Novel Approach to Identify Wood Species Optically using Fluorescence Lifetime Imaging Microscopy}, series = {SMSI 2021 Conference - Sensor and Measurement Science International}, booktitle = {SMSI 2021 Conference - Sensor and Measurement Science International}, pages = {169 -- 170}, year = {2021}, abstract = {This contribution presents the results obtained with fluorescence lifetime imaging microscopy (FLIM)within the optical identification and differentiation of the four wood species walnut, beech, spruce, and maple. The experimental setup as well as the evaluation algorithm, with which the experiments were carried out, is explained briefly.}, language = {en} } @inproceedings{LeiterWohlschlaegerAueretal.2021, author = {Leiter, Nina and Wohlschl{\"a}ger, Maximilian and Auer, Veronika and Versen, Martin and Laforsch, Christian}, title = {An algorithmic method to identify multiple wood species in a single image by their specific fluorescence lifetimes}, series = {OSA Imaging and Applied Optics Congress 2021 (3D, COSI, DH, ISA, pcAOP)}, booktitle = {OSA Imaging and Applied Optics Congress 2021 (3D, COSI, DH, ISA, pcAOP)}, doi = {10.1364/COSI.2021.CF2B.3}, pages = {CF2B.3}, year = {2021}, abstract = {Fluorescence lifetime imaging microscopy (FLIM) combined with an image processing algorithm is successfully used for the optical identification and areal separation of three wood species of maple, larch and nut in a single taken image.}, language = {en} } @inproceedings{WohlschlaegerHolstVersenetal.2021, author = {Wohlschl{\"a}ger, Maximilian and Holst, Gerhard and Versen, Martin and Laforsch, Christian}, title = {An optical method to differentiate wood from polymers using fluorescence lifetime imaging microscopy}, series = {OSA Optical Sensors and Sensing Congress 2021 (AIS, FTS, HISE, SENSORS, ES)}, booktitle = {OSA Optical Sensors and Sensing Congress 2021 (AIS, FTS, HISE, SENSORS, ES)}, doi = {10.1364/ES.2021.EW4G.6}, pages = {EW4G.6}, year = {2021}, abstract = {In this contribution investigations with fluorescence lifetime imaging microscopy (FLIM) are made to optically distinguish polymers and wood. The results show that the distinction and identification is possible in a graphical and calculative way.}, language = {en} } @inproceedings{WohlschlaegerVersenLaforsch2022, author = {Wohlschl{\"a}ger, Maximilian and Versen, Martin and Laforsch, Christian}, title = {Optical identification of car tire particles on soil using fluorescence lifetime imaging microscopy}, series = {Optical Sensors and Sensing Congress 2022 (AIS, LACSEA, Sensors, ES), Technical Digest Series (Optica Publishing Group, 2022)}, booktitle = {Optical Sensors and Sensing Congress 2022 (AIS, LACSEA, Sensors, ES), Technical Digest Series (Optica Publishing Group, 2022)}, doi = {10.1364/ES.2022.ETu3H.3}, pages = {ETu3H.3}, year = {2022}, abstract = {Tire wear is one of the major contributors of environmental pollution by microplastic. FD-FLIM in combination with an image processing algorithm are successfully applied to detect tyre wear on soil.}, language = {en} } @inproceedings{WohlschlaegerVersenLaforsch2021, author = {Wohlschl{\"a}ger, Maximilian and Versen, Martin and Laforsch, Christian}, title = {Non-destructive evaluation of treated polyethylene terephthalate films by fluorescence lifetime imaging}, series = {2021 IEEE Sensors Applications Symposium (SAS)}, booktitle = {2021 IEEE Sensors Applications Symposium (SAS)}, doi = {10.1109/SAS51076.2021.9530008}, pages = {1 -- 5}, year = {2021}, abstract = {The fluorescence decay time allows to identify and distinguish polymers from each other. Three differently treated biaxially-oriented polyethylene terephthalate films are examined with two excitation wavelengths of 445 and 488nm. The fluorescence decay time is dependent of the treatment method of the films and is a means for identification.}, language = {en} } @inproceedings{WohlschlaegerVersenLaforsch2022, author = {Wohlschlaeger, Maximilian and Versen, Martin and Laforsch, Christian}, title = {A novel approach to optically detect microplastic in an environmental matrix with Rapid-FLIM}, series = {Sensors and Measuring Systems; 21th ITG/GMA-Symposium}, booktitle = {Sensors and Measuring Systems; 21th ITG/GMA-Symposium}, pages = {1 -- 6}, year = {2022}, language = {en} } @inproceedings{LeiterWohlschlaegerVersenetal.2022, author = {Leiter, Nina and Wohlschlaeger, Maximilian and Versen, Martin and Laforsch, Christian}, title = {Non-destructive differentiation of treated and non-treated wood using fluorescence lifetime imaging microscopy}, series = {Sensors and Measuring Systems; 21th ITG/GMA-Symposium}, booktitle = {Sensors and Measuring Systems; 21th ITG/GMA-Symposium}, pages = {1 -- 6}, year = {2022}, language = {en} } @article{LeiterWohlschlaegerVersenetal.2022, author = {Leiter, Nina and Wohlschl{\"a}ger, Maximilian and Versen, Martin and Laforsch, Christian}, title = {An algorithmic method for the identification of wood species and the classification of post-consumer wood using fluorescence lifetime imaging microscopy}, series = {Journal of Sensors and Sensor Systems}, volume = {11}, journal = {Journal of Sensors and Sensor Systems}, number = {1}, doi = {10.5194/jsss-11-129-2022}, pages = {129 -- 136}, year = {2022}, abstract = {In this contribution the frequency domain fluorescence lifetime imaging microscopy (FD-FLIM) technique is evaluated for post-consumer wood sorting. The fluorescence characteristics of several wood samples were determined, whereby two excitation wavelengths (405 and 488 nm) were used. The measured data were processed using algorithmic methods to identify the wood species and post-consumer wood category. With the excitation wavelength of 405 nm, 16 out of 19 samples could be correctly assigned to the corresponding post-consumer wood category by means of the fluorescence lifetimes. Thus, the experimental results revealed the high potential of the FD-FLIM technique for automated post-consumer wood sorting.}, language = {en} } @inproceedings{WohlschlaegerVersenLaforsch2022, author = {Wohlschl{\"a}ger, Maximilian and Versen, Martin and Laforsch, Christian}, title = {Investigation of the Impact of CaCO3 Concentrations on the Fluorescence Lifetime of Polypropylene}, series = {2022 Conference on Lasers and Electro-Optics (CLEO)}, booktitle = {2022 Conference on Lasers and Electro-Optics (CLEO)}, pages = {1 -- 2}, year = {2022}, abstract = {The impact of fillers on the fluorescence lifetime of polymers is still unknown. Investigating polypropylene containing different CaCO 3 concentrations using FD-FLIM show an exponential increase in fluorescence lifetime proportional to the CaCO 3 density in polypropylene.}, language = {en} } @inproceedings{ManiyattuGeegyLeiteretal.2022, author = {Maniyattu, Georgekutty Jose and Geegy, Eldho and Leiter, Nina and Wohlschl{\"a}ger, Maximilian and Versen, Martin and Laforsch, Christian}, title = {Development of a neural network to identify plastics using Fluorescence Lifetime Imaging Microscopy}, series = {2022 IEEE Sensors Applications Symposium (SAS)}, booktitle = {2022 IEEE Sensors Applications Symposium (SAS)}, doi = {10.1109/SAS54819.2022.9881372}, pages = {1 -- 6}, year = {2022}, abstract = {Plastics have become a major part of human's daily life. An uncontrolled usage of plastic leads to an accumulation in the environment posing a threat to flora and fauna, if not recycled correctly. The correct sorting and recycling of the most commonly available plastic types and an identification of plastic in the environment are important. Fluorescence lifetime imaging microscopy shows a high potential in sorting and identifying plastic types. A data-based and an image-based classification are investigated using python programming language to demonstrate the potential of a neural network based on fluorescence lifetime images to identify plastic types. The results indicate that the data-based classification has a higher identification accuracy compared to the image-based classification.}, language = {en} } @inproceedings{WohlschlaegerVersenLaforsch2022, author = {Wohlschl{\"a}ger, Maximilian and Versen, Martin and Laforsch, Christian}, title = {Investigation of the Impact of CaCO3 Concentrations on the Fluorescence Lifetime of Polypropylene}, series = {Conference on Lasers and Electro-Optics}, booktitle = {Conference on Lasers and Electro-Optics}, organization = {Technical Digest Series (Optica Publishing Group, 2022)}, doi = {10.1364/CLEO_AT.2022.AM2M.2}, pages = {AM2M.2}, year = {2022}, abstract = {The impact of fillers on the fluorescence lifetime of polymers is still unknown. Investigating polypropylene containing different CaCO3 concentrations using FD-FLIM show an exponential increase in fluorescence lifetime proportional to the CaCO3 density in polypropylene.}, language = {en} }