Lehrstuhl für Physikalische Chemie II (Prof. Dr. Dr. Jürgen Popp)
Die Forschung der Arbeitsgruppe konzentriert sich hauptsächlich auf die Entwicklung und Anwendung innovativer Raman-basierter Methoden zur Beantwortung biomedizinischer Fragen. Raman-Spektroskopie und die verschiedenartigen Raman-basierten Technologien wie zum Beispiel die Raman-Mikroskopie, SERS oder CARS sind leistungsfähige Werkzeuge zur Bearbeitung eines breiten Spektrums bioanalytischer und biomedizinischer Probleme wie der schnellen Identifizierung von Pathogenen, der sensitiven Überwachung geringkonzentrierter Moleküle (beispielsweise Drogen oder Metabolite) oder der objektiven klinischen Beurteilung von Zell- und Gewebeproben zur Krebsfrüherkennung.
Multiplex electrochemical aptasensor for the simultaneous detection of linomycin and neomycin antibiotics
ErscheinungsjahrErschienen in:Talanta: the international journal of pure and applied analytical chemistry
W. Al borhani, A. Rhouati, D. Cialla-May, J. Popp, M. Zourob
A multiplexing immunosensing platform for the simultaneous detection of snake and scorpion venoms: Towards a better management of antidote administration
ErscheinungsjahrErschienen in:Talanta: the international journal of pure and applied analytical chemistry
A. AlMusharraf, A. Rhouati, D. Cialla-May, J. Popp, M. Zourob
Development of a label-free, functional, molecular and structural imaging system combining optical coherence tomography and Raman spectroscopy for in vivo measurement of rat retina
ErscheinungsjahrErschienen in:Biomedical Optics Express
R. Sentosa, M. Salas, C. Merkle, M. Eibl, W. de Jong, A. Amelink, M. Schmitt, I. Krestnikov, V. Shynkar, M. Kempe, T. Schmoll, B. Baumann, M. Andreana, A. Unterhuber, J. Popp, W. Drexler, R. Leitgeb
In vivo access to molecular information of retinal tissue is considered to play a critical role in enabling early diagnosis of ophthalmic and neurodegenerative diseases. The current gold standard of retina imaging, optical coherence tomography and angiography provides only the retinal morphology and blood perfusion, missing the full spectrum of molecular information. Raman spectroscopy addresses this gap while keeping the investigation non-invasive and label-free. Although previous studies have demonstrated the huge diagnostic potential of combining both modalities for in vivo biological tissue measurement, some have either employed unsafe optical power levels for in vivo retinal measurements or presented results that were negative or contradictory. In this study, we have developed an eye-safe multimodal in vivo label-free imaging system and demonstrate the potential of this device by investigating the retina of a living albino rat. The acquired Raman spectra showed relevant Raman bands in comparison with the previous ex vivo studies. Using this multimodal imaging system for non-invasive retina measurements of transgenic rodents holds the potential to advance the understanding of the pathophysiology of both ophthalmic and neurodegenerative diseases.
Surface-Enhanced Raman Spectroscopy for Biomedical Applications: Recent Advances and Future Challenges
ErscheinungsjahrErschienen in:ACS Applied Materials and Interfaces
L. Lin, R. Alvarez-Puebla, L. Liz-Marzán, M. Trau, J. Wang, L. Fabris, X. Wang, G. Liu, S. Xu, X. Han, L. Yang, A. Shen, S. Yang, Y. Xu, C. Li, J. Huang, S. Liu, J. Huang, I. Srivastava, M. Li, L. Tian, L. Nguyen, X. Bi, D. Cialla-May, P. Matousek, N. Stone, R. Carney, W. Ji, W. Song, Z. Chen, I. Phang, M. Henriksen-Lacey, H. Chen, Z. Wu, H. Guo, H. Ma, G. Ustinov, S. Luo, S. Mosca, B. Gardner, Y. Long, J. Popp, B. Ren, S. Nie, B. Zhao, X. Ling, J. Ye
Raman spectroscopy as a comprehensive tool for profiling endospore-forming bacteria
ErscheinungsjahrErschienen in:The analyst: the analytical journal of the Royal Society of Chemistry
M. Salbreiter, A. Wagenhaus, P. Rösch, J. Popp
Accurate and reliable bacterial identification at the genus and species levels is essential for effective clinical diagnostics. Pathogens such as Clostridium perfringens, Bacillus cereus, Clostridioides difficile, and Paraclostridium sordellii pose significant challenges due to their unique cultivation requirements and developmental traits. Building on our previous work demonstrating the differentiation of vegetative Clostridium cells from non-Clostridium genera, we now aim to extend this approach to distinguish endospores of the same species. Raman spectroscopy was utilized to develop a comprehensive library of endospore spectra, encompassing both pathogenic and non-pathogenic species. This extensive dataset forms the foundation for advanced analytical capabilities. Chemometric analysis of single-endospore Raman spectra revealed significant discriminatory power across multiple hierarchical levels, facilitating the distinction between vegetative cells and endospores. Furthermore, this method enabled precise genus- and species-level classification of endospores, underscoring its potential for high-resolution bacterial endospore identification. These results highlight the versatility and efficacy of Raman spectroscopy in addressing the challenges associated with the identification of bacterial endospores in diverse clinical and environmental contexts. These findings present the first comprehensive library of endospore Raman spectra, demonstrating that Raman spectroscopy combined with chemometric analysis is a robust and reliable method for differentiating endospores of Clostridium species from those of Bacillus, Clostridioides, and Paraclostridium. This approach holds significant promise as a precise diagnostic tool for bacterial endospore identification in clinical settings.
Impact of clinical preparation steps and use of sex-specific reference for accurate antibiotic monitoring in body fluids
ErscheinungsjahrErschienen in:Communications Medicine
C. Domes, L. Graul, T. Frosch, J. Popp, S. Hagel, M. Pletz, T. Frosch
Background: Effective antibiotic therapy in critically ill patients requires precise dosing tailored to individual conditions. However, physiological changes in these patients can complicate drug exposure prediction, leading to treatment failure or toxicity. Therapeutic drug monitoring (TDM) is crucial in optimizing antibiotic therapy, with Raman spectroscopy emerging as a promising method due to its speed and sensitivity. Methods: The utility of resonance Raman spectroscopy in analyzing clinical urine samples was investigated, specifically focusing on piperacillin concentrations. Samples subjected to various preparation techniques, including freezing, centrifugation, and filtration, were analyzed using deep UV resonance Raman spectroscopy. Data analysis involved preprocessing and chemometric modeling to assess concentration changes and the influence of sample matrix. Results: Sample preparation steps induce concentration changes in piperacillin, with freezing having the highest impact. Chemometric modeling reveals that freezing, filtration, and centrifugation, especially when combined, reduce drug concentration. Furthermore, the choice of urine reference for quantification impacts results, with sex-specific urine pools showing better accuracy compared to mixed pools. Conclusions: Resonance Raman spectroscopy effectively quantifies piperacillin concentrations in urine. Freezing, centrifugation, and filtration during sample preparation influence drug concentration. Using sex-specific urine pools as references yields more accurate quantification results. These findings underscore the importance of considering sample processing effects and reference selection in TDM studies, offering insights for optimizing antibiotic dosing in critically ill patients. Further validation on a larger scale is warranted to confirm these observations.
Characterizing Metabolic Shifts in Septic Murine Kidney Tissue Using 2P-FLIM for Early Sepsis Detection
ErscheinungsjahrErschienen in:Bioengineering
S. Greiner, M. Ebrahimi, M. Rodewald, A. Urbanek, T. Meyer-Zedler, M. Schmitt, U. Neugebauer, J. Popp
In this study, thin mouse kidney sections from healthy mice and those infected leading to acute and chronic sepsis were examined with two-photon excited fluorescence lifetime imaging (2P-FLIM) using the endogenous fluorescent coenzymes nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD). The results presented show that this approach is a powerful tool for investigating cell metabolism in thin tissue sections. An adapted measurement routine was established for these samples by performing a spectral scan, identifying a combination of two excitation wavelengths and two detection ranges suitable for detailed scan images of NADH and FAD. Selected positions in thin slices of the renal cortex of nine mice (three healthy, three with chronic sepsis, and three with acute sepsis) were studied using 2P-FLIM. In addition, overview images were obtained using two-photon excited fluorescence (2PEF) intensity. This study shows that healthy kidney slices differ considerably from those with acute sepsis with regard to their fluorescence lifetime signatures. The latter shows a difference in metabolism between the inner and outer cortex, indicating that outer cortical tubular cells switch their metabolism from oxidative phosphorylation to glycolysis in kidneys from mice with acute sepsis and back in later stages, as seen for mice with chronic infections. These findings suggest that 2P-FLIM could serve as a powerful tool for early-stage sepsis diagnosis and monitoring metabolic recovery during treatment.
Tracing the Background-Suppressed Vibrational Decay Time of a Molecular Monolayer with Time-Resolved Surface-Enhanced Broadband Coherent Anti-Stokes Raman Scattering
ErscheinungsjahrErschienen in:Laser and Photonics Reviews
P. Barman, A. Chakraborty, X. Wu, D. Akimov, T. Meyer-Zedler, C. Ronning, M. Schmitt, J. Popp, J. Huang
