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.
Raman imaging of molecular groups in the wavenumber silent region
Autoren
C. Schultz, J. Popp
Erscheinungsjahr
Erschienen in:
Analytical & bioanalytical chemistry
Raman imaging in the wavenumber silent region emerged around 15 years ago as a powerful tool for visualizing biomolecules and synthetic compounds in complex environments with minimal spectral and biological interference. Since then, the field has advanced from simple proof-of-concept studies using available tags to the rational design of highly efficient Raman labels with sharp silent region signatures, now applied to real biological and biomedical questions. This review traces the evolution from the versatility of label-free Raman to the increasing relevance of labeled strategies, emphasizing how tag design influences functionality, application, and impact. We highlight recent progress in both the synthesis and deployment of tags tailored for specific cellular targets and processes and discuss the emerging need for labeled strategies to meet the demands of sensitivity, multiplexing, and biocompatibility in complex systems. Through this design-to-application perspective, the review provides a comprehensive overview of the current capabilities and significant applications, and identifies key future directions to fully exploit the potential of silent region Raman imaging.
Pathway to versatile, point of care, and wearable photonics in the mid-infrared and fingerprint region based on quantum-cascade lasers and analytical and computational advances [Invited]
Autoren
S. Taccheo, T. Mayerhöfer, M. Doron, M. Lepage, R. Douté, A. Manca, A. Hobl, S. Messaoudene, M. Volpert, C. Constancias, R. Ballarini, K. Jourde, J. Coutard, B. Bourlon, A. D’Avolio, B. Bakir, J. Popp
Erscheinungsjahr
Erschienen in:
Optical Materials Express
This paper aims to propose and discuss a pathway to versatile, portable, and wearable photonics devices in the mid-infrared region. We address the benefits and challenges of mid-infrared spectroscopy in the fingerprint region and the development of low-cost mass production devices for real-world applications in the near future. Firstly, the paper briefly introduces the mid-infrared and fingerprint region and discusses the importance of the detection of mid-infrared biomarkers for point-of-care medical applications, stressing the importance of multi-wavelength probing systems. We also discuss the challenge of long-wavelength signals through the matter and the benefits of photo-acoustic detection. The pathway we envisage is twofold: the first is to improve and predict deviation from the standard Bouguer–Beer–Lambert approximation for light propagation in tissue and matter. This approach requires calibrated and wavelength-specific sources. Secondly, to address these requirements, the paper presents the potential for future low-cost personalized devices based on an array of quantum cascade lasers developed on low-cost C-MOS technology and using photo-acoustic detection. The technology was first developed for gas analyses, but we report on a recent successful wearable device for glucose monitoring, which passed clinical trials. This technology will allow the development of future widespread portable mid-infrared devices with potential application not only in healthcare, addressed here, but also in precise gas and environmental chemical monitoring. The ability to record mid-infrared biomarkers at the point of care will be fundamental for the personalized optical digital twin, which will be the cornerstone of future healthcare systems.
Impact of glycerol solution on myocardium tissue – Ex vivo deep-UV Raman spectroscopy study
Autoren
A. Jaafar, T. Vaczi, N. Tarcea, D. Akimov, T. Meyer-Zedler, M. Schmitt, J. Popp, V. Tuchin, M. Veres
Erscheinungsjahr
Erschienen in:
Frontiers of Optoelectronics
Cardiomyopathies are often characterized by significant fibrotic remodelling of the heart, marked by an abnormal accumulation of collagen type I. Label free Raman spectroscopy, a non-invasive diagnostic technique, holds promise for monitoring biochemical changes throughout the initiation and progression of different diseases, including cardiomyopathies. This study demonstrates the effectiveness of 70% glycerol as a hyperosmotic immersion liquid for in-depth controlling the optical properties of ex vivo myocardium tissue during deep-UV Raman spectroscopy with 244 nm excitation. The results revealed a considerable enhancement in the intensities of Raman peak, particularly the amide I region after glycerol treatment. This occurred across all depths (0−120 µm) and glycerol treatment durations (30 and 60 min). A noticeable enhancement of the Raman peak at 1647 cm −¹ was also observed that is attributable to structural transformations of the collagen due to the dehydration induced by glycerol. This finding suggest that deep-UV Raman can be employed as a specific probe of the collagen environment. As the amide I region reflects structural changes in collagen type I, these findings propose the potential of deep-UV Raman spectroscopy in combination with glycerol as optical clearing agent for monitoring collagen modifications.
Unveiling the molecular dynamics of a nitrile-containing 5-lipoxygenase-activating protein antagonist in primary macrophages through Raman spectroscopy
Autoren
C. Schultz, P. Jordan, P. Dahlke, Z. Gür Maz, E. Banoğlu, T. Meyer-Zedler, M. Schmitt, O. Werz, J. Popp
Erscheinungsjahr
Erschienen in:
Chemical science
The nitrile (–C 00000000000000000 00000000000000000 00000000000000000 01111111111111110 00000000000000000 01111111111111110 00000000000000000 01111111111111110 00000000000000000 00000000000000000 00000000000000000 N) functional group is a versatile pharmacophore motif that also serves as an intrinsic, bioorthogonal Raman tag in the silent wavenumber region (1800–2700 cm−¹). Here, we exploit this dual functionality to track the potent nitrile-containing 5-lipoxygenase-activating protein (FLAP) antagonist BRP-685 in primary human macrophages using label-free spontaneous and stimulated Raman scattering. This approach enables direct intracellular localization at biologically relevant, low micromolar concentrations without chemical modification or external labels. Quantitative Raman imaging reveals that BRP-685 preferentially accumulates in lipid droplets, distinct from its membrane-bound target site at the nuclear envelope/endoplasmic reticulum. Multiplexed analysis with an alkyne-tagged lipid analog uncovers a unique distribution pattern, suggesting that lipid droplets act as intracellular reservoirs for highly lipophilic drugs.
Sulfate-Directed Silver Dendrites with Enhanced Stability for Ultrasensitive SERS-Based Therapeutic Drug Monitoring
Autoren
A. Dwivedi, J. Dellith, A. Makarova, S. El-Mashtoly, J. Popp, V. Sivakov, D. Cialla-May
Erscheinungsjahr
Erschienen in:
Advanced Science
Silver-based surface-enhanced Raman spectroscopy (SERS) substrates offer exceptional signal enhancement but suffer from poor long-term stability due to oxidative degradation, limiting their utility for real-world applications. Here, we introduce sulfate-directed silver dendrites (s-AgDs) as oxidation-resistant SERS substrates with extended shelf life, reproducible signal performance, and sub-picomolar sensitivity. Sulfate ions promote anisotropic growth and form a surface-associated sulfate layer, resulting in dendritic morphologies with high hot-spot density and suppressed surface oxidation. The AgDs demonstrate robust SERS performance over seven months under ambient conditions. We demonstrate translational utility by detecting five clinically relevant drugs in aqueous and blood plasma matrices with minimal pretreatment and excellent reproducibility. These results establish s-AgDs as a stable, reproducible, and application-ready SERS platform for point-of-care therapeutic drug monitoring.
