Dr. rer. nat. Steffen Hackbarth
Profil
Zusammenfassung
Dr. Hackbarth entwickelt Photosensibilisatoren und photodynamische Verfahren zur Bekämpfung von Bakterien und Tumoren. Seine Expertise liegt in der Charakterisierung von Licht-aktivierten Molekülen, der Messung von Singulettsauerstoff und der Anwendung dieser Technologie für antimikrobielle und therapeutische Zwecke – als Alternative zu Antibiotika und konventionellen Behandlungen.
Skills
Stammdaten
Identität, Organisation und Kontakt aus HU-FIS.
Forschungsthemen7
3. Chinesisch-Deutsches Symposium "Singulettsauerstoff und photodynamische Effekte"
Quelle ↗Förderer: DFG sonstige Programme Zeitraum: 02/2019 - 04/2019 Projektleitung: Dr. rer. nat. Steffen Hackbarth
Antimikrobielle photodynamische Wirkung von Geweben
Quelle ↗Förderer: Wirtschaftsunternehmen / gewerbliche Wirtschaft Zeitraum: 04/2019 - 01/2020 Projektleitung: Dr. rer. nat. Steffen Hackbarth
Direkte Optische Überwachung der Lokalisation und Aktivität Hochselektiver Photosensibilisatoren für die Photodynamische Tumortherapie in vivo
Quelle ↗Förderer: Andere inländische Stiftungen Zeitraum: 11/2018 - 06/2023 Projektleitung: Dr. rer. nat. Steffen Hackbarth
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Publikationen25
Top 25 nach Zitationen — Quelle: OpenAlex (BAAI/bge-m3 embedded für Matching).
Singlet Oxygen Quantum Yields of Different Photosensitizers in Polar Solvents and Micellar Solutions
1998Journal of Porphyrins and Phthalocyanines · 725 Zitationen · DOI
The singlet oxygen luminescence method and the photochemical methods using 1,3-diphenylisobenzofuran ( DPBF ) or bilirubin ditaurate ( BDT ) as chemical quenchers were employed to determine the single oxygen quantum yields (Φ Δ ) of different phthalocyanines and tris(2,2″-bipyridyl)ruthenium(II) dichloride in dimethylformamide ( DMF ) or aqueous micellar solution of 0.1 M CTAC (cetyltrimethylammonium chloride). Additionally, a perylenetetracarboxylic acid diimide derivative was examined in DMF . In a series of tetrasulfonated phthalocyanines ( PTS ) the following order was found: ZnPTS > GaPTS > AlPTS ≈ H 2 PTS > CoPTS . In general, the singlet oxygen quantum yields are higher in DMF than in 0.1 M CTAC/H 2 O . The results obtained with the photochemical systems are comparable with those obtained by the photophysical method. The photochemical DPBF method results in absolute values of Φ Δ . However, in micellar solution, chain reactions occur when DPBF is used as chemical quencher in the photo-oxidative process. This problem can be overcome by adding sodium thiosulphate which is able to destroy the endoperoxide initially formed. BDT can be used as quencher in different solvents to determine Φ Δ relative to a photosensitizer with known singlet oxygen quantum yield in the respective solvent. In comparison to the chemical methods the luminescence method exhibits the advantage that side reactions of the quencher are excluded. But normally the Φ Δ values obtained are relative to a reference, since absolute determinations need much larger efforts.
Langmuir · 601 Zitationen · DOI
Several studies suggested that the cytotoxic effects of quantum dots (QDs) may be mediated by cadmium ions (Cd2+) released from the QDs cores. The objective of this work was to assess the intracellular Cd2+ concentration in human breast cancer MCF-7 cells treated with cadmium telluride (CdTe) and core/shell cadmium selenide/zinc sulfide (CdSe/ZnS) nanoparticles capped with mercaptopropionic acid (MPA), cysteamine (Cys), or N-acetylcysteine (NAC) conjugated to cysteamine. The Cd2+ concentration determined by a Cd2+-specific cellular assay was below the assay detection limit (<5 nM) in cells treated with CdSe/ZnS QDs, while in cells incubated with CdTe QDs, it ranged from approximately 30 to 150 nM, depending on the capping molecule. A cell viability assay revealed that CdSe/ZnS QDs were nontoxic, whereas the CdTe QDs were cytotoxic. However, for the various CdTe QD samples, there was no dose-dependent correlation between cell viability and intracellular [Cd2+], implying that their cytotoxicity cannot be attributed solely to the toxic effect of free Cd2+. Confocal laser scanning microscopy of CdTe QDs-treated cells imaged with organelle-specific dyes revealed significant lysosomal damage attributable to the presence of Cd2+ and of reactive oxygen species (ROS), which can be formed via Cd2+-specific cellular pathways and/or via CdTe-triggered photoxidative processes involving singlet oxygen or electron transfer from excited QDs to oxygen. In summary, CdTe QDs induce cell death via mechanisms involving both Cd2+ and ROS accompanied by lysosomal enlargement and intracellular redistribution.
ACS Nano · 283 Zitationen · DOI
In this study, the skin penetration and cellular uptake of amorphous silica particles with positive and negative surface charge and sizes ranging from 291 ± 9 to 42 ± 3 nm were investigated. Dynamic light scattering measurements and statistical analyses of transmission electron microscopy images were used to estimate the degree of particle aggregation, which was a key aspect to understanding the results of the in vitro cellular uptake experiments. Despite partial particle aggregation occurring after transfer in physiological media, particles were taken up by skin cells in a size-dependent manner. Functionalization of the particle surface with positively charged groups enhanced the in vitro cellular uptake. However, this positive effect was contrasted by the tendency of particles to form aggregates, leading to lower internalization ratios especially by primary skin cells. After topical application of nanoparticles on human skin explants with partially disrupted stratum corneum, only the 42 ± 3 nm particles were found to be associated with epidermal cells and especially dendritic cells, independent of their surface functionalization. Considering the wide use of nanomaterials in industries and the increasing interest for applications in pharmaceutics and cosmetics versus the large number of individuals with local or spread impairment of the skin barrier, e.g., patients with atopic dermatitis and chronic eczema, a careful dissection of nanoparticle-skin surface interactions is of high relevance to assess possible risks and potentials of intended and unintended particle exposure.
Kooperationen2
Bestätigte Forscher↔Partner-Paare aus HU-FIS — Gold-Standard-Positive für das Matching.
Photodynamische Inaktivierung von Bakterien im Sperma – eine Alternative zu Antibiotika in der Schweinezucht (PodiPig) - Teilprojekt B
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Photodynamische Inaktivierung von Bakterien im Sperma – eine Alternative zu Antibiotika in der Schweinezucht (PodiPig) - Teilprojekt B
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