Dr. rer. nat. Steffen Hackbarth
Profil
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
Initiierung bilateraler Kooperation mit AG Maeda /Kumamoto, Japan
Quelle ↗Förderer: DFG Sachbeihilfe Zeitraum: 03/2010 - 09/2010 Projektleitung: Dr. rer. nat. Steffen Hackbarth
Meeting Tetrapyrrole Discussion Group (Veranstaltung: 13.-14.09.2010, Berlin)
Quelle ↗Zeitraum: 06/2010 - 12/2011 Projektleitung: Dr. rer. nat. Steffen Hackbarth
Photodynamische Inaktivierung von Bakterien im Sperma – eine Alternative zu Antibiotika in der Schweinezucht (PodiPig) - Teilprojekt B
Quelle ↗Förderer: Bundesministerium für Landwirtschaft, Ernährung und Heimat Zeitraum: 01/2026 - 01/2029 Projektleitung: Dr. rer. nat. Steffen Hackbarth
Polymer Nanopartikel als Photosensibilisatoren
Quelle ↗Förderer: DAAD Zeitraum: 01/2016 - 12/2017 Projektleitung: Dr. rer. nat. Steffen Hackbarth
Mögliche Industrie-Partner10
Stand: 26.4.2026, 19:48:44 (Top-K=20, Min-Cosine=0.4)
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- DYnamic control in hybrid plasmonic NAnopores: road to next generation multiplexed single MOlecule detection
- 11 Treffer57.5%
- INTeractive RObotics Research NetworkP57.5%
- INTeractive RObotics Research Network
- 10 Treffer57.5%
- INTeractive RObotics Research NetworkP57.5%
- INTeractive RObotics Research Network
- 6 Treffer57.2%
- Design & Implementierung eines neuronalen Netzwerks für die Personendetektion (Transferbonus)P57.2%
- Design & Implementierung eines neuronalen Netzwerks für die Personendetektion (Transferbonus)
- 39 Treffer56.7%
- Surface-enhanced Raman spectroscopy in liquid biopsy for breast cancerP56.7%
- Surface-enhanced Raman spectroscopy in liquid biopsy for breast cancer
- 39 Treffer56.7%
- Surface-enhanced Raman spectroscopy in liquid biopsy for breast cancerP56.7%
- Surface-enhanced Raman spectroscopy in liquid biopsy for breast cancer
- 2 Treffer56.1%
- The Pathway to Inquiry Based Science TeachingP56.1%
- The Pathway to Inquiry Based Science Teaching
- 2 Treffer56.1%
- The Pathway to Inquiry Based Science TeachingP56.1%
- The Pathway to Inquiry Based Science Teaching
- 2 Treffer56.1%
- The Pathway to Inquiry Based Science TeachingP56.1%
- The Pathway to Inquiry Based Science Teaching
- 2 Treffer56.1%
- The Pathway to Inquiry Based Science TeachingP56.1%
- The Pathway to Inquiry Based Science Teaching
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 · 723 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 · 600 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.
Pharmaceutical Research · 241 Zitationen · DOI
Photochemical & Photobiological Sciences · 164 Zitationen · DOI
Journal of Photochemistry and Photobiology B Biology · 112 Zitationen · DOI
JDDG Journal der Deutschen Dermatologischen Gesellschaft · 104 Zitationen · DOI
Summary The increasing resistance of bacteria against antibiotics is one of the most important clinical challenges of the 21 st century. Within the gram‐positive bacteria the methicillin‐resistant Staphylococcus aureus and Enterococcus faecium represent the major obstacle to successful therapy. Apart from the development of new antibiotics it requires additional differently constituted approaches, like photodynamic inactivation in order to have further effective treatment options against bacteria available. Certain dyes, termed photosensitizers, are able to store the absorbed energy in long‐lived electronic states upon light activation with appropriate wavelengths and thus make these states available for chemical activation of the immediate surroundings. The interaction with molecular oxygen, which leads to different, very reactive and thus cytotoxic oxygen species, is highlighted. In this review the application of the photodynamic inactivation of bacteria will be discussed regarding the possible indications in dermatology, like localized skin and wound infections or the reduction of nosocomial colonization with multi‐resistant bacteria on the skin. The crucial advantage of the local application of photosensitizers followed by irradiation of the area of interest is the fact that independent of the resistance pattern of a bacterium a direct inactivation takes place similarly as with an antiseptic. In this review the physical‐chemical and biological basics of photo‐dynamic inactivation of bacteria (PIB) will be discussed as well as the possible dermatological indications.
Chemical Communications · 91 Zitationen · DOI
The very regioselective twofold cyclopropanation of C60 with a porphyrin bismalonate leads to a C2 symmetrical [60]fullerene–porphyrin dyad with pronounced electronic interactions between the two π–π stacked chromophores.
Journal of Photochemistry and Photobiology B Biology · 88 Zitationen · DOI
Laser Physics Letters · 78 Zitationen · DOI
The presented setup for singlet oxygen luminescence detection in cell suspensions outperforms the current setups by more than one order-of-magnitude gain in sensitivity. This not only allows precise determination of the singlet oxygen lifetime in cells but also reveals a previously unnoticeable behaviour of the singlet oxygen luminescence during low dose illumination.
Chemistry - A European Journal · 77 Zitationen · DOI
The nanoenvironment provided by the neighboring dendra characteristically influences the redox potentials and the photophysical properties of the tetraphenylporphyrin–zinc (Zn-TPP; denoted as P in Figure) chromophore within the dendrimers 1, which are based on C60 as a structure-determining core. Such functional dendrimers represent a new prototype of model systems for heme proteins (1).
Journal of Applied Microbiology · 75 Zitationen · DOI
In a world with bacteria that gain the ability to withstand the effects of antibiotics and are able to transmit on these resistances to the next generation, it becomes necessary to develop new approaches to inhibit the growth of multi-resistant bacteria. The photodynamic inactivation of bacteria is based on a three-component system by which the growth of the bacterial cells is inhibited. The well-directed oxidative damage is initiated by visible light of a certain wavelength, which excites a nontoxic photoactive molecule, called photosensitizer. Its reaction with oxygen causes the generation of cytotoxic species like singlet oxygen, which is highly reactive and causes the inactivation of the growth of bacteria.
European Journal of Pharmaceutics and Biopharmaceutics · 70 Zitationen · DOI
Journal of the American Chemical Society · 49 Zitationen · DOI
A generic method describes advanced tailoring of polymer drug carriers based on polymer-block-peptides. Combinatorial means are used to select suitable peptide segments to specifically complex small-molecule drugs. The resulting specific drug formulation agents render insoluble drugs water-soluble and enable precise adjustment of drug-release profiles beyond established block-copolymer carriers. While proof of principle is shown on chlorin as a partially approved drug for photodynamic cancer therapy, the concept is universal and applies to a broad spectrum of difficult drugs.
Bioorganic & Medicinal Chemistry Letters · 48 Zitationen · DOI
Photochemical & Photobiological Sciences · 44 Zitationen · DOI
Chemistry - A European Journal · 41 Zitationen · DOI
In view of increasing demands for efficient photosensitizers for photodynamic therapy (PDT), we herein report the synthesis and photophysical characterizations of new chlorin e6 trimethyl ester and protoporphyrin IX dimethyl ester dyads as free bases and Zn(II) complexes. The synthesis of these molecules linked at the β-pyrrolic positions to pyrano[3,2-c]coumarin, pyrano[3,2-c]quinolinone, and pyrano[3,2-c]naphthoquinone moieties was performed by using the domino Knoevenagel hetero Diels-Alder reaction. The α-methylenechromanes, α-methylenequinoline, and ortho-quinone methides were generated in situ from a Knoevenagel reaction of 4-hydroxycoumarin, 4-hydroxy-6-methylcoumarin, 4-hydroxy-N-methylquinolinone, and 2-hydroxy-1,4-naphthoquinone, respectively, with paraformaldehyde in dioxane. All the dyads as free bases and as Zn(II) complexes were obtained in high yields. All new compounds were fully characterized by 1D and 2D NMR techniques, UV/Vis spectroscopy, and HRMS. Their photophysical properties were evaluated by measuring the fluorescence quantum yield, the singlet oxygen quantum yield by luminescence detection, and also the triplet lifetimes were correlated by flash photolysis and intersystem crossing (ISC) rates. The fluorescence lifetimes were measured by a time-correlated single photon count (TCSPC) method, fluorescence decay associated spectra (FDAS), and anisotropy measurements. Magnetic circular dichroism (MCD) and circular dichroism (CD) spectra were recorded for one Zn(II) complex in order to obtain information, respectively, on the electronic and conformational states, and interpretation of these spectra was enhanced by molecular orbital (MO) calculations. Electrochemical studies of the Zn(II) complexes were also carried out to gain insights into their behavior for such applications.
Advanced Healthcare Materials · 40 Zitationen · DOI
Clinical applications of current photodynamic therapy (PDT) photosensitizers (PSs) are often limited by their absorption in the UV-vis range that possesses limited tissue penetration ability, leading to ineffective therapeutic response for deep-seated tumors. Alternatively, two-photon excited PS (TPE-PS) using NIR light triggered is one the most promising candidates for PDT improvement. Herein, multimodal polymer nanoparticles (PNPs) from polythiophene derivative as two-photon fluorescence imaging as well as two-photon-excited PDT agent are developed. The prepared PNPs exhibit excellent water dispersibility, high photostability and pH stability, strong fluorescence brightness, and low dark toxicity. More importantly, the PNPs also possess other outstanding features including: (1) the high <sup>1</sup> O<sub>2</sub> quantum yield; (2) the strong two-photon-induced fluorescence and efficient <sup>1</sup> O<sub>2</sub> generation; (3) the specific accumulation in lysosomes of HeLa cells; and (4) the imaging detection depth up to 2100 µm in the mock tissue under two-photon. The multifunctional PNPs are promising candidates as TPE-PDT agent for simultaneous cellular, deep-tissue imaging, and highly efficient in vivo PDT of cancer.
European Journal of Pharmaceutics and Biopharmaceutics · 38 Zitationen · DOI
Photophysical properties of pheophorbide-a-substituted diaminobutane poly-propylene-imine dendrimer
2001Chemical Physics · 37 Zitationen · DOI
Optics Communications · 35 Zitationen · DOI
Photochemical & Photobiological Sciences · 33 Zitationen · DOI
In vivo measurement of singlet oxygen luminescence kinetics is affected by the heterogeneity of biological samples. Even though singlet oxygen luminescence detection is technically getting easier, the analysis of signals from biological samples is still far from quantitative real time surveillance as it is aspired by the community. In this paper small unilamellar vesicles (SUVs) are used for modelling the general behaviour of heterogeneous samples. The geometry of the SUVs can be determined independently using dynamic light scattering. Therefore an accurate theoretical description of the generation, deactivation and diffusion of the singlet oxygen is possible. The theoretical model developed here perfectly fits the experimental results. Thus the location of the singlet oxygen generating a photosensitizer molecule can be exactly determined from the kinetics of the singlet oxygen luminescence. The application of the used theoretical approach thus allows for accurate quantitative measurements in SUVs.
Journal of Photochemistry and Photobiology B Biology · 33 Zitationen · DOI
Journal of the American Chemical Society · 32 Zitationen · DOI
Smooth and nonswelling spherical silica particles with a diameter of 100 nm and an aminopropyl coating are soluble in water at pH 11, coagulate quickly at pH 3, and redissolve at pH 9. Electron microscopy as well as visible spectra of covalently attached porphyrins indicate the aggregation state of the particles. Long-chain alpha,omega-dicarboxylic acids with a terminal oligoethyleneglycol (=OEG)-amide group were attached in a second self-assembly step to the remaining amine groups around the porphyrins. Form-stable 2-nm wells were thus obtained and were characterized by fluorescence quenching experiments using the bottom porphyrin as a target. The one-dimensional diffusion of fitting quencher molecules along the 2-nm pathway took several minutes. Porphyrins with a diameter above 2 nm could not enter the form-stable gaps at all. Added tyrosine stuck irreversibly to the walls of the nanowells and prevented the entrance of quencher molecules, the OEG-headgroups fixated 2,6-diaminoanthraquinone. A ring of methylammonium groups was then fixed at the walls of the wells at a distance of 5 or 10 A with respect to the bottom porphyrin. 2,6-Disulfonatoanthraquinone was attached only loosely to this ring, but the exactly fitting manganese(III) meso-(tetraphenyl-4-sulfonato)porphyrinate (Mn(III) TPPS) was tightly bound. Transient fluorescence experiments showed a fast decay time of 0.2 ns for the bottom porphyrin, when the Mn(III) TPPS was fixated at a distance of 5 A. Two different dyes have thus been immobilized at a defined subnanometer distance in an aqueous medium.
International Journal of Pharmaceutics · 31 Zitationen · DOI
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Photodynamische Inaktivierung von Bakterien im Sperma – eine Alternative zu Antibiotika in der Schweinezucht (PodiPig) - Teilprojekt B
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- Name
- Dr. rer. nat. Steffen Hackbarth
- Titel
- Dr. rer. nat.
- Fakultät
- Mathematisch-Naturwissenschaftliche Fakultät
- Institut
- Institut für Physik
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