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Peschel JM, Reichel LS, Hoffmann T, Enzensperger C, Schubert US, Traeger A, Gottschaldt M. Modification of Branched Poly(ethylene imine) with d-Fructose for Selective Delivery of siRNA into Human Breast Cancer Cells. Macromol Biosci 2023; 23:e2300135. [PMID: 37565461 DOI: 10.1002/mabi.202300135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 07/31/2023] [Indexed: 08/12/2023]
Abstract
Branched poly(ethylene imine) (bPEI) is frequently used in RNA interference (RNAi) experiments as a cationic polymer for the delivery of small interfering RNA (siRNA) because of its ability to form stable polyplexes that facilitate siRNA uptake. However, the use of bPEI in gene delivery is limited by its cytotoxicity and a need for target specificity. In this work, bPEI is modified with d-fructose to improve biocompatibility and target breast cancer cells through the overexpressed GLUT5 transporter. Fructose-substituted bPEI (Fru-bPEI) is accessible in three steps starting from commercially available protected fructopyranosides and bPEI. Several polymers with varying molecular weights, degrees of substitution, and linker positions on d-fructose (C1 and C3) are synthesized and characterized with NMR spectroscopy, size exclusion chromatography, and elemental analysis. In vitro biological screenings show significantly reduced cytotoxicity of 10 kDa bPEI after fructose functionalization, specific uptake of siRNA polyplexes, and targeted knockdown of green fluorescent protein (GFP) in triple-negative breast cancer cells (MDA-MB-231) compared to noncancer cells (HEK293T).
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Affiliation(s)
- Jan Matthias Peschel
- Institute of Organic and Macromolecular Chemistry, Friedrich Schiller University Jena, Humboldtstrasse 10, 07743, Jena, Germany
| | - Liên Sabrina Reichel
- Institute of Organic and Macromolecular Chemistry, Friedrich Schiller University Jena, Humboldtstrasse 10, 07743, Jena, Germany
| | - Tim Hoffmann
- Institute of Organic and Macromolecular Chemistry, Friedrich Schiller University Jena, Humboldtstrasse 10, 07743, Jena, Germany
| | | | - Ulrich Sigmar Schubert
- Institute of Organic and Macromolecular Chemistry, Friedrich Schiller University Jena, Humboldtstrasse 10, 07743, Jena, Germany
| | - Anja Traeger
- Institute of Organic and Macromolecular Chemistry, Friedrich Schiller University Jena, Humboldtstrasse 10, 07743, Jena, Germany
| | - Michael Gottschaldt
- Institute of Organic and Macromolecular Chemistry, Friedrich Schiller University Jena, Humboldtstrasse 10, 07743, Jena, Germany
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Pérez-Isidoro R, Guevara-Pantoja FJ, Ventura-Hunter C, Guerrero-Sánchez C, Ruiz-Suárez JC, Schubert US, Saldívar-Guerra E. Fluidized or not fluidized? Biophysical characterization of biohybrid lipid/protein/polymer liposomes and their interaction with tetracaine. Biochim Biophys Acta Gen Subj 2023; 1867:130287. [PMID: 36460234 DOI: 10.1016/j.bbagen.2022.130287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 11/19/2022] [Accepted: 11/23/2022] [Indexed: 12/03/2022]
Abstract
BACKGROUND Nanomedicine and the pharmaceutical industry demand the investigation of new biomaterials to improve drug therapies. Combinations of lipids, proteins, and polymers represent innovative platforms for drug delivery. However, little is known about the interactions between such compounds and this knowledge is key to prepare successful drug delivery systems. METHODS Biophysical properties of biohybrid vesicles (BhVs) composed of phospholipids, proteins, and amphiphilic block copolymers, assembled without using organic solvents, were investigated by differential scanning calorimetry and dynamic light scattering. We studied four biohybrid systems; two of them included the effect of incorporating tetracaine. Thermal changes of phospholipids and proteins when interacting with the amphiphilic block copolymers and tetracaine were analyzed. RESULTS Lysozyme and the copolymers adsorb onto the lipid bilayer modifying the phase transition temperature, enthalpy change, and cooperativity. Dynamic light scattering investigations revealed relevant changes in the size and zeta potential of the BhVs. Interestingly, tetracaine, a membrane-active drug, can fluidize or rigidize BhVs. CONCLUSIONS We conclude that positively charged regions of lysozyme are necessary to incorporate the block copolymer chains into the lipid membrane, turning the bilayer into a more rigid system. Electrostatic properties and the hydrophilic-lipophilic balance are determinant for the stability of biohybrid membranes. GENERAL SIGNIFICANCE This investigation provides fundamental information associated with the performance of biohybrid drug delivery systems and can be of practical significance for designing more efficient drug nanocarriers.
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Affiliation(s)
- R Pérez-Isidoro
- Centro de Investigación en Química Aplicada (CIQA), Enrique Reyna, 140, 25294 Saltillo, Coahuila, Mexico
| | | | - C Ventura-Hunter
- Centro de Investigación en Química Aplicada (CIQA), Enrique Reyna, 140, 25294 Saltillo, Coahuila, Mexico; Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstrasse 10, 97743 Jena, Germany
| | - C Guerrero-Sánchez
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstrasse 10, 97743 Jena, Germany; Jena Center for Soft Matter (JCSM), Friedrich-Schiller-University Jena, Philosophenweg 7, 07743 Jena, Germany
| | - J C Ruiz-Suárez
- CINVESTAV-Monterrey, PIIT, Apodaca, Nuevo León 66600, Mexico
| | - U S Schubert
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstrasse 10, 97743 Jena, Germany; Jena Center for Soft Matter (JCSM), Friedrich-Schiller-University Jena, Philosophenweg 7, 07743 Jena, Germany
| | - E Saldívar-Guerra
- Centro de Investigación en Química Aplicada (CIQA), Enrique Reyna, 140, 25294 Saltillo, Coahuila, Mexico.
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Wang L, Womiloju AA, Höppener C, Schubert US, Hoeppener S. On the stability of microwave-fabricated SERS substrates - chemical and morphological considerations. Beilstein J Nanotechnol 2021; 12:541-551. [PMID: 34194890 PMCID: PMC8204127 DOI: 10.3762/bjnano.12.44] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 05/11/2021] [Indexed: 06/13/2023]
Abstract
The stability of surface-enhanced Raman spectroscopy (SERS) substrates in different organic solvents and different buffer solutions was investigated. SERS substrates were fabricated by a microwave-assisted synthesis approach and the morphological as well as chemical changes of the SERS substrates were studied. It was demonstrated that the SERS substrates treated with methanol, ethanol, or N,N-dimethylformamide (DMF) were comparable and showed overall good stability and did not show severe morphological changes or a strong decrease in their Raman activity. Toluene treatment resulted in a strong decrease in the Raman activity whereas dimethyl sulfoxide (DMSO) treatment completely preserved or even slightly improved the Raman enhancement capabilities. SERS substrates immersed into phosphate-buffered saline (PBS) solutions were observed to be rather instable in low and neutral pH buffer solutions. Other buffer systems showed less severe influences on the SERS activity of the substrates and a carbonate buffer at pH 10 was found to even improve SERS performance. This study represents a guideline on the stability of microwave-fabricated SERS substrates or other SERS substrates consisting of non-stabilized silver nanoparticles for the application of different organic solvents and buffer solutions.
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Affiliation(s)
- Limin Wang
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstr. 10, 07743 Jena, Germany
- Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743 Jena, Germany
| | - Aisha Adebola Womiloju
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstr. 10, 07743 Jena, Germany
- Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743 Jena, Germany
| | - Christiane Höppener
- Leibniz-Institut of Photonic Technology e.V. (IPHT), Albert-Einstein-Straße 9, 07745 Jena, Germany
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Lessingstr. 10, 07743 Jena, Germany
| | - Ulrich Sigmar Schubert
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstr. 10, 07743 Jena, Germany
- Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743 Jena, Germany
| | - Stephanie Hoeppener
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstr. 10, 07743 Jena, Germany
- Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743 Jena, Germany
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Press AT, Butans MJ, Haider TP, Weber C, Neugebauer S, Kiehntopf M, Schubert US, Clemens MG, Bauer M, Kortgen A. Fast simultaneous assessment of renal and liver function using polymethine dyes in animal models of chronic and acute organ injury. Sci Rep 2017; 7:15397. [PMID: 29133918 PMCID: PMC5684357 DOI: 10.1038/s41598-017-14987-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 10/19/2017] [Indexed: 12/12/2022] Open
Abstract
Simultaneous assessment of excretory liver and kidney function is still an unmet need in experimental stress models as well as in critical care. The aim of the study was to characterize two polymethine-dyes potentially suitable for this purpose in vivo. Plasma disappearance rate and elimination measurements of simultaneously injected fluorescent dyes DY-780 (hepato-biliary elimination) and DY-654(renal elimination) were conducted using catheter techniques and intravital microscopy in animals subjected to different organ injuries, i.e. polymicrobial sepsis by peritoneal contamination and infection, ischemia-reperfusion-injury and glycerol-induced acute kidney-injury. DY-780 and DY-654 showed organ specific and determined elimination routes in both healthy and diseased animals. They can be measured simultaneously using near-infrared imaging and spectrophotometry. Plasma-disappearance rates of DY-780 and DY-654 are superior to conventional biomarkers in indicating hepatic or kidney dysfunction in different animal models. Greatest impact on liver function was found in animals with polymicrobial sepsis whereas glomerular damage due to glycerol-induced kidney-injury had strongest impact on DY-654 elimination. We therefore conclude that hepatic elimination and renal filtration can be assessed in rodents measuring plasma-disappearance rates of both dyes. Further, assessment of organ dysfunction by polymethine dyes correlates with, but outperforms conventional biomarkers regarding sensitivity and the option of spatial resolution if biophotonic strategies are applied. Polymethine-dye clearance thereby allows sensitive point-of-care assessment of both organ functions simultaneously.
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Affiliation(s)
- A T Press
- Department for Anesthesiology and Intensive Care Medicine, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
- Center for Sepsis and Control and Care, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
| | - M J Butans
- Department for Anesthesiology and Intensive Care Medicine, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
- Center for Sepsis and Control and Care, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
| | - T P Haider
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstr. 10, 07743, Jena, Germany
- Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany
| | - C Weber
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstr. 10, 07743, Jena, Germany
- Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany
| | - S Neugebauer
- Center for Sepsis and Control and Care, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
- Department for Clinical chemistry and Laboratory Medicine, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
| | - M Kiehntopf
- Center for Sepsis and Control and Care, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
- Department for Clinical chemistry and Laboratory Medicine, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
| | - U S Schubert
- Center for Sepsis and Control and Care, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstr. 10, 07743, Jena, Germany
- Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany
| | - M G Clemens
- Department of Biological Sciences and Center for Biomedical Engineering and Science, University of North Carolina at Charlotte, 9201 University City Blvd, Charlotte, NC, 28223, USA
| | - M Bauer
- Department for Anesthesiology and Intensive Care Medicine, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
- Center for Sepsis and Control and Care, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
- Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany
| | - A Kortgen
- Department for Anesthesiology and Intensive Care Medicine, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany.
- Center for Sepsis and Control and Care, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany.
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Radtke M, Stumpf S, Schröter B, Höppener S, Schubert US, Ignaszak A. Electrodeposited palladium on MWCNTs as ‘semi-soluble heterogeneous’ catalyst for cross-coupling reactions. Tetrahedron Lett 2015. [DOI: 10.1016/j.tetlet.2015.05.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Favretto ME, Krieg A, Schubert S, Schubert US, Brock R. Multifunctional poly(methacrylate) polyplex libraries: A platform for gene delivery inspired by nature. J Control Release 2015; 209:1-11. [PMID: 25862514 DOI: 10.1016/j.jconrel.2015.04.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 04/03/2015] [Accepted: 04/04/2015] [Indexed: 12/23/2022]
Abstract
Polymer-based gene delivery systems have enormous potential in biomedicine, but their efficiency is often limited by poor biocompatibility. Poly(methacrylate)s (PMAs) are an interesting class of polymers which allow to explore structure-activity relationships of polymer functionalities for polyplex formation in oligonucleotide delivery. Here, we synthesized and tested a library of PMA polymers, containing functional groups contributing to the different steps of gene delivery, from oligonucleotide complexation to cellular internalization and endosomal escape. By variation of the molar ratios of the individual building blocks, the physicochemical properties of the polymers and polyplexes were fine-tuned to reduce toxicity as well as to increase activity of the polyplexes. To further enhance transfection efficiency, a cell-penetrating peptide (CPP)-like functionality was introduced on the polymeric backbone. With the ability to synthesize large libraries of polymers in parallel we also developed a workflow for a mid-to-high throughput screening, focusing first on safety parameters that are accessible by high-throughput approaches such as blood compatibility and toxicity towards host cells and only at a later stage on more laborious tests for the ability to deliver oligonucleotides. To arrive at a better understanding of the molecular basis of activity, furthermore, the effect of the presence of heparan sulfates on the surface of host cells was assessed and the mechanism of cell entry and intracellular trafficking investigated for those polymers that showed a suitable pharmacological profile. Following endocytic uptake, rapid endosomal release occurred. Interestingly, the presence of heparan sulfates on the cell surface had a negative impact on the activity of those polyplexes that were sensitive to decomplexation by heparin in solution. In summary, the screening approach identified two polymers, which form polyplexes with high stability and transfection capacity exceeding the one of poly(ethylene imine) also in the presence of serum.
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Affiliation(s)
- M E Favretto
- Department of Biochemistry, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands; Dutch Polymer Institute (DPI), Eindhoven, The Netherlands
| | - A Krieg
- Dutch Polymer Institute (DPI), Eindhoven, The Netherlands; Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Jena, Germany; Jena Center for Soft Matter, Friedrich Schiller University Jena, Jena, Germany
| | - S Schubert
- Jena Center for Soft Matter, Friedrich Schiller University Jena, Jena, Germany; Institute of Pharmacy, Pharmaceutical Technology, Friedrich Schiller University Jena, Jena, Germany
| | - U S Schubert
- Dutch Polymer Institute (DPI), Eindhoven, The Netherlands; Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Jena, Germany; Jena Center for Soft Matter, Friedrich Schiller University Jena, Jena, Germany
| | - R Brock
- Department of Biochemistry, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands; Dutch Polymer Institute (DPI), Eindhoven, The Netherlands.
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Marquardt C, Tolstik T, Bielecki C, Kaufmann R, Crecelius AC, Schubert US, Settmacher U, Stallmach A, Dirsch O. MALDI imaging-based classification of hepatocellular carcinoma and non-malignant lesions in fibrotic liver tissue. Z Gastroenterol 2015; 53:33-9. [PMID: 25594705 DOI: 10.1055/s-0034-1385398] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Histopathologic differentiation of nodular lesions in cirrhotic liver is difficult even for experienced hepatopathologists especially regarding diagnosis of hepatocellular carcinoma (HCC) in biopsies. For this reason, new tissue markers are needed to reinforce histopathologic decision-making. With advances in molecular techniques, proteomic analysis may help to confirm the diagnosis of HCC. Matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) is a powerful technology which allows to determine and to localize proteins directly in tissue sections. Using MALDI IMS proteomic patterns of cryosections with lesions of HCC (n = 15) and non-malignant fibrotic liver tissue (n = 11) were investigated to establish a classification model of HCC, which was validated in an independent set of tissue to distinguish HCC (n = 10) from regenerative nodules (n = 8). By correlating generated mass spectrometric images with the histology of the tissue sections we found that the expression of 4 proteins as indicated by m/z 6274, m/z 6647, m/z 6222 and m/z 6853 was significantly higher in HCC tissue than in non-tumorous liver tissue. The generated classification model based on the most significant 3 differentially expressed proteins allowed a reliable prediction of benign and malignant lesions in fibrotic liver tissue with a sensitivity and specificity of 90 % in the validation set. The identified MALDI IMS proteomic signature can be diagnostically helpful to allow simplifying the diagnostic process and minimize the risks of delays in establishing the objective final diagnosis and initiating treatment of patients with HCC.
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Affiliation(s)
- C Marquardt
- Department of InternaI Medicine IV, Gastroenterology, Hepatology and Infectious Diseases, Jena University Hospital, Jena
| | - T Tolstik
- Department of InternaI Medicine IV, Gastroenterology, Hepatology and Infectious Diseases, Jena University Hospital, Jena
| | - C Bielecki
- Department of InternaI Medicine IV, Gastroenterology, Hepatology and Infectious Diseases, Jena University Hospital, Jena
| | - R Kaufmann
- Experimental Transplantation Surgery, Department of General, Visceral and Vascular Surgery, Jena University Hospital, Jena
| | - A C Crecelius
- Institute of Organic Chemistry and Macromolecular Chemistry, Friedrich-Schiller-University Jena
| | - U S Schubert
- Institute of Organic Chemistry and Macromolecular Chemistry, Friedrich-Schiller-University Jena
| | - U Settmacher
- Experimental Transplantation Surgery, Department of General, Visceral and Vascular Surgery, Jena University Hospital, Jena
| | - A Stallmach
- Department of InternaI Medicine IV, Gastroenterology, Hepatology and Infectious Diseases, Jena University Hospital, Jena
| | - O Dirsch
- Department of General, Visceral and Vascular Surgery, Jena University Hospital, Jena
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Bocklitz TW, Crecelius AC, Matthäus C, Tarcea N, von Eggeling F, Schmitt M, Schubert US, Popp J. Deeper understanding of biological tissue: quantitative correlation of MALDI-TOF and Raman imaging. Anal Chem 2013; 85:10829-34. [PMID: 24127731 DOI: 10.1021/ac402175c] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In order to achieve a comprehensive description of biological tissue, spectral information about proteins, lipids, nucleic acids, and other biochemical components need to be obtained concurrently. Different analytical techniques may be combined to record complementary information of the same sample. Established techniques, which can be utilized to elucidate the biochemistry of tissue samples are, for instance, MALDI-TOF-MS and Raman microscopic imaging. With this contribution, we combine these two techniques for the first time. The combination of both techniques allows the utilization and interpretation of complementary information (i.e., the information about the protein composition derived from the Raman spectra with data of the lipids analyzed by the MALDI-TOF measurements). Furthermore, we demonstrate how spectral information from MALDI-TOF experiments can be utilized to interpret Raman spectra.
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Affiliation(s)
- T W Bocklitz
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller-University Jena , Helmholtzweg 4, D-07743 Jena, Germany
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Hölzer S, Menzel M, Zia Q, Schubert US, Beiner M, Weidisch R. Blends of ethylene–octene copolymers with different chain architectures – Morphology, thermal and mechanical behavior. POLYMER 2013. [DOI: 10.1016/j.polymer.2013.07.041] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Guerrero-Sanchez C, Ortiz-Alvarado A, Schubert US. Temperature effect on the magneto-rheological behavior of magnetite particles dispersed in an ionic liquid. ACTA ACUST UNITED AC 2009. [DOI: 10.1088/1742-6596/149/1/012052] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Abstract
Polymeric materials containing coordinative units have become a field of increasing interest. The combination of inorganic metal-containing units and macromolecules leads to supramolecular structures with new properties. One promising approach to such systems is the application of metallo-supramolecular initiators for living and controlled polymerization methods. The utilization of bi- and terpyridine units and complexes for this purpose will be discussed in this article.
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Affiliation(s)
- U S Schubert
- Laboratory of Macromolecular and Organic Chemistry SMO, Eindhoven University of Technology, The Netherlands.
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Abstract
Metallo-supramolecular systems have been adsorbed in a controlled way onto graphite surfaces and visualized with molecular resolution for the first time. A parallel or orthogonal arrangement of the metal coordination arrays is evident depending on the specific ligands (see picture). Furthermore, simple nanomanipulations were performed by extracting single grids from the layer.
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Affiliation(s)
- A Semenov
- Organische Chemie III/Makromolekulare Chemie der Universität, D-89081 Ulm (Germany)
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