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Klaus Mullen - One of the best experts on this subject based on the ideXlab platform.
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amphiphilic dendrimers control protein binding and corona formation on liposome nanocarriers
Chemical Communications, 2020Co-Authors: Jessica Wagner, Marcel Dillenburger, Johanna Simon, Jennifer Oberlander, Katharina Landfester, Volker Mailander, Klaus MullenAbstract:Amphiphilic Polyphenylene dendrimers (PPDs) with distinct lipophilic and positively or negatively charged surface groups were adsorbed onto liposomes and their impact on protein adsorption in blood plasma was studied. The PPD corona reduced binding of specific opsonins and increased the adsorption of proteins controlling cellular uptake based on their surface patches.
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tailoring the emission of fluorinated bipyridine chelated iridium complexes
ACS omega, 2018Co-Authors: Martin Baumgarten, Guang Zhang, Dieter Schollmeyer, Klaus MullenAbstract:New functionalized tris(2′,6′-difluoro-2,3′-bipyridinato-N,C4′)iridium(III) ((dfpypy)3Irs) complexes, including small molecules and their dendrimer embedded analogoues, were synthesized and characterized. It is demonstrated that both the fac-(dfpypy)3Ir-based Polyphenylene dendrimers and (triisopropylsilyl)ethynyl (TIPSE)-substituted (dfpypy)3Ir complexes induce large bathochromic shifts (∼50 nm) of emission bands compared with fac-(dfpypy)3Ir. This is due to the pronounced 3π–π* character of emissive excited states and the extended conjugation. A further remarkable feature is the small bathochromic shift of the emissions of fac-tris(2-phenylpyridine)iridium (fac-(ppy)3Ir)-based Polyphenylene dendrimers when compared to those of the iridium (Ir) complex core. Obviously, the triplet metal-to-ligand charge transfer makes emission less sensitive to extended conjugation than the 3π–π* transition. This finding suggests new concepts for designing blue phosphorescent dendrimer emitters. Both the dendrimers and t...
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Expanding the limits of synthetic macromolecular chemistry through Polyphenylene Dendrimers
Journal of Nanoparticle Research, 2018Co-Authors: Brenton A. G. Hammer, Klaus MullenAbstract:Polyphenylene dendrimers (PPDs) are a unique class of macromolecules because their backbone is made from twisted benzene repeat units that result in a rigid, shape-persistent architecture as reported by Hammer et al. (Chem Soc Rev 44:4072–4090, 2015) and Hammer and Müllen (Chem Rev 116:2103–210, 2016) These dendrimers can be synthetically tailored at their core, scaffold, and surface to introduce a wide range of chemical functionalities that influence their applications. It is the balance between the macromolecular properties of Polyphenylene dendrimers with grandiose synthetic ingenuity that presents a template for the next generation of synthetic dendrimers to achieve complex structures other chemistry fields cannot. This perspective will look at how advances in synthetic chemistry have led to an explosion in the properties of Polyphenylene dendrimers from their initial stage, as PPDs that were used as precursors for nanographenes, to next-generation dendrimers for organic electronic devices, sensors for volatile organic compounds (VOCs), nanocarriers for small molecules, and even as complexes with therapeutic drugs and viruses, among others. Ideally, this perspective will illustrate how the evolution of synthetic chemistry has influenced the possible structures and properties of PPDs and how these chemical modifications have opened the door to unprecedented applications.
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diels alder polymerization a versatile synthetic method toward functional Polyphenylenes ladder polymers and graphene nanoribbons
Polymer Journal, 2018Co-Authors: Ian Chengyi Hou, Akimitsu Narita, Klaus MullenAbstract:The Diels–Alder reaction has been widely used in synthetic organic chemistry since its discovery in 1928. The catalyst-free nature, functional group tolerance and high efficiency of the Diels–Alder reaction also make it promising for the fabrication of functional polymeric materials. In particular, a large variety of functional Polyphenylenes (polymer structures mainly consisting of phenylenes) and ladder polymers (double-stranded polymers with periodic linkages connecting the strands) have been obtained by this method, offering potential applications such as polymer electrolyte membranes and gas separation. More recently, tailor-made Polyphenylenes prepared by Diels–Alder polymerization have been used as precursors of structurally well-defined graphene nanoribbons (ribbon-shaped nanometer-wide graphene segments) with different widths, exhibiting long lengths (>600 nm) and tunable electronic bandgaps. This article provides a comprehensive review of the use of Diels–Alder polymerization to build functional Polyphenylenes, ladder polymers and graphene nanoribbons. In this review, we summarize the use of Diels–Alder reaction in the synthesis of arylene-based polymers, including Polyphenylenes and ladder polymers, as well as graphene nanoribbons. These polymer materials are structurally related to each other, but rarely discussed all together in a same context. The importance and versatility of the Diels–Alder polymerization is highlighted for the synthesis of such polymers with various potential applications, for example, as polymer electrolyte membrane and organic semiconductors.
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interaction of a patterned amphiphilic Polyphenylene dendrimer with a lipid monolayer electrostatic interactions dominate
Langmuir, 2015Co-Authors: Masanari Okuno, Mischa Bonn, Markus Mezger, Rene Stangenberg, Martin Baumgarten, Klaus Mullen, Ellen H G BackusAbstract:Dendrimeric macromolecules with defined shape and size are promising candidates for delivering drug or DNA molecules into cells. In this work we study the influence of an amphiphilic Polyphenylene dendrimer on a model cell membrane consisting of a condensed 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid monolayer. A small surface pressure decrease is observed when the dendrimer solution is injected into the aqueous phase below the monolayer. X-ray reflectivity measurements show that the surface monolayer remains intact. The molecular-scale picture is obtained with sum-frequency generation spectroscopy. With this technique, we observe that the tails of the surfactant molecules become less ordered upon interaction with the amphiphilic Polyphenylene dendrimer. In contrast, the water molecules below the DPPC layer become more ordered. Our observations suggest that electrostatic interactions between the negative charge of the dendrimer and the positively charged part of the DPPC headgroup keep the dendrimer located below the headgroup. No evidence of dendrimer insertion into the membrane has been observed. Apparently before entering the cell membrane the dendrimer can stick at the hydrophilic part of the lipids.
Martin Baumgarten - One of the best experts on this subject based on the ideXlab platform.
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tailoring the emission of fluorinated bipyridine chelated iridium complexes
ACS omega, 2018Co-Authors: Martin Baumgarten, Guang Zhang, Dieter Schollmeyer, Klaus MullenAbstract:New functionalized tris(2′,6′-difluoro-2,3′-bipyridinato-N,C4′)iridium(III) ((dfpypy)3Irs) complexes, including small molecules and their dendrimer embedded analogoues, were synthesized and characterized. It is demonstrated that both the fac-(dfpypy)3Ir-based Polyphenylene dendrimers and (triisopropylsilyl)ethynyl (TIPSE)-substituted (dfpypy)3Ir complexes induce large bathochromic shifts (∼50 nm) of emission bands compared with fac-(dfpypy)3Ir. This is due to the pronounced 3π–π* character of emissive excited states and the extended conjugation. A further remarkable feature is the small bathochromic shift of the emissions of fac-tris(2-phenylpyridine)iridium (fac-(ppy)3Ir)-based Polyphenylene dendrimers when compared to those of the iridium (Ir) complex core. Obviously, the triplet metal-to-ligand charge transfer makes emission less sensitive to extended conjugation than the 3π–π* transition. This finding suggests new concepts for designing blue phosphorescent dendrimer emitters. Both the dendrimers and t...
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Tailoring the Emission of Fluorinated Bipyridine-Chelated Iridium Complexes
2018Co-Authors: Guang Zhang, Martin Baumgarten, Dieter Schollmeyer, Klaus MüllenAbstract:New functionalized tris(2′,6′-difluoro-2,3′-bipyridinato-N,C4′)iridium(III) ((dfpypy)3Irs) complexes, including small molecules and their dendrimer embedded analogoues, were synthesized and characterized. It is demonstrated that both the fac-(dfpypy)3Ir-based Polyphenylene dendrimers and (triisopropylsilyl)ethynyl (TIPSE)-substituted (dfpypy)3Ir complexes induce large bathochromic shifts (∼50 nm) of emission bands compared with fac-(dfpypy)3Ir. This is due to the pronounced 3π–π* character of emissive excited states and the extended conjugation. A further remarkable feature is the small bathochromic shift of the emissions of fac-tris(2-phenylpyridine)iridium (fac-(ppy)3Ir)-based Polyphenylene dendrimers when compared to those of the iridium (Ir) complex core. Obviously, the triplet metal-to-ligand charge transfer makes emission less sensitive to extended conjugation than the 3π–π* transition. This finding suggests new concepts for designing blue phosphorescent dendrimer emitters. Both the dendrimers and the TIPSE-substituted (dfpypy)3Ir complexes represent new green and the trimethylsilyl-functionalized (dfpypy)3Ir new blue phosphorescent emitters. Incorporation of TIPSE moieties into the ligands of iridium complex gives rise to enhanced phosphorescence
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interaction of a patterned amphiphilic Polyphenylene dendrimer with a lipid monolayer electrostatic interactions dominate
Langmuir, 2015Co-Authors: Masanari Okuno, Mischa Bonn, Markus Mezger, Rene Stangenberg, Martin Baumgarten, Klaus Mullen, Ellen H G BackusAbstract:Dendrimeric macromolecules with defined shape and size are promising candidates for delivering drug or DNA molecules into cells. In this work we study the influence of an amphiphilic Polyphenylene dendrimer on a model cell membrane consisting of a condensed 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid monolayer. A small surface pressure decrease is observed when the dendrimer solution is injected into the aqueous phase below the monolayer. X-ray reflectivity measurements show that the surface monolayer remains intact. The molecular-scale picture is obtained with sum-frequency generation spectroscopy. With this technique, we observe that the tails of the surfactant molecules become less ordered upon interaction with the amphiphilic Polyphenylene dendrimer. In contrast, the water molecules below the DPPC layer become more ordered. Our observations suggest that electrostatic interactions between the negative charge of the dendrimer and the positively charged part of the DPPC headgroup keep the dendrimer located below the headgroup. No evidence of dendrimer insertion into the membrane has been observed. Apparently before entering the cell membrane the dendrimer can stick at the hydrophilic part of the lipids.
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interaction of a patterned amphiphilic Polyphenylene dendrimer with a lipid mono layer electrostatic interactions dominate
Langmuir, 2015Co-Authors: Masanari Okuno, Mischa Bonn, Markus Mezger, Rene Stangenberg, Martin Baumgarten, Klaus Mullen, Ellen H G BackusAbstract:Dendrimeric macromolecules with defined shape and size are promising candidates for delivering drug or DNA molecules into cells. In this work we study the influence of an amphiphilic Polyphenylene dendrimer on a model cell membrane consisting of a condensed 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid monolayer. A small surface pressure decrease is observed when the dendrimer solution is injected into the aqueous phase below the monolayer. X-ray reflectivity measurements show that the surface monolayer remains intact. The molecular-scale picture is obtained with sum-frequency generation spectroscopy. With this technique, we observe that the tails of the surfactant molecules become less ordered upon interaction with the amphiphilic Polyphenylene dendrimer. In contrast, the water molecules below the DPPC layer become more ordered. Our observations suggest that electrostatic interactions between the negative charge of the dendrimer and the positively charged part of the DPPC headgroup keep the de...
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extending the limits of precision polymer synthesis giant Polyphenylene dendrimers in the megadalton mass range approaching structural perfection
Journal of the American Chemical Society, 2013Co-Authors: Thithanhtam Nguyen, Martin Baumgarten, Ali Rouhanipour, Hans Joachim Rader, Ingo Lieberwirth, Klaus MullenAbstract:The catalyst-free Diels–Alder synthesis of Polyphenylene dendrimers with a chromophore core has now been demonstrated to achieve the seventh to ninth generations upon divergent growth. Since standard analytical tools such as size-exclusion chromatography do not provide realistic molecular weights, MALDI-TOF mass spectrometry was applied to characterize the complete series of nine generations. Perfection and monodispersity were thus elucidated at such high masses. Transmission electron microscopy imaging was used to determine the size of these molecularly defined nanosized “particles” with diameters of up to 33 nm.
Simon Desmeules - One of the best experts on this subject based on the ideXlab platform.
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effectiveness of haemodiafiltration with heat sterilized high flux Polyphenylene hf dialyzer in reducing free light chains in patients with myeloma cast nephropathy
PLOS ONE, 2015Co-Authors: Mathieu Rousseaugagnon, Mohsen Agharazii, Sacha A. De Serres, Simon DesmeulesAbstract:Introduction In cases of myeloma cast nephropathy in need of haemodialysis (HD), reduction of free light chains using HD with High-Cut-Off filters (HCO-HD), in combination with chemotherapy, may be associated with better renal recovery. The aim of the present study is to evaluate the effectiveness of haemodiafiltration (HDF) in reducing free light chain levels using a less expensive heat sterilized high-flux Polyphenylene HF dialyzer (HF-HDF). Methods In a single-centre prospective cohort study, 327 dialysis sessions were performed using a 2.2 m2 heat sterilized high-flux Polyphenylene HF dialyzer (Phylther HF22SD), a small (1.1m2) or large (2.1 m2) high-cut-off (HCO) dialyzer (HCOS and HCOL) in a cohort of 16 patients presenting with dialysis-dependent acute cast nephropathy and elevated free light chains (10 kappa, 6 lambda). The outcomes of the study were the mean reduction ratio (RR) of kappa and lambda, the proportion of treatments with an RR of at least 0.65, albumin loss and the description of patient outcomes. Statistical analysis was performed using linear and logistic regression through generalized estimating equation analysis so as to take into account repeated observation within subjects and adjust for session duration. Results There were no significant differences in the estimated marginal mean of kappa RR, which were respectively 0.67, 0.69 and 0.70 with HCOL-HD, HCOS-HDF and HF-HDF (P = 0.950). The estimated marginal mean of the proportions of treatments with a kappa RR ≥0.65 were 68%, 63% and 71% with HCOL-HD, HCOS-HDF and HF-HDF, respectively (P = 0.913). The estimated marginal mean of lambda RR were higher with HCOL-HDF (0.78), compared to HCOL-HD and HF-HDF (0.62, and 0.61 respectively). The estimated marginal mean proportion of treatments with a lambda RR ≥0.65 were higher with HCOL-HDF (81%), compared to 57% in HF-HDF (P = 0.042). The median albumin loss were 7, 21 and 63 g/session with HF-HDF, HCOL-HD and HCOL-HDF respectively (P = 0.044). Among survivors, 9 out of 10 episodes of acute kidney injuries became dialysis-independent following a median time of renal replacement therapy of 40 days (range 7–181). Conclusion Therefore, in patients with acute dialysis-dependent myeloma cast nephropathy, in addition to chemotherapy, HDF with a heat sterilized high-flux Polyphenylene HF dialyzer could offer an alternative to HCO dialysis for extracorporeal kappa reduction with lower albumin loss.
Mathieu Rousseaugagnon - One of the best experts on this subject based on the ideXlab platform.
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effectiveness of haemodiafiltration with heat sterilized high flux Polyphenylene hf dialyzer in reducing free light chains in patients with myeloma cast nephropathy
PLOS ONE, 2015Co-Authors: Mathieu Rousseaugagnon, Mohsen Agharazii, Sacha A. De Serres, Simon DesmeulesAbstract:Introduction In cases of myeloma cast nephropathy in need of haemodialysis (HD), reduction of free light chains using HD with High-Cut-Off filters (HCO-HD), in combination with chemotherapy, may be associated with better renal recovery. The aim of the present study is to evaluate the effectiveness of haemodiafiltration (HDF) in reducing free light chain levels using a less expensive heat sterilized high-flux Polyphenylene HF dialyzer (HF-HDF). Methods In a single-centre prospective cohort study, 327 dialysis sessions were performed using a 2.2 m2 heat sterilized high-flux Polyphenylene HF dialyzer (Phylther HF22SD), a small (1.1m2) or large (2.1 m2) high-cut-off (HCO) dialyzer (HCOS and HCOL) in a cohort of 16 patients presenting with dialysis-dependent acute cast nephropathy and elevated free light chains (10 kappa, 6 lambda). The outcomes of the study were the mean reduction ratio (RR) of kappa and lambda, the proportion of treatments with an RR of at least 0.65, albumin loss and the description of patient outcomes. Statistical analysis was performed using linear and logistic regression through generalized estimating equation analysis so as to take into account repeated observation within subjects and adjust for session duration. Results There were no significant differences in the estimated marginal mean of kappa RR, which were respectively 0.67, 0.69 and 0.70 with HCOL-HD, HCOS-HDF and HF-HDF (P = 0.950). The estimated marginal mean of the proportions of treatments with a kappa RR ≥0.65 were 68%, 63% and 71% with HCOL-HD, HCOS-HDF and HF-HDF, respectively (P = 0.913). The estimated marginal mean of lambda RR were higher with HCOL-HDF (0.78), compared to HCOL-HD and HF-HDF (0.62, and 0.61 respectively). The estimated marginal mean proportion of treatments with a lambda RR ≥0.65 were higher with HCOL-HDF (81%), compared to 57% in HF-HDF (P = 0.042). The median albumin loss were 7, 21 and 63 g/session with HF-HDF, HCOL-HD and HCOL-HDF respectively (P = 0.044). Among survivors, 9 out of 10 episodes of acute kidney injuries became dialysis-independent following a median time of renal replacement therapy of 40 days (range 7–181). Conclusion Therefore, in patients with acute dialysis-dependent myeloma cast nephropathy, in addition to chemotherapy, HDF with a heat sterilized high-flux Polyphenylene HF dialyzer could offer an alternative to HCO dialysis for extracorporeal kappa reduction with lower albumin loss.
Mohsen Agharazii - One of the best experts on this subject based on the ideXlab platform.
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effectiveness of haemodiafiltration with heat sterilized high flux Polyphenylene hf dialyzer in reducing free light chains in patients with myeloma cast nephropathy
PLOS ONE, 2015Co-Authors: Mathieu Rousseaugagnon, Mohsen Agharazii, Sacha A. De Serres, Simon DesmeulesAbstract:Introduction In cases of myeloma cast nephropathy in need of haemodialysis (HD), reduction of free light chains using HD with High-Cut-Off filters (HCO-HD), in combination with chemotherapy, may be associated with better renal recovery. The aim of the present study is to evaluate the effectiveness of haemodiafiltration (HDF) in reducing free light chain levels using a less expensive heat sterilized high-flux Polyphenylene HF dialyzer (HF-HDF). Methods In a single-centre prospective cohort study, 327 dialysis sessions were performed using a 2.2 m2 heat sterilized high-flux Polyphenylene HF dialyzer (Phylther HF22SD), a small (1.1m2) or large (2.1 m2) high-cut-off (HCO) dialyzer (HCOS and HCOL) in a cohort of 16 patients presenting with dialysis-dependent acute cast nephropathy and elevated free light chains (10 kappa, 6 lambda). The outcomes of the study were the mean reduction ratio (RR) of kappa and lambda, the proportion of treatments with an RR of at least 0.65, albumin loss and the description of patient outcomes. Statistical analysis was performed using linear and logistic regression through generalized estimating equation analysis so as to take into account repeated observation within subjects and adjust for session duration. Results There were no significant differences in the estimated marginal mean of kappa RR, which were respectively 0.67, 0.69 and 0.70 with HCOL-HD, HCOS-HDF and HF-HDF (P = 0.950). The estimated marginal mean of the proportions of treatments with a kappa RR ≥0.65 were 68%, 63% and 71% with HCOL-HD, HCOS-HDF and HF-HDF, respectively (P = 0.913). The estimated marginal mean of lambda RR were higher with HCOL-HDF (0.78), compared to HCOL-HD and HF-HDF (0.62, and 0.61 respectively). The estimated marginal mean proportion of treatments with a lambda RR ≥0.65 were higher with HCOL-HDF (81%), compared to 57% in HF-HDF (P = 0.042). The median albumin loss were 7, 21 and 63 g/session with HF-HDF, HCOL-HD and HCOL-HDF respectively (P = 0.044). Among survivors, 9 out of 10 episodes of acute kidney injuries became dialysis-independent following a median time of renal replacement therapy of 40 days (range 7–181). Conclusion Therefore, in patients with acute dialysis-dependent myeloma cast nephropathy, in addition to chemotherapy, HDF with a heat sterilized high-flux Polyphenylene HF dialyzer could offer an alternative to HCO dialysis for extracorporeal kappa reduction with lower albumin loss.