Self‐Immolative RAFT‐Polymer End Group Modification

Scherger, Maximilian; Räder, Hans Joachim; Nuhn, Lutz

doi:10.1002/marc.202000752

Cited by 10 publications

(13 citation statements)

References 73 publications

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“…[120] Additionally, pH-and reductive responsive delivery systems have been introduced to trigger the on-demand immunodrug release and controlled carrier degradation more precisely. [121,122] The rapid progress of both junior scientists as well as many other researchers in Mainz is for sure related to the biomedical research infrastructure related to CRC 1066, and thus a continuity of the "Ringsdorf-Zentel lab spirit".…”

Section: How Did This Inspire Rudolf Zentel and Next Generations?mentioning

confidence: 99%

From Self‐Organization to Tumor‐Immune Therapy: How Things Started and How They Evolved

Barz

Nuhn

Hörpel³

et al. 2022

Macromol. Rapid Commun.

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BackgroundOn a sunny afternoon in summer 2021, Rudolf Zentel and Lutz Nuhn visited Helmut Ringsdorf in Mainz-Gonsenheim, Germany. It was the first time they were able to meet each other again in person after the long-lasting restrictions of the COVID-19 pandemic. While having a cup of coffee and a slice of cake on the garden terrace, Zentel and Ringsdorf looked back on the early days and "how things started and how they evolved". In a lively discussion the participants shared their thoughts on naïve ideas from the old days, how they continued, evolved and extended in the Zentel lab (Figure 1). These ideas were afterwards discussed and co-reflected by former students of the Ringsdorf lab (G. Hörpel, R. Zentel) and the Zentel lab (M. Barz, L.Nuhn). As a result, this perspective article was written, which brings together the individual opinions of the authors as -hopefully -a valuable contribution to Macromolecular Rapid Communication's special issue in honor of Rudolf Zentel upon his retirement. Starting PointThe starting point of the work in the Ringsdorf lab was polymer science in the 60s and 70s of the last century (or even better: "the last millennium", quotation by Ringsdorf). At that time, the beginning of the "plastic era" had just started a few decades previously, everything related to polymers was extremely modern, and research on this topic was well supported by chemical industries. Polymers and plastics entered everyday life as commodity

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Section: How Did This Inspire Rudolf Zentel and Next Generations?mentioning

confidence: 99%

From Self‐Organization to Tumor‐Immune Therapy: How Things Started and How They Evolved

Barz

Nuhn

Hörpel³

et al. 2022

Macromol. Rapid Commun.

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“…To achieve this, it is necessary to avoid the formation of disulfide bonds between the polymer chain ends. Some of the influencing factors could be the chemical structure of the polymer, the amine type, the solvent, the reaction time and the atmosphere (open air, N 2 ) [1][2][3][4][5].…”

Section: Aminolysis Of Linear and Star Pnvcl Polymers Containing Xanthate End-groups And Their Transformation Into Polymers Containing Thmentioning

confidence: 99%

“…Polymers prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization can be transformed just by eliminating the RAFT group [1][2][3][4][5]. Although there is a wide variety of possibilities, the removal of the RAFT groups by reaction with nucleophiles, especially the use of primary amines, is the most used method (aminolysis); nevertheless, it is often accompanied by the oxidation of terminal thiol groups resulting in chain-chain coupling, even if the reaction is carried out in the absence of oxygen.…”

Section: Introductionmentioning

confidence: 99%

Effective End-Group Modification of Star-Shaped PNVCL from Xanthate to Trithiocarbonate Avoiding Chemical Crosslinking

2021

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In this study, six-arm star-shaped poly(N-vinylcaprolactam) (PNVCL) polymers prepared by reversible addition–fragmentation chain transfer (RAFT) polymerization were subjected to aminolysis reaction using hexylamine. Chemically crosslinked gels or highly end-functionalized star polymers can be obtained depending mainly on the type of solvent used during the transformation of the RAFT functional group. An increase in the viscosity of the solution was observed when the aminolysis was carried out in THF. In contrast, when the reaction was conducted in dichloromethane, chain-end thiol (PNVCL)6 star polymers could be obtained. Moreover, when purified (PNVCL-SH)6 star polymers are in contact with THF, the gelation occurs in just a few minutes, with an obvious increase in viscosity, to form physical gels that become chemically crosslinked gels after 12 h. Interestingly, when purified (PNVCL-SH)6 star polymers were stirred in distilled water, even at high aqueous solution concentration (40 mg/mL), there was no increase in the viscosity or gelation, and no evident gels were observed. The analysis of the hydrodynamic diameter (Dh) by dynamic light scattering (DLS) did not detect quantifiable change even after 4 days of stirring in water. On the other hand, the thiol groups in the (PNVCL-SH)6 star polymers were easily transformed into trithiocarbonate groups by addition of CS2 followed by benzyl bromide as demonstrated by UV-Vis spectroscopical analysis and GPC. After the modification, the (PNVCL)6 star polymers exhibit an intense yellow color typical of the absorption band of trithiocarbonate group at 308 nm. To further demonstrate the highly effective new trithiocarbonate end-functionality, the PNVCL polymers were successfully chain extended with N-isopropylacrylamide (NIPAM) to form six-arm star-shaped PNIPAM-b-PNVCL block copolymers. Moreover, the terminal thiol end-functionality in the (PNVCL-SH)6 star polymers was linked via disulfide bond formation to l-cysteine to further demonstrate its reactivity. Zeta potential analysis shows the pH-responsive behavior of these star polymers due to l-cysteine end-functionalization. By this using methodology and properly selecting the solvent, various environment-sensitive star polymers with different end-groups could be easily accessible.

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“…[36] This approach requires the synthesis of polymers with highly defined end groups followed by a quantitative activation and conjugation of the cargo, as lately demonstrated by us for RAFT polymerization-derived end groups. [37] In the current study, we apply this approach for the first time to polycarbonate-based block copolymers obtained by organocatalytic ring-opening polymerization. The primary hydroxy end group could be converted into a pentafluorophenyl carbonate and subsequently derivatized with primary amine bearing fluorescent dyes.…”

Section: Introductionmentioning

confidence: 99%

End Group Dye‐Labeled Polycarbonate Block Copolymers for Micellar (Immuno‐)Drug Delivery

Czysch

Medina‐Montano

Dal

et al. 2022

Macromol. Rapid Commun.

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Defined conjugation of functional molecules to block copolymer end groups is a powerful strategy to enhance the scope of micellar carriers for drug delivery. In this study, an approach to access well-defined polycarbonate-based block copolymers by labeling their end groups with single fluorescent dye molecules is established. Following controlled polymerization conditions, the block copolymers' primary hydroxy end group can be converted into activated pentafluorophenyl ester carbonates and subsequently aminolyzed with fluorescent dyes that are equipped with primary amines. During a solvent-evaporation process, the resulting end group dye-labeled block copolymers self-assemble into narrowly dispersed ∼25 nm-sized micelles and simultaneously encapsulate hydrophobic (immuno-)drugs. The covalently attached fluorescent tracer can be used to monitor both uptake into cells and stability under biologically relevant conditions, including incubation with blood plasma or during blood circulation in zebrafish embryos. By encapsulation of the toll-like receptor 7/8 (TLR7/8) agonist CL075, immune stimulatory polymeric micelles are generated that get internalized by various antigen-presenting dendritic cells and promote their maturation. Generally, such end group dye-labeled polycarbonate block copolymers display ideal features to permit targeted delivery of hydrophobic drugs to key immune cells for vaccination and cancer immunotherapy.

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Self‐Immolative RAFT‐Polymer End Group Modification

Cited by 10 publications

References 73 publications

From Self‐Organization to Tumor‐Immune Therapy: How Things Started and How They Evolved

From Self‐Organization to Tumor‐Immune Therapy: How Things Started and How They Evolved

Effective End-Group Modification of Star-Shaped PNVCL from Xanthate to Trithiocarbonate Avoiding Chemical Crosslinking

End Group Dye‐Labeled Polycarbonate Block Copolymers for Micellar (Immuno‐)Drug Delivery

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