Enhancing the conjugation yield of brush polymer–protein conjugates by increasing the linker length at the polymer end-group

Background: Polyhydroxyalkanoates (PHAs) are a natural origin biodegradable polyesters consisted of various 3- and 4-hydroxyacid derived repeating units produced by microorganisms as energy storage. PHAs have been intensively studied due to their biodegradability and biocompatibility enabling their use both in packaging and agriculture as well as in medicine and pharmacy. PHAs obtained via biotechnological routes can possess various functional groups in their side chains. However, the diversity in their functionality is limited due to issues of conservation of functional groups during the polymer formation. Objective: The review focuses on recent progress in the area of synthesis of PHAs functionalized with various reactive as well as bioactive end and side groups. Conclusion: A potent route to resolve the problem of functional group diversity in natural origin PHAs involves post-polymerization modification, where the desired side groups can be created. On the contrary, synthetically produced PHA analogs obtained directly via ring-opening polymerization of β-lactones offer various functionalities at different position throughout the polymer chain. The desired α- and ω-end groups can be introduced into the polymer chain using specific polymerization, initiation or termination strategies, respectively. The preferred side chain functionality is obtained by choosing the appropriate β-lactone monomers bearing respective functional groups. All functional groups may also be subjected to additional chemical modification. The degradation of PHA as a method for producing functional polymers as well as their possible further applications are also discussed.

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Microbubbles Decorated with Dendronized Magnetic Nanoparticles for Biomedical Imaging. Effective Stabilization via Fluorous Interactions

10.3762/bxiv.2019.60.v1 ◽

2019 ◽

Author(s):

Da Shi ◽

Justine Wallyn ◽

Dinh-Vu Nguyen ◽

Francis Perton ◽

Delphine Felder-Flesch ◽

...

Keyword(s):

Molar Ratio ◽

Aqueous Dispersions ◽

Force Microscopy ◽

Atomic Force ◽

Microscopy Investigation ◽

End Groups ◽

Mixed Films ◽

Effective Stabilization ◽

Effective Result ◽

End Group

Dendrons fitted with three oligoethylene glycol (OEG) chains, one of which carrying a fluorinated or hydrogenated end group, and bearing a bisphosphonate polar head (C n X2 n +1OEG8Den, X = F or H; n= 2 or 4) were synthesized and grafted on the surface of iron oxide nanoparticles (IONPs) for microbubble-mediated imaging and therapeutic purposes. The size and stability of the dendronized IONPs (IONP@C n X2 n +1OEG8Den) in aqueous dispersions were monitored by dynamic light scattering. Investigation of the spontaneous adsorption of IONP@C n X2 n +1OEG8Den at the interface between air - or air saturated with perfluorohexane - and an aqueous phase establishes that exposure to the fluorocarbon gas markedly increases the rate of adsorption of the dendronized IONPs to the gas/water interface and decreases the equilibrium interfacial tension. This suggests that fluorous interactions are at play between the supernatant fluorocarbon gas and the fluorinated end groups of the dendrons. Furthermore, small, stable perfluorohexane-stabilized microbubbles (MBs) with a dipalmitoylphosphatidylcholine (DPPC) shell that incorporates IONP@C n X2 n +1OEG8Den (DPPC/Fe molar ratio 28:1) were prepared and characterized using both optical microscopy and an acoustical method of size determination. The dendrons fitted with fluorinated end groups lead to smaller and more stable MBs than those fitted with hydrogenated groups. The most effective result is already obtained with C2F5, for which MBs, ~1.0mm in radius, reach a half-life of ~6.0 h. An atomic force microscopy investigation of spin-coated mixed films of DPPC/IONP@C2X5OEG8Den combinations (molar ratio 28:1) shows that the IONPs grafted with the fluorinated dendrons are located within the phospholipid film, while those grafted with the hydrocarbon dendrons are completely absent from the phospholipid film.

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Biologic Activity of Daunorubicin Linked to Proteins via the Methylketone Side Chain

Tumori Journal ◽

10.1177/030089168106700602 ◽

1981 ◽

Vol 67 (6) ◽

pp. 521-524 ◽

Cited By ~ 17

Author(s):

Franco Zunino ◽

Romolo Gambetta ◽

Aristide Vigevani ◽

Sergio Penco ◽

Cristina Geroni ◽

...

Keyword(s):

Hela Cells ◽

Amino Sugar ◽

Specific Protein ◽

Side Chain ◽

Covalent Linkage ◽

Protein Conjugates ◽

Protein Carriers ◽

Biologic Activity ◽

Appreciable Reduction

New daunorubicin-protein conjugates were prepared by covalently linking the antitumor drug to various test proteins via its methylketone side chain. Attachment of daunorubicin to proteins was achieved by nucleophylic substitution reaction of the 14-bromo derivative of the drug, under mild coupling conditions. In contrast to conventional methods, this procedure did not involve reaction or modification of the amino sugar. As expected, the covalent linkage of the drug was generally associated with an appreciable reduction in the drug cytotoxicity to HeLa cells in vitro. The possible advantages of this method for coupling to specific protein carriers are discussed.

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Influence of side chain linker length on ion-transport properties of polymeric ionic liquids

Journal of Polymer Science Part B Polymer Physics ◽

10.1002/polb.24440 ◽

2017 ◽

Vol 55 (23) ◽

pp. 1718-1723 ◽

Cited By ~ 18

Author(s):

Jordan R. Keith ◽

Santosh Mogurampelly ◽

Bill K. Wheatle ◽

Venkat Ganesan

Keyword(s):

Ionic Liquids ◽

Ion Transport ◽

Transport Properties ◽

Side Chain ◽

Polymeric Ionic Liquids ◽

Linker Length

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The nature of the 5'-linked 5' nucleotide sequence at the 5' end of rabbit globin messenger ribonucleic acid

Biochemical Journal ◽

10.1042/bj1550637 ◽

1976 ◽

Vol 155 (3) ◽

pp. 637-644 ◽

Cited By ~ 10

Author(s):

J A Hunt ◽

G N Oakes

Keyword(s):

Messenger Rna ◽

Periodate Oxidation ◽

Hydroxyl Group ◽

Globin Mrna ◽

Pancreatic Ribonuclease ◽

Phosphodiester Bond ◽

Messenger Ribonucleic Acid ◽

End Groups ◽

A Charge ◽

End Group

Poly(A)-containing messenger RNA isolated from rabbit reticulocytes as estimated by periodate oxidation and condensation with [3H]isoniazid has two oxidizable end groups per molecule of mol. wt. 220000. When the mRNA is subjected to stepwise degradation by beta-elimination, only one oxidizable end-group is found. This indicates that one of the 2′,3′ hydroxyl end-groups is linked through the normal 3′-5′ phosphodiester bond, but that the other is linked in such a way that after stepwise degradation no new 2′,3 hydroxyl group is revealed. This structure could be a 5′-linked 5′-phospho di- or tri-ester. On digestion with ribonuclease the isoniazid-labelled RNA produced oligonucleotide hydrazones consistent with a poly(A) sequence at the 3′ end plus fragments that are not found after stepwise degradation. These fragments have a charge of -6 and -8 from pancreatic ribonuclease or -7 from ribonuclease T1 digestion. These charges are changed to -3.4 and -4.1 after pancreatic ribonuclease, ribonuclease T2 and alkaline phosphatase digestion. methyl-3H-labelled-poly(A)-containing RNA isolated from late erythroid cells contain a methyl-labelled fragment resistant to endonuclease and phosphodiesterase II digestion. After digestion with phosphodiesterase I this fragment produces methyl-3 H-labelled nucleotides with the electrophoretic mobility of pm7G and pAm. It is concluded that globin mRNA has the 5′ sequences m7G(5′)ppp′AmpYpGp ... and m7G(5′)pppAmpApGpYp.

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Design of Thienothiophene-Based Copolymers with Various Side Chain-End Groups for Efficient Polymer Solar Cells

Polymers ◽

10.3390/polym12122964 ◽

2020 ◽

Vol 12 (12) ◽

pp. 2964

Author(s):

Ying-Chieh Chao ◽

Jhe-Han Chen ◽

Yi-Jie Chiou ◽

Po-lin Kao ◽

Jhao-Lin Wu ◽

...

Keyword(s):

Solar Cells ◽

Microphase Separation ◽

Bulk Heterojunction ◽

Polymer Solar Cells ◽

Photophysical Properties ◽

Morphological Properties ◽

Side Chain ◽

Blend Films ◽

End Groups ◽

Thiophene Moiety

Three two-dimensional donor–acceptor conjugated copolymers consisting of a benzo[1,2-b:4,5-b′]dithiophene derivative and thieno[3,2-b]thiophene with a conjugated side chain were designed and synthesized for use in bulk heterojunction (BHJ) or nonfullerene polymer solar cells (PSCs). Through attaching various acceptor end groups to the conjugated side chain on the thieno[3,2-b]thiophene moiety, the electronic, photophysical, and morphological properties of these copolymers were significantly affected. It was found that the intermolecular charge transfer interactions were enhanced with the increase in the acceptor strength on the thieno[3,2-b]thiophene moiety. Moreover, a better microphase separation was obtained in the copolymer: PC71BM or ITIC blend films when a strong acceptor end group on the thieno[3,2-b]thiophene moiety was used. As a result, BHJ PSCs based on copolymer:PC71BM blend films as active layers exhibited power conversion efficiencies from 2.82% to 4.41%, while those of nonfullerene copolymer:ITIC-based inverted PSCs ranged from 6.09% to 7.25%. These results indicate the side-chain engineering on the end groups of thieno[3,2-b]thiophene unit through a vinyl bridge linkage is an effective way to adjust the photophysical properties of polymers and morphology of blend films, and also have a significant influence on devices performance.

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Modeling of Bottle-Brush Polymer Adsorption onto Mica and Silica Surfaces: Effect of Side-Chain Length

Macromolecules ◽

10.1021/ma902577m ◽

2010 ◽

Vol 43 (4) ◽

pp. 2076-2083 ◽

Cited By ~ 18

Author(s):

Per Linse ◽

Per M. Claesson

Keyword(s):

Chain Length ◽

Polymer Adsorption ◽

Side Chain ◽

Side Chain Length ◽

Silica Surfaces ◽

Brush Polymer ◽

Bottle Brush

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Spreading Characteristics of Molecularly Thin Lubricant on Surfaces With Groove-Shaped Textures: Effects of Molecular Weight and End-Group Functionality

Journal of Tribology ◽

10.1115/1.1509771 ◽

2003 ◽

Vol 125 (2) ◽

pp. 350-357 ◽

Cited By ~ 12

Author(s):

Hedong Zhang ◽

Yasunaga Mitsuya ◽

Maiko Yamada

Keyword(s):

Molecular Weight ◽

Monte Carlo ◽

Monte Carlo Method ◽

Ising Model ◽

Monte Carlo Simulations ◽

Simulation Method ◽

Solid Surfaces ◽

The Monte Carlo Method ◽

End Groups ◽

End Group

Effects of molecular weight and end-group functionality on spreading of molecularly thin perfluoropolyether (PFPE) film over solid surfaces with groove-shaped textures have been studied by experiments and Monte Carlo simulations. In the experiments, lubricant spreading on a surface with groove-shaped textures was measured by making use of the phenomenon in which diffracted light weakens in the lubricant-covered region. It is found that grooves serve to accelerate spreading and this effect increases for deeper grooves, and also the accelerating rate becomes larger for a lubricant having a larger molecular weight or functional end-groups. In the simulations, the Monte Carlo method based on the Ising model was extended to enable us to evaluate the effect of molecular weight on the spreading of non-functional lubricant inside a groove. The validity of the newly developed simulation method was well confirmed from the agreement between the simulation and experimental results.

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