Read by QxMD icon Read

Polymer Chemistry

Guocan Yu, Run Zhao, Dan Wu, Fuwu Zhang, Li Shao, Jiong Zhou, Jie Yang, Guping Tang, Xiaoyuan Chen, Feihe Huang
Supramolecular brush copolymers have attracted continuing interest due to their unusual architectures, fascinating properties, and potential applications in many fields involving smart stimuli-responsive drug delivery systems. Herein, the first pillararene-based amphiphilic supramolecular brush copolymer (P5-PEG-Biotin⊃PTPE) was constructed on the basis of the host-guest molecular recognition between a water-soluble pillar[5]arene (P5) and a viologen salt (M). P5-PEG-Biotin⊃PTPE self-assembled into supramolecular nanoparticles (SNPs), which were utilized as a self-imaging drug delivery vehicle by taking advantage of the aggregation-induced emission (AIE) effect...
October 28, 2016: Polymer Chemistry
P S Kulkarni, M K Haldar, M I Confeld, C J Langaas, X Yang, S Y Qian, S Mallik
Mitochondria is an attractive target to deliver anticancer drugs. We have synthesized a cationic triphenylphosphonium ion conjugated fluorescent polymer which self-assembles into nanosized polymersomes and targets the encapsulated anticancer drug doxorubicin to cancer cell mitochondria.
July 7, 2016: Polymer Chemistry
Yan Kang, Anaïs Pitto-Barry, Marianne S Rolph, Zan Hua, Ian Hands-Portman, Nigel Kirby, Rachel K O'Reilly
Amphiphilic nucleobase-containing block copolymers with poly(oligo(ethylene glycol) methyl ether methacrylate) as the hydrophilic block and nucleobase-containing blocks as the hydrophobic segments were successfully synthesized using RAFT polymerization and then self-assembled via solvent switch in aqueous solutions. Effects of the common solvent on the resultant morphologies of the adenine (A) and thymine (T) homopolymers, and A/T copolymer blocks and blends were investigated. These studies highlighted that depending on the identity of the common solvent, DMF or DMSO, spherical micelles or bicontinuous micelles were obtained...
April 28, 2016: Polymer Chemistry
Ignacio Insua, Evangelos Liamas, Zhenyu Zhang, Anna F A Peacock, Anne Marie Krachler, Francisco Fernandez-Trillo
Here we present new enzyme-responsive polyion complex (PIC) nanoparticles prepared from antimicrobial poly(ethylene imine) and an anionic enzyme-responsive peptide targeting Pseudomonas aeruginosa's elastase. The synthetic conditions used to prepare these nanomaterials allowed us to optimise particle size and charge, and their stability under physiological conditions. We demonstrate that these enzyme responsive PIC nanoparticles are selectively degraded in the presence of P. aeruginosa elastase without being affected by other endogenous elastases...
April 21, 2016: Polymer Chemistry
Liang Sun, Anaïs Pitto-Barry, Anthony W Thomas, Maria Inam, Kay Doncom, Andrew P Dove, Rachel K O'Reilly
Sequential ring-opening and reversible addition-fragmentation chain transfer (RAFT) polymerization was used to form a triblock copolymer of tetrahydropyran acrylate (THPA), 5-methyl-5-allyloxycarbonyl-1,3-dioxan-2-one (MAC) and l-lactide. Concurrent deprotection of the THPA block and crystallization-driven self-assembly (CDSA) was undertaken and allowed for the formation of cylindrical micelles bearing allyl handles in a short outer core segment. These handles were further functionalized by different thiols using photo-initiated thiol-ene radical reactions to demonstrate that the incorporation of an amorphous PMAC block within the core does not disrupt CDSA and can be used to load the cylindrical nanoparticles with cargo...
April 7, 2016: Polymer Chemistry
Peter C Nauka, Juneyoung Lee, Heather D Maynard
Polymers with oligoethylene glycol side chains are promising in therapeutic protein-polymer conjugates as replacements for linear polyethylene glycol (PEG). Branched PEG polymers can confer additional stability and advantageous properties compared to linear PEGs. However, branched PEG polymers suffer from low conjugation yields to proteins, likely due to steric interactions between bulky side chains of the polymer and the protein. In an effort to increase yields, the linker length between the protein-reactive functional end-group of the polymer chain and branched PEG side chain was systematically increased...
April 7, 2016: Polymer Chemistry
Daniel J Phillips, Thomas R Congdon, Matthew I Gibson
Antifreeze (glyco)proteins (AF(G)Ps) have potent ice recrystallisation inhibition (IRI) activity - a desirable phenomenon in applications such as cryopreservation, frozen food and more. In Nature AF(G)P activity is regulated by protein expression levels in response to an environmental stimulus; temperature. However, this level of regulation is not possible in synthetic systems. Here, a synthetic macromolecular mimic is introduced, using supramolecular assembly to regulate activity. Catechol-terminated poly(vinyl alcohol) was synthesised by RAFT polymerization...
March 7, 2016: Polymer Chemistry
Daniel B Wright, Joseph P Patterson, Nathan C Gianneschi, Christophe Chassenieux, Olivier Colombani, Rachel K O'Reilly
Amphiphilic block copolymers can assemble into a variety of structures on the nanoscale in selective solvent. The micelle blending protocol offers a simple unique route to reproducibly produce polymer nanostructures. Here we expand this blending protocol to a range of polymer micelle systems and self-assembly routes. We found by exploring a range of variables that the systems must be able to reach global equilibrium at some point for the blending protocol to be successful. Our results demonstrate the kinetics requirements, specifically core block glass transition temperature, Tg, and length of the block limiting the exchange rates, for the blending protocol which can then be applied to a wide range of polymer systems to access this simple protocol for polymer self-assembly...
February 28, 2016: Polymer Chemistry
Eric A Dailing, Devatha P Nair, Whitney K Setterberg, Kyle A Kyburz, Chun Yang, Tyler D'Ovidio, Kristi S Anseth, Jeffrey W Stansbury
Drug releasing shape memory polymers (SMPs) were prepared from poly(thiourethane) networks that were coated with drug loaded nanogels through a UV initiated, surface mediated crosslinking reaction. Multifunctional thiol and isocyanate monomers were crosslinked through a step-growth mechanism to produce polymers with a homogeneous network structure that exhibited a sharp glass transition with 97% strain recovery and 96% shape fixity. Incorporating a small stoichiometric excess of thiol groups left pendant functionality for a surface coating reaction...
January 28, 2016: Polymer Chemistry
Raquel Palao-Suay, María Rosa Aguilar, Francisco J Parra-Ruiz, Samarendra Maji, Richard Hoogenboom, N A Rohner, Susan N Thomas, Julio San Román
α-Tocopheryl succinate (α-TOS) is a well-known mitochondrially targeted anticancer compound. However, the major factor limiting the use of α-TOS is its low solubility in physiological media. To overcome this problem, the aim of this work is the preparation of new polymeric and active α-TOS-based nanovehicle with a precise control over its macromolecular architecture. Reversible addition-fragmentation chain transfer polymerization (RAFT) is used to synthesize an α-TOS amphiphilic block copolymer with highly homogeneous molecular weight and relatively narrow dispersity...
January 28, 2016: Polymer Chemistry
Han Byul Song, Austin Baranek, Christopher N Bowman
Photoinitiation of polymerizations based on the copper(i)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction enables spatio-temporal control and the formation of mechanically robust, highly glassy photopolymers. Here, we investigated several critical factors influencing photo-CuAAC polymerization kinetics via systematic variation of reaction conditions such as the physicochemical nature of the monomers; the copper salt and photoinitiator types and concentrations; light intensity; exposure time and solvent content...
January 21, 2016: Polymer Chemistry
Kaja Kaastrup, Alan Aguirre-Soto, Chen Wang, Christopher N Bowman, Jeffery Stansbury, Hadley D Sikes
In conjunction with a tertiary amine coinitiator, eosin, a photoreducible dye, has been shown to successfully circumvent oxygen inhibition in radical photopolymerization reactions. However, the role of O2 in the initiation and polymerization processes remains inconclusive. Here, we employ a UV-Vis/FT-NIR analytical tool for real-time, simultaneous monitoring of chromophore and monomer reactive group concentrations to investigate the eosin-activated photopolymerization of PEGDA-based hydrogels under ambient conditions...
2016: Polymer Chemistry
Helen R Thomas, Daniel J Phillips, Neil R Wilson, Matthew I Gibson, Jonathan P Rourke
The direct grafting of poly(N-isopropylacrylamide) to the basal plane of graphene oxide has been achieved in a single step: cleavage of the terminal thiocarbonylthio group on RAFT grown poly(N-isopropylacrylamide) reveals a reactive thiol that attacks the epoxides present across the surface of graphene oxide. The new composite material was characterised by a combination of SSNMR, FTIR, Raman, EDX, XPS, TGA and contact angle measurement; it shows enhanced thermal stability and solubility in water.
December 28, 2015: Polymer Chemistry
Tyler R Long, Amaraporn Wongrakpanich, Anh-Vu Do, Aliasger K Salem, Ned B Bowden
Hydrogen sulfide is emerging as a critically important molecule in medicine, yet there are few methods for the long-term delivery of molecules that degrade to release H2S. In this paper the first long-term release of a thiobenzamide that degrades to release H2S is described. A series of polymers were synthesized by the copolymerization of L-lactide and a lactide functionalized with 4-hydroxythiobenzamide. A new method to attach functional groups to a derivative of L-lactide is described based on the addition of a thiol to an α,β-unsaturated lactide using catalytic I2...
October 2015: Polymer Chemistry
Rajasekhar R Ramireddy, P Prasad, A Finne, S Thayumanavan
Zwitterionic amphiphilic homopolymers can be conveniently prepared in one-pot using activated ester-based polymer precursors. We show that these zwitterionic polymers can (i) spontaneously self-assemble to form micelle-like and inverse micelle-like assemblies depending on the solvent environment; (ii) act as hydrophilic and hydrophobic nanocontainers in apolar and polar solvents respectively; (iii) undergo pH-responsive surface charge and size variations; (iv) exhibit least cytotoxicity compared to structurally analogous amphiphilic homopolymers...
September 7, 2015: Polymer Chemistry
Si-Eun Kim, Jaqueline D Wallat, Emily C Harker, Abigail A Advincula, Jonathan K Pokorski
Polymeric fibers have drawn recent interest for uses in biomedical technologies that span drug delivery, regenerative medicine, and wound-healing patches, amongst others. We have recently reported a new class of fibrous biomaterials fabricated using coextrusion and a photochemical modification procedure to introduce functional groups onto the fibers. In this report, we extend our methodology to control surface modification density, describe methods to synthesize multifunctional fibers, and provide methods to spatially control functional group modification...
August 21, 2015: Polymer Chemistry
Prathamesh M Kharkar, Kristi L Kiick, April M Kloxin
Injectable depots that respond to exogenous and endogenous stimuli present an attractive strategy for tunable, patient-specific drug delivery. Here, the design of injectable and multimodal degradable hydrogels that respond to externally applied light and physiological stimuli, specifically aqueous and reducing microenvironments, is reported. Rapid hydrogel formation was achieved using a thiol-maleimide click reaction between multifunctional poly(ethylene glycol) macromers. Hydrogel degradation kinetics in response to externally applied cytocompatible light, reducing conditions, and hydrolysis were characterized, and degradation of the gel was controlled over multiple time scales from seconds to days...
August 21, 2015: Polymer Chemistry
Juneyoung Lee, Jeong Hoon Ko, En-Wei Lin, Peter Wallace, Frank Ruch, Heather D Maynard
Enzymes can catalyze various reactions with high selectivity and are involved in many important biological processes. However, the general instability of enzymes against high temperature often limits their application. To address this, we synthesized a trehalose-based hydrogel in two steps from commercial starting materials with minimal purification procedures. Mono- and multi-functional trehalose monomers were cross-linked by redox-initiated radical polymerization to form a hydrogel. Phytase, an important enzyme utilized in animal feedstock, was employed to study the effectiveness of the trehalose hydrogel to stabilize proteins against heat...
May 14, 2015: Polymer Chemistry
F Alves, I Nischang
We prepared new and scalable, hybrid inorganic-organic step-growth hydrogels with polyhedral oligomeric silsesquioxane (POSS) network knot construction elements and hydrolytically degradable poly(ethylene glycol) (PEG) di-ester macromonomers by in situ radical-mediated thiol-ene photopolymerization. The physicochemical properties of the gels are fine-tailored over orders of magnitude including functionalization of their interior, a hierarchical gel structure, and biodegradability.
March 28, 2015: Polymer Chemistry
Carolin Fleischmann, Jeffrey Gopez, Pontus Lundberg, Helmut Ritter, Kato L Killops, Craig J Hawker, Daniel Klinger
We herein report the development of crosslinked polyether particles as a reactive platform for the preparation of functional microgels. Thiol-ene crosslinking of poly(allyl glycidyl ether) in miniemulsion droplets - stabilized by a surface active, bio-compatible polyethylene glycol block copolymer - resulted in colloidal gels with a PEG corona and an inner polymeric network containing reactive allyl units. The stability of the allyl groups allows the microgels to be purified and stored before a second, subsequent thiol-ene functionalization step allows a wide variety of pH- and chemically-responsive groups to be introduced into the nanoparticles...
March 21, 2015: Polymer Chemistry
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"