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Macromolecular Rapid Communications Dec 2017Over the last ten years, the development of synthetic polymers containing controlled monomer sequences has become a prominent topic in fundamental and applied polymer... (Review)
Review
Over the last ten years, the development of synthetic polymers containing controlled monomer sequences has become a prominent topic in fundamental and applied polymer science. This emerging area is particularly broad and combines classical polymer chemistry tools with techniques imported from other domains such as biology, biochemistry, organic synthesis, engineering, and bioanalytics. Consequently, it also generates new structures, terminologies, and applications that are not within the traditional scope of polymer science. The term "sequence-controlled polymers" (SCPs) was recently proposed as a generic name to describe all these recent trends. However, since the field of SCPs has been growing very rapidly in recent literature, it is urgent to accurately define its scientific frontiers. In this important context, this review is an attempt to define, rationalize, and classify the field of SCPs. In particular, all synthetic approaches that have been reported for the synthesis of SCPs are discussed and categorized. In addition, the characterization tools, properties, and potential applications of these new polymers are described herein. Overall, this review serves as a reference guide for understanding the burgeoning field of SCPs.
Topics: Polymers
PubMed: 29160615
DOI: 10.1002/marc.201700582 -
Chemphyschem : a European Journal of... Jun 2017Polymer mechanochemistry is an emerging field at the interface of chemistry, materials science, physics and engineering. It aims at understanding and exploiting unique... (Review)
Review
Polymer mechanochemistry is an emerging field at the interface of chemistry, materials science, physics and engineering. It aims at understanding and exploiting unique reactivities of polymer chains confined to highly non-equilibrium stretched geometries by interactions with their surroundings. Macromolecular chains or their segments become stretched in bulk polymers under mechanical loads or when polymer solutions are sonicated or flow rapidly through abrupt contractions. An increasing amount of empirical data suggests that mechanochemical phenomena are widespread wherever polymers are used. In the past decade, empirical mechanochemistry has progressed enormously, from studying fragmentations of commodity polymers by simple backbone homolysis to demonstrations of self-strengthening and stress-reporting materials and mechanochemical cascades using purposefully designed monomers. This progress has not yet been matched by the development of conceptual frameworks within which to rationalize, systematize and generalize empirical mechanochemical observations. As a result, mechanistic and/or quantitative understanding of mechanochemical phenomena remains, with few exceptions, tentative. In this review we aim at systematizing reported macroscopic manifestations of polymer mechanochemistry, and critically assessing the interpretational framework that underlies their molecular rationalizations from a physical chemist's perspective. We propose a hierarchy of mechanochemical phenomena which may guide the development of multiscale models of mechanochemical reactivity to match the breadth and utility of the Eyring equation of chemical kinetics. We discuss the limitations of the approaches to quantifying and validating mechanochemical reactivity, with particular focus on sonicated polymer solutions, in order to identify outstanding questions that need to be solved for polymer mechanochemistry to become a rigorous, quantitative field. We conclude by proposing 7 problems whose solution may have a disproportionate impact on the development of polymer mechanochemistry.
Topics: Chemistry, Physical; Polymers
PubMed: 28256793
DOI: 10.1002/cphc.201601354 -
Annual Review of Food Science and... 2016The potential of organogels (oleogels) for oil structuring has been identified and investigated extensively using different gelator-oil systems in recent years. This... (Review)
Review
The potential of organogels (oleogels) for oil structuring has been identified and investigated extensively using different gelator-oil systems in recent years. This review provides a comprehensive summary of all oil-structuring systems found in the literature, with an emphasis on ethyl-cellulose (EC), the only direct food-grade polymer oleogelator. EC is a semicrystalline material that undergoes a thermoreversible sol-gel transition in the presence of liquid oil. This unique behavior is based on the polymer's ability to associate through physical bonds. These interactions are strongly affected by external fields such as shear and temperature, as well as by solvent chemistry, which in turn strongly affect final gel properties. Recently, EC-based oleogels have been used as a replacement for fats in foods, as heat-resistance agents in chocolate, as oil-binding agents in bakery products, and as the basis for cosmetic pastes. Understanding the characteristics of the EC oleogel is essential for the development of new applications.
Topics: Cellulose; Chemical Phenomena; Cosmetics; Fat Substitutes; Food Additives; Food Technology; Gels; Hot Temperature; Oils; Organic Chemicals; Phase Transition; Polymers
PubMed: 26735799
DOI: 10.1146/annurev-food-041715-033225 -
ACS Nano Jul 2023As a clinical unmet need, uncontrolled inflammation is characterized by the crosstalk between oxidative stress and an inflammatory response. Ferroptotic cell death plays...
As a clinical unmet need, uncontrolled inflammation is characterized by the crosstalk between oxidative stress and an inflammatory response. Ferroptotic cell death plays an essential role in uncontrolled inflammation. Hence ferroptosis inhibition is capable of managing hyper-inflammation, but the small molecular inhibitors show poor residence in cell membranes. The plasma membrane is the major site of lipid peroxidation that is the key event of ferroptosis. To address such a challenge, chiral radical trapping polymers were engineered by mimicking the structure of the cell membrane with imbedded helical proteins. The polymers were tailored to show an α-helix conformation that enabled increased hydrophobicity, prolonged membrane retention, and enhanced lipid radical trapping. The chiral polymers are amphiphilic, and the self-assembled micelles exhibited an extended blood circulation. At the lipopolysaccharide-induced macrophage and mice models, chiral polymer micelles effectively suppressed ferroptosis and repressed inflammatory cytokines. The current work provides an innovative means for attenuating uncontrolled inflammation by anti-ferroptotic polymer micelles.
Topics: Mice; Animals; Polymers; Micelles; Cell Death; Lipid Peroxidation; Inflammation
PubMed: 37352508
DOI: 10.1021/acsnano.2c12356 -
Acta Biomaterialia Oct 2022For the first time, the present review critically evaluates biodegradable polymer matrix composites containing graphene-related materials (GRMs) for antibacterial... (Review)
Review
For the first time, the present review critically evaluates biodegradable polymer matrix composites containing graphene-related materials (GRMs) for antibacterial applications while discussing their development, processing routes, mechanical properties, and antibacterial activity. Due to its suitable biological properties and processability, chitosan has been the most widely used biodegradable polymer for the fabrication of GRM-containing composites with antibacterial properties. The majority of biodegradable polymers (including cellulose-, gelatine-, PVA-, PCL-, and PHA-based polymers) exhibit little to no antibacterial effect alone; however, they show significant antibacterial activity (>70%) when combined with GRMs. In vitro and in vivo studies indicate that GRMs functionalization with biodegradable polymers also reduces potential GRM cytotoxicity. Overall, GRMs in biodegradable polymer matrices provide attractive antibacterial activity against a broad spectrum of bacteria (>30 different bacteria) along with improved mechanical properties over pristine polymers, where the type and the degree of improvement provided by GRMs depend on the specific matrix. For example, the addition of GRMs into chitosan, PVA, and PCL matrices increases their tensile strength by 80%, 180%, and 40%, respectively. Challenges remain in understanding the effects of processing routes and post-processing methods on the antibacterial activity and biocompatibility of biodegradable polymer/GRM composites. Given their promising properties and functionality, research on these composites is expected to further increase along with the implementation of new composite systems. These would include a wide range of applications, e.g., wound dressings, tissue engineering, drug delivery, biosensing, and photo-thermal therapy, as well as non-medical use, e.g., antibacterial food packaging, water treatment, and antibacterial fabrics. STATEMENT OF SIGNIFICANCE: Graphene-related materials (GRMs) in polymer matrices can provide excellent antibacterial activity against a broad spectrum of bacteria together with improved mechanical properties (e.g., tensile strength and elastic modulus) over pristine polymers; thus, research efforts and applications of biodegradable polymer matrix composites containing GRMs have increased notably in the last ten years. For the first time, the present review critically evaluates biodegradable polymer matrix composites containing GRMs for antibacterial applications while discussing their development, processing routes, mechanical properties, and antibacterial activity. Future research directions for each composite system are proposed to shed light on overcoming the existing challenges in composite performance (e.g., mechanical properties, toxicity) reported in the literature.
Topics: Anti-Bacterial Agents; Cellulose; Chitosan; Graphite; Polymers; Tensile Strength
PubMed: 35921991
DOI: 10.1016/j.actbio.2022.07.048 -
Proceedings of the National Academy of... Apr 2023Biomolecular phase separation has emerged as an essential mechanism for cellular organization. How cells respond to environmental stimuli in a robust and sensitive...
Biomolecular phase separation has emerged as an essential mechanism for cellular organization. How cells respond to environmental stimuli in a robust and sensitive manner to build functional condensates at the proper time and location is only starting to be understood. Recently, lipid membranes have been recognized as an important regulatory center for biomolecular condensation. However, how the interplay between the phase behaviors of cellular membranes and surface biopolymers may contribute to the regulation of surface condensation remains to be elucidated. Using simulations and a mean-field theoretical model, we show that two key factors are the membrane's tendency to phase-separate and the surface polymer's ability to reorganize local membrane composition. Surface condensate forms with high sensitivity and selectivity in response to features of biopolymer when positive co-operativity is established between coupled growth of the condensate and local lipid domains. This effect relating the degree of membrane-surface polymer co-operativity and condensate property regulation is shown to be robust by different ways of tuning the co-operativity, such as varying membrane protein obstacle concentration, lipid composition, and the affinity between lipid and polymer. The general physical principle emerged from the current analysis may have implications in other biological processes and beyond.
Topics: Polymers; Cell Membrane; Membranes; Membrane Proteins; Lipids
PubMed: 37018196
DOI: 10.1073/pnas.2212516120 -
Current Drug Delivery 2015Mucoadhesion can be defined as adhesion in biological setting. Process of mucoadhesion takes place in 3 stages- the first stage being that of wetting or swelling of... (Review)
Review
Mucoadhesion can be defined as adhesion in biological setting. Process of mucoadhesion takes place in 3 stages- the first stage being that of wetting or swelling of mucoadhesive polymer. Second stage involves interpenetration of the chains of mucoadhesive polymer and the third stage involves formation of chemical bonds between entangled chains. Several polymer related factors like molecular weight, chain length, degree of cross-linking, hydration, functional groups, charge, polymer concentration and several environmental and physiological factors like contact time, mucin turnover rate and mucus viscosity affect the degree of mucoadhesion. Formulation scientists have structured and engineered several mucoadhesive polymers for their usefulness in enhancement of bioavailability, controlled and targeted drug delivery. Mucoadhesive polymers can be classified as non-specific first generation polymers and novel second generation polymers based on the mechanism of mucoadhesion. Mucoadhesive drug delivery systems have been applied to buccal cavity, oesophagus, gastrointestinal tract, eye, nasal cavity, vagina and rectal cavity. Several in vitro/ex vivo and in vivo evaluation techniques have evolved for the evaluation of mucoadhesive strength of these polymers. This review provides historical perspective on mucoadhesive polymers and an understanding of the phenomenon of mucoadhesion, factors affecting mucoadhesion, types of mucoadhesive polymers, their practical applications and the various evaluation techniques for determination of mucoadhesive strength.
Topics: Adhesives; Chemical Phenomena; Drug Delivery Systems; Humans; Polymers
PubMed: 25911164
DOI: 10.2174/1567201811666140924124722 -
Results and Problems in Cell... 2022Genomic DNA, which controls genetic information, is stored in the cell nucleus in eukaryotes. Chromatin moves dynamically in the nucleus, and this movement is closely...
Genomic DNA, which controls genetic information, is stored in the cell nucleus in eukaryotes. Chromatin moves dynamically in the nucleus, and this movement is closely related to the function of chromatin. However, the driving force of chromatin movement, its control mechanism, and the functional significance of movement are unclear. In addition to biochemical and genetic approaches such as identification and analysis of regulators, approaches based on the physical properties of chromatin and cell nuclei are indispensable for this understanding. In particular, the idea of polymer physics is expected to be effective. This paper introduces our efforts to combine biological experiments on chromatin kinetics with theoretical analysis based on polymer physics.
Topics: Chromatin; Polymers; Chromosomes; Cell Nucleus; DNA
PubMed: 36348110
DOI: 10.1007/978-3-031-06573-6_8 -
Molecules (Basel, Switzerland) Aug 2019Polymerization provides an efficient strategy for synthesizing macromolecules with versatile functionality [...].
Polymerization provides an efficient strategy for synthesizing macromolecules with versatile functionality [...].
Topics: Biological Products; Biosensing Techniques; Drug Delivery Systems; Food Technology; Humans; Information Storage and Retrieval; Polymerization; Polymers; Tissue Engineering; Water Purification
PubMed: 31426353
DOI: 10.3390/molecules24162976 -
International Journal of Molecular... Sep 2022Using hybrid multi-particle collision dynamics (MPCD) and a molecular dynamics (MD) method, we investigate the effect of arms and shear flow on dynamical and structural...
Using hybrid multi-particle collision dynamics (MPCD) and a molecular dynamics (MD) method, we investigate the effect of arms and shear flow on dynamical and structural properties of the comb long-chain branched (LCB) polymer with dense arms. Firstly, we analyze dynamical properties of the LCB polymer by tracking the temporal changes on the end-to-end distance of both backbones and arms as well as the orientations of the backbone in the flow-gradient plane. Simultaneously, the rotation and tumbling behaviors with stable frequencies are observed. In other words, the LCB polymer undergoes a process of periodic stretched-folded-stretched state transition and rotation, whose period is obtained by fitting temporal changes on the orientation to a periodic function. In addition, the impact induced by random and fast motions of arms and the backbone will descend as the shear rate increases. By analyzing the period of rotation behavior of LCB polymers, we find that arms have a function in keeping the LCB polymer's motion stable. Meanwhile, we find that the rotation period of the LCB polymer is mainly determined by the conformational distribution and the non-shrinkable state of the structure along the velocity-gradient direction. Secondly, structural properties are numerically characterized by the average gyration tensor of the LCB polymer. The changes in gyration are in accordance with the LCB polymer rolling when varying the shear rate. By analyzing the alignment of the LCB polymer and comparing with its linear and star counterparts, we find that the LCB polymer with very long arms, like the corresponding linear chain, has a high speed to reach its configuration expansion limit in the flow direction. However, the comb polymer with shorter arms has stronger resistance on configuration expansion against the imposed flow field. Moreover, with increasing arm length, the comb polymer in shear flow follows change from linear-polymer-like to capsule-like behavior.
Topics: Molecular Conformation; Molecular Dynamics Simulation; Polymers; Rotation
PubMed: 36232591
DOI: 10.3390/ijms231911290