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Organic & Biomolecular Chemistry Jan 2022Amphiphilic polymers can self-assemble to form nanoparticles with different structures under suitable conditions. Polymer nanoparticles functionalized with aromatic azo... (Review)
Review
Amphiphilic polymers can self-assemble to form nanoparticles with different structures under suitable conditions. Polymer nanoparticles functionalized with aromatic azo groups are endowed with photo-responsive properties. In recent years, a variety of photoresponsive polymers and nanoparticles have been developed based on azobenzene, using different molecular design strategies and synthetic routes. This article reviews the progress of this rapidly developing research field, focusing on the structure, synthesis, assembly and response of photo-responsive polymer assemblies. According to the molecular structure, photo-responsive polymers can be divided into linear polymers containing azobenzene in a side chain, linear polymers containing azobenzene in the main chain, linear polymers containing azobenzene in an end group, branched polymers containing azobenzene and supramolecular polymers containing azobenzene. These systems have broad biomedical application prospects in the field of drug delivery and imaging applications.
Topics: Azo Compounds; Drug Delivery Systems; Nanostructures; Optical Imaging; Polymers
PubMed: 34908082
DOI: 10.1039/d1ob01823j -
Angewandte Chemie (International Ed. in... Jan 2020Mucoadhesive polymers are of significant interest to the pharmaceutical, medical device, and cosmetic industries. Polysaccharides possessing charged functional groups,...
Mucoadhesive polymers are of significant interest to the pharmaceutical, medical device, and cosmetic industries. Polysaccharides possessing charged functional groups, such as chitosan, are known for mucoadhesive properties but suffer from poor chemical definition and solubility, while the chemical synthesis of polysaccharides is challenging with few reported examples of synthetic carbohydrate polymers with engineered-in ionic functionality. We report the design, synthesis, and evaluation of a synthetic, cationic, enantiopure carbohydrate polymer inspired by the structure of chitosan. These water-soluble, cytocompatible polymers are prepared via an anionic ring-opening polymerization of a bicyclic β-lactam sugar monomer. The synthetic method provides control over the site of amine functionalization and the length of the polymer while providing narrow dispersities. These well-defined polymers are mucoadhesive as documented in single-molecule scale (AFM), bulk solution phase (FRAP), and ex vivo tissue experiments. Polymer length and functionality affects bioactivity as long, charged polymers display higher mucoadhesivity than long, neutral polymers or short, charged polymers.
Topics: Carbohydrates; Chitosan; Humans; Polymerization; Polymers
PubMed: 31701611
DOI: 10.1002/anie.201911720 -
Biomacromolecules Jan 2020Combining multiple stimuli-responsive functionalities into the polymer design is an attractive approach to improve nucleic acid delivery. However, more in-depth...
Combining multiple stimuli-responsive functionalities into the polymer design is an attractive approach to improve nucleic acid delivery. However, more in-depth fundamental understanding how the multiple functionalities in the polymer structures are influencing polyplex formation and stability is essential for the rational development of such delivery systems. Therefore, in this study the structure and dynamics of thermosensitive polyplexes were investigated by tracking the behavior of labeled plasmid DNA (pDNA) and polymer with time-resolved fluorescence spectroscopy using fluorescence resonance energy transfer (FRET). The successful synthesis of a heterofunctional poly(ethylene glycol) (PEG) macroinitiator containing both an atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain-transfer (RAFT) initiator is reported. The use of this novel PEG macroinitiator allows for the controlled polymerization of cationic and thermosensitive linear triblock copolymers and labeling of the chain-end with a fluorescent dye by maleimide-thiol chemistry. The polymers consisted of a thermosensitive poly(-isopropylacrylamide) (PNIPAM, N), hydrophilic PEG (P), and cationic poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA, D) block, further referred to as NPD. Polymer block D chain-ends were labeled with Cy3, while pDNA was labeled with FITC. The thermosensitive NPD polymers were used to prepare pDNA polyplexes, and the effect of the N/P charge ratio, temperature, and composition of the triblock copolymer on the polyplex properties were investigated, taking nonthermosensitive PD polymers as the control. FRET was observed both at 4 and 37 °C, indicating that the introduction of the thermosensitive PNIPAM block did not compromise the polyplex structure even above the polymer's cloud point. Furthermore, FRET results showed that the NPD- and PD-based polyplexes have a less dense core compared to polyplexes based on cationic homopolymers (such as PEI) as reported before. The polyplexes showed to have a dynamic character meaning that the polymer chains can exchange between the polyplex core and shell. Mobility of the polymers allow their uniform redistribution within the polyplex and this feature has been reported to be favorable in the context of pDNA release and subsequent improved transfection efficiency, compared to nondynamic formulations.
Topics: Acrylic Resins; Carbocyanines; DNA; Fluorescence Resonance Energy Transfer; Magnetic Resonance Spectroscopy; Methacrylates; Nylons; Plasmids; Polyethylene Glycols; Polymerization; Polymers; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Temperature
PubMed: 31500418
DOI: 10.1021/acs.biomac.9b00896 -
Biointerphases Dec 2018Dentin adhesive systems for composite tooth restorations are composed of hydrophilic/hydrophobic monomers, solvents, and photoinitiators. The adhesives undergo phase...
Dentin adhesive systems for composite tooth restorations are composed of hydrophilic/hydrophobic monomers, solvents, and photoinitiators. The adhesives undergo phase separation and concomitant compositional change during their application in the wet oral environment; phase separation compromises the quality of the hybrid layer in the adhesive/dentin interface. In this work, the adhesive composition in the hybrid layer can be represented using the phase boundaries of a ternary phase diagram for the hydrophobic monomer/hydrophilic monomer/water system. The polymer phases, previously unaccounted for, play an important role in determining the mechanical behavior of the bulk adhesive, and the chemomechanical properties of the phases are intimately related to the effects produced by differences in the hydrophobic-hydrophilic composition. As the composition of the polymer phases varies from hydrophobic-rich to hydrophilic-rich, the amount of the adsorbed water and the nature of polymer-water interaction vary nonlinearly and strongly correlate with the change in elastic moduli under wet conditions. The failure strain, loss modulus, and glass transition temperature vary nonmonotonically with composition and are explained based upon primary and secondary transitions observed in dynamic mechanical testing. Due to the variability in composition, the assignment of mechanical properties and the choice of suitable constitutive models for polymer phases in the hybrid layer are not straightforward. This work investigates the relationship between composition and chemomechanical properties of the polymer phases formed on the water-adhesive phase boundary using quasistatic and dynamic mechanical testing, mass transfer experiments, and vibrational spectroscopy.
Topics: Chemical Phenomena; Dental Cements; Mechanical Phenomena; Polymers; Quantitative Structure-Activity Relationship
PubMed: 30558430
DOI: 10.1116/1.5058072 -
Chemical Reviews Feb 2016This review discusses one-dimensional supramolecular polymers that form in aqueous media. First, naturally occurring supramolecular polymers are described, in... (Review)
Review
This review discusses one-dimensional supramolecular polymers that form in aqueous media. First, naturally occurring supramolecular polymers are described, in particular, amyloid fibrils, actin filaments, and microtubules. Their structural, thermodynamic, kinetic, and nanomechanical properties are highlighted, as well as their importance for the advancement of biologically inspired supramolecular polymer materials. Second, five classes of synthetic supramolecular polymers are described: systems based on (1) hydrogen-bond motifs, (2) large π-conjugated surfaces, (3) host-guest interactions, (4) peptides, and (5) DNA. We focus on recent studies that address key challenges in the field, providing mechanistic understanding, rational polymer design, important functionality, robustness, or unusual thermodynamic and kinetic properties.
Topics: Kinetics; Polymers; Thermodynamics; Water
PubMed: 26727633
DOI: 10.1021/acs.chemrev.5b00369 -
Advances in Colloid and Interface... Jul 2022Achievements in polymer chemistry enables to design artificial phase boundaries modified by imprints of selected molecules and some larger structures. These structures... (Review)
Review
Achievements in polymer chemistry enables to design artificial phase boundaries modified by imprints of selected molecules and some larger structures. These structures seem very useful for the design of new materials suitable for affinity chromatography and sensors. In this review, we are overviewing the synthesis of molecularly imprinted polymers (MIPs) and the applicability of these MIPs in the design of affinity sensors. Such MIP-based layers or particles can be used as analyte-recognizing parts for sensors and in some cases they can replace very expensive compounds (e.g.: antibodies, receptors etc.), which are recognizing analyte. Many different polymers can be used for the formation of MIPs, but conducing polymers shows the most attractive capabilities for molecular-imprinting by various chemical compounds. Therefore, the application of conducting polymers (e.g.: polypyrrole, polyaniline, polythiophene, poly(3,4-ethylenedioxythiophene), and ortho-phenylenediamine) seems very promising. Polypyrrole is one of the most suitable for the development of MIP-based structures with molecular imprints by analytes of various molecular weights. Overoxiation of polypyrrole enables to increase the selectivity of polypyrrole-based MIPs. Methods used for the synthesis of conducting polymer based MIPs are overviewed. Some methods, which are applied for the transduction of analytical signal, are discussed, and challenges and new trends in MIP-technology are foreseen.
Topics: Molecular Imprinting; Molecularly Imprinted Polymers; Polymers; Pyrroles
PubMed: 35609398
DOI: 10.1016/j.cis.2022.102693 -
Current Pharmaceutical Design 2018The rising incidence of antibiotic-resistant infections, combined with a declining number of new antibiotic drug approvals, has generated an alarming therapeutic gap... (Review)
Review
The rising incidence of antibiotic-resistant infections, combined with a declining number of new antibiotic drug approvals, has generated an alarming therapeutic gap that critically undermines public health. Host Defense Peptides (HDPs), sometimes referred to as "Nature's Antibiotics", are short chain, amphiphilic and cationic peptide sequences found in all multicellular organisms as part of their innate immunity. While there is a vast diversity in terms of HDP sequence and secondary structure, they all seem to share physiochemical characteristics that can be appropriated for macromolecular design by the synthetic polymer chemist. Over the past decade, remarkable progress has been made in the design and synthesis of polymer-based materials that effectively mimic HDP action - broad-spectrum antibacterial potency, rapid bactericidal kinetics, and minimal toxicity to human cells - while offering the additional benefits of low cost, high scalability, and lower propensity to induce resistance, relative to their peptide-based counterparts. A broad range of different macromolecular structures and architectures have been explored in this design space, including polynorbornenes, poly(meth)acrylates, poly(meth)acrylamides, nylon-2 polymers, and polycarbonates, to name a just few. Across all of these diverse chemical categories, the key determinants of antibacterial and hemolytic activity are the same as in HDPs: net cationic charge at neutral pH, well-balanced facial amphiphilicity, and the molecular weight of the compounds. In this review, we focus in particular on recent progress in the polymethacrylate category first pioneered by Kuroda and DeGrado and later modified, expanded upon and rigorously optimized by Kuroda's and many other groups. Key findings and future challenges will be highlighted.
Topics: Anti-Bacterial Agents; Bacteria; Drug Design; Humans; Molecular Structure; Polymers; Structure-Activity Relationship
PubMed: 29436992
DOI: 10.2174/1381612824666180213140732 -
Macromolecular Rapid Communications Dec 2023Polydiacetylenes, as a class of conjugated polymers with alternating conjugated C═C and C≡C bonds, have emerged as a promising probe material for biomedical Raman...
Polydiacetylenes, as a class of conjugated polymers with alternating conjugated C═C and C≡C bonds, have emerged as a promising probe material for biomedical Raman imaging, given their ultrastrong Raman scattering intensity. However, the relationship between the structure, especially the molecular length of polydiacetylenes, and their Raman scattering intensity remains unclear. In this work, a series of water-soluble polydiacetylenes, namely poly(deca-4,6-diynedioic acid) (PDDA) with different molecular weights (MWs), is prepared through controlled polymerization and degradation. The ultraviolet-visible (UV-vis) absorption spectroscopic and Raman spectroscopic studies on these polymers reveal that the Raman scattering intensity of PDDA increases nonlinearly with the MW. The MW-Raman scattering intensity relationship in the polymerization process is completely different from that in the degradation process. In contrast, the Raman scattering intensity increases more linearly with the maximal absorbance of the polymer, and the relationship between the Raman scattering intensity and the maximal absorbance of PDDA in the polymerization process is consistent with that in the degradation process. The Raman scattering intensity of PDDA hence exhibits a better dependence on the effective conjugation length of the polymer, which should guide the future design of conjugated polymers for Raman imaging applications.
Topics: Polymers; Spectrum Analysis, Raman; Polyacetylene Polymer; Molecular Weight
PubMed: 37713720
DOI: 10.1002/marc.202300412 -
Analytica Chimica Acta Jul 2022Since the invention of fully synthetic plastic in the 1900s, plastics have been extensively applied in various fields and represent a significant market due to their... (Review)
Review
Since the invention of fully synthetic plastic in the 1900s, plastics have been extensively applied in various fields and represent a significant market due to their satisfactory properties. However, the non-biodegradable nature of most plastics has contributed to the accumulation of plastic waste, which poses a threat to both the environment and living beings. Given this, biodegradable polymers have emerged as eco-friendly substitutes for non-biodegradable polymers, and standard test methods have been established to evaluate polymer biodegradability. Technological advancement and the weaknesses of conventional test methods drive the invention of sensors that enable real-time monitoring of biodegradability. Besides, biodegradable polymers have been utilized to make sensors with different functionalities. Given this, the current paper is the first to compare and contrast sensors capable of identifying biodegradable polymers. The detection using sensors represents an innovative perspective for real-time monitoring of biodegradability. Besides, sensors made from biodegradable polymers are included, and these sensors are of different types and show various applications. Finally, the challenges associated with developing these sensors are described to advance future research.
Topics: Biodegradation, Environmental; Plastics; Polymers
PubMed: 35690422
DOI: 10.1016/j.aca.2022.339989 -
Macromolecular Rapid Communications May 2024Large scale computer simulations are employed to analyze the conformations of network strands in polymer networks at preparation conditions (characterized by a polymer...
Large scale computer simulations are employed to analyze the conformations of network strands in polymer networks at preparation conditions (characterized by a polymer volume fraction of ϕ) and when swollen to equilibrium (characterized by a polymer volume fraction ϕ < ϕ). Network strands in end-linked model networks are weakly stretched and partially swollen at preparation conditions as compared to linear polymers in the same solvent at ϕ. Equilibrium swelling causes non-ideal chain conformations characterized by an effective scaling exponent approaching 7/10 on intermediate length scales for increasing overlap of the chains. The chain size in a network consists of a fluctuating and a time average "elastic" contribution. The elastic contribution swells essentially affinely ∝(ϕ/ϕ), whereas the swelling of the fluctuating part lies between the expected swelling of the entanglement constraints and the swelling of non-cross-linked chains in a comparable semi-dilute solution. The total swelling of chain size results from the changes of both fluctuating and non-fluctuating contributions.
Topics: Polymers; Computer Simulation; Molecular Conformation
PubMed: 38323367
DOI: 10.1002/marc.202400025