Mucoadhesion is defined as the adherence of a synthetic or natural polymer to a mucosal membrane via physical or chemical interactions. Mucoadhesive materials are widely used to develop dosage forms for transmucosal drug delivery via ocular, nasal, esophageal, oral, vaginal, rectal, and intravesical routes of administration. This review will discuss some of the most prominent and recent synthetic methodologies employed to modify polymeric materials in order to enhance their mucoadhesive properties. This includes chemical conjugation of polymers with molecules bearing thiol‐, catechol‐, boronate‐, acrylate‐, methacrylate‐, maleimide‐, and N‐hydroxy(sulfo)succinimide ester‐ groups. 相似文献
Macromolecules derived from 1,3‐dienes, such as polyisoprene (or natural rubber), are of considerable importance in polymer science. Given the parallels between P=C and C=C bonds, the prospect of polymerizing P‐containing 1,3‐dienes, such as 1‐phosphaisoprene, is intriguing due to the unique chemical functionality imparted by the heavier element combined with their structural relationship to natural rubber. Herein, we report the synthesis, characterization and coordination chemistry of the first polymers derived from Mes*P=CR−CH=CH2 (Mes*=2,4,6‐t‐Bu3C6H2; R=H, Me). In the case of 1‐phosphaisoprene (R=Me), the monomer is isolable and its anionic polymerization affords a polymer that retains P=C bonds in its microstructure. The chemical functionality of these novel materials is demonstrated by forming the macromolecular gold(I) complex where the P=C bond is retained for further chemical elaboration. 相似文献
Functional polymers with sulfobetaine or phosphorylcholine zwitterions as pendent groups are demonstrated as both ligands and host matrices for CsPbBr3 perovskite nanoparticles (PNPs). These polymers produce nanocomposite films with excellent NP dispersion, optical transparency, and impressive resistance to NP degradation upon exposure to water. Multidentate interactions of the zwitterion‐containing copolymers with the PNPs induce dispersed or weakly aggregated nanocomposite morphologies, depending on the extent of zwitterionic functionality in the polymer. Incorporating additional functionality into the polymers, such as benzophenone pendent groups, yields lithographically patternable films, while time‐resolved photoluminescence measurements provide insight into the electronic impact of PNPs in zwitterionic polymer matrices. 相似文献
Chlorinated conjugated polymers not only show great potential for the realization of highly efficient polymer solar cells (PSCs) but also have simple and high‐yield synthetic routes and low‐cost raw materials available for their preparation. However, the study of the structure–property relationship of chlorinated polymers is lagging. Now two chlorinated conjugated polymers, PCl(3)BDB‐T and PCl(4)BDB‐T are investigated. When the polymers were used to fabricate PSCs with the nonfullerene acceptor (IT‐4F), surprisingly, the PCl(3)BDB‐T:IT‐4F‐based device exhibited a negligible power conversion efficiency (PCE) of 0.18 %, while the PCl(4)BDB‐T:IT‐4F‐based device showed an outstanding PCE of 12.33 %. These results provide new insight for the rational design and synthesis of novel chlorinated polymer donors for further improving the photovoltaic efficiencies of PSCs. 相似文献
The development of polymeric anion‐exchange membranes (AEMs) combining high ion conductivity and long‐term stability is a major challenge for materials chemistry. AEMs with regularly distributed fixed cationic groups, based on the formation of microporous polymers containing the V‐shape rigid Tröger's base units, are reported for the first time. Despite their simple preparation, which involves only two synthetic steps using commercially available precursors, the polymers provide AEMs with exceptional hydroxide conductivity at relatively low ion‐exchange capacity, as well as a high swelling resistance and chemical stability. An unprecedented hydroxide conductivity of 164.4 mS cm?1 is obtained at a relatively a low ion‐exchange capacity of 0.82 mmol g?1 under optimal operating conditions. The exceptional anion conductivity appears related to the intrinsic microporosity of the charged polymer matrix, which facilitates rapid anion transport. 相似文献
Cell‐based therapies are gaining prominence in treating a wide variety of diseases and using synthetic polymers to manipulate these cells provides an opportunity to impart function that could not be achieved using solely genetic means. Herein, we describe the utility of functional block copolymers synthesized by ring‐opening metathesis polymerization (ROMP) that can insert directly into the cell membrane via the incorporation of long alkyl chains into a short polymer block leading to non‐covalent, hydrophobic interactions with the lipid bilayer. Furthermore, we demonstrate that these polymers can be imbued with advanced functionalities. A photosensitizer was incorporated into these polymers to enable spatially controlled cell death by the localized generation of 1O2 at the cell surface in response to red‐light irradiation. In a broader context, we believe our polymer insertion strategy could be used as a general methodology to impart functionality onto cell‐surfaces. 相似文献
The use of long‐lasting polymer coatings on biodevice surfaces has been investigated to improve material–tissue interaction, minimize adverse effects, and enhance their functionality. Natural polymers, especially chitosan, are of particular interest due to their excellent biological properties, such as biocompatibility, non‐toxicity, and antimicrobial properties. One way to produce chitosan coating is by covalent grafting with catechol molecules such as dopamine, caffeic acid, and tannic acid, resulting in an attachment ten times stronger than that of simple physisorption. Caffeic acid presents an advantage over dopamine because it allows direct chitosan grafting, due to its terminal carboxylic acid group, without the need of a linking arm, as employed in the dopamine approach. In this study, the grafting of chitosan using caffeic acid, over surfaces or in solution, is compared with dopamine grafting using poly(ethylene glycol) as a linking arm. The following coating properties are observed; covering and homogeneity are assessed by X‐ray photoelectron spectroscopy and atomic force microscopy analyses, hydrophilicity with contact angle measurements, stability with aging tests, anticorrosion behavior, and coating non‐toxicity. Results show that grafting using caffeic acid/chitosan in solution over a metallic surface may be advantageous, compared to traditional dopamine coating. 相似文献
Inspired by biological polymers, sequence‐controlled synthetic polymers are highly promising materials that integrate the robustness of synthetic systems with the information‐derived activity of biological counterparts. Polymer–biopolymer conjugates are often targeted to achieve this union; however, their synthesis remains challenging. We report a stepwise solid‐phase approach for the generation of completely monodisperse and sequence‐defined DNA–polymer conjugates using readily available reagents. These polymeric modifications to DNA display self‐assembly and encapsulation behavior—as evidenced by HPLC, dynamic light scattering, and fluorescence studies—which is highly dependent on sequence order. The method is general and has the potential to make DNA–polymer conjugates and sequence‐defined polymers widely available. 相似文献
We developed chitosan based surfactant polymers that could be used to modify the surface of existing biomaterials in order to improve their blood compatibility. These polymers consist of a chitosan backbone, PEG side chains to repel non-specific protein adsorption, and hexanal side chains to facilitate adsorption and proper orientation onto a hydrophobic substrate via hydrophobic interactions. Since chitosan is a polycationic polymer, and it is thrombogenic, the surface charge was altered to determine the role of this charge in the hemocompatibility of chitosan. Charge had a notable effect on platelet adhesion. The platelet adhesion was greatest on the positively charged surface, and decreased by almost 50% with the neutralization of this charge. A chitosan surface containing the negatively charged SO(3)(-) exhibited the fewest number of adherent platelets of all surfaces tested. Coagulation activation was not altered by the neutralization of the positive charge, but a marked increase of approximately 5-6 min in the plasma recalcification time (PRT) was displayed with the addition of the negatively charged species. Polyethylene (PE) surfaces were modified with the chitosan surfactant resulting in a significant improvement in blood compatibility, which correlated to the increasing PEG content within the polymer. Adsorption of the chitosan surfactants onto PE resulted in approximately an 85-96% decrease in the number of adherent platelets. The surfactant polymers also reduced surface induced coagulation activation, which was indicated by the PEG density dependent increase in PRTs. These results indicate that surface modification with our chitosan based surfactant polymers successfully improves blood compatibility. Moreover, the inclusion of either negatively charged SO(3)(-) groups or a high density of large water-soluble PEG side chains produces a surface that may be suitable for cardiovascular applications. 相似文献
The main techniques developed to characterize chitosan are recalled. The interaction of chitosan with oppositely charged surfactants was investigated giving very important surface activity effects. A few chemical modifications are described and the new properties obtained are mentioned: alkylation gives amphiphilic polymers having interesting thickening behavior; grafting cyclodextrin (chit‐CD) gives a polymer able to include hydrophobic molecules; grafting adamantane gives an amphiphilic polymer able to specifically interact with chit‐CD forming a temporary network with gel‐like behavior.
The viscosities of adamantane‐chitosan, cyclodextrin‐chitosan, and unmodified chitosan solutions studied here. 相似文献
Chitosan has many useful intrinsic properties (e.g., non-toxicity, antibacterial properties, and biodegradability) and can be processed into high-surface-area nanofiber constructs for a broad range of sustainable research and commercial applications. These nanofibers can be further functionalized with bioactive agents. In the food industry, for example, edible films can be formed from chitosan-based composite fibers filled with nanoparticles, exhibiting excellent antioxidant and antimicrobial properties for a variety of products. Processing ‘pure’ chitosan into nanofibers can be challenging due to its cationic nature and high crystallinity; therefore, chitosan is often modified or blended with other materials to improve its processability and tailor its performance to specific needs. Chitosan can be blended with a variety of natural and synthetic polymers and processed into fibers while maintaining many of its intrinsic properties that are important for textile, cosmeceutical, and biomedical applications. The abundance of amine groups in the chemical structure of chitosan allows for facile modification (e.g., into soluble derivatives) and the binding of negatively charged domains. In particular, high-surface-area chitosan nanofibers are effective in binding negatively charged biomolecules. Recent developments of chitosan-based nanofibers with biological activities for various applications in biomedical, food packaging, and textiles are discussed herein. 相似文献
pH‐Responsive polymers have great potential in biomedical applications, including the selective delivery of preloaded drugs to tissues with low pH values. These polymers usually contain acid‐labile linkages such as esters and acetals/ketals. However, these linkages are only mildly pH‐responsive with relatively long half‐lives (t1/2). Orthoester linkages are more acid‐labile, but current methods suffer from synthetic challenges and are limited to the availability of monomers. To address these limitations, a sugar poly(orthoester) was synthesized as a highly pH‐responsive polymer. The synthesis was achieved by using 2,3,4‐tri‐O‐acetyl‐α‐D ‐glucopyranosyl bromide as a difunctional AB monomer and tetra‐n‐butylammonium iodide (TBAI) as an effective promoter. Under optimal conditions, polymers with molecular weights of 6.9 kDa were synthesized in a polycondensation manner. The synthesized glucose poly(orthoester), wherein all sugar units were connected through orthoester linkages, was highly pH‐responsive with a half‐life of 0.9, 0.6, and 0.2 hours at pH 6, 5, and 4, respectively. 相似文献