Search

Among the polymer families, aliphatic polyesters stand out from this category thanks to their degradable and biocompatible properties. In particular, the γ‐lactones differ from other lactones by yielding polyesters that can be depolymerized back to the monomer and offer the advantage of counting various biobased monomers. As an example, α‐hydroxy‐γ‐butyrolactone (HBL) is a hydroxy‐functionalized monomer that can be obtained by a biological synthetic route from glucose. In this article, the ring‐opening copolymerization (ROCP) of HBL and l‐lactide (LLA) using t‐BuP4 as catalyst is investigated. The copolymerizations were conducted within a temperature range of 5–100°C, affording monomer conversions exceeding 80%. The characterization of the copolyesters revealed a branched structure consisting of different HBL patterns, including cyclic, linear, and branched motives. Performing a kinetic study of the copolymerization at room temperature provided a deeper understanding of the mechanism. By modulating the reaction parameters, copolymers of low molar masses with an HBL content of up to 33% were synthesized. High molar mass LLA/HBL‐based copolyesters, with Mw¯$$ \overline{\mathrm{Mw}} $$ up to 290,000 g/mol, were synthesized by a straightforward chain coupling reaction with a diisocyanate. [ABSTRACT FROM AUTHOR]

Free-radical copolymerization of cyclic ketene acetals (CKAs) and vinyl ethers (VEs) was investigated as an efficient yet simple approach for the preparation of functional aliphatic polyesters. The copolymerization of CKA and VE was first predicted to be quasi-ideal by DFT calculations. The theoretical prediction was experimentally confirmed by the copolymerization of 2-methylene-1,3-dioxepane (MDO) and butyl vinyl ether (BVE), leading to rMDO=0.73 and rBVE=1.61. We then illustrated the versatility of this approach by preparing different functional polyesters: 1) copolymers functionalized by fluorescent probes; 2) amphiphilic copolymers grafted with poly(ethylene glycol) (PEG) side chains able to self-assemble into PEGylated nanoparticles; 3) antibacterial films active against Gram-positive and Gram-negative bacteria (including a multiresistant strain); and 4) cross-linked bioelastomers with suitable properties for tissue engineering applications. [ABSTRACT FROM AUTHOR]

Atom transfer radical polyaddition (ATRPA) was utilized herein to synthesize a specific functional polyester. We conducted ATRPA of 4-vinylbenzyl 2-bromo-2-phenylacetate (VBBPA) inimer and successfully obtained a linear type poly(VBBPA) (PVBBPA) polyester with benzylic bromides along the backbone. To obtain a novel amphiphilic polymer bottlebrush, however, the lateral ATRP chain extension of PVBBPA with N-vinyl pyrrolidone (NVP) met the problem of quantitative dimerization. By replacing the bromides to xanthate moieties efficiently, we thus observed a pseudo linear first order reversible addition−fragmentation chain transfer (RAFT) polymerization to obtain novel poly(4-vinylbenzyl-2-phenylacetate)-g-poly(NVP) (PVBPA-g-PNVP) amphiphilic polymer bottlebrushes. The critical micelle concentration (CMC) and particle size of the amphiphilic polymer bottlebrushes were characterized by fluorescence spectroscopy, dynamic light scattering (DLS), and scanning electron microscopy (SEM) (CMCs < 0.5 mg/mL; particle sizes = ca. 100 nm). Toward drug delivery application, we examined release profiles using a model drug of Nile red at different pH environments (3, 5, and 7). Eventually, low cytotoxicity and well cell uptake of the Madin-Darby Canine Kidney Epithelial (MDCK) for the polymer bottlebrush micelles were demonstrated.

Tremendous progress has been made in the development of delivery carriers for small RNA therapeutics. However, most achievements have focused on the treatment of liver-associated diseases because conventional lipid and lipidoid nanoparticles (LNPs) readily accumulate in the liver after intravenous (i.v.) administration. Delivering RNAs to other organs and tumor tissues remains an ongoing challenge. Here, we utilized a 540-member combinatorial functional polyester library to discover nanoparticles (NPs) that enable efficacious siRNA delivery to A549 lung cancer cells in vitro and in vivo . PE4K-A13–0.33C6 and PE4K-A13–0.33C10 NPs were efficiently internalized into A549-Luc cells within 4 h. The addition of PEG 2000 DMG lipid or Pluronic F-127 onto the surface of the polyplexes reduced the surface charge of NPs, resulting in an increase of serum stability. We then explored aerosol delivery of stabilized PE4K-A13–0.33C6 and PE4K-A13–0.33C10 NPs to implanted orthotopic lung tumors. We found that by altering the administration route from i.v. to aerosol, the NPs could avoid liver accumulation and instead be specifically localized only in the lungs. This resulted in significant gene silencing in the A549 orthotopic lung tumors. Due to the ability to deliver siRNA to non-liver targets, this approach provides a privileged route for gene silencing in the lungs. [ABSTRACT FROM AUTHOR]

[Display omitted] • ε-Caprolactone and biosourced α-hydroxy-γ-butyrolactone are copolymerized by ring-opening polymerization. • Functional and branched copolyesters with various compositions are obtained. • La[ N (SiMe 3) 2 ] 3 was used as a catalyst. The growing awareness of environmental concerns and the fossil resources depletion have raised the need to develop sustainable and degradable polymers such as aliphatic polyesters. γ-Lactone-based polyesters are of great interest today due to their ability to depolymerize. The introduction of functional groups appeared also useful to tune the properties of such polyesters. This can be addressed by the use of functional monomers such as the sugar-based α-hydroxy-γ-butyrolactone (HBL). In this study, the synthesis of random copolyesters of HBL and ε-caprolactone (ε-CL) was investigated via ring-opening copolymerization in the presence of La[ N (SiMe 3) 2 ] 3 as a catalyst. High polymerization temperature (80 °C) was required for fast and high monomer conversions. The characterization of the copolyesters and kinetic investigations provided better insight into the polymerization mechanism and formation of various HBL monomer units (cyclic, linear and branched). La[ N (SiMe 3) 2 ] 3 catalyst afforded high HBL conversion ratio (over 85 %) for the copolymerization reaction enabling the synthesis of copolyesters with a ratio of HBL units ranging from 9 to 63 %. [ABSTRACT FROM AUTHOR]

Amine-functionalized polyesters are an important class of materials for biomedical applications due to their utility in gene and drug delivery, bioconjugation reactions, hydrogels, and controlled release systems. The synthesis of amino polyesters by ring-opening polymerization (ROP) is an ongoing challenge that is being aided by advances in reaction development. For the benefit of this important research area, this article highlights the related works of synthesizing amino polyesters by ROP as well as our recent synthesis of a new library of amino polyesters from amine-functionalized lactone monomers. 1 Polymerization of Lactone Monomers with Unprotected Amine Functionalities. 2 Synthesis of Amino-Functionalized Polyesters via Postpolymerization Modification of Functionalized Monomers. 3 Design of Novel Amino-Functionalized Lactone Monomers and Direct Synthesis of Amino Polyesters. [ABSTRACT FROM AUTHOR]

Conventional chemotherapeutics nonselectively kill all rapidly dividing cells, which produces numerous side effects. To address this challenge, we report the discovery of functional polyesters that are capable of delivering siRNA drugs selectively to lung cancer cells and not to normal lung cells. Selective polyplex nanoparticles (NPs) were identified by high-throughput library screening on a unique pair of matched cancer/normal cell lines obtained from a single patient. Selective NPs promoted rapid endocytosis into HCC4017 cancer cells, but were arrested at the membrane of HBEC30-KT normal cells during the initial transfection period. When injected into tumor xenografts in mice, cancer-selective NPs were retained in tumors for over 1 wk, whereas nonselective NPs were cleared within hours. This translated to improved siRNA-mediated cancer cell apoptosis and significant suppression of tumor growth. Selective NPs were also able to mediate gene silencing in xenograft and orthotopic tumors via i.v. injection or aerosol inhalation, respectively. Importantly, this work highlights that different cells respond differentially to the same drug carrier, an important factor that should be considered in the design and evaluation of all NP carriers. Because no targeting ligands are required, these functional polyester NPs provide an exciting alternative approach for selective drug delivery to tumor cells that may improve efficacy and reduce adverse side effects of cancer therapies. [ABSTRACT FROM AUTHOR]

Copyright of Polimery is the property of Industrial Chemistry Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Unique crosslinkable unsaturated polyesters were prepared by a one-pot lipase-catalyzed copolymerization of crude linoleic acid (LA), glycerol (G) and 1,18-cis-9-octanedecenedioic acid (oleic diacid, OD). The lipase used is Candida antarctica Lipase B (CALB) immobilized on Lewatit (N435). Experiments were conducted to assess N435’s efficiency of forming poly(OD-co-G-co-LA) as a function of: (i) LA content in the co-monomer feed and (ii) reaction time. For comonomer feed ratio (OD:G:LA) 1:1:0.67, M n reached ∼9500 in 8h, trisubstituted G-units increased to 64% and monomer was largely depleted. When LA and OD remained in products, a lower temperature thermal decomposition peak at about 280°C was observed in addition to a higher temperature decomposition peak at ∼475°C. By increasing LA content in the comonomer feed from 1:1:1 to 1:1:1.33, M n decreased from 11,000 to 6300 while trisubstituted G-units increased from 92 to nearly 100%. Thus, by varying the feed ratio of LA, polymeric triglyceride-type structures were formed with control of chain length and trisubstituted G-unit content. Since G-units may be substituted in various ways with OD and LA, calculations were performed that determined the relative proportion of different substitution patterns in products. A hypothetical structure showing general characteristics of the substitution at glycerol units for one such product is presented. [Copyright &y& Elsevier]

We describe the use of organic catalysis for the ring-opening polymerization of functionalized lactones and conversion of the resulting aliphatic polyesters into crosslinked nanoparticles that carry additional functional groups amenable to further modification. Specifically, highly functional aliphatic polyester homopolymers, as well as random and block copolymers, were prepared by 1,5,7-triazabicyclo[4.4.0]dec-5-ene catalysis, giving polyesters with pendent alkene and alkyne groups. Azide-alkyne click and thiol-ene chemistries were used for postpolymerization modification of diblock copolymers possessing alkene groups on one block and alkyne groups on the other block. The polyesters were crosslinked using azide/alkyne cycloaddition, by reaction of α,ω-diazides with the pendent alkynes on the polyester backbone. This gave polyester nanoparticles possessing alkene functionality, which were subjected to further modification using thiol-ene reactions to introduce additional functionality. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 [ABSTRACT FROM AUTHOR]

Abstract: Functional aliphatic polyesters are biodegradable polymers with many possibilities to tune physico-chemical characteristics such as hydrophilicity and degradation rate as compared to traditional polyesters (e.g. PLLA, PLGA and PCL), making the materials suitable for drug delivery or as scaffolds for tissue engineering. Lately, a large number of polyesters have been synthesized by homopolymerization of functionalized monomers or co-polymerization with other monomers mainly via ring-opening polymerization (ROP) of cyclic esters. This review presents the recent trends in the synthesis of these materials and their application for protein delivery and tissue engineering. [Copyright &y& Elsevier]

Copyright of Polimery is the property of Industrial Chemistry Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Atom transfer radical polyaddition (ATRPA) was utilized herein to synthesize a specific functional polyester. We conducted ATRPA of 4-vinylbenzyl 2-bromo-2-phenylacetate (VBBPA) inimer and successfully obtained a linear type poly(VBBPA) (PVBBPA) polyester with benzylic bromides along the backbone. To obtain a novel amphiphilic polymer bottlebrush, however, the lateral ATRP chain extension of PVBBPA with N-vinyl pyrrolidone (NVP) met the problem of quantitative dimerization. By replacing the bromides to xanthate moieties efficiently, we thus observed a pseudo linear first order reversible addition–fragmentation chain transfer (RAFT) polymerization to obtain novel poly(4-vinylbenzyl-2-phenylacetate)-g-poly(NVP) (PVBPA-g-PNVP) amphiphilic polymer bottlebrushes. The critical micelle concentration (CMC) and particle size of the amphiphilic polymer bottlebrushes were characterized by fluorescence spectroscopy, dynamic light scattering (DLS), and scanning electron microscopy (SEM) (CMCs < 0.5 mg/mL; particle sizes = ca. 100 nm). Toward drug delivery application, we examined release profiles using a model drug of Nile red at different pH environments (3, 5, and 7). Eventually, low cytotoxicity and well cell uptake of the Madin-Darby Canine Kidney Epithelial (MDCK) for the polymer bottlebrush micelles were demonstrated. [ABSTRACT FROM AUTHOR]

Conventional chemotherapeutics nonselectively kill all rapidly dividing cells, which produces numerous side effects. To address this challenge, we report the discovery of functional polyesters that are capable of delivering siRNA drugs selectively to lung cancer cells and not to normal lung cells. Selective polyplex nanoparticles (NPs) were identified by high-throughput library screening on a unique pair of matched cancer/normal cell lines obtained from a single patient. Selective NPs promoted rapid endocytosis into HCC4017 cancer cells, but were arrested at the membrane of HBEC30-KT normal cells during the initial transfection period. When injected into tumor xenografts in mice, cancer-selective NPs were retained in tumors for over 1 wk, whereas nonselective NPs were cleared within hours. This translated to improved siRNA-mediated cancer cell apoptosis and significant suppression of tumor growth. Selective NPs were also able to mediate gene silencing in xenograft and orthotopic tumors via i.v. injection or aerosol inhalation, respectively. Importantly, this work highlights that different cells respond differentially to the same drug carrier, an important factor that should be considered in the design and evaluation of all NP carriers. Because no targeting ligands are required, these functional polyester NPs provide an exciting alternative approach for selective drug delivery to tumor cells that may improve efficacy and reduce adverse side effects of cancer therapies., Competing Interests: The authors declare no conflict of interest.