Complex sameness: Separation of mixed poly(lactide-co-glycolide)s based on the lactide:glycolide ratio

Skidmore, Sarah; Hadar, Justin; Garner, John; Park, Haesun; Park, Kinam; Wang, Yan; Jiang, Xiaohui

doi:10.1016/j.jconrel.2019.03.002

Cited by 44 publications

(28 citation statements)

References 28 publications

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“…The block copolymers were synthesized following the procedure described previously with the modification that PEG‐diol was utilized as the initiator . Prior to synthesis, all glassware was washed in acetone and dried at 100 °C followed by cooling in a desiccator.…”

Section: Methodsmentioning

confidence: 99%

“…Gel permeation chromatography–external standard (GPC–ES) was performed according to methods described previously . Briefly, samples were dissolved at a concentration of 2 mg/mL in either DCM or THF and 0.22 μm filtered prior to analysis.…”

Section: Methodsmentioning

confidence: 99%

“…GPC–4D analysis was performed using the system described previously . Briefly, the molecular weights were determined by a GPC–4D system, consisting of an Agilent 1260 Infinity II HPLC system connected to Dawn Heleos II (MALLS) coupled to Dynapro Nanostar DLS via an optical cable, Optilab T‐rEX (RI detector) and Viscostar III viscometer operated by Astra 7 software (Wyatt).…”

Section: Methodsmentioning

confidence: 99%

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Narrow molecular weight margins for the thermogelling property of polyester–polyether block copolymers in aqueous solutions

Garner

Hadar

Skidmore

et al. 2019

J of Applied Polymer Sci

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Polyester–polyether block copolymers with thermogelling properties have been widely used in pharmaceutical and biomedical applications for their biocompatibility and degradation to nontoxic components. The biodegradable polymers, such as poly(lactide‐co‐glycolide) and poly(lactide‐co‐caprolactone) (PLCL), have been used as the polyester block. The most commonly used polyether has been poly(ethylene glycol) (PEG). The thermogelling polymers dissolve in cold water, but become a semisolid gel at higher temperatures, for example, body temperature. This thermogelling property, however, occurs only within very narrow molecular weight ranges of the polyester at given polyether blocks. Only a few hundred Dalton differences in the polyester block can turn a thermogelling polymer into a water‐insoluble polymer. This study describes the hydrophilic and hydrophobic block sizes for endowing the thermogelling property and a simple, water‐free, synthesis of new thermogelling PLCL–PEG–PLCL triblock polymers. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48673.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Narrow molecular weight margins for the thermogelling property of polyester–polyether block copolymers in aqueous solutions

Garner

Hadar

Skidmore

et al. 2019

J of Applied Polymer Sci

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“…73 With all other factors equal, the sequence distribution, defined as the term "blockiness", may result in differences leading to variations in PLGA solubility and degradation behavior. The "blockiness" can be calculated according to two descriptions, one by the definition of Skidmore et al, 53 in which Rc value is obtained by the ratio of IG-G to IG-L; while the other is the Rcms value (the ratio of IG-L to IG-G) by the definition of Hausberger and DeLuca. 44 In this paper, we chose the former as the term investigated below since the former result could more straightly present impact of G-G units on PLGA polymer hydrolysis and degradation.…”

Section: Monomer Sequence Analysismentioning

confidence: 99%

Characterization of Commercial PLGAs by NMR Spectroscopy

Sun

Walker

Beck-Broichsitter

et al. 2021

Preprint

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Poly(lactic- co -glycolic acid) (PLGA) is among the most common of biodegradable polymers studied in various biomedical applications such as drug delivery and tissue engineering. To facilitate the understanding of the often overlooked PLGA microstructure on important factors affecting PLGA performance, we measured four key parameters of 17 commonly used commercial PLGA polymers (Resomer ®, Expansorb ®, Purasorb ®, Lactel ®, and Wako ® ) by NMR spectroscopy. 1 HNMR and 13 CNMR spectra were used to determine lactic to glycolic ratio (L/G ratio), polymer end-capping, glycolic blockiness ( Rc ), and average glycolic and lactic block lengths ( L G and L L ). In PLGAs with a labeled L/G ratio of 50/50 and acid end capping, the actual lactic content slightly decreased as molecular weight increased in both Resomer ® and Expansorb ®. Whether or not acid- or ester-, termination of these PLGAs was confirmed to be consistent with their brand labels. Moreover, in the ester end-capped 75/25 L/G ratio group, the blockiness value ( Rc ) of Resomer ® RG 756S ( Rc : 1.7) was highest in its group; whereas for the 50/50 acid end-capped group, Expansorb ® DLG 50-2A ( Rc : 1.9) displayed notably higher values than their counterparts. Resomer ® RG 502 ( L L : 2.6, L G : 2.5) and Expansorb ® DLG 50-2E ( L L : 2.5, L G : 2.6) showed the lowest block lengths, suggesting they may undergo a steadier hydrolytic process compared to random, heterogeneously distributed PLGA.

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“…Its degradation products, lactic acid and glycolic acid, are metabolic products and can be cleared by natural metabolic pathways. To date, around 20 injectable PLGA-based formulations have been approved by the Food and Drug Administration of the USA [4]. Therefore, in the present study, PLGA was selected as the primary raw biomaterial for fabrication of composite scaffolds.…”

mentioning

confidence: 99%

Preparation of antibacterial and osteoconductive 3D-printed PLGA/Cu(I)@ZIF-8 nanocomposite scaffolds for infected bone repair

Zou

Jiang

et al. 2020

J Nanobiotechnol

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Background: The repair of large bone defects is a great challenge in clinical practice. In this study, copper-loaded-ZIF-8 nanoparticles and poly (lactide-co-glycolide) (PLGA) were combined to fabricate porous PLGA/Cu(I)@ZIF-8 scaffolds using three-dimensional printing technology for infected bone repair. Methods: The surface morphology of PLGA/Cu(I)@ZIF-8 scaffolds was investigated by transmission electron microscopy and scanning electron microscopy. The PLGA/Cu(I)@ZIF-8 scaffolds were co-cultured with bacteria to determine their antibacterial properties, and with murine mesenchymal stem cells (MSCs) to explore their biocompatibility and osteoconductive properties. The bioactivity of the PLGA/Cu(I)@ZIF-8 scaffolds was evaluated by incubating in simulated body fluid. Results: The results revealed that the PLGA/Cu(I)@ZIF-8 scaffolds had porosities of 80.04 ± 5.6% and exhibited good mechanical properties. When incubated with H 2 O 2 , Cu(I)@ZIF-8 nanoparticles resulted generated reactive oxygen species, which contributed to their antibacterial properties. The mMSCs cultured on the surface of PLGA/Cu(I)@ZIF-8 scaffolds were well-spread and adherent with a high proliferation rate, and staining with alkaline phosphatase and alizarin red was increased compared with the pure PLGA scaffolds. The mineralization assay showed an apatite-rich layer was formed on the surface of PLGA/Cu(I)@ZIF-8 scaffolds, while there was hardly any apatite on the surface of the PLGA scaffolds. Additionally, in vitro, Staphylococcus aureus cultured on the PLGA/Cu(I)@ZIF-8 scaffolds were almost all dead, while in vivo inflammatory cell infiltration and bacteria numbers were dramatically reduced in infected rats implanted with PLGA/Cu@ZIF-8 scaffolds. Conclusion: All these findings demonstrate that PLGA/Cu(I)@ZIF-8 scaffolds possess excellent antibacterial and osteoconductive properties, as well as good biocompatibility and high bioactivity. This study suggests that the PLGA/ Cu(I)@ZIF-8 scaffolds could be used as a promising biomaterial for bone tissue engineering, especially for infected bone repair.

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Complex sameness: Separation of mixed poly(lactide-co-glycolide)s based on the lactide:glycolide ratio

Cited by 44 publications

References 28 publications

Narrow molecular weight margins for the thermogelling property of polyester–polyether block copolymers in aqueous solutions

Narrow molecular weight margins for the thermogelling property of polyester–polyether block copolymers in aqueous solutions

Characterization of Commercial PLGAs by NMR Spectroscopy

Preparation of antibacterial and osteoconductive 3D-printed PLGA/Cu(I)@ZIF-8 nanocomposite scaffolds for infected bone repair

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