Poly(2-oxazoline)s: synthesis and biomedical applications

Yang, Limin; Wang, Faming; Ren, Pengfei; Zhang, Tianzhu; Zhang, Qianli

doi:10.1007/s13233-023-00116-x

“…The bursts of the repeating FRBs typically exhibit subbursts and frequency drifts (Pleunis et al 2021). For seeking the burst nature, analysis of the energy function (E-function) and event rate for a given repeating FRB source and/or from a sample of one-off FRBs has been extensively investigated (e.g., Deng et al 2019;Lu & Piro 2019;Dai & Zhong 2020;Luo et al 2020;Li et al 2021a;Zhang et al 2021aZhang et al , 2021bLyu et al 2021;Wei et al 2021;Hashimoto et al 2022;Zhang et al 2022Zhang et al , 2023. However, the origin and radiation physics of FRBs are still under debate.…”

Section: Introductionmentioning

confidence: 99%

Narrowly Banded Spectra with Peak Frequency around 1 GHz of FRB 20201124A: Implications for Energy Function and Radiation Physics

Lyu,

Liang,

Li

2024

ApJ

0

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The radiation physics of fast radio bursts (FRBs) remains an open question. Current observations have discovered that narrowly banded bursts of FRB 20201124A are active in 0.4–2 GHz, and their spectral peak frequency ( ν p obs ) is mostly toward ∼1 GHz. Utilizing a sample of 1268 bursts of FRB 20201124A detected with the Five-hundred-meter Aperture Spherical radio Telescope (FAST), we show that the 1σ spectral regime of 71.4% of the events (in-band bursts) is within the FAST bandpass. The intrinsic burst energies ( E BWe obs ) and spectral widths ( σ s obs ) are well measured by fitting the spectral profile with a Gaussian function. The derived E BWe obs and σ s obs distributions are lognormal and centered at log E BWe obs / erg = 37.2 ( σ = 0.76 ) and log σ s obs / GHz = − 1.16 ( σ = 0.17 ) . Our Monte Carlo simulation analysis infers its intrinsic ν p distribution as a normal function centered at ν p,c = 1.16 GHz (σ = 0.22) and its intrinsic energy function as Φ ( E ) ∝ E − 0.60 e − E / E c with E c = 9.49 × 1037 erg. We compare these results with that of typical repeating FRBs 20121102A and 20190520B, which are active over a broad frequency range at several specific frequencies, and discuss possible observational biases on the estimation of the event rate and energy function. Based on these results, we argue that FRB 20201124A likely occurs in a fine-tuned plasma for maser radiation at a narrow frequency range, while FRB 20121102A and FRB 20190520B could involve clumpy plasma conditions that make maser emission around several specific frequencies in a broad range.

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“…Poly(2-oxazoline)s are interesting polymers that can be prepared in a variety of architectures and functionalities . In past, their utilization in a wide range of applications was suggested, including in pigment dispersant, adhesive component , or drug delivery systems, , while recently, the attention has been shifted toward biomedical applications. − Among different poly(2-oxazoline)s, poly(2-isopropenyl-2-oxazoline) (PIPOx) has been pointed as a promising material and was reported as biocompatible, since in vitro cytotoxicity measurements and ex vivo proliferation tests proved non-cytotoxicity of PIPOx. − PIPOx has been recently reported as a platform for the preparation of thermosensitive polymers, biocompatible hydrogels, polymer networks with antimicrobial properties, or molecular imprinting for controlled release of selected anticancer drugs …”

Section: Introductionmentioning

confidence: 99%

Atom Transfer Radical Polymerization of 2-Isopropenyl-2-Oxazoline in Solution and from the Surface of Carbonyl Iron Particles toward Fabrication of a Cytocompatible Magneto-Responsive Hybrid Filler

Ilčíková

¹

,

Mrlík

²

,

Cvek

³

et al. 2023

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Atom transfer radical polymerization (ATRP) of 2isopropenyl-2-oxazoline was optimized both in solution and initiated from carbonyl iron (CI) particle surface (SI-ATRP) in order to obtain polymers with well-defined molar mass and narrow dispersity. The polymerization procedure was thoroughly investigated by size exclusion chromatography and 1 H NMR and optimized from the point of view type of initiator, ligand, copper catalyst, and solvent. Finally, the poly(2-isopropenyl-2-oxazoline) (PIPOx) with controlled molar masses up to 20,000 g/mol and dispersity in the range of 1.2−1.5 were successfully prepared, while high conversions could be reached. Polymerization conditions using halogen exchange leading to well-defined PIPOx were also developed and used for SI-ATRP. SI-ATRP was finally applied for synthesis of magnetic CI-PIPOx core−shell particles with two various molar masses of the grafted PIPOx. Finally, as a proof of applicability of such hybrid particles, the particles were dispersed in the phosphate buffer saline and glycerol to obtain the magnetorheological fluid with blood-like characteristics. Magnetorheological and cytotoxicity investigations proved that noncytotoxic CI-PIPOx core−shell particles provided the system with sufficient yield stress values to act as an embolization agent.

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“…acetic-formic acid . Furthermore, poly(2-ethyl-2-oxazoline) (PEtOx) is used as a sacrificial component in scaffold production, which was selected based on its good electrospinnability and high biocompatibility. − The pore size of scaffolds is very important because a limited pore size is a frequently arising problem with nanofibrous scaffolds, limiting cell infiltration and growth. ,− The pore size should be at least the size of the cell (human tenocytes are typically 20.2 ± 4.4 μm wide) to enable cell infiltration. , Some studies even suggest that the pore size should be significantly larger than the cell size, with Han et al demonstrating that 200–300 μm pore size scaffolds are suitable for tenocyte adhesion and proliferation . In this work, it is proposed that yarn electrospinning of PCL with PEtOx as a sacrificial polymer could lead to porous nanoyarn scaffolds upon dissolution of PEtOx to provide more space for the cells to grow.…”

Section: Introductionmentioning

confidence: 99%

Cell Guiding Multicomponent Nanoyarn Tendon Scaffolds with Tunable Morphology and Flexibility

Schynkel,

Meeremans,

Meyer

et al. 2023

ACS Appl. Mater. Interfaces

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Nanofibrous scaffolds are widely investigated for tendon tissue engineering due to their porous structure, high flexibility, and the ability to guide cells in a preferred direction. Previous research has shown that providing a microenvironment similar to in vivo settings improves tissue regeneration. Therefore, in this work, ingenious multicomponent nanoyarn scaffolds that mimic the fibrillar and tubular structures of tendons are developed for the first time through electrospinning and bundling nanoyarns followed by electrospinning of a nanofibrous shell around the bundle. Multicomponent nanoyarn scaffolds out of poly(εcaprolactone) with varying porosity, density, and diameter were successfully produced by coelectrospinning with water-soluble poly(2-ethyl-2-oxazoline) as a sacrificial component. The diameter and fiber orientation of the nanoyarns were successfully tuned based on parameter-morphology models obtained by the design of experiments. Cyclic bending tests were performed, indicating that the flexibility of the multicomponent nanoyarn scaffolds depends on the morphology and can be tuned through controlling the number of nanoyarns in the bundle and the porosity. Indirect and direct cell culture tests using mouse and equine tendon cells revealed excellent cytocompatibility of the nanofibrous products and demonstrated the potential of the nanoyarns to guide the growing cells along the nanofiber direction, which is crucial for tendon tissue engineering.

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Poly(2-oxazoline)s: synthesis and biomedical applications

Cited by 8 publications

References 138 publications

Narrowly Banded Spectra with Peak Frequency around 1 GHz of FRB 20201124A: Implications for Energy Function and Radiation Physics

Narrowly Banded Spectra with Peak Frequency around 1 GHz of FRB 20201124A: Implications for Energy Function and Radiation Physics

Atom Transfer Radical Polymerization of 2-Isopropenyl-2-Oxazoline in Solution and from the Surface of Carbonyl Iron Particles toward Fabrication of a Cytocompatible Magneto-Responsive Hybrid Filler

Cell Guiding Multicomponent Nanoyarn Tendon Scaffolds with Tunable Morphology and Flexibility

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