Microstructure characterization and thermal analysis of hybrid block copolymer α-methoxy-poly(ethylene glycol)-block-poly[ε-(benzyloxycarbonyl)-l-lysine] for biomedical applications

Izunobi, Josephat U.; Higginbotham, Clement L.

doi:10.1016/j.molstruc.2010.05.026

Cited by 20 publications

(20 citation statements)

References 72 publications

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“…An overlap of the second glass transition ( T ′ g ) and crystalline melting ( T m ) temperatures is observed in the heating curves of MPEG 112 ‐ b ‐PLL(Z) 10 and MPEG 112 ‐ b ‐PLL(Z) 39 whereas the thermogram of MPEG 112 ‐ b ‐PLL(Z) 17 shows these thermal events to be proximal to each other. T m and T ′ g of MPEG 112 ‐ b ‐PLL(Z) 17 are convincingly assigned with the aid of modulated temperature DSC . In the case of MPEG 112 ‐ b ‐PLL(Z) 10 and MPEG 112 ‐ b ‐PLL(Z) 39 , however, DSC cooling experiments were undertaken to resolve the incidences of overlap of these salient transition events.…”

Section: Resultsmentioning

confidence: 97%

“…In the 1 H NMR spectra, the protons of the methoxy (C H 3 O–) and oxyethylene (−(OC H 2 C H 2 ) n –) moieties resonate as singlets at 3.24 and 3.51 ppm, respectively (Fig. S2) . The benzyl methylene (C 6 H 5 C H 2 –) singlet is observed around 5.00 ppm while the multiplets centred around 3.00 and 2.00–1.00 ppm are assigned to the side‐chain methylene protons.…”

Section: Resultsmentioning

confidence: 99%

“…S2). 53 The benzyl methylene (C 6 H 5 CH 2 -) singlet is observed around 5.00 ppm while the multiplets centred around 3.00 and 2.00-1.00 ppm are assigned to the side-chain methylene protons. The fine structures and symmetry exhibited by the 1 H NMR spectra of 3a-3c reflect their chain microstructure.…”

Section: Ir and 1 H Nmr Spectroscopymentioning

confidence: 99%

“…It is pertinent to note that the method of N ‐carboxyanhydride preparation and, crucially, its purity have a significant effect on the ROP and resulting HBC. We have found that strict anhydrous conditions during synthesis and work‐up, coupled with the sparging of the reaction mixture with nitrogen gas (to drive the hydrogen chloride evolved) are beneficial …”

Section: Introductionmentioning

confidence: 99%

“…We have found that strict anhydrous conditions during synthesis and work-up, coupled with the sparging of the reaction mixture with nitrogen gas (to drive the hydrogen chloride evolved) are beneficial. 53 This report describes the synthesis (ROP) and characterization of α-methoxy-poly(ethylene glycol)-block-poly[ε-(benzyloxycarbonyl)-L-lysine] (MPEG n -b-PLL(Z) m ; 3a-3c), with varying DPs of L-lysine, using infrared (IR) and NMR spectroscopy and gel permeation chromatography (GPC). Their thermal properties were also examined via TGA, derivative thermogravimetric analysis (DTGA) and DSC.…”

Section: Introductionmentioning

confidence: 99%

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Conformational and thermal analyses of α‐methoxy‐poly(ethylene glycol)‐block‐poly[ϵ‐(benzyloxycarbonyl)‐l‐lysine] hybrid block copolymers

Izunobi

Higginbotham

2012

Polymer International

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Hybrid block copolymers find applications in drug delivery, tissue engineering, biomimetics and bioimaging, amongst others, mainly due to their propensity to form phase‐separated microdomains as well as to the aggregation of their polypeptide segments. They not only enhance control over structure at the nanometre scale but also yield materials that can interface with various biosystems for different utilities. α‐Methoxy‐poly(ethylene glycol)‐block‐poly[ϵ‐(benzyloxycarbonyl)‐l‐lysine] hybrid block copolymers of varying degrees of polymerization, MPEGn‐b‐PLL(Z)m, were synthesized by N‐carboxyanhydride ring‐opening polymerization and characterized using infrared and NMR spectroscopy and gel permeation chromatography. Their secondary structures and bulk conformations were investigated using circular dichroism spectroscopy and wide‐angle X‐ray diffraction, respectively, whereas thermogravimetric analysis (TGA), derivative TGA and differential scanning calorimetry were employed for thermal analyses. The resulting block copolymers exhibited microphase separation and suppressed degrees of crystallinity with increasing l‐lysine content and adopted α‐helix and β‐sheet secondary structures in aqueous milieu. The copolymers were also more thermally stable than their constituent homopolymers. Interestingly, the effects of the retention of the Nϵ‐benzyloxycarbonyl moiety on polymer properties proved considerable. The hybrid block copolymers herein afforded hierarchical structures of potential utility in the biomedical and pharmaceutical fields. © 2012 Society of Chemical Industry

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Section: Ir and 1 H Nmr Spectroscopymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Conformational and thermal analyses of α‐methoxy‐poly(ethylene glycol)‐block‐poly[ϵ‐(benzyloxycarbonyl)‐l‐lysine] hybrid block copolymers

Izunobi

Higginbotham

2012

Polymer International

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Self‐assembled nanoparticles based on pullulan‐g‐poly(Z‐L‐lysine) for controlled drug delivery: Synthesis, characterization and preliminary studies on the encapsulation of indomethacin

Vieira,

Matos,

Carvalho

et al. 2024

J of Applied Polymer Sci

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Novel biocompatible systems suitable for the controlled release of active ingredients are under the spotlight within the last few years. The present investigation focuses on the preparation of nanoparticles (NPs) based on the amphiphilic copolymer pullulan‐graft‐poly(Z‐L‐lysine) bearing different amounts of lysine (10, 20, and 30 wt%), and on the evaluation of their ensuing viability to encapsulate the hydrophobic nonsteroidal anti‐inflammatory drug indomethacin (INDO). The copolymers are synthesized by ring‐opening polymerization, characterized by NMR and FTIR, and their critical aggregation concentration is determined by fluorescence. The NPs are prepared with and without INDO using different copolymer/solvent ratios and INDO/copolymer ratios. The hydrodynamic diameter and polydispersity of the NP suspensions are monitored by dynamic light scattering for 30 days. Their sizes vary between 208 and 338 nm, and some reach the micrometric range (19–73 μm). INDO‐free NPs are identified as spherical‐shaped by atomic force microscopy. Two formulations are tested in terms of encapsulation efficiency (EE = 43%–89%), and the drug crystallinity (DC = 7%–27%) which is determined by differential scanning calorimetry, indicating a reduction with respect to pristine INDO. The results suggest that the copolymers prepared herewith have potential to be applied as carriers for new drug delivery systems of class II drugs.

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Preparation and characterization of poly(ethylene glycol)-block-poly[ε-(benzyloxycarbonyl)-l-lysine] thin films for biomedical applications

2014

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Microstructure characterization and thermal analysis of hybrid block copolymer α-methoxy-poly(ethylene glycol)-block-poly[ε-(benzyloxycarbonyl)-l-lysine] for biomedical applications

Cited by 20 publications

References 72 publications

Conformational and thermal analyses of α‐methoxy‐poly(ethylene glycol)‐block‐poly[ϵ‐(benzyloxycarbonyl)‐l‐lysine] hybrid block copolymers

Conformational and thermal analyses of α‐methoxy‐poly(ethylene glycol)‐block‐poly[ϵ‐(benzyloxycarbonyl)‐l‐lysine] hybrid block copolymers

Self‐assembled nanoparticles based on pullulan‐g‐poly(Z‐L‐lysine) for controlled drug delivery: Synthesis, characterization and preliminary studies on the encapsulation of indomethacin

Preparation and characterization of poly(ethylene glycol)-block-poly[ε-(benzyloxycarbonyl)-l-lysine] thin films for biomedical applications

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