Poly-(lactide-co-glycolide)–b-poly(ethylene glycol)–b-poly(lactide-co-glycolide) (1700–1500–1700 Da, LA/GA 15:1, 94%:6% LA/GA, PolySciTech) and 4-aminopyridine (4-AP, Sigma-Aldrich) were used without further purification. 4-AP was incorporated in PLGA–PEG–PLGA triblock copolymer solution (1× PBS, pH 7.4, polymer concentration: 20 wt %), stirred at 4 °C until it was completely dissolved, and characterized using proton nuclear magnetic resonance (1H NMR) to confirm the composition. Experiments using 1H NMR were carried out with Bruker Avance II 600 MHz instrument equipped with a TCI cryo-probe. Standard presaturation pulse programs from the Bruker pulse sequence library were used to suppress residual D2O solvent. The samples were prepared at room temperature and experiments were performed at 25°C.
Avance 2 600 mhz instrument
Manufactured by Bruker
Sourced in United States
The Avance II 600 MHz instrument is a high-performance nuclear magnetic resonance (NMR) spectrometer manufactured by Bruker. It operates at a magnetic field strength of 14.1 Tesla, providing a 600 MHz frequency for proton analysis. The Avance II 600 MHz is designed to deliver high-resolution data for structural elucidation and quantitative analysis of a wide range of chemical and biological samples.
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3 protocols using avance 2 600 mhz instrument
1
Characterization of 4-AP Loaded PLGA-PEG-PLGA Triblock Copolymer
2
Synthesis and Characterization of MAG
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All reagents were commercially available and used without further purification. MAG was purchased from Xinmingtai Chemical Co., Ltd. (Wuhan, China). All reactions were monitored by thin-layer chromatography on silica gel F254 (Qindao Haiyang Chemical Co., Qindao, China). The products were purified by column chromatography (300–400 mesh silica gel, Qindao Haiyang Chemical Co., Qindao, China). All NMR spectra were recorded on a Bruker Avance II 600 MHz instrument (Bruker, Billerica, MA, USA) using CDCl3 or DMSO-d6 as the solvent with TMS as the internal standard. Chemical shifts (δ) were reported in parts per million (ppm) and the coupling constants (J) were given in Hertz. High-resolution electrospray ionization mass spectrometry (HR-ESI-MS) spectra were recorded on a Thermo Scientific LTQ Orbitrap XL mass spectrometer (Bruker, Bremerhaven, Germany) with electrospray ionization. Taxol was purchased from Shanghai yuanye Bio-Technology Co., Ltd. (Shanghai, China, batch numbers: H15F10X80839). Anti-HIF-1α antibodies were purchased from Abcam (Cambridge, UK, batch numbers: GR244245-51). Anti-MMP-9 and MMP-2 antibodies were purchased from Proteintech Group (Chicago, IL, USA, batch numbers of MMP-9: 00074416; batch numbers of MMP-2: 00066968).
3
Characterizing Amber Resin Molecular Structure
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In this study, to establish
the average molecular structure of resin, elemental analysis and solid-state 13C NMR spectroscopy were used to study the amber, and MALDI
TOF MS was used to analyze the relative molecular mass of resins.
The analyses are presented in greater detail as follows:
the average molecular structure of resin, elemental analysis and solid-state 13C NMR spectroscopy were used to study the amber, and MALDI
TOF MS was used to analyze the relative molecular mass of resins.
The analyses are presented in greater detail as follows:
Relative elemental
contents (C, H,
N, O, and S) were analyzed by using an Elementar Vario EL III. Five
organic elements were tested separately, and the chemical components
of amber samples were obtained.
(2) FT-IR
spectroscopy was performed on a Bruker Vertex-70
V Fourier transform infrared spectrometer (GIG, CAS) using the KBr
pressed disk technique. The spectra were collected in the range of
4000–400 cm–1 with 64 scans and the
resolution was 4 cm–1.
(3) Solid-state 13C NMR analysis of amber
samples was performed on a Bruker AVANCE II 600 MHz instrument using
a 4 mm probe at a spinning speed of 14,000 Hz and a spectral width
of 150.6 M Hz, as per the DP/MAS method. The number of scans of the
method was 5 k.
(4) The resin molecular
masses were detected by using
a TOF/TOF 5800 system (SCIEX) in the positive ion mode. The MALDI
stage was operated in the continuous motion mode. The mass range of
the instrument was from 100 to 4000 Da.
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