Drx 600 mhz nmr spectrometer

NMR spectra were recorded on DRX-400 and DRX-600 MHz NMR spectrometer (Bruker, Billerica, MA, USA) with tetramethylsilane (TMS) as an internal standard. HRESIMS were carried out on a LTQ-Orbitrap XL (Thermo Finnigan, San Jose, CA, USA). Specific rotation was obtained on an IP-digi300 polarimeter (InsMark, Shanghai, China) at 20 °C. SC-XRD data were collected on a Bruker D8 venture diffractometer (Bruker, Billerica, MA, USA). Silica gel (200–300 mesh; Qingdao Haiyang Chemical Co., Ltd., Qingdao, China), LiChroprep RP-18 (40–63 mm; Darmstadt, Germany) and Sephadex LH-20 (25–100 μm; Pharmacia Biotek, Copenhagen, Denmark) were used for column chromatography. Thin-layer chromatography (TLC) was carried out with glass precoated Silica gel GF₂₅₄ plates (Qingdao Haiyang Chemical Co., Ltd.). Compounds were visualized under UV light and by spraying with phosphomolybdic acid followed by heating. All solvents were analytical grade.

The ultraviolet–visible (UV–vis) spectra of cRGD, PEG, and cRGD-PEG were recorded on a UV-3101PC spectroscope (Shimadzu, Japan). Electrospray-ionization mass spectrometry (LCQ Orbitrap XL, USA) was used to characterize the molecular weights of Por-R₆-CHO and its intermediate products. The gel permeation chromatography (GPC, Agilent 1200 Series, USA) with tetrahydrofuran as mobile phase was applied to determine the outflow time of cRGD-PEG, cPRP and cPRP at pH 5.0. The cPRP ¹H nuclear magnetic resonance (NMR) spectra were generated under different pH conditions using a Bruker DRX 600 MHz NMR spectrometer (USA) and hexadeuterated dimethyl sulfoxide (DMSO-d6). Transmission electron microscopy (TEM, Thermo Scientific Talos L120C, USA) was used to evaluate the morphology of the GNA002-loaded nanoparticles. The diameter, zeta potential, and PDI of the cPRP nanoparticles were measured by dynamic light scattering (DLS, Zetasizer Nano ZS, UK). High-performance liquid chromatography (HPLC, AB Sciex Quadrupole 5500, USA) was performed using a C18 4.6 × 250-mm column to determine the GNA002 concentration in the GNA002@cPRP nanoparticles.