| Products/Services Used | Details | Operation |
|---|---|---|
| Peptide Synthesis | C- and N-terminal inserted cysteine pHLIP peptides were commercially synthesized by GenScript (NJ, USA) with certified analysis (protein sequences shown in Fig. 1a). Poly-D-lysine (PDL, 30–70 kDa) in phosphate buffered saline (PBS, 1 mg mL−1, 100 μL) was first mixed with maleimide–(PEG)24–succinimidyl ester (Thermo Scientific Pierce, USA) in DMSO (10 μg μL−1, 20 μL) at room temperature. After 1 h, the PEG–maleimide modified PDL was purified via centrifugation with a Zeba spin desalting column (7 kDa cutoff, Thermo Fisher Scientific, USA). The resulting filtrate was then mixed with pHLIP peptide solutions (2 μg μL−1, 100 μL in PBS). The desired pHLIP modified PDLs were obtained through centrifugation with the Zeba spin desalting column. The UV absorbance spectra of the resulting modified polymers were obtained with a T9 UV-Vis spectrometer (Persee Analytics Inc., China) in PBS. The fluorescence emission spectra were recorded with an F-4500 fluorescence spectrometer (Hitachi, Japan) using the excitation wavelength at 280 nm. The circular dichroism (CD) spectra were obtained with a J-810 CD spectrometer (JASCO Inc., USA) at 25 °C in PBS at pH 4.0 and 8.0 containing 1.0 mg mL−1 lipids including 1,2-distearoyl-sn-glycero-3-phosphocholine, 1,2-dioleoyl-sn-glycero-3-phosphocholine and cholesterol at a weight ratio of 2:1:1. | Get A Quote |
Superparamagnetic iron oxide nanoclusters (SPIONs) modified with pH (low) insertion peptide (pHLIP) could be advantageous for magnetic resonance imaging (MRI) diagnosis of liver tumors at the early stage due to their unique responsiveness to the tumor acidic microenvironment when tumor markers are unknown. However, many critical aspects including the effectiveness of selective MRI in liver tumors, types of delivery and the potential safety profile in cirrhosis need to be fully evaluated. In this study, we report the evaluation of non-targeting, C- or N-pHLIP modified SPIONs as the contrast agent for selective MRI of liver tumors and their potential toxicity profile in cirrhosis. It was found that N-pHLIP modifi... More
