Time-, spectral- and spatially resolved EPR spectroscopy enables simultaneous monitoring of diffusion of different guest molecules in nano-pores

A nano-preparation approach to enable the delivery of daphnoretin to potentiate the therapeutical efficacy in hepatocellular cancer

Daphnoretin (DAP), isolated from a traditional Chinese medicine Wikstroemia indica (Linn. C. A. Meyer), could induce apoptosis of hepatocellular cancer (HCC) and inhibit tumor growth. However, the application of DAP in cancer therapies was hampered because to its poor solubility. Herein, this study aimed to design an approach of double-targeted nano-preparation to enable the delivery of DAP to potentiate the therapeutical efficacy in liver cancer via glycyrrhetinic acid-polyethylene glycol-block-poly (D,L-lactic acid)/polyethylene glycol-block-poly (D,L-lactic acid)-DAP (GPP/PP-DAP). In particular, the purity of separated DAP was up to 98.12% for preparation research. GPP/PP-DAP was successfully prepared by the thin-film hydration method. Subsequently, the GPP/PP-DAP was optimized by univariate analysis and the response surface methodology, producing a stable and systemically injectable nano-preparation. Impressively, on the one hand, cytotoxicity studies showed that the IC₅₀ of the GPP/PP-DAP was lower than that of free DAP. On the other hand, the GPP/PP-DAP was more likely to be endocytosed by HepG2 cells and targeted to the liver with orthotopic tumors, potentiating the therapeutical efficacy in HCC. Collectively, both in vitro and in vivo results indicated the excellent tumor inhibition and liver targeting of GPP/PP-DAP, suggesting the nano-preparation could serve as a potential drug delivery system for natural ingredients with anti-hepatoma activity to lay the theoretical foundation for clinical application.

O-carboxymethyl chitosan based pH/hypoxia-responsive micelles relieve hypoxia and induce ROS in tumor microenvironment

The hypoxia in tumor microenvironment (TME) can upregulate the HIF-1α and PD-L1 expression and cause immunosuppression of tumor. In this study, a carboxymethyl chitosan-based pH/hypoxia-responsive and γ-Fe₂O₃/isosorbide dinitrate carrying micelle was designed, and it could catalyze endogenous H₂O₂ to generate oxygen and relieve hypoxia in TME, so as to relieve the overexpression of HIF-1α and PD-L1 in tumor; meanwhile, it could react with H₂O₂ to release ROS via Fenton reaction and induce cytotoxicity in tumor. Along with these multiple effects, this carboxymethyl chitosan-based micelles could provide a comprehensive strategy for tumor treatment.

Solute Diffusion into Polymer Swollen by Supercritical CO2 by High-Pressure Electron Paramagnetic Resonance Spectroscopy and Chromatography

High-pressure electron paramagnetic resonance (EPR) was used to measure translational diffusion coefficients (D_tr) of a TEMPONE spin probe in poly(D,L-lactide) (PDLLA) and swollen in supercritical CO₂. D_tr was measured on two scales: macroscopic scale (>1 μm), by measuring spin probe uptake by the sample; and microscopic scale (<10 nm), by using concentration-dependent spectrum broadening. Both methods yield similar translational diffusion coefficients (in the range 5-10 × 10^-12 m²/s at 40-60 °C and 8-10 MPa). Swollen PDLLA was found to be homogeneous on the nanometer scale, although the TEMPONE spin probe in the polymer exhibited higher rotational mobility (τ_corr = 6 × 10^-11 s) than expected, based on its D_tr. To measure distribution coefficients of the solute between the swollen polymer and the supercritical medium, supercritical chromatography with sampling directly from the high-pressure vessel was used. A distinct difference between powder and bulk polymer samples was only observed at the start of the impregnation process.