Docetaxel-loaded redox-sensitive nanoparticles self-assembling from poly(caprolactone) conjugates with disulfide-linked poly(ethylene glycol)

In this study, novel redox-sensitive nanoparticles (NPs) were fabricated from the poly(caprolactone) conjugates with disulfide-linked poly(ethylene glycol) (DDMAT- mPEG-S-S-PCL, DPSP). The DPSP polymer was synthesized by ring-opening polymerization (ROP) and reversible addition-fragmentation chain transfer (RAFT) polymerization. The obtaining of the DPSP polymer was confirmed by the ¹H nuclear magnetic resonance (¹H NMR) and Fourier transform infrared spectroscopy (FTIR) spectra. The DPSP NPs were fabricated with the solvent-evaporation method. Docetaxel (DTX) was employed as a model drug and encapsulated into the DPSP NPs. The in vitro anti-tumor activity of the DTX-loaded DPSP NPs and free DTX against the breast cancer cells (4T1) were evaluated by MTT assay. The cargo-free DPSP NPs were in circular shapes with an average diameter of 107.8 ± 0.4 nm. These NPs displayed redox-responsive behavior in the presence of glutathione. Animal experiments indicated that the DPSP NPs showed excellent blood compatibility and good bio-security. Cell tests suggested that the DPSP NPs could be taken in by 4T1 cells, smoothly, which improved the anti-tumor activity of free DTX.

Fabrication of poly(t-butyl betaine carboxylate)-based nanoparticles and study on their in vivo biosecurity

The purpose of this article was to fabricate the novel poly(t-butyl betaine carboxylate)-S-S-poly (1, 3-dioxan-2-one) nanoparticles (PCB-tBU-S-S-PDI NPs) and study their in vivo biosecurity. The poly(t-butyl betaine carboxylate) (PCB-tBU) segment was conjugated to the poly(1, 3-dioxan-2-one)(PDI) moity with a disulfide bond to obtain the copolymer PCB-tBU-S-S-PDI. Hydrogen nuclear magnetic resonance (¹H NMR) and Fourier transform infrared spectroscopy (FTIR) spectra were applied to study the structure of PCB-tBU-S-S-PDI. The cargo-free NPs were administrated to Sprague-Dawley (SD) rats by intraperitoneal injection every 3 days for 30 days. Then, the blood routine examination, blood biochemistry, and histologic slides of rat's organs were carried out to monitor the in vivo biosecurity of cargo-free PCB-tBU-S-S-PDI NPs. ¹H NMR and FTIR spectra confirmed the successfully synthesis of PCB-tBU-S-S-PDI. The cargo-free NPs showed spherical morphology with an average of 139.8 ± 0.26 nm. The results of blood biochemistry and blood routine examination suggested that the cargo-free PCB-tBU-S-S-PDI NPs did not show any influence on the liver and renal functions of treated rats. Significantly, the physiological slides of treated rat's organs did not show any physiological and pathological changes. These phenomena suggested that the PCB-tBU-S-S-PDI NPs had good biosecurity, and it could be used as a vehicle for antineoplastic drug delivery.