Polymer nanomedicines based on micelle-forming amphiphilic or water-soluble polymer-doxorubicin conjugates: Comparative study of in vitro and in vivo properties related to the polymer carrier structure, composition, and hydrodynamic properties.

The study compared the physico-chemical and biological properties of a water-soluble star-like polymer nanomedicine with three micellar nanomedicines formed by self-assembly of amphiphilic copolymers differing in their hydrophobic part (statistical, block and thermosensitive block copolymers). All nanomedicines showed a pH-responsive release of the drug, independent on polymer structure. Significant penetration of all polymer nanomedicines into tumor cells in vitro was demonstrated, where the most pronounced effect was observed for statistical- or diblock copolymer-based micellar systems. Tumor accumulation in vivo was dependent on the stability of the nanomedicines in solution, being the highest for the star-like system, followed by the most stable micellar nanomedicines. The star-like polymer nanomedicine showed a superior therapeutic effect. Since the micellar systems exhibited slightly lower systemic toxicity, they may exhibit the same efficacy as the star-like soluble system when administered at equitoxic doses. In conclusion, treatment efficacy of studied nanomedicines was directly controlled by the drug pharmacokinetics, namely by their ability to circulate in the bloodstream for the time needed for effective accumulation in the tumor due to the enhanced permeability and retention (EPR) effect. Easy and scalable synthesis together with the direct reconstitution possibility for nanomedicine application made these nanomedicines excellent candidates for further clinical evaluation.

Polymer Cancerostatics Containing Cell-Penetrating Peptides: Internalization Efficacy Depends on Peptide Type and Spacer Length.

Cell-penetrating peptides (CPPs) are commonly used substances enhancing the cellular uptake of various cargoes that do not easily cross the cellular membrane. CPPs can be either covalently bound directly to the cargo or they can be attached to a transporting system such as a polymer carrier together with the cargo. In this work, several CPP-polymer conjugates based on copolymers of N-(2-hydroxypropyl)methacrylamide (pHPMA) with HIV-1 Tat peptide (TAT), a minimal sequence of penetratin (PEN), IRS-tag (RYIRS), and PTD4 peptide, and the two short hydrophobic peptides VPMLK and PFVYLI were prepared and characterized. Moreover, the biological efficacy of fluorescently labeled polymer carriers decorated with various CPPs was compared. The experiments revealed that the TAT-polymer conjugate and the PEN-polymer conjugate were internalized about 40 times and 15 times more efficiently than the control polymer, respectively. Incorporation of dodeca(ethylene glycol) spacer improved the cell penetration of both studied polymer-peptide conjugates compared to the corresponding spacer-free polymer conjugates, while the shorter tetra(ethylene glycol) spacer improved only the penetration of the TAT conjugate but it did not improve the penetration of the PEN conjugate. Finally, a significantly improved cytotoxic effect of the polymer conjugate containing anticancer drug pirarubicin and TAT attached via a dodeca(ethylene glycol) was observed when compared with the analogous polymer-pirarubicin conjugate without TAT.

Multimodal PSSMA-Functionalized GdF3 : Eu3+ (Tb3+ ) Nanoparticles for Luminescence Imaging, MRI, and X-Ray Computed Tomography.

Biocompatible poly(4-styrenesulfonic acid-co-maleic acid)-stabilized GdF3 : Eu3+ (Tb3+ ) nanoparticles were obtained by a one-step coprecipitation method in ethylene glycol or water. The particles are very small (3 nm), have a narrow size distribution, and were detectable by fluorescence, magnetic resonance, and X-ray contrast imaging. These properties allow multimodal imaging, which has prospective applications in the simultaneous and detailed detection of diseased tissues.