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Upconverting nanoparticles (UCNPs) are of particular interest in nanomedicine for in vivo deep-tissue optical cancer bioimaging due to their efficient cellular uptake dependent on polymer coating. In this study, particles, ca. 25 nm in diameter, were prepared by a high-temperature coprecipitation of lanthanide chlorides. To ensure optimal dispersion of UCNPs in aqueous milieu, they were coated with three different polymers containing reactive groups, i.e., poly(ethylene glycol)-alendronate (PEG-Ale), poly(N,N-dimethylacrylamide-co-2-aminoethylacrylamide)-alendronate (PDMA-Ale), and poly(methyl vinyl ether-co-maleic acid) (PMVEMA). All the particles were characterized by TEM, DLS, FTIR, and spectrofluorometer to determine the morphology, hydrodynamic size and ξ-potential, composition, and upconversion luminescence. The degradability/dissolution of UCNPs in water, PBS, DMEM, or artificial lysosomal fluid (ALF) was evaluated using an ion-selective electrochemical method and UV-Vis spectroscopy. The dissolution that was more pronounced in PBS at elevated temperatures was decelerated by polymer coatings. The dissolution in DMEM was relatively small, but much more pronounced in ALF. PMVEMA with multiple anchoring groups provided better protection against particle dissolution in PBS than PEG-Ale and PDMA-Ale polymers containing only one reactive group. However, the cytotoxicity of the particles depended not only on their ability to rapidly degrade, but also on the type of coating. According to MTT, neat UCNPs and UCNP@PMVEMA were toxic for both rat cells (C6) and rat mesenchymal stem cells (rMSCs), which was in contrast to the UCNP@Ale-PDMA particles that were biocompatible. On the other hand, both the cytotoxicity and uptake of the UCNP@Ale-PEG particles by C6 and rMSCs were low, according to MTT assay and ICP-MS, respectively. This was confirmed by a confocal microscopy, where the neat UCNPs were preferentially internalized by both cell types, followed by the UCNP@PMVEMA, UCNP@Ale-PDMA, and UCNP@Ale-PEG particles. This study provides guidance for the selection of a suitable nanoparticle coating with respect to future biomedical applications where specific behaviors (extracellular deposition vs. cell internalization) are expected. [ABSTRACT FROM AUTHOR]

Purpose: Dysfunction of the retinal pigment epithelium (RPE) causes numerous forms of retinal degeneration. RPE replacement is a modern option to save vision. We aimed to test the results of transplanting cultured RPEs on biocompatible membranes. Methods: We cultivated porcine primary RPE cells isolated from cadaver eyes from the slaughterhouse on two types of membranes: commercial polyester scaffolds Transwell (Corning Inc., Kenneburg, ME, USA) with 0.4 µm pore size and prepared Poly (L‐lactide‐co‐DL‐lactide) (PDLLA) nanofibrous membranes with an average pore size of 0.4 µm. Results: Five types of assays were used for the analysis: immunocytochemistry (ICC), phagocytosis assay, Western blotting, real‐time qPCR (RT‐qPCR) and electron microscopy. RT‐qPCR demonstrated that RPEs cultured on nanofibrous membranes have higher expressions of BEST1 (bestrophin 1), RLBP1 (retinaldehyde‐binding protein 1), RPE65 (retinal pigment epithelium‐specific 65 kDa protein), PAX6 (transcription factor PAX6), SOX9 (transcription factor SOX9), DCT (dopachrome tautomerase) and MITF (microphthalmia‐associated transcription factor). ICC of the RPEs cultured on nanofibrous membranes showed more intensive staining of markers such as BEST1, MCT1 (monocarboxylate transporter 1), Na+/K+ATPase, RPE65 and acetylated tubulin in comparison with commercial ones. Additionally, the absence of α‐SMA proved the stability of the RPE polarization state and the absence of epithelial‐to‐mesenchymal transition. RPE possessed high phagocytic activity. Electron microscopy of both membranes confirmed a confluent layer of RPE cells and their genuine morphological structure, which was comparable to native RPEs. Conclusions: Retinal pigment epitheliums cultured on polylactide nanofibrous membranes improved the final quality of the cell product by having better maturation and long‐term survival of the RPE monolayer compared to those cultured on commercial polyester scaffolds. PDLLA‐cultured RPEs are a plausible source for the replacement of non‐functioning RPEs during cell therapy. [ABSTRACT FROM AUTHOR]

Block copolymer comprising of hydrophilic poly[N-(2-hydroxypropyl)methacrylamide] (PHP) and reactive poly[N-(2-hydrazinyl-2-oxoethyl)methacrylamide] (PMAH) was synthesized by a reversible addition-fragmentation chain transfer (RAFT) polymerization and conjugated with doxorubicin (Dox) and/or RGDS targeting peptide via one-step reaction using N-γ-maleimidobutyryl-oxysuccinimide ester. The resulting copolymer served as a coating of magnetic γ-Fe2O3 nanoparticles that were tested in cell proliferation and in vivo experiments on a mice model with inoculated rat C6 glioblastoma tumor. The nanoparticles conjugated with RGDS peptide and doxorubicin easily engulfed both C6 tumor cell line, primary glioblastoma (GB) cells, and human mesenchymal stem cells (hMSC) used as a control; the particles decreased the GB cell growth by 45% compared to control cells without any treatment. Moreover, the γ-Fe2O3@P(HP-MAH)-RGDS-Dox nanoparticles injected into C6 glioblastoma cell-derived tumors grown in the posterior flank of mice decreased the tumor size and more apoptotic cells were spread compared to that treated with free Dox. [ABSTRACT FROM AUTHOR]