Search for: All records

The present study expands the versatility of cationic poly(2‐oxazoline) (POx) copolymers as a polyethylene glycol (PEG)‐free platform for gene delivery to immune cells, such as monocytes and macrophages. Several block copolymers are developed by varying nonionic hydrophilic blocks (poly(2‐methyl‐2‐oxazoline) (pMeOx) or poly(2‐ethyl‐2‐oxazoline) (pEtOx), cationic blocks, and an optional hydrophobic block (poly(2‐isopropyl‐2‐oxazoline) (iPrOx). The cationic blocks are produced by side chain modification of 2‐methoxy‐carboxyethyl‐2‐oxazoline (MestOx) block precursor with diethylenetriamine (DET) or tris(2‐aminoethyl)amine (TREN). For the attachment of a targeting ligand, mannose, azide‐alkyne cycloaddition click chemistry methods are employed. Of the two cationic side chains, polyplexes made with DET‐containing copolymers transfect macrophages significantly better than those made with TREN‐based copolymer. Likewise, nontargeted pEtOx‐based diblock copolymer is more active in cell transfection than pMeOx‐based copolymer. The triblock copolymer with hydrophobic block iPrOx performs poorly compared to the diblock copolymer which lacks this additional block. Surprisingly, attachment of a mannose ligand to either copolymer is inhibitory for transfection. Despite similarities in size and design, mannosylated polyplexes result in lower cell internalization compared to nonmannosylated polyplexes. Thus, PEG‐free, nontargeted DET‐, and pEtOx‐based diblock copolymer outperforms other studied structures in the transfection of macrophages and displays transfection levels comparable to GeneJuice, a commercial nonlipid transfection reagent.

 

We explored the potential of biomimetic thin films fabricated by means of matrix-assisted pulsed laser evaporation (MAPLE) for releasing combinations of active substances represented by flavonoids (quercetin dihydrate and resveratrol) and antifungal compounds (amphotericin B and voriconazole) embedded in a polyvinylpyrrolidone biopolymer; the antifungal activity of the film components was evaluated using in vitro microbiological assays. Thin films were deposited using a pulsed KrF* excimer laser source which were structurally characterized using atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR). High-quality thin films with chemical structures similar to dropcast ones were created using an optimum laser fluence of ~80 mJ/cm2. Bioactive substances were included within the polymer thin films using the MAPLE technique. The results of the in vitro microbiology assay, which utilized a modified disk diffusion approach and were performed using two fungal strains (Candida albicans American Type Culture Collection (ATCC) 90028 and Candida parapsilosis American Type Culture Collection (ATCC) 22019), revealed that voriconazole was released in an active form from the polyvinylpyrrolidone matrix. The results of this study show that the MAPLE-deposited bioactive thin films have a promising potential for use in designing combination devices, such as drug delivery devices, and medical device surfaces with antifungal activity. 

This paper reports on the mechanical wear studies on Ultra High Molecular Weight Polyethylene (UHMWPE) against Nano-structured Diamond-Coated Ti-6Al-4V Alloy using a knee simulator under a clinically relevant conditions.