Cylindrical Zwitterionic Particles via Interpolyelectrolyte Complexation on Molecular Polymer Brushes.

The fabrication of macromolecular architectures with high aspect ratio and well-defined internal and external morphologies remains a challenge. The combination of template chemistry and self-assembly concepts to construct peculiar polymer architectures via a bottom-up approach is an emerging approach. In this study, a cylindrical template-namely a core-shell molecular polymer brush-and linear diblock copolymers (DBCP) associate to produce high aspect ratio polymer particles via interpolyelectrolyte complexation. Induced, morphological changes are studied using cryogenic transmission electron and atomic force microscopy, while the complexation is further followed by isothermal titration calorimetry and ξ-potential measurements. Depending on the nature of the complexing DBCP, distinct morphological differences can be achieved. While polymers with a non-ionic block lead to internal compartmentalization, polymers featuring zwitterionic domains lead to a wrapping of the brush template.

Bisphosphonate-functionalized micelles for targeted delivery of curcumin to metastatic bone cancer.

Metastatic (secondary) bone cancer is one of the major causes of death in patients with advanced cancer. A lack of options for the targeted delivery of a desired therapeutic payload to multiple tumour modules located in the bone is still one of the foremost hurdles in the treatment/prevention of metastatic bone cancer. Curcumin has a proven anticancer potential with known challenges for application as a pharmaceutical agent. We have previously shown that micellar formulations could overcome some of these challenges and enhances its anti-cancer activity. In this study, we have developed a targeted drug delivery system using bisphosphonate (alendronate) conjugated Pluronic F127 micelles that could efficiently target, and specifically deliver curcumin to the osteolytic tumour microenvironment in the bone. Characterization of the formulation of curcumin-encapsulated alendronate-conjugated micelles demonstrated that the micelles have nanoscale size (∼27 nm) with a positive surface charge (+2.87 mV) and 4% drug loading. The alendronate-conjugated micelles showed significant bone-targeting potential. Rapid binding of the micelles to hydroxyapatite surface suggested that these nanoparticles are promising carriers for effective and targeted delivery of curcumin to osteolytic tumours in the bone.

Transparent Low Molecular Weight Poly(Ethylene Glycol) Diacrylate-Based Hydrogels as Film Media for Photoswitchable Drugs.

Hydrogels have shown a great potential as materials for drug delivery systems thanks to their usually excellent bio-compatibility and their ability to trap water-soluble organic molecules in a porous network. In this study, poly(ethylene glycol)-based hydrogels containing a model dye were synthesized by ultraviolet (UV-A) photopolymerization of low-molecular weight macro-monomers and the material properties (dye release ability, transparency, morphology, and polymerization kinetics) were studied. Real-time infrared measurements revealed that the photopolymerization of the materials was strongly limited when the dye was added to the uncured formulation. Consequently, the procedure was adapted to allow for the formation of sufficiently cured gels that are able to capture and later on to release dye molecules in phosphate-buffered saline solution within a few hours. Due to the transparency of the materials in the 400⁻800 nm range, the hydrogels are suitable for the loading and excitation of photoactive molecules. These can be uptaken by and released from the polymer matrix. Therefore, such materials may find applications as cheap and tailored materials in photodynamic therapy (i.e., light-induced treatment of skin infections by bacteria, fungi, and viruses using photoactive drugs).