Preparation of thin polymer films with drug release and protein adsorption resistance

Lysosome-targeted ruthenium(II) complex encapsulated with pluronic® F-127 induces oncosis in A549 cells

Transition metal complexes with characteristics of unique packaging in nanoparticles and remarkable cancer cell cytotoxicity have emerged as potential alternatives to platinum-based antitumor drugs. Here we report the synthesis, characterization, and antitumor activities of three new Ruthenium complexes that introduce 5-fluorouracil-derived ligands. Notably, encapsulation of one such metal complex, Ru3, within pluronic® F-127 micelles (Ru3-M) significantly enhanced Ru3 cytotoxicity toward A549 cells by a factor of four. To determine the mechanisms underlying Ru3-M cytotoxicity, additional in vitro experiments were conducted that revealed A549 cell treatment with lysosome-targeting Ru3-M triggered oxidative stress, induced mitochondrial membrane potential depolarization, and drastically reduced intracellular ATP levels. Taken together, these results demonstrated that Ru3-M killed cells mainly via a non-apoptotic pathway known as oncosis, as evidenced by observed Ru3-M-induced cellular morphological changes including cytosolic flushing, cell swelling, and cytoplasmic vacuolation. In turn, these changes together caused cytoskeletal collapse and activation of porimin and calpain1 proteins with known oncotic functions that distinguished this oncotic process from other cell death processes. In summary, Ru3-M is a potential anticancer agent that kills A549 cells via a novel mechanism involving Ru(II) complex triggering of cell death via oncosis.

Surface-Initiated Controlled Radical Polymerization: State-of-the-Art, Opportunities, and Challenges in Surface and Interface Engineering with Polymer Brushes

The generation of polymer brushes by surface-initiated controlled radical polymerization (SI-CRP) techniques has become a powerful approach to tailor the chemical and physical properties of interfaces and has given rise to great advances in surface and interface engineering. Polymer brushes are defined as thin polymer films in which the individual polymer chains are tethered by one chain end to a solid interface. Significant advances have been made over the past years in the field of polymer brushes. This includes novel developments in SI-CRP, as well as the emergence of novel applications such as catalysis, electronics, nanomaterial synthesis and biosensing. Additionally, polymer brushes prepared via SI-CRP have been utilized to modify the surface of novel substrates such as natural fibers, polymer nanofibers, mesoporous materials, graphene, viruses and protein nanoparticles. The last years have also seen exciting advances in the chemical and physical characterization of polymer brushes, as well as an ever increasing set of computational and simulation tools that allow understanding and predictions of these surface-grafted polymer architectures. The aim of this contribution is to provide a comprehensive review that critically assesses recent advances in the field and highlights the opportunities and challenges for future work.

Protein adsorption and cell adhesion/detachment behavior on dual-responsive silicon surfaces modified with poly(N-isopropylacrylamide)-block-polystyrene copolymer

Diblock copolymer grafts covalently attached to surfaces have attracted considerable attention because of their special structure and novel properties. In this work, poly(N-isopropylacrylamide)-block-polystyrene (PNIPAAm-b-PS) brushes were prepared via surface-initiated consecutive atom-transfer radical polymerization on initiator-immobilized silicon. Because of the inherent thermosensitivity of PNIPAAm and the hydrophobicity difference between the two blocks, the modified surfaces were responsive to both temperature and solvent. Moreover, the diblock copolymer brushes exhibited both resistance to nonspecific protein adsorption and unique cell interaction properties. They showed strong protein resistance in both phosphate-buffered saline and blood plasma. In particular, fibrinogen adsorption from plasma at either room temperature or body temperature was less than 8 ng/cm(2), suggesting that the surfaces might possess good blood compatibility. In addition, the adhesion and detachment of L929 cells could be "tuned", and the ability to control the detachment of cells thermally was restored by block polymerization of hydrophobic, cell-adhesive PS onto a thicker PNIPAAm layer. In addition to providing a simple and effective design for advanced cell-culture surfaces, these results suggest new biomedical applications for PNIPAAm.