More than 2 decades of active investigations in the field of polymer brushes have revealed continuous and growing interest in different aspects of synthesis, properties, and applications of tethered polymers. In this article, we report on our recent advances in brush synthesis. The method we explore is based on the combination of ''grafting through'' approach with the functional anchoring polymer layer technique. We introduce the photoinitiated ''version'' of synthesis of polyacrylamide brushes. Both homogeneous depositions and laterally resolved gradient and patterned samples have been prepared by this technique. The results for flat polymer brushes, that is, thickness, stability, and contact angles, are complimented by kinetic parameters as deducted from analysis of gradient samples obtained by the method of a sliding mask.A microscopic shadow mask is used to fabricate patterned brushes. The microscopically patterned brushes demonstrate high lateral resolution limited by optical phenomena. Finally, we have performed a viability assaying of neuronal cell on both flat and patterned brushes. Sufficient restraint of cell adhesion on polyacrylamide photobrushes and very low cytotoxicity of the brush components (polymer brush itself, anchoring layer) make photografting a promising platform to control cell deposition and surface localization.

Supramolecular assemblies of block copolymers (BSAs) with low molecular weight additives require preferential interactions between the additive and one of the blocks. So far, only hydrogen bonds (HB) were explored to obtain BSAs. We report on three novel BSAs of block copolymer PS-block-P4VP with commercially valuable additives of the EDOT family. Two of the additives ((3,4-ethylenedioxythiophene) (EDOT) and 3,4-(2,2-dimethylpropylenedioxy)thiophene (ProDOT)) form the BSAs based on interactions others than HB. The morphology and some properties of the BSAs were studied by means of AFM, FTIR, and spectroscopic ellipsometry. The BSAs reveal cylindrical morphology with periodicity of ∼30 nm. In thin films the orientation of the cylinders can be switched from perpendicular to parallel by annealing in vapors of a suitable solvent. Extraction with a selective solvent results in porous films with porosity of ∼15%. These non-HB BSAs were compared with the HB BSA of HMeDOT as well as HABA BSA reported recently. The nature of the non-HB interactions is briefly discussed.

The development of antimicrobial resistance to conventional antibiotics is a major global health challenge. Infections caused by multidrug-resistant gram-negative bacteria have been named one of the most urgent global health threats. Considerable efforts are devoted to developing new antibiotic drugs and investigating the mechanism of antibiotic resistance. Recently, Anti-Microbial Peptides (AMPs) have emerged as a new platform for the target and design of novel drug resistant anti-microbial agents promising a new therapeutic strategy. AMPs are rapid, potent, possess an unusually broad spectrum of activity, and have shown efficacy as topical agents. Unlike traditional therapeutics that interfere with essential bacterial enzymes, AMPs interact with microbial membranes through electrostatic interactions and physically damage cell integrity. However, naturally occurring AMPs have limited selectivity and modest efficacy. Therefore, recent efforts have focused on the development of synthetic AMP analogs as suitable drug targets. This work explores the development of novel antimicrobial agents which mimic the structure of graft-copolymers and mirror the mode of action of an AMP. Chitosan-graft-polypeptide side chains are synthesized by the ring-opening polymerization of N-carboxyanhydrides of L-lysine and L-leucine initiated from the functional groups of chitosan. The derivatives with random- and block-copolymer side chains are explored as drug targets. These graft copolymer systems exhibit activity against clinically significant pathogens and disrupt biofilm formation. This work highlights the potential of chitosan-graft-polypeptide structures in biomedical applications.

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Infections caused by multidrug-resistant Gram-negative bacteria have been named one of the most urgent global health threats due to antimicrobial resistance. Considerable efforts have been made to develop new antibiotic drugs and investigate the mechanism of resistance. Recently, Anti-Microbial Peptides (AMPs) have served as a paradigm in the design of novel drugs that are active against multidrug-resistant organisms. AMPs are rapid-acting, potent, possess an unusually broad spectrum of activity, and have shown efficacy as topical agents. Unlike traditional therapeutics that interfere with essential bacterial enzymes, AMPs interact with microbial membranes through electrostatic interactions and physically damage cell integrity. However, naturally occurring AMPs have limited selectivity and modest efficacy. Therefore, recent efforts have focused on the development of synthetic AMP analogs with optimal pharmacodynamics and an ideal selectivity profile. Hence, this work explores the development of novel antimicrobial agents which mimic the structure of graft copolymers and mirror the mode of action of AMPs. A family of polymers comprised of chitosan backbone and AMP side chains were synthesized via the ring-opening polymerization of the N-carboxyanhydride of l-lysine and l-leucine. The polymerization was initiated from the functional groups of chitosan. The derivatives with random- and block-copolymer side chains were explored as drug targets. These graft copolymer systems exhibited activity against clinically significant pathogens and disrupted biofilm formation. Our studies highlight the potential of chitosan-graft-polypeptide structures in biomedical applications.