Structurally Heterogeneous Amphiphilic Conetworks of Poly(vinyl imidazole) Derivatives with Potent Antimicrobial Properties and Cytocompatibility

Highly Efficient Thiol-Michael Addition Post-Modification toward Potent Degradable Antibacterial Polyesters with Guanidine Moiety

We have previously synthesized poly(3-methylene-1,5-dioxepan-2-one) (PMDXO) that could be modified through the thiol-Michael addition reaction to afford versatile degradable polymers. Herein, we find that the γ-oxa in PMDXO exerts a dramatically accelerating effect on the thiol-Michael addition post-modification, which makes PMDXO a promising platform polymer for synthesizing guanidinium-functionalized aliphatic polyesters under mild and approximately stoichiometric conditions. The relationship between polymer structure and antibacterial performance was investigated. A promising cationic polyester, P20-2C, which shows extremely low hemolytic activity, moderate cytotoxicity, and broad-spectrum potent bactericidal capability against 214 clinically isolated ESKAPE strains, is obtained. The good biocompatibility and potent in vivo antibacterial efficacy of P20-2C have been demonstrated in mice using three bacterial infection models, including MDR E. coli-infected peritonitis and MRSA-infected subcutaneous abscess and skin wound. Finally, a multimodal bactericidal mechanism of membrane disruption plus reactive oxygen species upregulation is proposed for P20-2C against E. coli and S. aureus.

Constructing Self-Renewing Silicone-Hydrogel Hybrid Coatings with Integrated Fouling Resistant/Release/Killing Mode toward Superior Biofouling Defense

Silicone hydrogel coatings, which integrate fouling self-release and fouling resistant properties, represent a groundbreaking advancement in environmentally friendly biofouling mitigation, but are still plagued by static fouling conditions and longevity concerns. In this work, Schiff base chemistry and a sol-gel technique is leverage to develop degradable silicone-hydrogel hybrid antifouling coatings by incorporating amphiphilic silicone-based polymers with terephthalaldehyde (TPE) and cinnamaldehyde (CAL). The synergistic combination of flexible Si─O bonds in the polymer backbone and reversible covalent crosslinking imparts exceptional flexibility (hardness of 0.135), controlled degradability, and dynamic surface self-renewal capabilities, ensuring sustained antifouling performance through surface dynamic stability. During degradation, the amphiphilic polymers will self-enrich at the interface, forming a dual-functional surface that combines fouling release and fouling resists properties. The antibacterial TPE and natural CAL, anchored within the polymer network, exhibit environment-responsive release behavior, effectively suppressing bacterial proliferation and biofilm adhesion. The optimized coating achieves a bactericidal rate of 98.8%, an anti-bacterial adhesion rate of 99.8%, and a predicted anti-fouling longevity of 5.5 years with a thickness of 200 µm. This innovative approach enables a new anti-biofouling coating that involves unique fouling control mode, thereby meeting the diverse application.

The First Example of a Model Amphiphilic Polymer Conetwork Containing a Hydrophobic Oligopeptide: The Case of End-Linked Tetra[Poly(ethylene glycol)-b-oligo(L-alanine)]

Herein we describe the development of the first model amphiphilic polymer conetwork (APCN) comprising a short hydrophobic hexa(L-alanine) segment being the outer block of an amphiphilic four-armed star block copolymer with inner poly(ethylene glycol) (PEG) blocks bearing benzaldehyde terminal groups and end-linked with another four-armed star PEG homopolymer (tetraPEG star) bearing aryl-substituted acylhydrazide terminal groups. The present successful synthesis that yielded the peptide-containing model APCN was preceded by several unsuccessful efforts that followed different synthetic strategies. In addition to the synthetic work, we also present the structural characterization of the peptide-bearing APCN in D2O using small-angle neutron scattering (SANS).

Bicontinuous Nanophasic Conetworks of Polystyrene with Poly(dimethylsiloxane) and Divinylbenzene: From Macrocrosslinked to Hypercrosslinked Double-Hydrophobic Conetworks and Their Organogels with Solvent-Selective Swelling

Polymer conetworks, which consist of two or more covalently crosslinked polymer chains, not only combine the individual characteristics of their components, but possess various unique structural features and properties as well. In this study, we report on the successful synthesis of a library of polystyrene-l-poly(dimethylsiloxane) (PSt-l-PDMS) ("l" stands for "linked by") and polystyrene-l-poly(dimethylsiloxane)/divinylbenzene (PSt-l-PDMS/DVB) polymer conetworks. These conetworks were prepared via free radical copolymerization of styrene (St) with methacryloxypropyl-telechelic poly(dimethylsiloxane) (MA-PDMS-MA) as macromolecular crosslinker in the absence and presence of DVB with 36:1 and 5:1 St/DVB ratios (m/m), the latter leading to hypercrosslinked conetworks. Macroscopically homogeneous, transparent conetworks with high gel fractions were obtained over a wide range of PDMS contents from 30 to 80 m/m%. The composition of the conetworks determined by elemental analysis was found to be in good agreement with that obtained from the 1H NMR spectra of the extraction residues, as a new method which can be widely used to easily determine the composition of multicomponent networks and gels. DSC, SAXS, and AFM measurements clearly indicate bicontinuous disordered nanophase separated morphology for all the investigated conetworks with domain sizes in the range of 3-30 nm, even for the hypercrosslinked PSt-l-PDMS/DVB conetworks with extremely high crosslinking density. The cocontinuous morphology is also proved by selective, composition-dependent uniform swelling in hexane for the PDMS and in 1-nitropropane for the PSt domains. The Korsmeyer-Peppas type evaluation of the swelling data indicates hindered Fickian diffusion of both solvents in the conetwork organogels. The unique nanophasic bicontinuous morphology and the selective swelling behavior of the PSt-l-PDMS and PSt-l-PDMS/DVB conetworks and their gels offer a range of various potential applications.

Dynamic Covalent Amphiphilic Polymer Conetworks Based on End-Linked Pluronic F108: Preparation, Characterization, and Evaluation as Matrices for Gel Polymer Electrolytes

We present the development of a platform of well-defined, dynamic covalent amphiphilic polymer conetworks (APCN) based on an α,ω-dibenzaldehyde end-functionalized linear amphiphilic poly(ethylene glycol)-b-poly(propylene glycol)-b-poly(ethylene glycol) (PEG-b-PPG-b-PEG, Pluronic) copolymer end-linked with a triacylhydrazide oligo(ethylene glycol) triarmed star cross-linker. The developed APCNs were characterized in terms of their rheological (increase in the storage modulus by a factor of 2 with increase in temperature from 10 to 50 °C), self-healing, self-assembling, and mechanical properties and evaluated as a matrix for gel polymer electrolytes (GPEs) in both the stretched and unstretched states. Our results show that water-loaded APCNs almost completely self-mend, self-organize at room temperature into a body-centered cubic structure with long-range order exhibiting an aggregation number of around 80, and display an exceptional room temperature stretchability of ∼2400%. Furthermore, ionic liquid-loaded APCNs could serve as gel polymer electrolytes (GPEs), displaying a substantial ion conductivity in the unstretched state, which was gradually reduced upon elongation up to a strain of 4, above which it gradually increased. Finally, it was found that recycled (dissolved and re-formed) ionic liquid-loaded APCNs could be reused as GPEs preserving 50-70% of their original ion conductivity.