Multifunctional Antibacterial Materials Comprising Water Dispersible Random Copolymers Containing a Fluorinated Block and Their Application in Catheters.

Inhibiting the attachment of bacteria and the formation of biofilms on surfaces of materials and devices is the key to ensure public safety and is also the focus of attention and research. Here we report on the synthesis of multifunctional antibacterial materials based on water dispersible random copolymers containing a fluorinated block, poly(acrylic acid-co-1H,1H,2H,2H-perfluorododecyl acrylate) (PAA-co-PFDA), and poly(hexamethylene biguanide) hydrochloride (PHMB). PAA-co-PFDA copolymers were synthesized through a simple free radical polymerization. After lightly cross-linking of PAA-co-PFDA and complexation with PHMB, multifunctional antibacterial PAA-co-PFDA/PHMB complex nanoparticles were generated, which can form transparent coatings on various substrates. The resultant coating has aggregation-induced emission character which can be used to observe the uniformity of the coating on a catheter and has a potential application as a fluorescence probe. It has been demonstrated that the PAA-co-PFDA/PHMB complex nanoparticle coatings can resist bacterial adhesion in physiological environment and exhibit excellent antibacterial activity in infection environment. In vitro and in vivo experiments indicated that the PAA-co-PFDA/PHMB complex nanoparticle coated catheters exhibited excellent antibacterial activity and possessed good biocompatibility. This method is simple and scalable, which is important for future commercialization. The attractive multifunctional properties of the PAA-co-PFDA/PHMB complex nanoparticles, such as antifouling, antimicrobial, emission, and pH-responsive release character, have great potential application in a wide range of biomedical fields.

Surface-Adaptive and On-Demand Antibacterial Sponge for Synergistic Rapid Hemostasis and Wound Disinfection.

Uncontrolled hemorrhage is the leading factor causing death in military trauma and clinical practice and is usually accompanied with bacterial infection. The fabrication of a functional hemostatic sponge for combating bacteria is of vital importance. Poly(hexamethylene biguanide) hydrochloride (PHMB) has been shown to have a remarkable bactericide effect. However, PHMB after use might have a toxic effect on humans. Herein, a powerful surface-adaptive, on-demand antibacterial hemostatic sodium alginate/gelatin sponge is fabricated by sequential spray-assisted layer-by-layer assembly of PHMB and hyaluronic acid (HA). The HA upper layer could endow the coating surface with better biocompatibility under physiological conditions. Once bacteria invade, the secreted hyaluronidase could degrade the upper HA layer, and then the exposed PHMB layer could kill the bacteria. The coated sponge shows excellent biocompatibility, as negatively charged HA can prevent the exposure of bactericidal PHMB. Moreover, the coated sponge exhibited excellent hemostatic properties in vitro and in vivo by aggregating and activating blood cells. Our strategy provides a novel approach to the design of surface-adaptive and on-demand bactericidal coatings on the surface of hemostatic sponges, which has the advantage of avoiding infection complications during hemostasis.

Polymeric hole-shaped polyhedral aggregates: Preparation, characterization, and antibacterial adhesion properties.

The diverse morphologies of aggregates formed by the self-assembly of block copolymers in selective solvents have attracted widespread attention, but the design of aggregate shapes is still limited owing to the thermodynamic favorability of sphere formation. In this paper, we report our discovery that polyhedral aggregates can be formed by the self-assembly of 1H,1H,2H,2H-perfluoro-1-dodecanol (PFD)-grafted amphiphilic polystyrene-b-poly(acrylic acid) (PS-b-PAA-g-PFD) copolymers in water at room temperature. It is determined that the crystallization of fluorocarbon side chains at the surface of PS-b-PAA-g-PFD aggregates induces the formation of a polyhedral shape. The morphology of aggregates can be controlled by the dialysis temperature, the grafting ratio of PFD in PS-b-PAA-g-PFD copolymers, and the initial copolymer concentration. The layers of polyhedral aggregates show excellent antibacterial adhesion properties. We anticipate that this method will expand the promise of self-assembly for the synthesis of a series of nonspherical micellar nanoparticles, which have promising applications in various fields.

Water-Insoluble Polymeric Guanidine Derivative and Application in the Preparation of Antibacterial Coating of Catheter.

Antibacterial coatings have been considered as an effective method for preventing the implant-associated infections caused by the bacterial colonization. In this study, we report a water-insoluble polyelectrolyte-surfactant complex, poly(hexamethylene biguanide) hydrochloride-sodium stearate (PHMB-SS) that can be facilely coated onto the surfaces of biomedical catheter and kill the bacteria by releasing the PHMB and prevent the generation of the biofilm. The PHMB-SS-coated surfaces showed better bactericidal activity toward Staphylococcus aureus and Escherichia coli. The PHMB-SS-coated catheters could not only relatively prevent the bacterial colonization in vitro but also in an implant-associated bacterial infection animal model in vivo. Moreover, no significant cytotoxicity and host response were observed in vitro and in vivo, indicating the high biocompatibility of the coating. The water-insoluble antibacterial coating reported in this work represents a novel approach to build a simple and effective coating for the prevention of device-associated infections.

Autofluorescent Polymers: 1 H,1 H,2 H,2 H-Perfluoro-1-decanol Grafted Poly(styrene- b-acrylic acid) Block Copolymers without Conventional Fluorophore.

Recently, although several unconventional luminescent polymers have been synthesized, it still remains a significant challenge to prepare various new fluorescent polymers by functionalization of nonfluorescent polymers. A nonfluorescent 1 H,1 H,2 H,2 H-perfluoro-1-decanol grafted to nonfluorescent polystyrene- b-poly(acrylic acid) block copolymers through simply esterification reaction can exhibit strong blue emission. On the basis of control experiments and theoretical simulation, we have proposed that the luminescence stems from interchain n → π* interaction between the lone pair (n) of hydroxyl O atoms of carboxyl units and empty π* orbital of ester carbonyl unit. In addition, the fluorescent polymers are successfully employed for fluorescence imaging in living HeLa cell.