Alideertu Dong

N-halamine-decorated polystyrene nanoparticles based on 5-allylbarbituric acid: from controllable fabrication to bactericidal evaluation.

N-halamine-based antibacterial polystyrene nanoparticles with different particle size ranged from 91.5 nm to 562.5 nm were facilely fabricated by surfactant-free emulsion polymerization with 5-allylbarbituric acid served as N-halamine precursor. Effect of experimental parameters such as monomer concentration, initiator concentration, and ionic strength on particle size was investigated systematically. N-halamine-based antibacterial polystyrene nanoparticles showed enhanced antibacterial activity against both Gram-positive species Staphylococcus aureus and Gram-negative species Pseudomonas aeruginosa compared with bulk powder N-halamine. Biocidal activity of N-halamine-based antibacterial polystyrene nanoparticles can be tailored effectively by tuning particle size. Stability and bactericidal activity of N-halamine-based antibacterial polystyrene nanoparticles was detected as a function of extending period.

Tailored synthesis of amine N-halamine copolymerized polystyrene with capability of killing bacteria

Novel amine N-halamine copolymerized polystyrene (ANHCPS) nanostructures were controllably fabricated as potent antibiotics by using the surfactant-free emulsion copolymerization for killing pathogenic bacteria. The morphology and size of the ANHCPS were well tailored by tuning reaction conditions such as monomer molar ratio, temperature, and copolymerization time. Effect of chlorination aging time on the oxidative chlorine content in the ANHCPS was established, and the oxidative chlorine content was determined by the modified iodometric/thiosulfate technique. Antibacterial behavior of the ANHCPS on bacterial strain was evaluated using Staphylococcus aureus and Escherichia coli as model pathogenic bacteria via the plate counting technique, inhibition zone study, and time-kill assay. Antimicrobial results illustrated that the ANHCPS possessed superior antibacterial capability of killing pathogenic bacteria. The destruction induced by the ANHCPS on bacterial surface structure was proven by using SEM technique. The effect of the oxidative chlorine content and morphology/size on the antimicrobial capability was constructed as well. This study provides us a novel approach for controllably synthesizing amine N-halamine polymers, and making them the potent candidates for killing bacteria or even the control of microorganism contamination.

Assessment of 2,2,6,6-tetramethyl-4-piperidinol-based amine N-halamine-labeled silica nanoparticles as potent antibiotics for deactivating bacteria

Novel potent antibiotics, amine N-halamine-labeled silica nanoparticles (ANHLS NPs) based on 2,2,6,6-tetramethyl-4-piperidinol (TMP), were skillfully synthesized via the encapsulation of silica nanoparticles with amine N-halamine polymer for effective killing pathogenic bacteria. The particle size and coating thickness of amine N-halamine of ANHLS NPs were well controlled by tuning size of silica NPs and polymer encapsulation period, respectively. Effect of chlorination time on the oxidative chlorine content in ANHLS NPs was well elucidated by the aid of the modified iodometric/thiosulfate technique. Antimicrobial action of the ANHLS NPs on bacterial strain was evaluated using Staphylococcus aureus and Escherichia coli as model pathogenic bacteria. Bactericidal assessment showed that the ANHLS NPs exerted powerful bactericidal capability toward both two model bacteria. Time-kill assay demonstrated the significance of the oxidative chlorine content and contact time on antibacterial behavior. Size effect experiment displayed the decisive role of the size in controlling the biocidal activity. Plausible antibacterial mechanism of the ANHLS NPs against pathogenic bacteria was also discussed. Such a systematic investigation of the ANHLS NPs provides us a novel idea of making them the promising candidates for deactivating bacteria or even disease control.

Bactericidal evaluation of N-halamine-functionalized silica nanoparticles based on barbituric acid

Novel N-halamine-functionalized silica nanoparticles (NHFS NPs) were facilely fabricated from the 5-allylbarbituric acid (ABBA) by a seeded copolymerization using colloidal silica nanoparticles as support and ABBA-based N-halamine copolymers as shell. The NHFS NPs with spherical morphology and legible core-shell structure have the average diameter of 538.5 nm and the average shell thickness of 19.8 nm. The NHFS NPs possessed improved antimicrobial activity against both Gram-positive and Gram-negative bacteria compared with their bulk powder counterparts. The structural effect of N-halamine on bactericidal activity was clarified through the comparison between barbituric acid-based NHFS NPs and hydantoin-structural NHFS NPs. Effects of colloidal silica support and comonomer methyl methacrylate on particles morphology and the corresponding antimicrobial activity were comparatively investigated as well. Antibacterial tests revealed that N-halamine nanomaterials originated from barbituric acid derivative displayed powerful antibacterial performance and long-term stability.

Design, synthesis and biocidal effect of novel amine N-halamine microspheres based on 2,2,6,6-tetramethyl-4-piperidinol as promising antibacterial agents

Novel superior antibiotics, i.e. amine N-halamine microspheres based on 2,2,6,6-tetramethyl-4-piperidinol, were first synthesized by the aid of the radical copolymerization for deactivating pathogenic bacteria. The effects of copolymerization period on particle size and copolymer component of the products were elucidated. The oxidative chlorine content in amine N-halamine microspheres was determined by the modified iodometric/thiosulfate technique. The effect of chlorination period on oxidative chlorine content was investigated as well. Bactericidal behaviour of the products on bacterial strain was tested by selecting Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) as model pathogenic bacteria. Antibacterial assessment, including the plate counting technique, zone of inhibition study, and antibacterial kinetic test, demonstrated that amine N-halamine microspheres exerted powerful bactericidal capability. Effects of the contacting period, particle size, and oxidative chlorine content on antimicrobial activity were also established. High stability of amine N-halamine microspheres as a function of soaking period was finally confirmed. Such a systematic investigation of amine N-halamines provides us a novel idea of making them promising candidates for deactivating bacteria and even in disease control.

Surface arming magnetic nanoparticles with amine N-halamines as recyclable antibacterial agents: Construction and evaluation.

Magnetic recyclable antibacterial nanomaterials, i.e., magnetic amine N-halamine nanoparticles (Fe3O4@SiO2/CTMP NPs), were constructed by arming magnetic silica nanoparticles (Fe3O4@SiO2 NPs) with amine N-halamine (CTMP). Magnetic iron oxide nanoparticles were encapsulated into silica layers followed by anchoring antibacterial amine N-halamines to give magnetic/antibacterial bi-functional agents with core-shell structure. Since the presence of Fe3O4 NPs in core, the products offer super-paramagnetic behavior, which made them separable magnetically after the antibacterial behavior. Their sterilizing effect on bacterial strain was evaluated using Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) as model bacteria via the plate counting technique, zone of inhibition study, and time kill assay. Antibacterial mechanism study illustrated that the products integrate both the contact mechanism and the release mechanism for attacking bacteria. The significant effect of oxidative chlorine content and concentration of the products on antibiotic action were confirmed. Thanks to the magnetic property, the potential recyclability of the products was achieved. Most significantly, the products retain effective antibacterial action even after five cycles. These findings revealed that the products Fe3O4@SiO2/CTMP NPs have promising applications in the antibacterial fields.

Synthesis and bactericidal evaluation of imide N-halamine-loaded PMMA nanoparticles

Imide N-halamine-loaded poly(methyl methacrylate) nanoparticles (PMMA) based on barbituric acid were synthesized as novel antimicrobial agents using radical copolymerization. Evidence for loading imide N-halamine on PMMA nanoparticles has been inferred from different techniques like 1H NMR, FTIR, TEM, SEM, and XPS analyses. The sterilizing effect of the products on bacterial strains was systematically evaluated by selecting Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa as model pathogenic bacteria. The zone of inhibition study and the spread plate technique suggested that the imide N-halamine-loaded PMMA nanoparticles possessed powerful bactericidal activity towards both Gram-positive and Gram-negative bacteria. The effects of contact period, N-halamine structure, particle size, and chlorine content on biocidal efficiency were investigated as well. Long-term stability of the imide N-halamine-loaded PMMA nanoparticles was also confirmed as a function of storage period.

Controllable immobilization of polyacrylamide onto glass slide: synthesis and characterization

A novel route was introduced to synthesize dense polyacrylamide (PAM) onto the glass slide surface. To investigate the surface chemistry of the PAM on the glass slides, X-ray photoelectron spectroscopy (XPS) was utilized to obtain detailed chemical state information on the PAM layer constituents. The XPS peak data were consistent with the presented model of the PAM on the glass slide surface. Scanning electron microscopy and atomic force microscope data indicated the presence of PAM on the glass slides, which consist of nodules. The results showed that PAM was successfully immobilized onto glass slides with a two-tier structure under aqueous condition and a monolayer structure under anhydrous condition. Compared with those under aqueous condition, the controllability of the molecular layer on glass slides and the reproducibility under anhydrous condition were much better, which makes anhydrous condition an advisable condition for the study of the reaction mechanisms of glass slides modified by PAM.

N-Halamine polymer from bipolymer to amphiphilic terpolymer with enhancement in antibacterial activity

A novel N-halamine terpolymer, i.e., P(ADMH-MMA-HEMA)-Cl, with high antibacterial efficacies were fabricated via a free-radical copolymerization of 3-allyl-5,5-dimethylhydantoin(ADMH), methyl methacrylate(MMA), and hydroxyethyl methacrylate (HEMA), followed by a chlorination treatment using sodium hypochlorite as chlorinating agent. A controllable synthesis of P(ADMH-MMA-HEMA)-Cl was achieved by tuning chlorination conditions, such as chlorination temperature, reactant concentration, chlorination time, etc. A series of antibacterial assays were conducted, and the as-prepared products P(ADMH-MMA-HEMA)-Cl showed good killing capabilities against both Gram-positive and Gram negative bacteria. Remarkably, compared to N-halamine biopolymer counterparts, e.g., P(ADMH-HEMA)-Cl and P(ADMH-MMA)-Cl, and the as-prepared N-halamine terpolymer P(ADMH-MMA-HEMA)-Cl presented the enhancement in antibacterial efficiency toward pathogens. It is believed that this approach offers great potential to be utilized in various fields where antibacterial properties are highly required.