Search

In this work, a novel N-halamine precursor, 1-glycidyl-s-triazine-2,4,6-trione (GTT), was synthesized through the reaction of cyanuric acid with epichlorohydrin in a facile condition. The pad–dry–cure technique was used to coat GTT onto cotton fabrics through the covalent surface modification of the cotton fibers. The GTT-coated cotton was characterized by FTIR spectroscopy and SEM. The N-halamine moieties attached to the cotton fibers could be rendered antimicrobial by treatment with a dilute sodium hypochlorite solution. The N-halamine-modified cotton fabrics demonstrated excellent antimicrobial efficacy against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli O157:H7) bacteria in brief contact times. Over 71% of the chlorine lost after the equivalent of 50 machine washes could be regained upon rechlorination. The chlorinated coated fabrics showed great rechargeability within one week under UVA light irradiation.

The inherent antimicrobial properties and biodegradability of chitosan make it an ideal candidate for antimicrobial materials. In this study, N-halamine precursor 3-glycidyl-5,5-dimethylhydantoin (GH) was synthesized and bonded onto chitosan by a ring opening reaction between chitosan and GH. The chitosan film modified with the N-halamine precursor could be rendered biocidal after exposure to a dilute household bleach solution. Syntheses routes, characterization data, and antimicrobial test results are presented. The chlorinated films with 2.60 × 10(18) atoms/cm(2) of active chlorine were challenged with Staphylococcus aureus (ATCC 6538) and Escherichia coli O157:H7 (ATCC 43895) and showed good efficacy against these two bacterial species with log reductions of 7.4 and 7.5 within 10 and 5 min of contact time, respectively. These films may serve as potential materials for food packaging and biomedical applications.

A novel heterocyclic N-halamine acetate homopolymer was synthesized and characterized by ATR-IR, NMR and MALDI-TOF spectroscopy and TGA and DSC analysis. The homopolymer was coated onto poly(lactic acid) (PLA) meltblown nonwoven fabric, and the surfaces were rendered biocidal upon exposure to dilute sodium hypochlorite solution. The coatings were quite stable versus UVA and florescent light exposure. Moreover, they exhibited long-term shelf-life stability, and they were rechargeable when oxidative chlorine on the surfaces was partially exhausted after three months storage. It was found that the chlorinated fabrics exhibited effective antimicrobial activity with about six logs inactivation of Staphylococcus aureus and Escherichia coli O157:H7 within 30 min of contact time. The coated PLA possesses potential for use in antimicrobial food packaging, filters, and hygiene products.

Chitosan is a promising candidate as an antimicrobial agent in food packaging materials and biomaterials due to its biocompatibility, biodegradability, non-toxicity and biocidal activity. In this study, chitosan derivatives, α-(5,5-dimethyl hydantoin amino)-chitosan (CS-HDH), were synthesized. The CS-HDH nanospheres were prepared by ionic gelation method and characterized by SEM, FT-IR, XRD, and TGA-DTG. The prepared novel chitosan nanospheres in the range of 200–300 nm had good dispersibility. The CS-HDH nanospheres were used to prepare antibacterial PVA hybrid films by solvent evaporation technique. The surface morphology and thermal property of hybrid films were measured by SEM, AFM, and TGA-DTG. The results of antibacterial test showed that the hybrid film with 1.24 × 1018 atoms/cm2 of active chlorine exhibited excellent antibacterial properties against Staphylococcus aureus and Escherichia coli O157:H7, and all of bacteria could be inactivated within 5 min. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44204.

Quaternary ammonium salts Quats-C8, Quats-C12, and Quats-C18 with different alkyl chain lengths have been successfully synthesized, and used for modifying silk fabrics. The optimum reaction conditions of initiator concentration, curing temperature, curing time, and monomer concentration have been studied. The modified fabrics of silk-g-C8, silk-g-C12, and silk-g-C18 were characterized by FTIR spectra. Antibacterial test showed that the modified silk fabrics possessed potent antibacterial activity against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The carbon number in the alkyl chain of monomers Quats-C8, Quats-C12, and Quats-C18 can affect the antibacterial efficacy. With longer alkyl chain, the antibacterial efficacy increased. The quaternary ammonium salts-modified silk fabrics have small change on the tensile strength and wrinkle recovery angle, and have shown potential practical application.

N-(hydroxymethyl) acrylamide (NMA) was immobilized on cotton surfaces through etherification, and then methacryla- mide (MA) was grafted onto the treated surface. The coatings were characterized by ATR-IR spectroscopy and were rendered biocidal upon exposure to dilute household bleach. The treated fabrics were challenged with Gram-negative and Gram-positive bacteria; both NMA and NMA/MA-treated fabrics inactivated about 8 logs of Escherichia coli O157:H7 and Staphylococcus aureus within only 5 min of contact time. The coatings were also quite stable toward ultraviolet (UVA) light exposure and repeated laundering. More- over, a substantial improvement in wrinkle recovery angle was obtained for the NMA/MA-treated fabrics. The new acyclic acrylamide N-halamine coating should be less expensive to produce and use than previous cyclic N-halamine coatings developed in these labora- tories. V C 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 128: 4405-4410, 2013

A vinyl N-halamine acrylamide monomer was copolymerized with silane-, epoxide-, and hydroxyl group-containing monomers. The resultant copolymers were coated onto cotton fabric through hydrolysis of alkoxy groups with formation of silyl ether bonding, opening of the epoxide ring and subsequent reaction with hydroxyl groups on cellulose, and by crosslinking between the hydroxyl groups on the copolymer and on cellulose, respectively. The coatings were rendered biocidal upon exposure to dilute household bleach solution. All of the coatings provided complete inactivation of about six log of Staphylococcus aureus and Escherichia coli O157:H7 within minutes of contact time. The effects of the aforementioned tethering groups on wash fastness and ultraviolet light exposure were also studied.

To achieve biocidal properties, a cyclic N-halamine precursor, 7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]-decane-2,4-dione (TTDD), was synthesized and introduced into nanosized polyacrylonitrile fibrous mat by an electrospinning technique. It was rendered antimicrobial by exposure to dilute hypochlorite solution. Synthesis routes and characterization data are presented. Scanning electron microscopy (SEM) demonstrated that the ultrafine fiber possessed average diameter 414 nm (from 240 to 650 nm). The chlorinated nanofibrous composites provided about 4.9 log reductions of both Gram-positive bacteria Staphylococcus aureus (ATCC 6538) and Gram-negative bacteria Escherichia coli O157:H7 (ATCC 43895) within 5 min of contact time. This is indicative of promising possible applications in the filtration of water and air. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Three heterocyclic N-halamine structures containing amine, amide, or both functional groups were immobilized onto cotton fabric through epoxide tethering. The coatings were rendered biocidal upon exposure to dilute household bleach solution. The coatings exhibited superior biocidal functionality with complete inactivation of about 6 logs of Staphylococcus aureus and Escherichia coli O157:H7 within 2–10 min contact time depending on the structure. Moreover, the coatings were quite stable against repeated laundering so that recharging was not even necessary after 50 washing cycles. Stability of the coatings against ultraviolet light exposure was studied with a comparison of the amide- and amine-containing N-halamines.

A series of copolymers containing units of a novel hydantoinylacrylamide and the sodium salt of 2-(acrylamido)-2-methylpropanesulfonic acid have been synthesized. The homopolymer of the hydantoinylacrylamide compound was insoluble in water, while the copolymers with the sulfonic acid sodium salt were water-dispersible/soluble, with the solution becoming completely transparent when the feed ratio for the copolymer contained 7 parts of the hydantoin moiety to 3 parts of the sodium sulfonate moiety. The polymers were added into a commercial water-based latex paint, and upon drying, the painted surfaces treated with the water-miscible copolymers were rendered antimicrobial following chlorination with dilute household bleach. The chlorinated homopolymer failed to provide an antimicrobial property for the paint because of its tendency to isolate into aggregates in the paint, while the completely miscible copolymers were capable of 6-log inactivation of Staphylococcus aureus and Escherichia coli O157:H7 within 5 min of contact time.

The composite fibers of cellulose, starch, and a commercial hindered amine light stabilizer have been produced in various concentrations of the components using 1-butyl-3-methylimidazolium chloride as the spinning solvent in order to evaluate their physical properties. The composite fibers allowed desirable properties of both polymers to be retained, while producing fibers of reasonable physical properties. The halogenated hindered amine light stabilizer exhibited remarkably good resistance towards repeated ultraviolet light irradiation and halogenation cycles.

A new N-halamine acrylamide monomer having 31 wt.% chlorine loading capability was synthesized and then copolymerized with a tethering siloxane monomer in several feed ratios. The resulting copolymers were coated onto cotton fabric and rendered biocidal upon treatment with 1% household bleach. The halogenated coated fabrics provided a total of 8-logs inactivation of both Gram-negative and Gram-positive bacteria within 5 min of contact time. The equimolar and siloxane-rich copolymers were noticeably stable on cotton fabric toward washing cycles, as only 10% of the copolymers were hydrolyzed from the cotton surface after the equivalent of 50 machine washes. The halogenated coated fabrics lost about half of the chlorine slowly within 24 h under UVA light irradiation with some decomposition observed.

Two N-halamine copolymer precursors, poly(2,2,6,6-tetramethyl-4-piperidyl methacrylate-co-acrylic acid potassium salt) and poly(2,2,6,6-tetramethyl-4-piperidyl methacrylate-co-trimethyl-2-methacryloxyethylammonium chloride) have been synthesized and successfully coated onto cotton fabric via a layer-by-layer (LbL) assembly technique. A multilayer thin film was deposited onto the fiber surfaces by alternative exposure to polyelectrolyte solutions. The coating was rendered biocidal by a dilute household bleach treatment. The biocidal efficacies of tested swatches composed of treated fibers were evaluated against Staphylococcus aureus and Escherichia coli. It was determined that chlorinated samples inactivated both S. aureus and E. coli O157:H7 within 15 min of contact time, whereas the unchlorinated control samples did not exhibit significant biocidal activities. Stabilities of the coatings toward washing and ultraviolet light exposure have also been studied. It was found that the stability toward washing was superior, whereas the UVA light stability was moderate compared to previously studied N-halamine moieties. The layer-by-layer assembly technique can be used to attach N-halamine precursor polymers onto cellulose surfaces without using covalently bonding tethering groups which limit the structure designs. In addition, ionic precursors are very soluble in water, thus promising for biocidal coatings without the use of organic solvents.

Phenyl substitution at position 5 on the hydantoin ring of a series of N-halamine derivatives, including an antimicrobial siloxane used for coating surfaces, has been employed to better understand the biocidal activities and stabilities of these compounds in the presence of water and exposure to ultraviolet irradiation. This phenyl derivatization of the hydantoin ring at its 5 position does, in fact, affect the antimicrobial efficacy of the siloxane against Staphylococcus aureus and Escherichia coli O157:H7, and its stability toward hydrolyses and ultraviolet light exposure. The phenyl substitution caused weakening of the N-Cl bond at the 1 position on the hydantoin ring, leading to an increase in biocidal activity but a decrease in stability. Model compounds were studied experimentally and theoretically at the (U)B3LYP/6-311++G(2d,p) level of theory in order to better explain the observations. It was found that the phenyl moiety at position 5 on the hydantoin ring can interact with the oxidative chlorine atom bonded to the amide nitrogen atom at position 1 which then results in a less stable N-Cl bond.

Magnetostrictive microcantilever (MSMC), as a high-performance biosensor platform, was introduced recently. By using physical absorption, an antibody against Escherichia coli is immobilized onto the surface of the MSMC to form a biosensor. The real-time and in situ detection of E. coli in water using the biosensor is reported. The responses of the biosensor in E. coli suspension with different concentrations were studied, which were used to determine the detection limit of the biosensor. It is confirmed by using SEM observation and a control sensor approach, respectively, that the experimentally observed response of the biosensor is due to the binding of E. coli on the surface of the biosensor. It is found that the detection limit is improved by reducing the size of the MSMC, which is consistent with the theoretical calculation. For an MSMC with the size of 1.5 mm × 0.8 mm × 35 μm, the detection limit is 105 cfu/ml.

Low concentrations of acyclic amide monomers, methacrylamide (MAM) and acrylamide (AM), were copolymerized with vinyl acetate (VAc). No significant differences between the synthesized copolymers and poly(VAc) were seen by 1H-NMR, FTIR, and DSC analysis. Biocidal films, formed by coating the copolymers onto polyester transparency slides and polyester fabric swatches, were chlorinated by exposure to sodium hypochlorite solutions. Both S. aureus and E. coli O157: H7 were completely inactivated within 1 min on the transparency slides and polyester fabric swatches derived from poly(VAc-co-MAM). The chlorine on the films was stable under UVA irradiation and the surfaces were rechargeable upon chlorine loss.

Foodborne illness is a common public health problem because food can be contaminated by pathogens at any point from farm to dinner table. This paper shows a comparison of capturing a small quantity of a specific bacterial pathogen in a large volume of liquid using a biomolecular filter immobilized with different bioreceptors. The filter consists of support frames, which are made of a soft magnetic material, and solenoid coils for magnetization/demagnetization of the frames. The biomolecular filter is a planar, multi-layered arrangement of strip-shaped magnetoelastic (ME) biosensors with bioreceptor immobilization. These ME biosensors are magnetically held and arrayed on the filter frames. The pathogen of interest in a large volume of liquid is captured by the bioreceptor immobilized on the ME biosensors, when a large volume of liquid passes through. At the same time, non-specific debris can be passed through the biomolecular filter, in order to avoiding a common clogging issue from conventional bead filters. In this work, E2 phage and antibody, are immobilized each on ME biosensors to capture Salmonella Typhimurium in a large volume of water. The capture efficiencies and effects of multiplication of filter layers with E2 phage and the antibody on Salmonella capture efficiency will be discussed.

Swabbing, as an inexpensive, easy-to-use, and widely accepted sampling method, has been used to help magnetoelastic (ME) biosensing system for the surface pathogen quick detection. This paper introduced a modification method using a surfactant, Tween20, to help to improve the recovery rate of different swabs. In our previous research, swabbing substituted the direct ME sensor detection on the sample surfaces, which improved the detection area of one sensor from 0.2X1 mm2 into 30X30 mm2. This amendment altered the former surface spot measurement into a large area measurement. To improve the accuracy of this swabbing technique to a better level, a higher recovery rate is needed. Tween20, a stable and relatively non-toxic surfactant, was employed to modify the fibers of swabs so that after the pathogens are picked up, they would be easier to be released into DI water and detected by ME sensors. In this research, traditional swabs, such as cotton-tipped, rayon-tipped, and novel flocked swabs are used for comparison.

A commercial m-aramid as N-halamine precursor has been coated onto polyethylene terephthalate (PET) fabric surface by pad-dry-curing process. The process is accomplished by padding the scoured PET fabric through the homogeneous m-aramid solution, drying at 150°C for 3 min, and curing at 230°C for 3 min. The PET surface coated with m-aramid was characterized using fourier transform infrared-attenuated total reflection (FTIR-ATR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). FTIR exhibits new bands in the 1645 and 1524 cm−1 regions as characteristic of m-aramid bands, which indicate the PET fabric coated with m-aramid. XPS results show a distinguishable peak at binding energy 398.7 eV, which confirms the nitrogen atom of m-aramid on the PET surface. In addition, SEM image shows a layer of coating onto the PET surfaces, which demonstrates the presence of m-aramid coating on the surface of the PET. After exposure to dilute sodium hypochlorite solution, exhibition of antimicrobial activity on the coated PET is attributed to the conversion of N-halamine moieties from the N-halamine precursor. The chlorinated PET showed high antimicrobial activity against Gram-negative and Gram-positive bacteria. The chlorinated PET coated with 10% m-aramid exhibited about 6 log reductions of S. aureus and E. coli O157:H7 at a contact time of 10 and 30 min, respectively. Furthermore, the antimicrobial activity was durable and rechargeable after 25 wash cycles. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

An N-halamine precursor, 3-(5'-methyl-5'-hydantoinyl)acetanilide (I), was synthesized in our laboratory and loaded onto electrospun polyacrylonitrile fiber to prepare nanosized biocidal materials, which could be rendered antimicrobial by exposure to household bleach. Differential scanning calorimetry was used to study the thermal properties of the nanofibers with and without the N-halamine precursor and its chlorinated derivative loaded. Scanning electron microscopy demonstrated that the ultrafine fibers formed with diameters from 250 to 600 nm. Chlorinated nanofibrous mats composed of the fibers were challenged with Staphylococcus aureus (ATCC 6538) and Escherichia coli O157:H7 (ATCC 43895); they showed promising inactivation efficacies against the two bacterial species within 5 minutes of contact. Potential uses of the antimicrobial fibers include filters for industrial water and air disinfection and protective clothing.

A new N -halamine precursor, 3-(2,3-dihydroxypropyl)-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione (TTDD diol), was synthesized and bonded onto cotton fabrics. Fabrics with variable amounts of chlorine loading were prepared by using several concentrations of TTDD diol. A second N -halamine precursor, 3-(3-triethoxysilylpropyl)-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione (TTDD siloxane), was also synthesized and bound to cotton for comparison purposes. The coated cotton fabrics contained two types of N–Cl moieties after chlorination of the amine and amide groups. Swatches with variable chlorine loadings were challenged with Staphylococcus aureus and Escherichia coli O157:H7 as a function of contact time. The biocidal test results showed that the chlorine loadings and surface hydrophobicities influenced the antimicrobial efficacies. The chlorinated swatches have also been employed to oxidize the simulant of chemical mustard to the less toxic sulfoxide derivative.

The monomers of the compounds 6-phenyl-3-(3′-triethoxysilylpropyl)-1,3,5-triazinane-2,4-dione and 6,6-dimethyl-3-(3′-triethoxysilylpropyl)-1,3,5-triazinane-2,4-dione have been synthesized and coated on the surfaces of silica gel particles and cellulose. Exposure to diluted sodium hypochlorite solutions renders these polymers antimicrobial. The treated polymers inactivated (7 logs) both Staphylococcus aureus and Escherichia coli O157:H7 with brief contact times. The coated cotton fabrics showed great stability and rechargeability following exposure to UV and ambient light.

Copolymers of an N-halamine siloxane and a quaternary ammonium salt siloxane were prepared using 5,5-dimethylhydantoin and trimethylamine as functional groups. The solubility of this siloxane copolymer in water was dramatically improved over that of a hydantoinyl siloxane homopolymer developed earlier. The biocidal activity of cotton swatches coated with the copolymer was evaluated against S. aureus and E. coli O157:H7; the antimicrobial fabric with 0.23%−0.26% chlorine loading could inactivate 107 colony forming units (CFU) of bacteria within 1−5 min of contact. It was observed that a 1 wt % coating bath could provide a coating that could be chlorinated to greater than a 0.20% chlorine loading for a copolymer having a 9:1 ratio of hydantoin to quat moieties. The stability of the oxidative chlorine loading on the cotton swatches was not affected by the presence of the very hydrophilic quat functional group. Use of the copolymer in an antimicrobial coating application will be desirable because no organic s...

An N-halamine precursor containing two hydroxyl groups (diol) has been synthesized. The N-halamine diol precursor was coated onto cotton fabrics with the assistance of the cross-linking agent BTCA. The surface of the coated cotton could be rendered biocidal by exposure to dilute hypochlorite solutions. Syntheses routes, characterization data, and antimicrobial test results will be presented. The durability and rechargeability of chlorine on the coated cotton was determined according to an AATCC standard washing test. The chlorinated cotton swatches were challenged with Staphylococcus aureus ( ATCC 6538 ) and Escherichia coli O157:H7 ( ATCC 43895 ) and showed excellent efficacy against these two bacterial species within a brief time of contact. Over 70% of the chlorine lost after repeated washing or UVA irradiation could be regained upon rechlorination.

The N-halamine monomer 3-(4'-vinylbenzyl)-5,5-dimethylhydantoin (VBDMH) was synthesized and employed to form thin films on the surfaces of polyester fibers by surface polymerization with the aid of a cationic surfactant. The coated samples were characterized by FTIR and SEM. The thin film coatings could be rendered biocidal by exposure to dilute sodium hypochlorite. The antimicrobial polyesters were challenged with Staphylococcus aureus and Escherichia coli O157:H7. Complete inactivation of S. aureus and E. coli O157:H7 was observed within 10 and 30 min of contact time, respectively. The chlorine bonded to the coatings was very stable under standard washing tests and UVA irradiation tests, and much of the lost chlorine could be regenerated by rechlorination.

Variation of alkyl substitution at position 5 on the hydantoin ring of a series of N-halamine siloxane derivatives has been employed to better understand the biocidal activities of these compounds for use in preparing antimicrobial coatings. The alkyl derivatization of the hydantoin ring at its 5 position, while an essentially constant chlorine loading is maintained at the 1 position, has shown that there is little dependence of the antimicrobial efficacy against Escherichia coli O157:H7 on the alkyl chain length, in contrast to reported observations for biocidal quaternary ammonium salt derivatives. The stabilities of the derivatives toward hydrolyses and ultraviolet light exposure have also been found to not be dependent upon the nature of the alkyl substituent group. These observations led to the conclusion that the 5,5-dimethyl derivative would be recommended for use, since it is the least expensive alternative.

The monomer 3-(4′-vinylbenzyl)-5,5-dimethylhydantoin (VBDMH) was synthesized and used to coat cotton fibers by admicellar polymerization using a cationic surfactant. The coated thin-film on cotton was characterized by FTIR and SEM. After chlorination with dilute sodium hypochlorite, the polymeric-coated cotton fabrics effectively inactivated both Staphylococcus aureus and Escherichia coli O157:H7 in relatively brief contact times. The stability and rechargeability of the coated cotton fabrics were very good as evidenced by standard washing tests.

N-halamine silane syntheses and coatings of cotton fabrics as siloxanes were addressed for a series of silanes. The coated fabrics were chlorinated by exposure to dilute sodium hypochlorite with a range of chlorine loadings from 0.20% to 0.26%. Two types of N–Cl moieties were involved in the N-halamine siloxanes, amine and amide. The siloxane-coated cotton swatches were very effective in inactivating Escherichia coli O157:H7 and Staphylococcus aureus, each in 10 min contact time. The N–Cl bond and compound stabilities under UV irradiation and ambient light exposure were also investigated. Both UV and laboratory light stability tests show that most of the chlorine on cotton coated with 3-(3-triethoxysilylpropyl)-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione could be regenerated after irradiation, while most of the lost chlorine from 5,5-dimethyl-3-(3′-triethoxysilylpropyl)hydantoin and 4-[3-triethoxysilylpropoxyl]-2,2,6,6-tetramethylpiperidine could not be recovered upon rechlorination.

This article presents the results of an investigation into the enhancement of sensitivity and thermal stability of polyclonal antibody immobilized magnetoelastic biosensors. The Langmuir–Blodgett (LB) monolayer technique was employed for antibody (specific to Salmonella sp.) immobilization on rectangular shaped strip magnetoelastic sensors. Biosensor performance was investigated by exposing to graded concentrations (5 × 101–5 × 108 cfu mL−1) of Salmonella typhimurium solutions in a flow through mode. Bacterial binding to the antibody on the sensor surfaces changed the resonance parameters, and these changes were quantified by the sensor’s resonance frequency shift. An increase in the sensitivity from 159 Hz decade−1 for a 2 mm sensor to 246 Hz decade−1 for a 1 mm sensor was observed during the dose–response measurements. The stability of the biosensor was also investigated by storing the biosensor at 25, 45 and 65 °C. The binding activity of the stored biosensor was estimated by measuring the changes in resonance frequency after exposure to the bacterial solutions (109 cfu mL−1). Binding activity was also confirmed by counting bound S. typhimurium cells on the sensor surface using Scanning Electron Microscopy (SEM) micrographs. The results show that at each temperature, the binding activity of the biosensor gradually decreased over the testing period. Degradation of biosensor accelerated at higher storage temperatures. The activation energy of biosensor system degradation was determined to be 7.7 kcal mol−1.

A series of new N-halamine epoxide precursors, 3-glycidyl-5,5-dialkylhydantoins (GH's), has been synthesized by a very facile and economic method. Cellulose surfaces can be treated with GH's and re...

An N-halamine precursor, m-aminophenyl hydantoin ( m-APH), which was rendered antimicrobial through exposure to chlorine bleach, was synthesized and was applied on cotton fabric using polycarboxylic acids as crosslinking agents. Particularly, 1,2,3,4-butanetetracarboxylic acid (BTCA) with m-APH treated cotton fabric resulted in the highest increased wrinkle recovery angle and chlorine content simultaneously. Durability and rechargeability were measured through an AATCC test method and antimicrobial efficacy of BTCA/ m-APH treated cotton fabric against Gram-positive and Gram-negative bacteria showed a 6 log reduction within 1 min of contact time.

The monomer and polymer of the compound 3-(3-triethoxysilylpropyl)-7,7,9,9-tetramethyl-1,3,8-triaza spiro[4.5]decane-2,4-dione have been prepared and bonded to the surfaces of silica gel particles and cellulose, and the monomer has been copolymerized with a polyurethane formulation. Treatment of these polymers with dilute sodium hypochlorite solutions renders them antimicrobial. The oxidative chlorine immobilized on the materials is stable for extended periods and can be regenerated upon eventual loss by further exposure to dilute chlorine bleaching solutions. Data are presented showing that the treated materials are biocidal against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli O157:H7. The new siloxane is superior to previous N-halamine siloxane technology in that the N-halamine moiety contains two nitrogen binding sites for chlorine, one of which is a very stable hindered amine site.

In this article, a magnetoelastic sensor immobilized with polyclonal antibody for the detection of Salmonella typhimurium in food products is described. The remote query nature of magnetoelastic sensors enables the detection of bacterial species in sealed and opaque containers. Bacterial binding to the antibody on the sensor surfaces changed the resonance parameters, and these changes were quantified by the shift in the sensor’s resonance frequency. Response of the sensors to increasing concentrations (5 × 101–5 × 108 cfu/ml) of S. typhimurium in three different food products (water, fat-free milk and apple juice) was studied and similar responses were observed. These results were also further ascertained by Scanning Electron Microscopy (SEM) studies. A detection limit of 5 × 103 cfu/ml, with a sensitivity of 139 Hz/decade was obtained for the sensors tested in water samples, as compared to 129 Hz/decade in apple juice and 127 Hz/decade in fat free milk. A 2 × 0.4 × 0.015 mm sensor was employed in all the investigations. The dissociation constant K d and the binding valencies for S. typhimurium spiked in water samples was 435 cfu/ml and 2.33 respectively; as compared to 309 cfu/ml and 2.38 for apple juice; and 1389 cfu/ml and 1.85 for fat free milk samples. Bacterial binding was specific and a divalent binding was observed.

The sterically hindered amine monomer 4-[3-triethoxysilylpropoxyl]-2,2,6,6-tetramethylpiperidine has been synthesized and covalently bonded to the surfaces of silica gel particles and cellulose (cotton) and copolymerized in a polyurethane coating formulation. Upon exposure to dilute sodium hypochlorite (household bleach), a very stable N-Cl bond is formed in situ at the hindered amine nitrogen site. This source of oxidative chlorine provides an antimicrobial function to the silica gel, cotton, and polyurethane. Stability, regenerability, and biocidal efficacy data are presented. The new N-halamine materials were remarkably effective against Staphylococcus aureus and Escherichia coli O157 : H7 in brief periods of contact. The materials should find application in water treatment and medical applications. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

A water dispersible terpolymer of [2-(methacryloyloxy)ethyl]trimethylammonium chloride, glycidyl methacrylate and hydantoinyl acrylamide was synthesized and coated on poly(ethylene terephthalate) fabrics through a pad-dry-cure procedure. The coatings were rendered biocidal upon exposure to dilute household bleach solution. The halogenated fabrics exhibited great antimicrobial functionality with about six logs inactivation of S. aureus and E. coli O157:H7 within only two min of contact time. Moreover, the coatings were found to be very stable against repeated washings and UVA light exposure. It was shown that [2-(methacryloyloxy)ethyl]trimethylammonium monomer is very useful in preparing waterborne N-halamines which can impart rechargeable, effective, and stable antimicrobial coatings to poly(ethylene terephthalate) fabrics. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43088.

An N-halamine precursor monomer, 2,2,6,6-tetramethylpiperidinyl acrylate (TMPA), was synthesized and successfully grafted onto cotton fibers via an impregnation process (IP) and electron-beam irradiation (EB). The grafted cotton fibers could provide antibacterial efficacy after chlorination through a dilute sodium hypochlorite solution. The antibacterial efficacy was challenged against Staphylococcus aureus and Escherichia coli. The cotton fibers grafted with TMPA and acrylic acid by EB inactivated all of the bacteria within 30 min of contact, whereas the samples grafted with TMPA via an IP could not completely kill the bacteria with 60 min. The breaking strength and UVA light stability also improved significantly. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42023.

Fibers have been produced from a blend of poly(acrylonitrile) and poly(styrene hydantoin). The fibers were extruded from a single solvent, dimethyl acetamide. The fiber properties from the blended polymers were somewhat poorer than those from the unmodified acrylic fiber, but were still acceptable. The fibers from the polymer blend could be chlorinated to produce halamines and thus rendered antimicrobial. Antimicrobial test results showed efficacy against S. aureus. The ability to regenerate the halamines (and the antimicrobial functionality) lasted through 50 home laundry washings. The chlorine absorption was shown to be proportional to the specific surface area (m2/g) of the fibers, as might be expected for hydrophobic materials which can react with aqueous reagents only on the fiber surface. Although the fibers produced here were rather larger than those typically used in clothing, the data suggest that a typical diameter fiber of the composition produced here would have a specific surface area to allow chlorine absorption approaching 0.5 %. This level of retained chlorine would certainly produce a highly satisfactory antimicrobial effect - substantially better than the experimental data shown herein.

A new N-halamine precursor, 5-methyl-5-aminomethylhydantoin (AH), was synthesized. This N-halamine precursor can be coated onto cotton surfaces with the addition of the crosslinking agent butanetetracarboxylic acid (BTCA) and rendered biocidal by exposure to halogen solutions either before or after curing the coating or material. Standard washing tests show that covalently bound AH/BTCA on the cotton swatches can survive repeated washing cycles. After 50 washing cycles, chlorinated cotton swatches had lost 98.7 % of oxidative Cl+, but after rechlorination, almost 43.5 % of Cl+ was regained. Biocidal tests indicated that the cotton swatches coated with chlorinated AH/BTCA were effective against Gram positive Staphylococcus aureus and Gram negative Escherichia coli.

A novel, durable, long lasting, N -halamine siloxane monomer precursor, 5,5′-ethylenebis[5-methyl-3-(3-triethoxysilylpropyl)hydantoin] has been prepared and characterized by 1 H-NMR and FTIR for the purpose of functionalizing the surfaces of various materials. In this work, the precursor N -halamine moiety was attached by siloxane covalent bonding to surfaces of cotton fibers. Simulated laundering tests indicated that the chlorinated N -halamine structure could survive many repeated home launderings. The materials were rendered biocidal after exposure to oxidative halogen solutions, i.e. dilute household bleach. Once chlorinated, these materials were biocidal against Staphylococcus aureus and Escherichia coli . Upon loss of the halogen from either long-term use or consumption by the microbes on the surfaces, they could be simply recharged by further exposure to dilute bleach to regain biocidal activity.

The bactericidal effect of electrolyzed oxidizing (EO) water was evaluated on Escherichia coli O157:H7-inoculated and Salmonella-inoculated shrimp. The shrimp were inoculated on day 0 and stored frozen at -20°C. Bacterial enumeration was done on days 0, 24, 49, and 119 of frozen storage. Acidic EO water at 40 ppm free available chlorine was as effective as aqueous chlorine of the same concentration and was significantly more effective (P < 0.05) than tap water in reducing pathogen load on the inoculated shrimp. Further reduction of pathogen numbers was observed after each frozen storage period. Prewashing with alkaline EO water did not enhance the bactericidal activity of the acidic EO water on the shrimp. The washed acidic EO water of the inoculated shrimp had a nondetectable bacterial population compared with treated aqueous chlorine, alkaline EO water, and tap water. Non-inoculated shrimp subjected to similar treatments were served cooked or uncooked to a minimum of 10 experienced panelists for sensory evaluation on days 0, 24, 49, and 119 of frozen storage. The cooked shrimp were evaluated for the presence of off-odor, juiciness, tenderness, shrimpy flavor, aftertaste, and overall acceptability; whereas the raw shrimp were evaluated for color, firmness, presence of off-odors, melanosis, and overall acceptability. Raw shrimp thawed from each frozen storage period were stored at refrigeration temperature (4 °C) for 3 d to observe for melanosis. No difference of sensory attributes was detected among the various treatment groups. Therefore, acidic EO water can be used as an effective disinfectant to replace aqueous chlorine for thawing shrimp blocks.

The bacterial reduction of Salmonella and Escherichia coli O157:H7-inoculated apples and lettuce by ClO2 at 0, 5, 10, 20, and 40 ppm with and without 170-kHz ultrasonic treatments for 3, 6, and 10 min, respectively, have been studied. The treatments of ClO2 at 20 and 40 ppm for 3, 6, and 10 min or at 5 and 10 ppm for 6 and 10 min with 170-kHz ultrasonication caused 3.115 to 4.253 log reductions in Salmonella and 2.235 to 3.865 log reduction in E. coli O157:H7 on inoculated apples. Using combined ClO2 and ultrasonication to treat 4.48 × 104 CFU/g Salmonella and 1.07 × 105 CFU/g E. coli O157:H7-inoculated lettuce, the bacterial reductions were 2.257 to 2.972 and 1.357 to 2.264 log, respectively. The residual ClO2 decreased with increasing treatment times, over 80% of ClO2 was detected after the 3-min treatment, and more than 70% remained after the 10-min treatment time. No bacteria were recovered from the posttreatment solutions of ClO2 or ClO2 combined with ultrasonication. The temperature of the ClO2 treatment was 20.1 °C, and it increased to 40.1, 44.9, and 50.3 °C, with 170-kHz ultrasonic treatments for 3, 6, and 10 min, respectively, on apples.

The monomer 5,5-dimethyl-3-(3′-triethoxysilylpropyl)hydantoin and its hydrolysis product polymer poly[3-(5,5-dimethylhydantoinylpropyl)hydroxysiloxane] were employed to functionalize the surfaces of silica gel particles in order to produce an adhered film that becomes biocidal upon chlorination with dilute sodium hypochlorite bleach. The biocidal efficacy of the functionalized silica gel was demonstrated in a cartridge filter experiment against the bacterial pathogens Staphylococcus aureus and Escherichia coli O157:H7. Complete 6 log inactivations of the two bacterial species were observed within 30 s of contact. Moreover, upon loss of biocidal activity due to depletion of bound chlorine, the coated silica gel particles could be recharged by further exposure to dilute bleach. Potential uses of the biocidal silica gel include disinfection and odor control in water treatment facilities and recirculating baths. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3448–3454, 2006

An immunoassay system was developed for efficient detection of prohibited meat and bone meal (MBM) in animal feed. Monoclonal antibodies (MAbs) were raised against bovine smooth muscle autoclaved at 130 degrees C for 20 min. Among the 1,500 supernatants of hybridoma cells screened, MAbs 3E1, 1G3, and 3E10 were selected and characterized in this study. The first set of MAbs produced, 3E1 and 1G3, had stronger reactivity against MBM than against smooth muscle that was heat treated at 90 degrees C for 10 min. However, reactivity gradually increased against smooth muscle that was autoclaved at 130 degrees C for up to 1 h. The enzyme-linked immunosorbent assay for detection of MBM in animal feed was optimized with the MAb 3E10 because of its superior performance. MAb 3E10 diluted to 100-fold was used to differentiate bovine MBM from that of other species in ingredients used for commercial animal feeds and could detect down to 0.05% MBM mixed in animal feed.

The monomer 3-triethoxysilylpropyl-5,5-dimethylhydantoin has been polymerized on the surfaces of sand particles to produce an adhered film that, upon chlorination with dilute sodium hypochlorite bleach, becomes biocidal. The biocidal efficacy of this coated sand has been demonstrated in a cartridge filter experiment against the bacterial pathogens Staphylococcus aureus and Escherichia coli. Complete inactivation was observed within 1 min of contact for the former bacterium and in the interval of 1–5 min for the latter. Upon a loss of biocidal activity due to the depletion of bound chlorine, the coated sand particles can be recharged by further exposure to dilute bleach. Synthetic methods and test data are presented. Potential uses of biocidal sand include disinfection and odor control in water treatment facilities and recirculating baths. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1161–1166, 2005

For the detection of prohibited meat and bone meal (MBM) in animal feed, monoclonal antibodies (MAbs) were raised against heat-stable h-caldesmon purified from bovine intestinal smooth muscle. The obtained hybridoma cells were screened against extracts of the bovine MBM and heat-treated smooth muscle, and MAb 5E12 was identified as having the best performance. Antibody 5E12 did not react with animal feed, milk product, plant proteins, and other ingredients used for commercial animal feed except for the gelatin. This antibody diluted to 100-fold was able to detect MBM mixed in animal feed at 0.05% in an ELISA, and it showed strong affinity toward bovine smooth muscle autoclaved at 130 °C. Therefore, this antibody can be used in the ELISA system for field testing of the presence of MBM in animal feed. Keywords: Meat and bone meal; animal feed; monoclonal antibody; ELISA; immunoassay