Antibacterial Functionality Research Articles

Enzymatic grafting of lactoferrin onto silk fibroins for antibacterial functionalization

Enzymatic oxidation of tyrosine side-chains in proteins could produce reactive o-quinones that might subsequently react with the primary amino groups of functional compounds, which provided a worthwhile reference for functionalization of fibrion materials. In the present work the potential for using tyrosinase to graft the bovine lactoferrin onto Bombyx mori silk fibroin was examined. Lactoferrin could adsorb onto silk fibers and covalently bind to the previous enzymatically oxidized fibroin surface. The enzyme-generated quinones in silk fibers also might cause self-crosslinking of fibroin peptides, which led to beneficial changes of silk properties. For the fabric treated with tyrosinase and lactoferrin slight improvements of dyeability and strength were obtained in comparison to the control. The combinedly treated fabric showed encouraging resistance to S. aureus and E. coli, the antibacterial activities reached to 87.0 % and 76.4 %, respectively. The durability of the antibacterial silk was noticeably higher than that of the sample treated with lactoferrin alone.

Cellulosic/wool pigment prints with remarkable antibacterial functionalities

Several bio-active agents namely choline chloride, triclosan derivative, PEG-600 and 4-hydroxybenzophenone were successfully included into solvent-free pigment formulations, in a single-stage process, followed by screen printing and microwave-fixation to obtain antibacterial functionalized cellulosic/wool pigment prints. Results obtained signify that both the improvement in functionalization and coloration properties are governed by type of antibacterial agent, kind of substrate as well as pigment colorant. The imparted antibacterial activity of the loaded bio-active agents follows the decreasing order: G+ve (Staphylococcus aureus)>G−ve (Escherichia coli), keeping other parameters constant. The imparted functional and coloration properties showed no significant decrease even after 15 washings. Mode of interactions among the nominated substrates, the pigment paste constituents and the bioactive agents were also proposed.

Antibacterial activity and cytotoxicity of multi-walled carbon nanotubes decorated with silver nanoparticles

Recently, various nanoscale materials, including silver (Ag) nanoparticles, have been actively studied for their capacity to effectively prevent bacterial growth. A critical challenge is to enhance the antibacterial properties of nanomaterials while maintaining their biocompatibility. The conjugation of multiple nanomaterials with different dimensions, such as spherical nanoparticles and high-aspect-ratio nanotubes, may increase the target-specific antibacterial capacity of the consequent nanostructure while retaining an optimal biocompatibility. In this study, multi-walled carbon nanotubes (MWCNTs) were treated with a mixture of acids and decorated with Ag nanoparticles via a chemical reduction of Ag cations by ethanol solution. The synthesized Ag-MWCNT complexes were characterized by transmission electron microscopy, X-ray diffractometry, and energy-dispersive X-ray spectroscopy. The antibacterial function of Ag-MWCNTs was evaluated against Methylobacterium spp. and Sphingomonas spp. In addition, the biocompatibility of Ag-MWCNTs was evaluated using both mouse liver hepatocytes (AML 12) and human peripheral blood mononuclear cells. Finally, we determined the minimum amount of Ag-MWCNTs required for a biocompatible yet effective antibacterial treatment modality. We report that 30 μg/mL of Ag-MWCNTs confers antibacterial functionality while maintaining minimal cytotoxicity toward both human and animal cells. The results reported herein would be beneficial for researchers interested in the efficient preparation of hybrid nanostructures and in determining the minimum amount of Ag-MWCNTs necessary to effectively hinder the growth of bacteria.

Preparation, characterization and antibacterial functionalization of cotton fabric using dimethyl diallyl ammonium chloride-allyl glycidyl ether-methacrylic/nano-ZnO composite

Abstract The polymer dimethyl diallyl ammonium chloride-allyl glycidyl ether-methacrylic shortened as P(DMDAAC-AGE-MAA) was prepared via free radical polymerization. P(DMDAAC-AGE-MAA)/nano-ZnO composites were obtained after mixing the polymer under different pH with nano-ZnO. P(DMDAAC-AGE-MAA)/nano-ZnO composites were characterized by Fourier transformation infrared (FT-IR), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results showed that nano-ZnO existed among the composites, and the polymer chain did not encapsulate nano-ZnO. The crystal structure of polymer changed because of the complexation of the polymer with nano-ZnO. The morphologies of P(DMDAAC-AGE-MAA)/nano-ZnO composites were core–shell and long strip structure when the pH of polymer was 2.6 and 3.0. After composite materials were loaded onto cotton fabrics, the surface morphology of the fabrics was characterized by scanning electron microscope (SEM). The antibacterial properties of P(DMDAAC-AGE-MAA) polymer and P(DMDAAC-AGE-MAA)/nano-ZnO composites treated cottons and treated cottons after being washed 5 times (equivalent of household washing 25 times) were tested against the bacterium Staphylococcus aureus (S. aureus, ATCC25923) and the fungus Candida albicans (C. albicans, ATCC10231). P(DMDAAC-AGE-MAA)/nano-ZnO treated cottons had higher antibacterial activities than P(DMDAAC-AGE-MAA) treated cottons.

부추 당침액의 유산균 발효에 따른 항산화 및 ACE저해활성

본 연구는 최근 국민들이 많은 관심을 갖는 식물발효 효소액 중 부추 당침액(부추:설탕 1:3)을 유산균(Lactobacillus acidophilus AML 0422, Lactobacillus brevis HLJ 59, Lactobacillus helveticus AML0410, Lactobacillus plantarum KCTC 13093) 발효를 통해 발효 부추액의 항균활성 및 항산화활성과 항고혈압활성 등의 기능성을 발효 전 후의 유효특성을 조사하였다. 유산균을 이용하여 발효한 발효 부추액은 S. aureus KCTC 1916에 대해 31.43 mm의 높은 항균력을 보이는 것으로 조사되었으며, 총 폴리페놀함량, 총 플라보노이드 함량과 DPPH 활성 소거능이 160.8-178 mg/ml, 100-108 mg/ml, 82.8-93.5%로 각각 조사되었다. DPPH 활성 소거능에 있어서는 Vitamin C 50 ppm과 유사한 활성을 보이는 것으로 나타났다. 심혈관질환 및 뇌혈관질환 등 고혈압과 관련이 깊은 ACE 저해활성은 유산균의 종류에 따라 50.4-67%로 발효전인 32.6%보다 좋은 활성을 보이는 것으로 조사되었다. 이상의 결과를 종합하였을 때 유용 유산균을 이용한 부추 당침액의 발효산물은 항균활성, 항산화활성과 ACE 저해활성 등 우수한 생리활성 효과를 나타내는 것으로 조사되었다. In recent years, the growing interest in the health care benefits of sugared-plant fermented enzymes has led to increased consumption. This study investigated the fermentation of sugared-buchu (Leek:sugar, 1:3) by lactic acid bacteria (Lactobacillus acidophilus AML 0422, Lactobacillus brevis HLJ 59, Lactobacillus helveticus AML0410, Lactobacillus plantarium KCTC 13093) and the antibacterial activity, antioxidant activity, and functionality (e.g., anti-hypertensive activity) of the fermented product. The fermented sugared-buchu showed high antibacterial activity against Staphylococcus aureus KCTC 1916, at 31.43 mm, and its total polyphenols, total flavonoid content, and DPPH scavenging activity were 160.8-178 mg/ml, 100-108 mg/ml, and 51.4-58.1%, respectively. DPPH scavenging activity was to that of vitamin C (50 ppm). ACE inhibitory activity was 50.4-67%, depending on the strain of lactic acid bacteria, and the control of sugared-buchu activity was higher than 32.6%. These results suggest that sugared-buchu fermented with lactic acid bacteria has strong antibacterial, antioxidant, and ACE inhibitory activities.

Synthesis of New Biobased Antibacterial Methacrylates Derived from Tannic Acid and Their Application in UV-Cured Coatings

A series of biobased UV-curable antibacterial resins were synthesized through modifying tannic acid (TA) with varied amount of glycidyl methacrylate (GMA). The obtained TA-based methacrylates exhibited good film-forming property and can be cross-linked under UV irradiation. Thus, antibacterial functionalities can be tethered in the coating matrix, eliminating the loss of antibacterial ingredients. The antibacterial properties of resins and corresponding coatings against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli were tested. The resins with high content of phenolic hydroxyl groups retained strong antibacterial ability while the ones with a relatively low content of phenolic hydroxyl groups did not, which indicated that the antimicrobial effects of TA greatly depended on the content of phenolic hydroxyl groups. The applications of UV-curable antibacterial resins in coatings were also studied. The cured coatings of TA-G5 resins with the highest content of phenolic hydroxyl groups exhibited the highest antibacterial activity with 5 log reduction. The basic properties of UV-cured coatings were also fully characterized, and the results demonstrated that the novel UV-curable resins had potential applications in UV-curable antibacterial coatings.

One-pot synthesis of antibacterial monomers with dual biocidal modes

ObjectivesThe present study reported a method for preparing a blend of antibacterial quaternary ammonium silanes and quaternary ammonium methacryloxy silane (QAMS) based on the sol–gel reaction between dimethyldiethoxy silane and two trialkoxysilanes, one with an antibacterial quaternary ammonium functionality and the other with a methacryloxy functionality. MethodsReaction products of the sol–gel reaction were characterised by direct infusion mass spectrometry, FTIR and proton, carbon and silicon NMR. This blend of monomers was incorporated into an experimental universal adhesive for evaluation of antimicrobial activity against Streptococcus mutans biofilms, microtensile bond strength and cytotoxicty. Retention of quaternary ammonium species on polymerised adhesive, leaching of these species from the adhesive and the ability of resin–dentine interfaces to inhibit S. mutans biofilms were evaluated over a 3-month water-ageing period. ResultsThe antibacterial adhesive version killed bacteria in S. mutans biofilms not only through the release of non-copolymerisable quaternary ammonium silane species (release-killing), but also via immobilised quaternary ammonium methacryloxy silane that are copolymerised with adhesive resin comonomers (contact-killing). Contact-killing was retained after water-ageing. The QAMS-containing universal adhesive has similar tensile bond strength as the control and two commercially available universal adhesives, when it was used for bonding to dentine in the etch-and-rinse mode and self-etching mode. Incorporation of the antimicrobial quaternary ammonium species blend did not adversely affect the cytotoxicity of the universal adhesive formulation. ConclusionsInstead of using quaternary ammonium dimethacrylates and nanosilver, an alternative bimodal antimicrobial strategy for formulating antimicrobial universal dentine adhesives is achieved using the one-pot sol–gel synthesis scheme. Clinical SignificanceThe QAMS containing universal dentine adhesives with dual antimicrobial activity is a promising material aimed at preventing second caries and prolonging the longevity of resin composite restorations.

Silver nanocluster-silica composite antibacterial coatings for materials to be used in mobile telephones

Antibacterial coatings containing different amount of metallic silver nanoclusters embedded in a silica matrix have been deposited by co-sputtering technique on several different polymers used in mobile telephones components such as: screens, covers, and microphone felts. Sputtering parameters have been varied to obtain different coating thickness and silver content, in order to meet antibacterial, aesthetic and functional requirements for each component. In particular, an antibacterial functionality has been obtained for screens, covers and felts without affecting their respective transparency, aesthetic and acoustic properties. The optimal parameters for each part have been used to obtain an antibacterial mobile telephone suitable for personnel operating in hospitals or other environments with potentially high bacterial contamination.

Synthesis and Antimicrobial Study of Some Methyl 4-O-palmitoyl-α-L-rhamnopyranoside Derivatives

4-O-Palmitoylation of methyl a-L-rhamnopyranoside ( 2 ) was carried out via blocking-deblocking technique. Methyl a-L-rhamnopyranoside ( 2 ) was first converted into 2,3-O-isopropylidene derivative ( 5 ) which on palmitoylation followed by deacetonation gave the desired 4-O-palmitoylrhamnopyranoside ( 7 ) in good yield. A number of 2,3-di-O-acyl derivatives of 7 were also prepared to get newer rhamnopyranosides ( 8 - 14 ) of biological importance. All the rhamnopyranosides ( 2 , 5 - 14 ) were employed as test chemicals for in vitro antibacterial and antifungal functionality test against ten human pathogenic bacteria and four fungi, respectively. The study revealed that some of the tested rhamnopyranoside derivatives showed excellent antimicrobial functionalities as compared to the standard antibiotic.

Enhanced Antibacterial Properties of Polyester and Polyacrylonitrile Fabrics Using Ag-NP Dispersion/Microwave Treatment

A Ag-nanoparticle (Ag-NP) dispersion was successfully synthesized using a glucose/Ag-nitrate/polyvinyl pyrrolidone (PVP)/sodium hydroxide reduction formulation. The resultant Ag-NP dispersion was successfully used alone and in combination with Disperse Orange 31 or Basic Blue 9 dyes to impart antibacterial properties against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria to polyester and polyacrylonitrile fabrics respectively using microwave treatment. An increase in Ag-NP dispersion concentration by 50% and prolonged microwave irradiation by two minutes significantly improved the antibacterial performance. The EDX spectrum of the Ag-NP loaded substrates confirmed the presence of elemental Ag (Ag0) on the fabrics’ surface. Addition of selected disperse or basic dye to the Ag-NP treatment bath produced disperse or basic dyeings with darker depth of shades and remarkable antibacterial functionality.

N-halamine-bonded cotton fabric with antimicrobial and easy-care properties

N-halamine precursor 2,2,6,6-tetramethyl piperidinol (TMP), a hindered amine light stabilizer, was bonded onto cotton fabric by using 1,2,3,4-butanetetracarboxylic acid (BTCA) as a crosslinking agent. A variety of treating conditions including TMP concentration, curing temperature and time, and catalyst were studied. The treated fabrics were characterized using FTIR spectra and scanning electron microscope (SEM). The cotton fabric treated with TMP precursor could be rendered biocidal upon exposure to dilute household bleach. The chlorinated cotton swatches showed great efficacy and inactivated 100 % of Staphylococcus aureus with 7.1 log reduction with 5 min of contact and 83.25 % of E. coli O157:H7 at 10 min of contact. In addition, the wrinkle recovery angle of the treated cotton fabrics increased from 229 ° of untreated cotton fabrics to 253 °. This study provided a practical finishing process to produce cotton fabrics with easy care and antibacterial functionalities at the same time.

Enabling Antibacterial Coating via Bioinspired Mineralization of Nanostructured ZnO on Fabrics under Mild Conditions

Herein, we present an environmentally benign method capable of mineralization and deposition of nanomaterials to introduce antibacterial functionalities into cotton fabrics under mild conditions. Similar to the way in which many naturally occurring biominerals evolve around the living organism under ambient conditions, this technique enables flexible substrates like the cotton fabric to be coated with inorganic-based functional materials. Specifically, our strategy involves the use of long-chain polyamines known to be responsible in certain biomineralization processes, to nucleate, organize, and deposit nanostructured ZnO on cotton bandage in an aqueous solution under mild conditions of room temperature and neutral pH. The ZnO-coated cotton bandages as characterized by SEM, confocal micro-Raman spectroscopy, XRD, UV-DRS, and fluorescence microscopy demonstrate the importance of polyamine in generating a stable and uniform coating of spindle-shaped ZnO particles on individual threads of the fabric. As the coating process requires only mild conditions, it avoids any adverse effect on the thermal and mechanical properties of the substrate. Furthermore, the ZnO particles on cotton fabric show efficient antibacterial activity against both gram-positive and gram-negetive bacteria. Therefore, the developed polyamine mediated bioinspired coating method provides not only a facile and "green" synthesis for coating on flexible substrate but also the fabrication of antibacterial enabled materials for healthcare applications.

Synthesis of antibacterial cellulose materials using a “clickable” quaternary ammonium compound

Development of advanced functional materials from naturally abundant polymers such as cellulose are of significant importance. Of particular interest is embedding antibacterial functionality to cellulose materials to make permanent antibacterial materials and devices. In the present research, a “clickable” quaternary ammonium compound, N-(2-ethoxy-2-oxoethyl)-N,N-dimethylprop-2yn-1-aminium bromide (EdMPABr) was synthesized via a simple reaction with nearly stoichiometric yield and well characterized with 1D (1H, 13C) and 2D (COSY, HSQC) NMR and ATR-FTIR. EdMPABr can be covalently bonded to many molecules containing an azido group to form non-leaching antibacterial materials via the simple Cu(I)-catalyzed alkyne-azide [2 + 3] cycloaddition reaction. As an example, EdMPABr was attached to our previously reported 3-O-azidopropoxypoly(ethylene glycol)-2,6-di-O-thexyldimethylsilyl cellulose (3-N3PEG-2,6-TDMS cellulose, DS = 0.54 at C3 determined by 1H NMR). Significant antibacterial activity of the synthesized 3-O-quaternary ammonium-2,6-di-O-thexyldimethylsilyl cellulose (3-QA-2,6-TDMS cellulose, DS = 0.30 at C3 determined by using N content from elemental analysis) was confirmed by testing against the representative bacteria Escherichia coli. By linking the EdMPABr to the honeycomb film of 3-N3PEG-2,6-TDMS cellulose, the formed honeycomb film exhibited both antibacterial and antifouling properties. This research provides a simple and robust route towards the development of permanent antibacterial materials and biomedical devices.

Combined antimicrobial finishing and pigment printing of cotton/polyester blends

This study demonstrates the possibility of enhancing the antibacterial functionality and pigment printing properties of cotton/polyester blends (50/50 and 35/65) in one step. Inclusion of chitosan (10g/kg), choline chloride (15g/kg), triclosan derivative (20g/kg), hyperbranched poly amide-amine/silver or zinc oxide nanoparticles (HBPAA/Ag-NP's hybrid or HBPAA/ZnO-NP's hybrid – 20g/kg) into a pigment print formulation followed by printing and microwave curing at 386W for 5min results in an improvement in antibacterial activity and pigment printability. It was further noted that, in all cases, the G+ve (S. aureus) bacteria is more susceptible to the action of the immobilized antibacterial agents than the G−ve bacteria (E. coli). The functionalized pigment prints exhibited very sufficient antibacterial activity even after 20 washing cycles. Modes of interactions were proposed, and surface modification was also confirmed by SEM and EDX analysis.

A smart approach to add antibacterial functionality to cellulosic pigment prints

This study was devoted to enhancing the antibacterial functionality of pigment printed cotton, linen and viscose fabrics. Ag-NP's/PVP colloid, triclosan derivatives, chitosan or choline chloride was successfully incorporated into the pigment paste followed by printing and microwave curing to impart antibacterial activity to the cellulosic prints. Results obtained demonstrate that the modified pigment prints exhibit a remarkable antibacterial activity against the G+ve (Staphylococcus aureus) and G−ve (Escherichia coli) bacteria with a noticeable durability after 20 washing cycles without adversely affecting the printing and softness properties. The extent of printability and functionality of the nominated substrates are significantly governed by the type of: bio-active ingredient, binder, pigment and substrate. TEM, SEM and EDX analysis confirmed the formation of Ag-NP's/PVP colloid, of particle size range 7–14nm, deposition of cross-linked-binder film onto the modified pigment prints, and the existence of elementary Ag and Si loaded onto fabrics surface, respectively.

Utilization of monochloro-triazine β-cyclodextrin for enhancing printability and functionality of wool

Monochloro-triazine β-cyclodextrin (MCT-βCD) was successfully utilized to modify the wool fabric structure. The modified wool exhibited better post-printing, using different dyestuffs, and outstanding antibacterial activities most probably due to the remarkable capacity of grafted βCD moieties to form guest–host inclusion complexes in addition to the positive role of wool's active sites. The following treatment sequence: pre-modification, post-printing, followed by after-treatment with Ag-NP's colloid or triclosan derivatives was investigated. The extent of improvement in the aforementioned properties is governed by the degree of pre-modification, type of dyestuff and extent of fixation, type of antibacterial agent, its mode of interaction and extent of loading onto the modified printed wool. The imparted antibacterial functionalities were retained, more than 75%, even after 15 washing cycles.

Superhydrophobic chitosan-based coatings for textile processing

A simple method to design the superhydrophobic anti-bacterial textile for biomedical applications was developed. For the coating formulation the spraying of nanoparticles dispersion over the textile sample was applied, allowing the way to get multiscale textured layer on a top of cotton fabric. The anti-bacterial functionality of coating is supported by using chitosan-based nanoparticles. In our approach the fabrication of nanoparticles was based on electrostatic interaction between amine group of chitosan and negatively charged fluoroanion. It was demonstrated that the relative number of fluoroanions per elementary unit of chitosan plays the crucial role in the structure of aggregates in the coating and its wettability as well as in durability of coatings in contact with aqueous media.

Antibacterial functionalization of cotton and polyester fabrics with a finishing agent based on silver-doped calcium phosphate powders

Textiles are suitable materials for the growth of pathogenic microorganisms. Therefore, various antibacterial finishes have already been developed for textile products. In this work an antibacterial finishing agent containing calcium phosphate-based silver-doped powder was developed for the functionalization of textiles and applied to 100% cotton and 100% polyester knitted fabric samples. Firstly, silver-doped antibacterial powder was synthesized by using a wet chemical method. A size reduction process was applied for reducing the particle size of the powder from micron size to submicron scale. The aqueous dispersion was stabilized by coating the powder surfaces with polyethylene glycol. In order to obtain laundering durability, an aqueous emulsion of an acrylic copolymer was added to the antibacterial solution. The resultant product was applied to all fabric samples by a conventional pad-dry-cure method. The treated fabrics were washed 20 times and the antibacterial efficiency was evaluated after each 10 laundry cycles according to the JIS-L 1902:2002 method against Gram (-) E. coli bacteria. To see the effect of antibacterial finishing on the physical properties of fabrics, the bursting strength, air permeability and color efficiency of the treated and untreated samples were measured and compared. It was found that the antibacterial solution did not affect significantly the bursting strength and color efficiency values of the fabrics, while air permeability was decreased. On the other hand, treated fabric samples preserved their strong antibacterial activities against E. coli after 20 laundry cycles.

Copper and Silver ion Implantation of Aluminium Oxide-Blasted Titanium Surfaces: Proliferative Response of Osteoblasts and Antibacterial Effects

Implant infection still represents a major clinical problem in orthopedic surgery. We therefore tested the in vitro biocompatibility and antibacterial effects of copper (Cu)- and silver (Ag)-ion implantation. Discs of a commonly used titanium alloy (Ti6AlV4) with an aluminium oxide-blasted surface were treated by Cu- or Ag-ion implantation with different dosage regimen (ranging from 1e15-17 ions cm(-2) at energies of 2-20 keV). The samples were seeded with primary human osteoblasts and cell attachment and proliferation was analyzed by an MTT-assay. In comparison to the reference titanium alloy there was no difference in the number of attached viable cells after two days. After seven days the number of viable cells was increased for Cu with 1e17 ions cm(-2) at 2 and 5 keV, and for Ag with 1e16 ions cm(-2) at 5 keV while it was reduced for the highest amount of Ag deposition (1e17 ions cm(-2) at 20 keV). Antibacterial effects on S.aureus and E.coli were marginal for the studied dosages of Cu but clearly present for Ag with 1e16 ions cm(-2) at 2 and 5 keV and 1e17 ions cm(-2) at 20 keV. These results indicate that Ag-ion implantation may be a promising methodological approach for antibacterial functionalization of titanium implants.

A novel approach for adding smart functionalities to cellulosic fabrics.

A water soluble nanocomposite, based on Ag-nanoparticles (Ag-NPs) loaded on hyperbranched poly (amide-amine, HBPAA) was prepared, characterized and utilized in functional finishing as well as in combined reactive dyeing/and functional finishing of linen, cotton and viscose fabrics. Incorporation of the nanocomposite alone and in combination with reactive dyes in easy care finishing formulations brought about an outstanding antibacterial functionality of the finished and the dyed/finished fabrics even after 15 laundering cycles along with a slight negative impact on other performance properties. Improvement or decrement in the functional, comfort, and dyeing properties is governed by the type of cellulosic substrate.