Antibacterial Filler Research Articles

Modification of egg shell powder with in situ generated copper and cuprous oxide nanoparticles by hydrothermal method**Thailand Patent filed with Registration Number: 1903001590.

The poultry waste of egg shells was cleaned and finely powdered which was subsequently modified with in situ generated copper nanoparticles (CuNPs) and cuprous oxide nanoparticles (Cu2ONPs) by one step hydrothermal method. The modified egg shell powder (MESP) was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, x-ray diffraction, thermogravimetric analysis and antibacterial tests. The MESP had in situ generated spherical CuNPs and Cu2ONPs in the size range of 50 nm to 120 nm. The spectral analysis indicated lowering of intensity of the peaks of MESP indicating the involvement of the functional groups of the protein component of ESP in the generation and stabilization of the nanoparticles. X-ray analysis indicated the generation of both CuNPs and Cu2ONPs in MSEP. The thermal analysis indicated lowering of the thermal stability for MESP. The MESP exhibited excellent antibacterial activity against both the Gram negative and Gram positive bacteria. Hence the low cost MESP with in situ generated CuNPs and Cu2ONPs can be used as antibacterial cleaning powder for houseware and also as antibacterial filler in the preparation of polymer composites.

Silver nanoparticles encapsulated in silica: Synthesis, characterization and application as antibacterial fillers in the ethylene polymerization

Silver nanoparticles (AgNPs) were synthesized via three routes where silver was reduced by either citric acid (R1), glucose (R2) or glycerol (R3), and were stabilized with (3-aminopropyl) triethoxysilane (APTES). All nanoparticles were encapsulated in silica by the sol-gel process (SiAgE). Structural, textural, morphological and antibacterial properties of SiAgE were determined by: SEM, TGA, XRD, UV–VIS, FT-IR, BET, SAXS and disc diffusion. These SiAgE had antimicrobial properties, and they were used in ethylene polymerization using the Cp2ZrCl2/MAO catalytic system. The catalytic activities were high, and the percentages by weight of the fillers ranged from 1.1 to 1.6 wt%. The antibacterial properties of the nanocomposite films were studied by two tests: disc diffusion and the Parallel Streak method. The polyethylene (PE)/SiAgE nanocomposites inhibited the proliferation of Staphylococcus aureus (Gram positive) and Escherichia coli (Gram negative) bacteria in contact with the films, thus showing potential to be used as active packages in medicine.

Modification of agricultural waste tamarind fruit shell powder by in situ generation of silver nanoparticles for antibacterial filler applications

The tamarind fruit shell powder (TFSP) from agricultural waste was modified by in situ generation of silver nanoparticles (AgNPs) using the one-step hydrothermal method and characterized by SEM, EDX, FTIR spectral, XRD, and antibacterial tests. SEM analysis indicated the in situ generation of AgNPs with an average size of 90 nm. FTIR analysis proved no structural changes between unmodified and modified TFSP. XRD analysis indicated in situ generation of AgNPs in the modified TFSP. Further, the TFSP with in situ generated AgNPs inhibited the growth of bacteria and hence can be used as antibacterial low-cost filler in making biocomposites.

Comparisons of the restoring and reinforcement effects of carboxymethyl chitosan-silk fibroin (Bombyx Mori/Antheraea Yamamai/Tussah) on aged historic silk

This work presents the results of the reinforcement effects of regenerated silk fibroin solutions (SF) of Bombyx-Mori, Antheraea-Yamamai and Tussah on aged historic silk. Furthermore, Carboxymethyl-chitosan (CMC) was utilized as reinforcement and antibacterial filler to further improving the mechanical properties and antibacterial effects. To clarify the rationale behind this process, comprehensive characterization was applied, and a speculative explanation was provided. The results showed that Bombyx-mori and Tussah have better restoring effects than Antheraea-yamamai. CMC has good compatibility to the SF, and the addition of CMC has significantly contributed to the improvement the mechanical properties and thermal stability of the restored silk, which is due to the formation of chemical bonding, strong hydrogen bonding and the construction of polymer network structure. The enhancement of crystallinity and reduction of β-turns structure indicate that the micro-defects in the crystallization zone of the aged silk has been restored, and the ordered arrangement in the long-range ordered structure has been improved within a certain range. It was found that the CMC acted as antifungal agents when introduced on the aged historic silk, reducing the growth of Aspergillus niger, Aspergillus flavus and Paecilomyces variotii to a certain extent, which were commonly found in storage areas of libraries.

Design of antibacterial polyethylene terephthalate masterbatch functionalized by modified nano‐Mg(OH)2

ABSTRACTIn this work, antibacterial polyethylene terephthalate (PET) masterbatch (APM) was prepared by melting‐and‐mixing technology, with nano‐Mg(OH)2 as antibacterial fillers and pure‐PET slices as basic materials. In addition, titanate coupling agents and stearic acid were used as additives to improve the compatibility of nano‐Mg(OH)2 and PET. The scanning electron microscope (SEM) characterization indicated that the modified nano‐Mg(OH)2 particles (10, 20, and 30%) wrapped by PET with a diameter ranging of 0.1–0.5 μm were well dispersed in APM. Moreover, the attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR) results indicated the existence of titanate coupling agents and stearic acid in APM. Furthermore, the antibacterial test showed that nano‐Mg(OH)2 and APM had excellent antibacterial property against Escherichia coli (E. coli) and resulted in the protein leakage of E. coli. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46755.

Properties of Experimental Dental Composites Containing Antibacterial Silver-Releasing Filler.

Secondary caries is one of the important issues related to using dental composite restorations. Effective prevention of cariogenic bacteria survival may reduce this problem. The aim of this study was to evaluate the antibacterial activity and physical properties of composite materials with silver sodium hydrogen zirconium phosphate (SSHZP). The antibacterial filler was introduced at concentrations of 1%, 4%, 7%, 10%, 13%, and 16% (w/w) into model composite material consisting of methacrylate monomers and silanized glass and silica fillers. The in vitro reduction in the number of viable cariogenic bacteria Streptococcus mutans ATCC 33535 colonies, Vickers microhardness, compressive strength, diametral tensile strength, flexural strength, flexural modulus, sorption, solubility, degree of conversion, and color stability were investigated. An increase in antimicrobial filler concentration resulted in a statistically significant reduction in bacteria. There were no statistically significant differences caused by the introduction of the filler in compressive strength, diametral tensile strength, flexural modulus, and solubility. Statistically significant changes in degree of conversion, flexural strength, hardness (decrease), solubility (increase), and in color were registered. A favorable combination of antibacterial properties and other properties was achieved at SSHZP concentrations from 4% to 13%. These composites exhibited properties similar to the control material and enhanced in vitro antimicrobial efficiency.

Synthesis and characterization of silver phosphate/calcium phosphate mixed particles capable of silver nanoparticle formation by photoreduction

Silver phosphate is a semi-conductor sensitive to UV-Vis radiation (<530nm). Exposure to radiation removes electrons from the oxygen valence shell, which are scavenged by silver cations (Ag+), forming metallic silver (Ag0) nanoparticles. The possibility of silver nanoparticle formation in situ by a photoreduction process was the basis for the application of mixed calcium phosphate/silver phosphate particles as remineralizing and antibacterial fillers in resin-based dental materials. Mixed phosphate particles were synthesized, characterized and added to a dimethacrylate resin in 20% or 30% mass fractions to investigate their efficacy as ion-releasing fillers for dental remineralization and antibacterial activity. The formation of metallic silver nanoparticles after exposure to visible radiation from a dental curing unit (peak emission: 470nm) was demonstrated by particle X-ray diffraction and scanning electron microscopy analysis of the composite fractured surface. Calcium and phosphate release from materials containing the mixed particles were similar to those containing pure CaP particles, whereas Streptococcus mutans colonies were reduced by three orders of magnitude in relation to the control, which can be attributed to silver release. As expected, the optical properties of the materials containing mixed phosphate particles were compromised by the presence of silver. Nevertheless, materials containing mixed phosphate particles presented higher fracture strength and elastic modulus than those with pure CaP particles.

Antibacterial performance of ZnO-based fillers with mesoscale structured morphology in model medical PVC composites

Three different ZnO-based antibacterial fillers having different morphologies in microscale region were prepared by the use of the microwave assisted synthesis protocol created in our laboratory with additional annealing in one case. Further, PVC composites containing 0.5–5wt.% of ZnO based antibacterial fillers were prepared by melt mixing and characterized by scanning electron microscopy (SEM) and X-ray diffractometry (XRD). Mechanical testing showed no adverse effect on the working of polymer composites due to either of the fillers used or the applied processing conditions in comparison with the neat medical grade PVC. The surface antibacterial activity of the compounded PVC composites was assessed against Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 6538P according to ISO 22196: 2007 (E). All materials at almost all filler loading levels were efficient against both species of bacteria. The material with the most expanding morphology assuring the largest contact between filler and matrix achieved an excellent level of more than 99.9999% reduction of viable cells of E. coli in comparison to untreated PVC and performed very well against S. aureus, too. A correlation between the morphology and efficacy of the filler was observed and, as a result, a general rule was formulated which links the proneness of the microparticles to perform well against bacteria to their shape and morphology.

Sterile filler finds wider use in medical compounding

Using the reclaimed co-product of acetylene gas production - carbide lime - ReBASE Corporation has developed a sterile resin filler. White Knight is said to be capable of controlling the environment required for bacterial growth. Unlike common calcium hydroxide, which will not work in plastics as an anti-bacterial filler, White Knight filler is processed with a special method of encapsulating the hydroxide within a calcium carbonate coating (or shell). The material can then be blended in polymers in much the same way as calcium carbonate but has distinct advantages including reduced weight, bacteria control, smoother extrusion and flame retardancy. ReBASE Corporation has undertaken recent tests with this material and reports the findings to Plastics Additives & Compounding.

In vitro inhibition of caries around a resin composite restoration containing antibacterial filler

Class V cavities were prepared and restored with resin composite containing antibacterial filler powder (Apacider-AW, Ap-AW) using experimental restorations. The restored teeth were incubated in vitro with the cariogenic bacteria Streptococcus mutans IFO 13955. Ground sections were then prepared and examined using macrophotography. Lesions of the outer and inner wall were noted, and the depths to which the lesions penetrated were measured. We found that, in restorations containing 1–5 wt% Ap-AW, caries penetrated the marginal area, while in restorations containing 10 wt% Ap-AW the margin remained free of caries out to a distance of about 1.1 and 1.8 mm on the occlusal and gingival sides, respectively.

Bacteriological and Mechanical Evaluation of Resin Composites Containing Antibacterial Filler (Apacider)

Bacteriological and Mechanical Evaluation of Resin Composites Containing Antibacterial Filler (Apacider)