Structure,surface analysis and bioactivity of Mn doped zinc oxide nanoparticles

Undoped zinc oxide nanoparticles and Mn (5 atomic % & 10 atomic %) doped zinc oxide nanoparticles were prepared by soft chemical method. Antibacterial, antioxidant and anticancer activities in breast cancer cell line MDAMB231 of prepared nanoparticles were investigated. The nanoparticles were characterized using XRD, SEM, EDAX, UV–Vis, FT-IR, and room temperature PL Analysis. Antimicrobial activity was tested against both gram positive and gram negative human pathogens. The antioxidant potential of prepared nanoparticles was estimated using Phosphomolybdate and DPPH assay. The MTT assay was used for cytotoxicity evaluation of prepared nanoparticles against breast cancer cell line MDAMB231. XRD patterns confirmed the nanoparticles were crystallized hexagonal wurtzite structure with an average size of 38.95 ?nm. The absorption wavelength was observed at 361 ?nm in UV–Vis spectrum of Mn (10 atomic %) doped ZnO nanoparticles. The Mn (5 atomic %) doped ZnO nanoparticles exhibited significant antibacterial activity against the gram negative bacteria Escherichia coli, Klebsiella pneumonia at all concentrations. Undoped zinc oxide nanoparticles and Mn doped zinc oxide nanoparticles were effective against the breast cancer cell line MDAMB231.     

Synthesis, characterization and antimicrobial investigation of mechanochemically processed silver doped ZnO nanoparticles

The application of nanomaterials has gained considerable momentum in various fields in recent years due to their high reactivity, excellent surface properties and quantum effects in the nanometer range. The properties of zinc oxide (ZnO) vary with its crystallite size or particle size and often nanocrystalline ZnO is seen to exhibit superior physical and chemical properties due to their higher surface area and modified electronic structure. ZnO nanoparticles are reported to exhibit strong bacterial inhibiting activity and silver (Ag) has been extensively used for its antimicrobial properties since ages. In this study, Ag doped ZnO nanoparticles were synthesized by mechanochemical processing in a high energy ball mill and investigated for antimicrobial activity. The nanocrystalline nature of zinc oxide was established by X-ray diffraction (XRD) studies. It is seen from the XRD data obtained from the samples, that crystallite size of the zinc oxide nanoparticles is seen to decrease with increasing Ag addition. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) data also supported the nanoparticle formation during the synthesis. The doped nanoparticles were subjected to antimicrobial investigation and found that both increase in Ag content and decrease in particle size contributed significantly towards antimicrobial efficiency. It was also observed that Ag doped ZnO nanoparticles possess enhanced antimicrobial potential than that of virgin ZnO against the studied microorganisms of Escherichia coli and Staphylococcus aureus.     

Electrodeposition of silver nanoparticles on a zinc oxide film: improvement of amperometric sensing sensitivity and stability for hydrogen peroxide determination

A strategy to fabricate a hydrogen peroxide (HP) sensor is developed by electrodepositing silver nanoparticles (Ag NPs) on a modified glassy carbon electrode (GCE) with a zinc oxide (ZnO) film. The Ag NPs/ZnO/GCE has been characterized by scanning electron microscopy, cyclic voltammetry, and chronoamperometry. It has been found that the Ag NPs synthesized in the presence of ZnO film provide an electrode with enhanced sensitivity and excellent stability. The sensitivity to HP is enhanced 3-fold by using Ag NPs/ZnO/GCE compared to Ag NPs/GCE. The HP sensor exhibits good linear behavior in the concentration range 2 µM to 5.5 mM for the quantitative analysis of HP with a detection limit of 0.42 µM (S/N?=?3).     

Experimental and Theoretical Study of Enhanced Photocatalytic Activity of Mg‐Doped ZnO NPs and ZnO/rGO Nanocomposites

A systematic experimental and theoretical study of the origin of the enhanced photocatalytic performance of Mg‐doped ZnO nanoparticles (NPs) and Mg‐doped ZnO/reduced graphene oxide (rGO) nanocomposites has been performed. In addition to Mg, Cd was chosen as a doping material for the bandgap engineering of ZnO NPs, and its effects were compared with that of Mg in the photocatalytic performance of ZnO nanostructures. The experimental results revealed that Mg, as a doping material, recognizably ameliorates the photocatalytic performance of ZnO NPs and ZnO/graphene nanocomposites. Transmission electron microscopy (TEM) images showed that the Mg‐doped and Cd‐doped ZnO NPs had the same size. The optical properties of the samples indicated that Cd narrowed the bandgap, whereas Mg widened the bandgap of the ZnO NPs and the oxygen vacancy concentration was similar for both samples. Based on the experimental results, the narrowing of the bandgap, the particle size, and the oxygen vacancy did not enhance the photocatalytic performance. However, Brunauer–Emmett–Teller (BET) and Barret–Joyner–Halenda (BJH) models showed that Mg caused increased textural properties of the samples, whereas rGO played an opposite role. A theoretical study, conducted by using DFT methods, showed that the improvement in the photocatalytic performance of Mg‐doped ZnO NPs was due to a higher electron transfer from the Mg‐doped ZnO NPs to the dye molecules compared with pristine ZnO and Cd‐doped ZnO NPs. Moreover, according to the experimental results, along with Mg, graphene also played an important role in the photocatalytic performance of ZnO.     

Facile synthesis of silver doped-copper oxide nano materials utilizing areca catechu (AC) leaf extract and their antidiabetic and anticancer studies

The present research highlights physical significance of green combination of metal oxide nanomaterials utilizing medicinal plant which has widely analyzed in different medical applications i.e., medicinal science, therapeutics. In this paper, we discussed environmentally benign approach for synthesizing silver doped copper oxide nanoparticles (Ag–CuO NPs) utilizing (ACLE). Scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) were utilized to confirm the size, crystalline structure and surface morphology of the obtained nanomaterials. The monoclinic crystalline structure of the Ag–CuO NPs as produced was revealed by XRD patterns. Morphological analysis disclosed the nano-based spherical configuration of Ag–CuO NPs, as well as their morphology and elemental composition. The anti-diabetic effect of Ag–CuO NPs was further investigated utilizing a yeast cell model and amylase inhibition. Here, a decrease in intracellular glucose and a delay in carbohydrate digestion indicate promising antidiabetic action. Furthermore, the prepared nanomaterial showed anticancer potential against the MCF-7 cancer cell line, with an IC ₅₀ value of 11.21 g/ml.     

Biomedical application and hidden toxicity of Zinc oxide nanoparticles

Zinc oxide nanoparticles (ZnO NPs) represent a novel type of metal oxide nanoparticles enabling a new horizon for biomedical applications spanning from diagnosis to treatment. ZnO NPs are extensively used in commercial products such as sunscreens and daily-care products. Apart from that, ZnO NPs are used in food packaging and ointments and as an antimicrobial and antifungal agent. They are extensively used for many biomedical applications noticeably in pharmaceutics and theranostics. Its exceptional optical, electrical, and physiochemical properties, notably its incredible surface chemistry, make ZnO NPs a reliable option for bioimaging, biosensors, antimicrobial action, and drug and gene delivery. The present review covers findings and developments in ZnO NPs research in relation to its application and toxicity mechanism. A special emphasis has been given to the neurotoxic potential of the ZnO NPs and glial cell toxicity. Various factors contributing to the toxic potential of ZnO NPs and cell signaling pathways concerning its toxicity are also discussed. Available data point toward the risk of uncontrollable use of zinc nanoformulation. With increasing use, ZnO NPs pose a severe threat both to the ecosystem and human beings. In a nutshell, the review outlines the current state of the art of ZnO NPs.     

Effect of Mg doping on morphology,photocatalytic activity and related biological properties of Zn1−xMgxO nanoparticles

The objective of this study is to synthesize ZnO and Mg doped ZnO (Zn_1−xMg_xO) nanoparticles via the sol-gel method, and characterize their structures and to investigate their biological properties such as antibacterial activity and hemolytic potential.Nanoparticles (NPs) were synthesized by the sol-gel method using zinc acetate dihydrate (Zn(CH₃COO)₂.2H₂O) and magnesium acetate tetrahydrate (Mg(CH₃COO)₂.4H₂O) as precursors. Methanol and monoethanolamine were used as solvent and sol stabilizer, respectively. Structural and morphological characterizations of Zn_1−xMg_xO nanoparticles were studied by using XRD and SEM-EDX, respectively. Photocatalytic activities of ZnO and selected Mg-doped ZnO (Zn_1−xMg_xO) nanoparticles were investigated by degradation of methylene blue (MeB). Results indicated that Mg doping (both 10% and 30%) to the ZnO nanoparticles enhanced the photocatalytic activity and a little amount of Zn0.90 Mg0.10 O photocatalyst (1.0 mg/mL) degraded MeB with 99% efficiency after 24 h of irradiation under ambient visible light. Antibacterial activity of nanoparticles versus Escherichia coli ( E. coli ) was determined by the standard plate count method. Hemolytic activities of the NPs were studied by hemolysis tests using human erythrocytes. XRD data proved that the average particle size of nanoparticles was around 30 nm. Moreover, the XRD results indicatedthat the patterns of Mg doped ZnO nanoparticles related to ZnO hexagonal wurtzite structure had no secondary phase for x ≤ 0.2 concentration. For 0 ≤ x ≤ 0.02, NPs showed a concentration dependent antibacterial activity against E. coli . While Zn_0.90Mg_0.10 O totally inhibited the growth of E. coli , upper and lower dopant concentrations did not show antibacterial activity.     

Bacteria and bacteriophage inactivation by silver and zinc oxide nanoparticles

Microbial contaminants such as bacteria and viruses are of great concern in water. As nanotechnology continues to grow, understanding the interactions of nanoparticles with bacteria and viruses is important to protect public health and the environment. In this study, the effect of two commonly used nanoparticles, silver nanoparticles (AgNPs, average particle size=21 nm) and zinc oxide nanoparticles (ZnO NPs, average particle size=39 nm), on the growth of bacteria (Eschericia coli) and bacteriophages (MS2) were evaluated using a standard double agar layer (DAL) method and a turbidimetric microtiter assay. A 1-h prior exposure of MS2 to nanoparticles did not inactivate MS2 at the highest nanoparticle concentrations tested (5mg/L total Ag and 20 mg/L ZnO). No bacteriophage inactivation was observed in the presence of AgNPs, Ag(+)/AgNPs (50:50 in mass ratio) or Ag(+) ions, all at the total Ag concentration of 5mg/L. In a binary (bacteria-phages) system where the E. coli host was exposed to MS2 and nanoparticles simultaneously, the dynamic changes of active bacteria and MS2 phages during incubation demonstrated that exposure of AgNPs (5mg/L Ag) and ZnO NPs (20mg/L ZnO) increased the number of phages by 2-6 orders of magnitude. These results suggested that exposure of nanoparticles could greatly facilitate bacterial viruses like MS2 to infect the E. coli host.     

Improvement of the performance of dye sensitized solar cell using ZnO nanorods array deposited with Ag nanoparticles as photoanode

Well-aligned zinc oxide (ZnO) nanorods (NRs) arrays deposited with Ag nanoparticles (NPs) are prepared by a liquid phase epitaxial growth process followed by a reduction of Ag on the surface of the ZnO NRs. Transmission electron microscopy images show that most Ag NPs are deposited on the upper part of the ZnO NRs, and the overall optical absorption in the range of visible light can be enhanced due to the surface plasmon resonance of the Ag NPs. ZnO NRs with and without Ag NPs are used to assemble dye sensitized solar cells. Devices fabricated from the Ag NPs/ZnO NRs composite arrays exhibit a higher open voltage, short circuit current and fill factor than that fabricated from the bare ZnO NRs array, thus, the overall efficiency of the as-fabricated cell is increased from less than 0.5?% to 0.8?%. The main reason for the enhancement of the device performance may be ascribed to that the electron transfer back from ZnO to the dye and electrolyte is blocked by the Schottky barrier at the Ag/ZnO interface, resulting in a great increase of the electron density at the ZnO conduction band.     

Antibacterial study of Eucalyptus grandis fabricated zinc oxide and magnesium doped zinc oxide nanoparticles and its characterization

Mg-doped zinc oxide and zinc oxide nanoparticles were prepared by using methanolic seed extract from the Eucalyptus grandis plant via a green approach. Phytoconstituents present in seed extract act as capping and stabilizing agents for the biosynthesis of nanoparticles. Doping of Mg to zinc oxide nanoparticles increases the bandgap energy, thus enhancing its chemical, physical and optical properties. Further, it was characterized by various techniques such as scanning electron microscopy giving morphological information about the wurtzite hexagonal structure of bio-synthesized nanoparticles. X-ray diffraction technique tells about the crystalline nature of particles and the average crystallite size for zinc oxide and doped zinc oxide nanoparticles. Mg as a dopant enhances the properties of nanoparticles, thus making it more efficiently applicable as an antibacterial agent against Escherichia coli, gram-negative bacteria.     

Influence on electrochemical impedance and photovoltaic performance of natural DSSC using Terminalia catappa based on Mg-doped ZnO photoanode

In this paper, we report the successful fabrication of a novel dye-sensitized solar cell (DSSCs) using Mg doped ZnO as photoanode and natural dye Terminalia catappa as sensitizer. We synthesized Mg doped ZnO nanoparticles at different Mg concentrations (2%, 4%, 6%, and 8%) by employing a simple solvothermal route. The structural, morphology, composition and optical investigations of synthesized Mg doped ZnO nanoparticles are carried out using XRD, FE-SEM, EDAX, TEM, SAED, FTIR and UV–visible measurements. The XRD results confirmed the formation of hexagonal-wurtzite structure for the Mg doped ZnO nanoparticles and increase of crystalline size with increasing dopant concentration up to 6% is observed. FESEM analysis indicated a gradual change in the surface morphology with increasing Mg concentration and the size of the nanoparticles are slightly reduced at higher Mg concentration. The HRTEM images and SAED pattern also confirmed the formation of wurtzite hexagonal phase of ZnO. The band gap energies calculated from the UV–visible spectra using Tauc's plots indicated decrease of band gap energy with dopant concentration. The DSSCs fabricated using Mg doped ZnO photo-anodes and Terminalia catappa sensitizer showed higher efficiency at higher Mg concentration and observed increase in efficiency is discussed based on slower charge carrier recombination and higher carrier life time as evidenced from the electrochemical impedance analysis.     

Biosynthesis of TiO<Subscript>2</Subscript> nanoparticles using <Emphasis Type="Italic">Justicia gendarussa</Emphasis> leaves for photocatalytic and toxicity studies

Eco-friendly biosynthesis of polycrystalline titanium dioxide (TiO₂) nanoparticles (NPs) was synthesised using Justicia gendarussa (J. gendarussa) leaf extract as oxidizing agents. They were compared with TiO₂ NPs synthesized using the glacial acetic acid and also studied was the combined effect of synthesis of TiO₂ NPs. The crystalline nature and structural formation of TiO₂ NPs synthesized by different methods were confirmed by the X-ray diffraction technique, and functional groups of materials were confirmed by FT-IR spectroscopy. The synthesized materials were investigated for photocatalytic activity for methylene blue under UV irradiation and toxicity activity against MCF-7 and MDA-MB-231 cells. The result indicates that TiO₂ NPs synthesised by J. gendarussa showed superior and enhanced activity against MCF-7 and MDA-MB-231. Biosynthesized TiO₂ NPs showed higher photodegradation of dyes when compared with other TiO₂ NPs synthesized by different methods. This is due to the alterations in band gap; structural changes and surface area in nanoparticles that increased the activity. Also, nanosphere/disc like morphology of TiO₂ NPs is confirmed using TEM.     

Health impact and safety of engineered nanomaterials

Many engineered nanomaterials (NMs) are being synthesized and explored for potential use in consumer and medical products. Already, nanoparticles (NPs) of titanium dioxide (TiO(2)), zinc oxide (ZnO), silver (Ag) and other metals or their oxides are present in commercial products such as sunscreens, cosmetics, wound dressings, surgical tools, detergents, automotive paints and tires. More recent and advanced FDA-approved use of NMs includes quantum dots (QDs) in live cell imaging, zirconium oxides in bone replacement and prosthetic devices and nanocarriers in drug delivery. The benefits from nanotechnology are aplenty, comprising antimicrobial activities, scratch- and water-resistance, long-lasting shine, improved processor speeds and better display resolution, to name a few. While developers of these products often focus on the exciting beneficial aspects of their products, safety and toxicity issues are often not discussed in detail. Long-term effects such as chronic exposure and environmental pollution are even less documented. Along with widespread manufacture and use of NMs, concerns for occupational hazards, proper handling, disposal, storage, shipping and clean up are expected to rise. This review focus on the possible biological impact of engineered NPs, serving as a reminder that nanomaterials can become a double-edged sword if not properly handled.     

Zein films with ZnO and ZnO:Mg quantum dots as functional nanofillers: New nanocomposites for food package with UV-blocker and antimicrobial properties

The preparation of a new nanocomposite by combining zein and quantum dots (QDs) was the main interest of the present work. By the sol-gel method, colloidal ethanolic dispersions of zinc oxide (ZnO) particles and ZnO particles doped with magnesium (II) (ZnO:Mg) were obtained, sized 4.26 and 3.65 nm, respectively, as determined by UV–Vis spectroscopy. The prepared QDs were used as nanofillers in order to obtain zein-based nanocomposite films, which displayed good visual appearance, homogeneity, and transparency. The presence of QDs increased the hydrophobicity and reduced, up to three times, the amount of water uptake of the composite films when compared to pure zein. Those effects were more pronounced for ZnO:Mg QDs. TEM, FTIR, and fluorescence microscopy analysis indicated that zein interacts more effectively with ZnO:Mg than with ZnO. In addition, and most importantly, the presence of QDs in the films showed an important advantage when compared to those of pure zein: the extended UV-blocking in the absorbance spectra. The antimicrobial assays demonstrated that the ZnO NPs, loaded into zein films, are promising antibacterial materials since the inhibition of growth of S. aureus reached (96.5 ± 4.9)% at 44.8 wt% of ZnO NPs. Therefore, the nanocomposites show promising features for the development of food packaging, UV protective films, and for the development of new and sustainable materials.     

Synthesis,magnetic properties and X-ray analysis of Zn0.97X0.03O nanoparticles (X = Mn,Ni, and Co) using Scherrer and size–strain plot methods

Un-doped and doped ZnO nanoparticles (Zn_0.97X_0.03O-NPs, X = Mn, Co, and Ni) were synthesized from a metal acetate precursor and acetic acid by a modified sol–gel combustion method. The compounds were synthesized at calcination temperatures of 650 °C for 1 h. The synthesized un-doped/doped ZnO-NPs were characterized by X-ray diffraction analysis (XRD) and high-magnification transmission electron microscopy (TEM). The XRD results revealed that the sample product was crystalline with a hexagonal wurtzite phase. The TEM showed ZnO-NPs nearly spherical shapes and a non-uniform shape for doped ZnO-NPs. The crystalline development in the ZnO-NPs was investigated by X-ray peak broadening. The size–strain plot (SSP) method was used to study the individual contributions of crystallite sizes and lattice strain on the peak broadening of the un-doped and doped ZnO-NPs. Physical parameters such as strain, stress and energy density values were calculated more precisely for all reflection peaks of XRD corresponding to the wurtzite hexagonal phase of ZnO lying in the range of 20–80° from the SSP results. The vibrating sample magnetometer (VSM) was also used to study the magnetic behavior of the samples in the ceramic form. The obtained results showed that strain play an important role in peak broadening; moreover, the mean crystalline size of the un-doped and doped ZnO-NPs estimated from the TEM and the SSP method were highly inter-correlated.     

Synthesis of aptamer-functionalized Ag nanoclusters for MCF-7 breast cancer cells imaging

Aptamer-functionalized silver nanoclusters(Ag NCs) have been attracting a lot of interest as label-free probes which have been successfully applied to both cell imaging and molecular detection.MUCl aptamer is an ssDNA aptamer that specifically binds to MUCl mucin which is a large transmembrane glycoprotein whose expression level increases at least 10-fold in primary and metastatic breast cancers.Using C4A4C3-linker-MUCl as template,the Ag NCs were synthesized through one-pot process.The fluorescence intensity of Ag NCs was found to be closely related to the length and type(poly adenine or thymine) of the linker,the optimum linker being-AAAAA-.Using the C4A4C3-A5-MUC1 as the scaffold,the synthesized Ag NCs emitted fluorescence with high quantum yield(QY) of 66.5%.Based on the specific interaction between the MUCl aptamer and MUCl mucin,the C4A4C3-A5-MUC1-stabilized Ag NCs could recognize and differentiate the MCF-7 breast cancer cells from MDA-MB-231 breast cancer and A549 human lung cancer cells.     

Synthesis of zinc oxide nanoparticles (ZnO NPs) using pure bioflavonoid rutin and their biomedical applications: antibacterial,antioxidant and cytotoxic activities

Research on Chemical Intermediates - The present study reports an eco-friendly green synthesis of zinc oxide nanoparticles (ZnO NPs) using the bioflavonoid rutin. The synthesized ZnO NPs were...     

Synthesis and antitumor activity of new silver(I)-N-heterocyclic carbene complexes

Abstract

In this study, two novel benzimidazole-based N-heterocyclic carbene ligands (1a-b) and their silver(I) complexes (2a-b) were synthesized. All new compounds were characterized by FT-IR, LC-MS, ¹H NMR, and ¹³C NMR spectroscopies. The in vitro antitumor activities of NHC ligands (1a-b) and their silver(I) complexes (2a-b) against DU-145 human prostate cancer cells, MDA-MB-231 and MCF-7 human breast cancer cells and L-929 (normal cells adipose from mouse) were also determined using MTT analysis for 24?h, 48?h, and 72?h. The results showed that while NHC ligands did not have in vitro antitumor activity on MCF-7, MDA-MB-231 and DU-145 cells, Ag(I)-NHC complexes have in vitro antitumor activities. The in vitro antitumor activity of 2a was found to be lower than that of 2b. Ag(I)-NHC complexes were observed to have higher IC₅₀ values for non-cancerous cell lines than cancer cells.     

Effects of emulsifying agents on the safety of titanium dioxide and zinc oxide nanoparticles in sunscreens

The use of titanium oxide (TiO₂) and zinc oxide (ZnO) nanoparticles (NPs) in sunscreen formulations has increased considerably, and might pose a serious health hazard worldwide. A thorough investigation into the toxicity induced by such components is highly necessary. In this study, the effects of TiO₂ and ZnO NPs on HaCaT cells were tested in the presence and absence of emulsifiers (cyclopentasiloxane, jojoba ester, and lecithin). Cell viability results revealed that the toxicity of NPs was highly dose dependent and influenced by the emulsifier type. The emulsifiers themselves are minimally toxic. However, when used in combination with TiO₂ and ZnO, they were highly toxic to HaCaT cells. Transmission electron microscopy revealed that the cells showed least permeability to NPs dispersed in lecithin compared to other emulsifiers. In conclusion, the toxicity of NPs may be highly dependent on the emulsifier type and be varied. In particular, lecithin can be used as a potential alternative emulsifier in sunscreens.     

Efficient photodegradation of methyl orange and bactericidal activity of Ag doped ZnO nanoparticles

In the present work, silver-doped ZnO (Ag–ZnO NPs) with different concentrations of silver ions (0.3, 0.5, 1.0 and 1.5 mol %) were synthesized by using a simple co-precipitation method. The Ag–ZnO NPs were primarily characterized by XRD, FT-IR, SEM, EDS, TEM, UV–Vis. DRS, PL and BET surface area. The XRD analysis of Ag–ZnO NPs shows a wurtzite structure and optimized Ag–ZnO NPs (1.0 mol %) exhibit a lower crystallite size of 15.96 nm than that of bare ZnO (19.07 nm). Optical study shows a decrease in band gap from 3.13 to 2.97 eV as the concentration of Ag ions increases from 0.3 to 1.5 mol%. TEM images reveal the spherical shape particle with sizes ranging between 10 and 15 nm. From the multipoint BET plot, the surface area of Ag–ZnO NPs found 38.06 m²/gwhich is higher than the ZnO NPs (34.48 m²/g). The photocatalytic study demonstrated that the Ag–ZnO NPs (1.0 mol %) has an excellent photodegradation efficiency of Methyl Orange (96.74%)with a 26% increment as compared to bare ZnO (70.47%). Furthermore, the bactericidal activity of Ag–ZnO NPs (1.0 mol %) was investigated against four different bacterial strains. The results explored that the Gram-negative bacteria (E. coli and P. vulgaris) are more sensitive than Gram-positive (S. aureus and B. cereus) to Ag–ZnO NPs. Overall, the anticipated material is economical and reusable for photodegradation and antibacterial activity.