No Abstract available.
Nanoparticles*

BACKGROUND: Relationships among portable scanning mobility particle sizer (P-SMPS), condensation particle counter (CPC), and surface area monitor (SAM), which are different metric measurement devices, were investigated, and two widely used research grade (RG)-SMPSs were compared to harmonize the measurement protocols. METHODS: Pearson correlation analysis was performed to compare the relation between P-SMPS, CPC, and SAM and two common RG-SMPS. RESULTS: For laboratory and engineered nanoparticle (ENP) workplaces, correlation among devices showed good relationships. Correlation among devices was fair in unintended nanoparticle (UNP)-emitting workplaces. This is partly explained by the fact that shape of particles was not spherical, although calibration of sampling instruments was performed using spherical particles and the concentration was very high at the UNP workplaces to allow them to aggregate more easily. Chain-like particles were found by scanning electron microscope in UNP workplaces. The CPC or SAM could be used as an alternative instrument instead of SMPS at the ENP-handling workplaces. At the UNP workplaces, where concentration is high, real-time instruments should be used with caution. There are significant differences between the two SMPSs tested. TSI SMPS showed about 20% higher concentration than the Grimm SMPS in all workplaces. CONCLUSIONS: For nanoparticle measurement, CPC and SAM might be useful to find source of emission at laboratory and ENP workplaces instead of P-SMPS in the first stage. An SMPS is required to measure with high accuracy. Caution is necessary when comparing data from different nanoparticle measurement devices and RG-SMPSs.
Calibration ; Nanoparticles*

BACKGROUND: To evaluate the changes in the radiation dose and temperature distribution on irradiated egg albumin and nanoparticle (Fe3O4) powder mixed egg albumin. METHODS: A new type of phantom was designed by fabricating a 30x30x30cm acryl square inside a 3x3x3cm small square and dividing it into two parts. In the control group, only egg albumin was irradiated, and in the test group, 25nm 20mg/cc, 25nm 40mg/cc, and 1 um 40 mg/cc nanoparticles with egg albumin were irradiated. The radiation isodose distributions and temperature changes were then observed. RESULTS: No significant changes were observed in the radiation dose and temperature distribution. CONCLUSION: The nanoparticles were considered not to have had any effect on the radiation dose and temperature distribution under the experimental conditions. Further studies can be conducted based on the changes in the mixture material.
Nanoparticles ; Ovum

Introduction: The biosynthesis of nanoparticles has been proposed as a cost-effective and environmental friendly alternative to chemical and physical methods. The present study was aimed to characterise Catharanthus roseus (C. roseus)-silver nanoparticles (AgNPs) using a standardised C. roseus aqueous extract. Methods: The standardisation was performed by using Liquid Chromatography/Time-of-Flight ion trap Mass Spectrometry. An optimised C. roseus-AgNPs have been previously synthesised. Further characterisation of C. roseus-AgNPs was evaluated by zeta potential analysis and fourier transform infrared spectroscopy (FTIR). Results: The chromatography analysis has revealed presence of thirteen possible indole alkaloids in C. roseus extract which were lochrovicine, lochnerine, vinleurosine, vindolinine, tabersonine, catharanthine, serpentine, catharosine, vincristine, catharine, ajmalicine, vinleurosine, and vindolicine. Zeta potential analysis exhibited the value at -16.6 mV. FTIR spectrum of C. roseus aqueous extract showed the absorption band at 3210.83 cm-1 (C-H stretch), 2934.11 (C-H bond), 1578.15 (N=O stretch), 1388.76 and 1314.89 (N=O bend), 1119.29 (C-O bond) and 729.94 (C-Cl bond). In comparison, FTIR spectrum of C. roseus-AgNP s showed the absorption band at 2925.01 and 2924.97 (C-H bond), 1622.93 (C-C=C symmetric stretch), 1383.19 and 1384.13 (N-O bend), 1037.92/1038.76/1238.3/1117.2 (C-O bond), 3169.4 (O-H bond), 774.59 and 691.53 (C-Cl bond). Conclusion: The present findings have shown that the C. roseus aqueous extract contains alkaloids that may responsible as reducing and stabilising agents in the synthesis of AgNPs.
silver nanoparticles

Medical magnetic nanoparticles are nano-medical materials with superparamagnetism, which can be collected in the tumor tissue through blood circulation, and magnetic particle imaging technology can be used to visualize the concentration of magnetic nanoparticles in the living body to achieve the purpose of tumor imaging. Based on the nonlinear magnetization characteristics of magnetic particles and the frequency characteristics of their magnetization, a differential detection method for the third harmonic of magnetic particle detection signals is proposed. It was modeled and analyzed, to study the nonlinear magnetization response characteristics of magnetic particles under alternating field, and the spectral characteristics of magnetic particle signals. At the same time, the relationship between each harmonic and the amount of medical magnetic nanoparticle samples was studied. On this basis, a signal detection experimental system was built to analyze the spectral characteristics and power spectral density of the detected signal, and to study the relationship between the signal and the excitation frequency. The signal detection experiment was carried out by the above method. The experimental results showed that under the alternating excitation field, the medical magnetic nanoparticles would generate a spike signal higher than the background sensing signal, and the magnetic particle signal existed in the odd harmonics of the detected signal spectrum. And the spectral energy was concentrated at the third harmonic, that is, the third harmonic magnetic particle signal detection that meets the medical detection requirement could be realized. In addition, the relationship between each harmonic and the particle sample volume had a positive growth relationship, and the detected medical magnetic nanoparticle sample volume could be determined according to the relationship. At the same time, the selection of the excitation frequency was limited by the sensitivity of the system, and the detection peak of the third harmonic of the detection signal was reached at the excitation frequency of 1 kHz. It provides theoretical and technical support for the detection of medical magnetic nanoparticle imaging signals in magnetic particle imaging research.
Magnetics ; Magnetite Nanoparticles

Aims: This study examined the mycosynthesis of phosphorus nanoparticles (PNPs) and its application as a fertilizer for flax plant. Methodology and results: A total of thirty eight fungal isolates were isolated and screened for their abilities to synthesize PNPs. The fungal isolate was determined and identified as Aspergillus fumigatus (NCBI GenBank accession No. MN610566-MN610567). The biosynthesized nanoparticles were characterized by particle size analyzer, UV-visible spectrophotometer, transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDX) and fourier transform infrared spectroscopy (FT-IR). They were found to have an average diameter of 45.1 nm, regular round shape, EDX confirms the 54.63 atom % of phosphorous. The cytotoxicity of produced nanoparticles was performed to determine the safe dose that will be applied in agricultural experiment and was found to be 12.5 μg/mL. Pot experiment was performed to determine the fertilizing impact of mycosynthesized PNPs on flax plant and to equate their influence with granular single super phosphate. Results revealed that growth parameters, phosphorus content and microbial activities in the rhizosphere of flax plants were highly significantly (p ≤ 0.05) affected by foliar application of PNPs in presence of half dose of super phosphate. The TEM-micrographs of stained ultrastructural leaves showed that the PNPs treated leaves in the presence of half dose of super phosphate had normal cell structure similar to control, while the cell structure of leaves treated with PNPs but did not receive super phosphate were adversely affected. Conclusion, significance and impact of study This study clearly indicated that the application of low cost biosynthesised PNPs could save about 50% of recommended dose of phosphorus fertilizer. This study also demonstrates that it is not preferred to use PNPs as a fertilizer alone without adding super phosphate. Hence, this investigation suggests that further studies should be established to detect the safety of this nanofertilizers.
Nanoparticles--chemistry ; Aspergillus fumigatus

Background: Response surface methodology (RSM) is a cost-effective multivariate technique employed in optimization of pharmaceutical formulations. Central composite experiment design is one of the common designs under RSM used for determining optimum nanoparticle formulation parameters. Objectives: To optimize a formulation for meropenem-loaded chitosan alginate nanoparticles using central composite experimental design. Methodology: Meropenem loaded chitosan-alginate nanoparticles were fabricated using aqueous sodium alginate solution and ionotropic gelation with calcium chloride and chitosan, using an optimized formulation derived from a central composite design. The fabricated Mer-CS/Alg NPs were characterized for their particle size, zeta potential, encapsulation efficiency, and loading capacity. The central composite design has been used to adequately assess the influence of two factors namely meropenem concentration and Alg/CS mass ratio on the responses based on a limited number of 13 triplicate formulation runs. Results: This study successfully formulated meropenem-loaded chitosan/alginate nanoparticles. The optimal formulation of the Mer- CS/Alg NPs was 1.7 mg/mLcurcumin, and a Alg/CS mass ratio of 9.8:1. Based on the predicted values of the response variable, the optimal formulation would have a particle size of 490.64 nm, zeta potential of -28.59 mVand a loading capacity of 76.89%. Conclusion The central composite experimental design successfully optimized the nanoparticle formulation of meropenem and chitosan/alginate polymer solution. The optimum formulation produced nanoparticles with adequate size, high stability, and high drug load.
Meropenem ; Nanoparticles ; Research Design

Silver nanoparticles have been widely used in medicinal and biological fields. Their biological evaluation is an important researchful field. In this paper are summarized the status quo of nano-hydroxyapatite biological evaluation at home and abroad. Although silver nanoparticles showed good biological compatibility when they were tested by contrast to ISO 10993 standards, some reports have proved that many medical devices loaded with silver could release silver ions (Ag+) which could translocate in blood circulation and cumulate in some organs such as liver and kidney. It may induce hepatotoxicity or renal toxicity and may lead to death in some situation extremely exposed to a certain dose of Ag+. The dimension of silver nanoparticles is close to silver ions and some reports have proved that they could translocate in body, so it is suggested that silver nanoparticles should induce the same toxicity with silver ions. In addition, silver nanoparticles have shown cytotoxicity in some experiment in vitro. But the mechanisms of its cytotoxity are not clear; it may attribute to the silver ions that release from silver nanoparticles or to the silver nanoparticles that permeate through cell membrane. Hence, there are some potential anxieties for the biological safety of silver nanoparticles.
Metal Nanoparticles ; toxicity ; Silver ; toxicity

Aims: This study was designed to evaluate the effectiveness of the synthesised carvacrol loaded chitosan nanoparticles (CLCNPs) on the growing and pre-formed biofilms of Listeria monocytogenes isolated from slaughterhouses. Methodology and results: The swab samples were collected from knives, hocks and cutting tables representing slaughterhouses meat contact surfaces (MCS), while those samples from walls and floors represent slaughterhouses meat non-contact surfaces (MNCS). The bacteriological analysis revealed the existence of L. monocytogenes with a prevalence rate of 3.3, 10 and 6.7% for knives, hocks and cutting tables, respectively and 2.2 and 6.6% for walls and floors, respectively. The isolates L. monocytogenes were assayed for biofilm production by the crystal violet binding assay method. Among the 10 L. monocytogenes isolates, 10%, 50% and 30% of the isolates were found to be strong, moderate and weak biofilm producers, respectively. The activities of carvacrol, chitosan nanoparticles (NPs) and CLCNPs against the only strong biofilm producer strain of L. monocytogenes were tested by microtiter plate assay. The minimum inhibitory concentrations (MIC) values were 3.75 mg/mL for CAR, 5 mg/mL for chitosan NPs and 0.62 mg/mL for CLCNPs. CLCNPs inhibit the produced biofilm by 35.79, 73.37 and 77.76%, when 0.5 MIC, 1 MIC and 2 MIC were used, respectively. Furthermore, the pre-formed L. monocytogenes biofilms were significantly reduced from 1.01 (control) OD570 to 0.40 and 0.29 OD570 by applying 2 MIC and 4 MIC doses, respectively. Conclusion, significance and impact of study The data generated is promising to develop bio-green disinfectants to inhibit biofilm formation by L. monocytogenes in the food processing environment and control its adverse effects for consumers.
Chitosan--chemistry ; Listeria monocytogenes ; Nanoparticles

OBJECTIVES: This study aims to evaluate the size-dependent toxicity of spherical silver nanoparticles (Ag NPs) to an endemic benthic organism, Glyptotendipes tokunagai. METHODS: Ag nanoparticles of three nominal sizes (50, 100, and 150 nm) capped with polyvinyl pyrrolidone (PVP-Ag NPs) were used. Their physicochemical properties, acute toxicity (48 hours), and bioaccumulation were measured using third instar larvae of G. tokunagai. RESULTS: The aggregation and dissolution of PVP-Ag NPs increased with exposure time and concentration, respectively, particularly for 50 nm PVP-Ag NPs. However, the dissolved concentration of Ag ions was not significant compared with the median lethal concentration value for AgNO3 (3.51 mg/L). The acute toxicity of PVP-Ag NPs was highest for the smallest particles (50 nm), whereas bioaccumulation was greatest for the largest particles (150 nm). However, larger PVP-Ag NPs were absorbed and excreted rapidly, resulting in shorter stays in G. tokunagai than the smaller ones. CONCLUSIONS: The size of PVP-Ag NPs significantly affects their acute toxicity to G. tokunagai. In particular, smaller PVP-Ag NPs have a higher solubility and stay longer in the body of G. tokunagai, resulting in higher toxicity than larger PVP-Ag NPs.
Chironomidae ; Ions ; Larva ; Nanoparticles* ; Polyvinyls ; Silver* ; Solubility