Combined electrical-electrochemical phenotypic profiling of antibiotic susceptibility of in vitro biofilm models.

More than 65% of bacterial infections are caused by biofilms. However, standard biofilm susceptibility tests are not available for clinical use. All conventional biofilm models suffer from a long formation time and fail to mimic in vivo microbial biofilm conditions. Moreover, biofilms make it difficult to monitor the effectiveness of antibiotics. This work creates a powerful yet simple method to form a target biofilm and develops an innovative approach to monitoring the antibiotic's efficacy against a biofilm-associated infection. A paper-based culture platform can provide a new strategy for rapid microbial biofilm formation through capillary action. A combined electrical-electrochemical technique monitors bacterial metabolism rapidly and reliably by measuring microbial extracellular electron transfer (EET) and using electrochemical impedance spectroscopy (EIS) across a microbe-electrode interface. Three representative pathogens, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus, form their biofilms controllably within an hour. Within another hour their susceptibilities to three frontline antibiotics with different action modes (gentamicin, ciprofloxacin, and ceftazidime) are examined. Our antibiotic susceptibility testing (AST) technique provides a quantifiable minimum inhibitory concentration (MIC) of those antibiotics against the in vitro biofilm models and characterizes their action mechanisms. The results will have an important positive effect because they provide immediately actionable healthcare information at a reduced cost, revolutionizing public healthcare.

Hantzsch reaction using copper nitrate hydroxide-containing mesoporous silica nanoparticle with C3N4 framework as a novel powerful and reusable catalyst.

Copper nitrate hydroxide (CNH)-containing mesoporous silica nanoparticle (MSN) with g-C3N4 framework (MSN/C3N4/CNH) was fabricated via a four-step hydrothermal synthesis method. Functionalized MSN-based C3N4 was prepared, decorated with CNH, and identified by different physicochemical techniques such as FT-IR, XRD, SEM, EDX, and STA analyses. Then, MSN/C3N4/CNH composite was utilized as a robust catalyst for the fast fabrication of biologically active polyhydroquinoline derivatives with high yields between 88 and 97% via Hantzsch reaction under mild reaction conditions and short reaction time (within 15 min) owing to synergistic influence of Lewis acid and base sites. Moreover, MSN/C3N4/CNH can be straightforwardly recovered and used up to six reaction cycles without a conspicuous decrease in efficiency.

All-electrical antibiotic susceptibility and resistance profiling of electrogenic Pseudomonas aeruginosa.

There is a pressing need for evidence-based, non-surgical therapy guidance for biofilm-based infections. Conventional phenotypic or genotypic or emerging antibiotic susceptibility testing (AST) techniques cannot provide clinically relevant guidelines and widely adaptable stewardship for effective biofilm treatment because they are mainly limited to planktonic bacteria and suffer from many technical and operational challenges. Here, we created an all-electrical, reliable, rapid AST device to monitor antibiotic efficacy in bacterial biofilms that can be practically translatable to clinical settings and industrial antibiotic developments. The electrons metabolically produced by a Pseudomonas aeruginosa biofilm provided a strong signal for monitoring bacterial growth and treatment efficacy while a 3-D paper-based culturing platform provided a new strategy for rapid biofilm formation through capillary action. When antibiotics are effective against the pathogenic biofilm, their metabolic activities are inhibited, decreasing their electron transfer reactions. The changes in electrical outputs can be measured to assess the treatment effectiveness against pathogenic biofilms. Within 100 minutes, our six-well AST device successfully distinguished antibiotic-susceptible and -resistant P. aeruginosa biofilms, provided a quantifiable minimum inhibitory concentration (MIC) of antibiotics, and characterized the bacterial antibiotic action mechanisms.

Improving the thermal stability of natural bioactive ingredients via encapsulation technology.

Bioactive compounds (bioactives) such as phenolic acids, coumarins, flavonoids, lignans and carotenoids have a marked improvement effect on human health by acting on body tissues or cells. Nowadays, with increasing levels of knowledge, consumers prefer foods that can provide bioactives beside the necessary nutrients (e.g., vitamins, essential fatty acids and minerals). However, an important barrier for incorporating bioactives into foods is their low thermal stability. Nevertheless, thermal processing is widely used by the food industries to achieve food safety and desired texture. The aim of this work is to give an overview of encapsulation technology to improve thermal stability of bioactives incorporated into different food products. Almost all thermal analysis and non-thermal methods in the literature suggest that incorporation of bioactives into different walls can effectively improve the thermal stability of bioactives. The level of such thermal enhancement depends on the strength of the bioactive interaction and wall molecules. Furthermore, contradictory results have been reported in relation to the effect of encapsulation technique using the same wall on thermal stability of bioactives. To date, the potential to increase the thermal resistance of various bioactives by gums, carbohydrates, and proteins have been extensively studied. However, further studies on the comparison of walls and encapsulation methods to form thermally stable carriers seem to be needed. In this regard, the same nature of bioactives and the specific protocol in the report of study results should be considered to compare the data and select the optimum conditions of encapsulation to achieve maximum thermal stability.

Accelerated antibiotic susceptibility testing of pseudomonas aeruginosa by monitoring extracellular electron transfer on a 3-D paper-based cell culture platform.

Pseudomonas aeruginosa is the most important opportunistic pathogen leading to serious and life-threatening infections, especially in immunocompromised patients. Because of its remarkable capacity to resist antibiotics, the selection of the right antibiotics with the exact dose for the appropriate duration is critical to effectively treat the infections and prevent antibiotic resistance. Although conventional genotypic and phenotypic antibiotic susceptibility testing (AST) methods have been dramatically advanced, they have suffered from many technical and operational issues as a generalized antibiotic stewardship program. Furthermore, given that most microbial infections are caused by their biofilms, the existing AST methods do not provide evidence-based antibiotic prescribing guidance for biofilm-based infections because the results are based on individual bacteria traditionally grown in their planktonic form. In this work, we create an innovative susceptibility testing technique for P. aeruginosa that offers clinically relevant guidelines and widely adaptable stewardship to effectively treat the infections and minimize antibiotic resistance. Our approach evaluates the antibiotic efficacy by continuously monitoring the accumulated electrical outputs from the bacterial extracellular electron transfer (EET) process in the presence of antibiotics. Our innovative paper-based culturing 3-D scaffold promotes surface-associated growth of bacterial colonies and biofilms. The platform replicates a natural habitat for P. aeruginosa where it can grow similarly to sites it infects. Our technique enables an all-electrical, real-time, easy-to-use, portable AST that can be easily translatable to clinical settings. The entire procedure takes 96 min to provide evidence-based antimicrobial prescribing guidance for biofilm-based infections.

Practical application of nanoencapsulated nutraceuticals in real food products; a systematic review.

In recent decades, due to the increase in awareness, most consumers prefer foods that not only satisfy their primal urge of hunger but also include health-promoting effects on the body. Therefore, the food industry has an increasing tendency to apply the nutrients (like vitamins, essential fatty acids and minerals) and replace synthetic additives with natural bioactives (like phenolics and essential oils) to produce functional products. However, low dispersibility and shelf-stability as well as presenting unpleasant taste and odor are the most critical barriers for direct incorporation of these useful compounds into foods. In this context, nanoencapsulation has been proposed as a relatively new solution to overcome the mentioned limitations. However, fewer studies have focused on incorporating the bioactive-loaded nanocarriers into the food matrices. This study intends to help the development of functional food production by doing an exhaustive review on the incorporation of nanoencapsulated ingredients into the real food system and resulted interaction of nanocarriers and food products. According to the literature, incorporation of the nanoencapsulated bioactive ingredients into foods can be effectively used to enhance their stability during the processing and storage stage and their bioavailability as well as to delay lipid oxidation and microbial growth in food, without negatively affecting physicochemical, organoleptic and qualitative properties. However, some published results to date declared that food matrix might adversely affect the bioavailability and antimicrobial activity of nanoencapsulated ingredients. It seems that further studies are required to contribute to the choice of appropriate healthy ingredients and wall materials for incorporating into a given food structure.

New MOF/COF Hybrid as a Robust Adsorbent for Simultaneous Removal of Auramine O and Rhodamine B Dyes.

In this study, by hybridization of zinc-based metal-organic framework-5 (MOF-5) and melamine-terephthaldehyde-based intergrade two-dimensional π-conjugated covalent organic framework (COF), a novel MOF-5/COF (M5C) hybrid material was prepared and characterized by Fourier transform infrared, field emission scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis. MOF-5 has a well-defined cubic structure, and the proposed COF has an orderly and spherical nanosize shape. The prepared MOF-5/COF was applied as an effective adsorbent for rapid and high-efficient simultaneous removal of auramine O (AO) and rhodamine B (RB) cationic dyes via electrostatic, H-bonding, Lewis acid-base interactions, and π-π stacking from aqueous solution. The effect of experimental parameters such as pH, M5C mass, contact time, and AO and RB dyes concentration was investigated for removal efficiency and optimized. The M5C adsorbent showed an adsorption capacity of 17.95 and 16.18 mg/g for AO and RB dyes, respectively, at pH 9.5. The adsorption study of AO and RB dyes by M5C comprises both isotherm and kinetic studies. The equilibrium adsorption data followed by Langmuir isotherm and the adsorption kinetic process were found to be a pseudo-second-order model. The robustness adsorption efficiency of MOF/COF hybrids can be attributed to the formation of amide bonds between COF and MOFs, which improve the stability of the adsorbent.

Assessment and selection of the best treatment alternative for infectious waste by Sustainability Assessment of Technologies (SAT) methodology.

The objective of this paper was to select the best infectious waste treatment alternative by Sustainability Assessment of Technologies (SAT) methodology. This study was carried in four educational hospitals of Ardabil University of Medical Sciences. The average waste produced in hospitals was 4.7 kg/bed/day. The average of common waste, infectious waste, sharp waste, and chemical and pharmaceutical waste was 2.18, 2.42, 0.04, and 0.05 kg/bed/day, respectively. In detailed assessment, a weighted sum matrix method was used to rank the different technologies of infectious wastes treatment. Finally, the highest score was found for Autoclave with a shredder (64.53), and hydroclave (63.32), autoclave (60.61), central incineration (55.12) and chemical treatment (54.25) were ranked second to fifth, respectively. Most participants emphasized the need for an autoclave with a shredder in the treatment of infectious hospital waste in Ardabil. However, the environmental and economic criteria and other aspects of treatment infectious hospital waste should be considered.Implications: Today health-care wastes (HCWs) have become a substantial public health and environmental concern all over the world, particularly in developing countries. In response to the need for a technology assessment framework to identify and select the best possible environmental technology option, IETC-UNEP developed a new methodology known as Sustainable Assessment of Technologies (SAT). The methodology takes a systems approach and stresses information, expertise and stakeholder participation. In applying this methodology to developing countries, it seems necessary to make some changes on its criteria, based on local conditions.

Cu-metal-organic framework supported on chitosan for efficient condensation of aromatic aldehydes and malononitrile.

In this study, a novel copper-based metal-organic framework (Cu-MOF)-immobilized modified chitosan (CS-CA), CS-CA/Cu-MOF, has been constructed easily and applied as an extremely efficient and economic mesoporous catalyst for the Knoevenagel condensation between aromatic aldehydes with malononitrile under mild reaction conditions. The resultant catalyst is characterized via various techniques including FTIR, XRD, FE-SEM, EDX, TEM, BET and STA analyses. The CS-CA/Cu-MOF was reused eight times without a noteworthy decrease in the catalytic activity. The use of CS-CA/Cu-MOF results in outstanding catalytic activity, high recyclability, very short reaction time at 25 °C, and an easy work-up process for the Knoevenagel condensation.

Application of different nanocarriers for encapsulation of curcumin.

Curcumin is the main polyphenol of the curcuminoid class of turmeric, a well-known spice belonging to the ginger family. In addition to its common applications like coloring and antioxidant agent as food additives, it has a broad range of favorable biological functions, such as anti-inflammatory, anti-microbial, anti-diabetic activities, and anti-cancer potentials against various cancers. However, curcumin suffers from some limitations including short shelf life due to its poor chemical stability, low bioavailability due to its poor absorption, low water solubility, rapid metabolism and rapid systemic elimination. Nanoencapsulaion has been addressed as an innovative and emerging technology for resolving these shortcomings. In this review, the different delivery systems used for loading of curcumin have been considered and explained including lipid-based, chemical polymer and biopolymer-based, nature-inspired, special equipment-based and surfactant-based techniques. Also, implications of nanoencapsulated curcumin in food, pharmaceutical and cosmetic uses are discussed. In this sense, the relevant recent studies in the past few years along with upcoming challenges have been covered. Although incorporation of curcumin into nanocarriers can be a possible solution to overcome its inherent constraints, there are some rational concerns about their toxicological safety once they enter into the biological paths. Therefore, future investigations could focus on assessment of their biological fate during digestion and absorption within human body.

Synthesis and characterization of optically active magnetic PAI/Fe3O4 nanocomposites.

This work presents the preparation and characterization of hybrid organic-inorganic optically active poly(amide-imide)/nano-Fe3O4 composites with different amount of modified Fe3O4 nanoparticles as new nanocomposites by ultrasonic irradiation and characterized by Fourier transform infrared spectra, X-ray diffraction, scanning electron microscopy (SEM), thermogravimetric analysis and vibrating sample magnetometry. The surface of Fe3O4 nanoparticles was modified with 3-aminopropyltriethoxyl silane because of the homogeneous distribution of nano-Fe3O4 in polymer matrix, which the SEM results confirmed that the Fe3O4 nanoparticles were dispersed uniformly in polymer matrix. Furthermore, as compared with pure polymer, thermogravimetric analysis data indicated an improvement of thermal stability of nanocomposites.

The enhancement of pistachio green hull extract functionality via nanoliposomal formulation: studying in soybean oil.

Phenolic compounds of pistachio green hull extract (PGHE) were incorporated into nanoliposomes (NLs). The NLs were prepared with different concentrations of phenolic compounds of PGHE (500, 750 and 1000 ppm) and particle size, polydispersity index (PDI), zeta potential and encapsulation efficiency (EE) were investigated. The antioxidant activity of free and incorporated phenolic compounds of PGHE were evaluated in soybean oil during 39 days of storage by measuring peroxide (PV), thiobarbituric acid (TBA) values and color. The total phenolic content and IC50 (DPPH assay) of PGHE were 614.91 ± 0.45 mg gallic acid equivalent/g fresh weight of extract and 10 ± 0.05 µg/ml extract, respectively. The prepared NLs had 101.86-105.81 nm size and PDI = 0.202-0.235. The zeta potential value of NLs varied between -47.7 and -52.3 mV. The highest EE (32.47%) was observed for NLs containing 1000 ppm of phenolic compounds. The lowest PV and TBA values were related to free phenolic compounds at 500 mg/kg oil. In comparison with free phenolic compounds, loaded NLs had lower antioxidant activity, but encapsulation could improve the stability, gradual release and solubility of phenolic compounds in soybean oil. The color of NLs containing oil samples remained constant during the storage, but free phenolic compounds changed the oil`s color. All concentrations of free and incorporated phenolic compounds had also higher antioxidant activity than BHT. Finally, 500 ppm of phenolic compounds of PGHE in its incorporated forms could be recommended as a substitute for synthetic antioxidant in soybean oil.

Nanoliposomal carriers for improvement the bioavailability of high - valued phenolic compounds of pistachio green hull extract.

In present study, nanoliposomes were prepared by thin hydration method with different concentrations of phenolic compounds (500, 750 and 1000ppm) of pure extract and lecithin (1, 2 and 3%w/w) and characterized by considering the particle size, polydispersity index (PDI), zeta potential, encapsulation efficiency (EE) and morphology. The results showed that nanoliposome (90.39-103.78nm) had negative surface charge varied from -51.5±0.9 to -40.2±0.2mV with a narrow size distribution (PDI≈0.069-0.123). Nanoliposomes composed of 1% lecithin with 1000ppm of phenolic compounds had the highest EE (52.93%). The FTIR analysis indicated the formation of hydrogen bonds between the polar zone of phospholipid and the OH groups of phenolic compounds. Phenolic compounds also increased phase transition temperature (Tc) of nanoliposomes (2.01-7.24°C). Moreover, nanoliposomes had considerable stability during storage. Consequently, liposome is an efficient carrier for protection and improving PGHE biofunctional actives in foodstuffs.

Ultrasonic-assisted magnetic solid phase extraction of morphine in urine samples by new imprinted polymer-supported on MWCNT-Fe3O4-NPs: Central composite design optimization.

Multiwalled carbon nanotubes (MWCNTs) were magnetized with Fe3O4 nanoparticles (MWCNTs-Fe3O4-NPs) and subsequently coated by vinyl end groups (Vinyltrimethoxysilane). MWCNT-Fe3O4-NPs were used as support for a new morphine (MO) molecularly imprinted polymer (MWCNT-Fe3O4-NPs@MO-MIP) by surface imprinting polymerization method. The MWCNT-Fe3O4-NPs@MO-MIP was characterized by FTIR, VSM and SEM techniques and successfully used for determination of MO. Ultrasonic-assisted magnetic solid phase extraction followed by UV-vis spectrophotometer (UAMSPE-UV-vis) was investigated for MWCNT-Fe3O4-NPs@MO-MIP and compared with non-imprinted polymer (NIP) using batch method. Central composite design under response surface methodology was used for the evaluation of the effect of variables, individually, as well as their possible interaction effects on the adsorption process. The variables such as sonication time, MWCNT-Fe3O4-NPs@MO-MIP mass, initial concentration of MO and pH were investigated in this study. At optimum experimental conditions, UAMSPE-UV-vis method was exhibited a linear range of 0.8-8.7mgL(-1) of the MO concentration with a detection limit of 0.18mgL(-1). The relative standard deviation for the analyte was found to be lower than 2.32%. The MWCNT-Fe3O4-NPs@MO-MIP adsorption capacity was found to be 37.01mgg(-1). The enrichment and preconcentration factors were found to be 107.01 and 98.21, respectively. The developed method was finally applied successfully to the determination of MO in urine and wastewater samples with the recoveries ranged from 96.40 to 105.6%.

Controlled radical polymerization of an acrylamide containing L-alanine moiety via ATRP.

Homopolymerization of an optically active acrylamide having an amino acid moiety in the side chain, N-acryloyl-L-alanine (AAla) was carried out via atom transfer radical polymerization (ATRP) at room temperature using 2-hydroxyethyl-2'-methyl-2'-bromopropionate (HMB) or sodium-4-(bromomethyl)benzoate (SBB) as initiator in pure water, methanol/water mixture and pure methanol solvents. The polymerization reaction resulted in the optically active biocompatible amino acid-based homopolymer in good yield with narrow molecular weight distribution. The number average molecular weight increased with conversion and polydispersity was low. The structure and molecular weight of synthesized polymer were characterized by (1)H NMR, FT-IR spectroscopic techniques and size-exclusion chromatography.

Optically active poly(amide-imide)/TiO2 nanocomposites containing amino acid moieties: synthesis and properties.

The novel optically active poly(amide-imide) (PAI)/TiO2 nanocomposites containing fluorene moieties have been successfully synthesized through ultrasonic irradiation. The surface of nanoparticles was chemically modified with γ-aminopropyltriethoxyl silane to enhance the compatibility with polymeric matrix and to avoid the aggregation of nanoparticles. The dispersion of surface-modified TiO2 in PAI film was confirmed by the transmission electron microscope (TEM) analysis showing the well-dispersed nanosized TiO2 nanoparticles. The thermal stabilities and optical properties of PAI/surface-modified TiO2 nanocomposite films were also investigated. The thermogravimetric analysis data showed an improvement of thermal stability of novel nanocomposite films as compared to the pure polymer.

Association of nitrate, nitrite, and total organic carbon (TOC) in drinking water and gastrointestinal disease.

OBJECTIVE: We aimed to investigate the amounts of nitrate, nitrite, and total organic carbon (TOC) in two drinking water sources and their relationship with some gastrointestinal diseases. METHODS: This cross-sectional study was conducted in 2012 in Iran. Two wells located in residential areas were selected for sampling and measuring the TOC, nitrate (NO3(-)), and nitrite (NO2(-)). This water is used for drinking as well as for industrial and agricultural consumption. Nitrate and nitrite concentrations of water samples were analyzed using DR 5000 spectrophotometer. The information of patients was collected from the records of the main referral hospital of the region for gastrointestinal diseases. RESULTS: In both areas under study, the mean water nitrate and nitrite concentrations were higher in July than in other months. The mean TOC concentrations in areas 1 and 2 were 2.29 ± 0.012 and 2.03 ± 0.309, respectively. Pollutant concentration and gastrointestinal disease did not show any significant relationship (P > 0.05). CONCLUSION: Although we did not document significant association of nitrite, nitrate, and TOC content of water with gastrointestinal diseases, it should be considered that such health hazards may develop over time, and the quality of water content should be controlled to prevent different diseases.

Microwave-induced synthesis of new optically active and soluble polyamides containing pendent 4-(2-phthalimidiylpropanoylamino)benzoylamino-groups.

An aromatic chiral diacid monomer, 5-[4-(2-phthalimidiylpropanoylamino)-benzoylamino]isophthalic acid was synthesized in five steps under conventional heating in high yield and purity. A series of soluble, thermally stable and optically active polyamides (PA)s containing pendent groups made of phthalimide, flexible L: -alanine and benzamide sequence have been successfully synthesized under microwave irradiation. Excellent yields and very short reaction time were the main characteristics of this method. The same polymerization reactions were also carried out by conventional thermal heating and the results are compared. The resulting PAs had inherent viscosity in the range of 0.50-0.79 dL g(-1). All of the these polymers are readily dissolved in various solvents such as N-methyl-2-pyrrolidinone, N,N-dimethylacetamide and N,N-dimethylformamide and showed glass-transition temperature above 200 degrees C. Thermogravimetric analysis demonstrated that the 10% weight-loss temperatures in nitrogen were 372 and 422 degrees C for selected two PAs. All of these polymers showed optical rotation which is due to successful insertion of L: -alanine in the structure of chiral diacid monomer.

A simple and rapid spectrophotometric method for determination of ultra trace amounts of thallium(III) with 4-(4'-N,N-dimethylaminophenyl) urazole as a new reagent.

A simple and selective spectrophotometric method is proposed for the determination of ultra trace amounts of Tl(III). The reported method is based on the oxidation of 4-(4'-N,N-dimethylaminophenyl)urazole (DAPU) to the corresponding triazolinedione (TAD) by Tl(III) at pH 4.0. The reaction was monitored spectrophotometrically by measuring the increasing color of TAD compound at 514 nm by the fixed-time method. At a given time of 2.0 min at 30 degrees C, the working range of calibration was 5.0 x 10(-8) - 2.0 x 10(-5) M Tl(III) and detection limit of 5.0 x 10(-8) M was obtained. The influences of pH, reagent concentration, ionic strength and temperature were studied. The effect of diverse ions on the determination of Tl(III) by the proposed method was also investigated. Thallium in real samples was determined by this method, with satisfactory results.