Poly(vinyl alcohol) /Alginate nanofibrous mats containing Malva Sylvestris extract: Synthesis, characterization, in vitro and in vivo assessments for burn wound applications.

An important part of wound healing is providing effective wound care, coupled with preventing wound infection, which slows or disrupts healing. There are currently many herbal plants that have historical supernatural properties that show remarkable wound healing abilities. These herbal extracts have shown promising results when applied to electrospun nanofibrous mats platforms for wound healing. Accordingly, Malva Sylvestris extract (MS) was electrospun into polyvinyl alcohol/alginate nanofibrous mats (PVA/ALG). Field Emission Scanning Electron Microscopy (FESEM) demonstrated that the fiber diameter ranged from approximately 100-200 nm in nanofibrous mats, with a uniform appearance without beads. MS extract was detected in nanofibrous mats by Fourier Transform Infrared Spectroscopy (FTIR). A major benefit of incorporating MS extract into PVA/ALG nanofibrous mats is that their alterations have resulted in enhanced mechanical characteristics. The nanofibrous mats containing MS extracts showed significantly increased antibacterial efficacy against Gram-positive and Gram-negative bacteria. Based on the findings from in vivo experiments, the PVA/ALG/MS1 (M2) dressing demonstrated a wound closure rate of 93-94 % within 21 days of treatment in rats, indicating its significant potential for use as a wound dressing agent in the treatment of burn injuries. The combination of PVA, ALG, and MS1 in this nanofibrous mats exhibited beneficial properties, including biocompatibility, suitable mechanical strength, and the ability to promote cellular proliferation and angiogenesis, further validating its effectiveness as a wound healing dressing.

Catecholamines polymerization crosslinking for alginate-based burn wound dressings developed with ciprofloxacin and zinc oxide interactions.

There is an increasing demand for stable and durable wound dressings to treat burn injuries and infections. Bioactive electrospun nanofibrous mats with antibacterial properties are promising for wound dressing usage. Electrospinning of biopolymers for wound dressing applications needs post-spinning crosslinking to prevent mat dissolution in moist wound environments. Here, we prepared durable wound dressing by using the Dopamine (DA) polymerization crosslinking in Alginate (ALG)/Polyvinyl alcohol (PVA) nanofibrous mats, which are developed by Ciprofloxacin (CIP) and Zinc oxide (ZO). The nanofibrous mats were investigated by FESEM, FTIR, mechanical strength, water contact angle, degradation, degree of swelling, and WVTR tests. The analyses demonstrate the nanofibrous mats with uniform and unbranched fibers, with a hydrophilic nature, which was porous, durable, and stable. Also, it showed the CIP and ZO addition enhanced their durability by crosslinking reinforcement. In addition, the drug release and antibacterial assays demonstrated the pH-sensitive release with more drug release at higher pH (bacterial invasion) and impressive antibacterial activity (up to 99 %). In the burn wound model in rats, the ALG/PVA/DA/CIP/ZO nanofibrous mats displayed excellent wound healing ability in wound closure and tissue regeneration. Also, complete re-epithelization and remodeling and highest collagen synthesis in histological assessment.

Smartphone-assisted quantitative colorimetric identification of thrombin based on peroxidase mimetic features of fibrinogen-gold nanozymes.

Fibrinogen-modified gold nanoparticles (Fib-AuNPs) and 3,3',5,5'-tetramethylbenzidine (TMB) substrate besides hydrogen peroxide (H2O2) were applied for assessment of the biomarker thrombin. Fib-AuNPs have catalytic active sites for the oxidation of TMB besides H2O2 and cause the color change of the substrate. Moreover, they can lead to the enhancement in the absorption wavelengths of 650 and 370 nm. By the addition of thrombin to Fib-AuNPs, fibrinogen turns into fibrin, and AuNPs are surrounded by fibrin. Therefore, their active catalytic sites for the oxidation of TMB besides H2O2 are covered by fibrin and cannot cause color change and absorption increase as before. The relationship between the average variations of the color intensity and changes in the absorption wavelengths at 650 and 350 nm with different concentrations of bovine thrombin added to Fib-AuNPs was studied. In such manner, three sensitive colorimetric approaches have been developed for the identification of bovine thrombin with the linear range of 20-120 pM and the limit of detection (LOD) of 17.54 pM for the average color intensity (G + B), the linear range of 20-120 pM and the LOD of 13.41 pM for the absorption peak at 650 nm, and the linear range of 40-140 pM with the LOD of 18.85 pM for absorption peak at 370 nm. The practical application of this biosensing platform was indicated through the successful determination of bovine thrombin in bovine serum. The satisfactory RSD ( < 10%) and recovery values (99.11-107.61%) confirmed the feasibility of the fabricated sensor.

Investigation of microbial fuel cell performance based on the nickel thin film modified electrodes.

Microbial fuel cells (MFCs) are a self-sustaining and environmentally friendly system for the simultaneous was tewater treatment and bioelectricity generation. The type and material of the electrode are critical factors that can influence the efficiency of this treatment process. In this study, graphite plates and carbon felt were modified through the electrodeposition of nickel followed by the formation of a biofilm, resulting in conductive bio-anode thin film electrodes with enhanced power generation capacity. The structural and morphological properties of the electrode surfaces were characterized using X-ray diffraction, energy-dispersive X-ray spectroscopy, elemental mapping, and field-emission scanning electron microscopy techniques. Maximum voltage, current density, and power generation were investigated using a dual-chamber MFC equipped with a Nafion 117 membrane and bio-nickel-doped carbon felt (bio-Ni@CF) and bio-nickel-doped graphite plate (bio-Ni@GP) electrodes under constant temperature conditions. The polarization and power curves obtained using different anode electrodes revealed that the maximum voltage, power and current density achieved with the bio-Ni@CF electrode were 468.0 mV, 130.72 mW/m2 and 760.0 mA/m2 respectively. Moreover, the modified electrodes demonstrated appropriate stability and resistance during successful runs. These results suggest that nickel-doped carbon-based electrodes can serve as suitable and stable supported catalysts and conductors for improving efficiency and increasing power generation in MFCs.

Fabrication of an ultra-sensitive electrochemical DNA biosensor based on CT-DNA/NiFe2O4NPs/Au/CPE for detecting rizatriptan benzoate.

A novel and first electrochemical biosensor based on Deoxyribonucleic acid (DNA) as a biological component to measure an antimigraine drug, rizatriptan benzoate (RZB) for patients under treatment in biological samples was developed. A carbon paste electrode (CPE) was modified by calf thymus (CT) double-stranded (ds)-DNA, nickel ferrite magnetic nanoparticles (NiFe2O4NPs), and gold nanoparticles (AuNPs). The morphology of the CT-DNA/NiFe2O4NPs/AuNPs/CPE was characterized by Field emission scanning electron microscope (FESEM). The presence of NiFe2O4NPs and AuNPs was confirmed by energy-dispersive X-ray spectroscopy (EDS) image of the NiFe2O4NPs/AuNPs/CPE surface. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used to determine the structure and electrochemical characteristics of the CT-DNA/NiFe2O4NPs/AuNPs/CPE. Differential pulse voltammetry (DPV) was used to investigate the electrochemical behavior of RZB. Chronoamperometry (CA) was applied to study the effect of CT-DNA immobilization time on the peak oxidation current of RZB accumulated on the surface of the CT-DNA/NiFe2O4NPs/AuNPs/CPE. The results showed that, under optimum conditions, the prepared electrode responded linearly to RZB concentrations between 0.01 and 2.0 µM, with a 0.0033 µM detection limit (LOD) and 0.01 µM limit of quantification (LOQ). The parameters influencing the biosensor performance (temperature, CT-DNA immobilization time, and RZB/CT-DNA accumulation time) were optimized. DPV showed the displacement of the peak potential towards positive values and the reduction of its current, indicating that the drug could intercalate between the guanine base pairs of CT-DNA. Our biosensor was successfully applied for RZB measurement in human urine, blood serum, plasma samples, and tablets. The presented biosensor was fast response, sensitive, selective, cost-effective, and easy-to-use for RZB determination in pharmaceutical formulations and biological samples.

Assessment of the effective parameters for the enhancement of light-harvesting power in the photoelectrochemical microbial fuel cell.

Photo-assisted microbial fuel cells (PMFCs) are novel bioelectrochemical systems that employ light to harvest bioelectricity and efficient contaminant reduction. In this study, the impact of different operational conditions on the electricity generation outputs in a photoelectrochemical double chamber configuration Microbial fuel cell using a highly useful photocathode are evaluated and their trends are compared with the photoreduction efficiency trends. As a photocathode, a binder-free photo electrode decorated with dispersed polyaniline nanofiber (PANI)-cadmium sulphide Quantum Dots (QDs) is prepared here to catalyse the chromium (VI) reduction reaction in a cathode chamber with an improvement in power generation performance. Bioelectricity generation is examined in various process conditions like photocathode materials, pH, initial concentration of catholyte, illumination intensity and time of illumination. Results show that, despite the harmful effect of the initial contaminant concentration on the reduction efficiency of the contaminant, this parameter exhibits a superior ability for improving the power generation efficiency in a Photo-MFC. Furthermore, the calculated power density under higher light irradiation intensity has experienced a significant increase, which is due to an increment in the number of photons produced and an increase in their chance of reaching the electrodes surface. On the other hand, additional results indicate that the power generation decreases with the rise of pH and has witnessed the same trend as the photoreduction efficiency.

Wound Healing: An Overview of Wound Dressings on Health Care.

Chronic wound healing is a time-consuming and complicated process. Severe risk for wound healing that can be life-threatening is bacterial invasion and wound during the healing process. Therefore, it is necessary to use a sui barrier to create a controlled environment for wound healing. Various wound dressings such as hydrocolloids, hydrogels, sponges, foams, films, and micro and nanofibers have been explored in recent decades. High surface-to-volume ratio, high similarity to the biological structure of the extracellular matrix, high porosity and very small pore size are some advantages of nanofibers that have become potential candidates for wound healing applications. Different methods are used to fabricate nanofibers like drawing-processing, template synthesis, self-assembly, phase separation, force-spinning and electrospinning. Electrospinning is the most desirable method due to the possibility of producing independent, accessible and controllable nanofibers. The fiberbased wound dressings and their manufacturing methods have been extensively discussed.

A novel sensing platform for electrochemical detection of metronidazole antibiotic based on green-synthesized magnetic Fe3O4 nanoparticles.

The spread of antibiotic resistant genes has become a serious global concern. Thus, the development of efficient antibiotic monitoring systems to reduce their environmental risks is of great importance. Here, a potent electrochemical sensor was fabricated to detect metronidazole (MNZ) on the basis of green synthesis of Fe3O4 nanoparticles (NPs) using Sambucus ebulus L. leaves alcoholic plant extract as a safe and impressive reducing and stabilizing agent. Several analyses such as X-ray diffraction (XRD), Fourier transform infrared spectrophotometer (FTIR), thermogravimetric analysis (TGA), field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDX), and dynamic light scattering (DLS) confirmed the production of homogeneous, monodisperse, regular, and stable magnetite NPs with a spherical morphology. The as-prepared Fe3O4NPs were afterwards applied to evaluate the electrochemical activity of MNZ by merging them with graphene nanosheets (GR NSs) on the glassy carbon electrode (GCE). The GR/Fe3O4NPs/GCE represented extraordinary catalytic activity toward MNZ with two dynamic ranges of 0.05-5 µM and 5-120 µM, limit of detection (LOD) of 0.23 nM, limit of quantification (LOQ) of 0.76 nM, and sensitivity of 7.34 µA µM-1 cm-2. The fabricated sensor was further employed as a practical tool for electrochemical detection of MNZ in real aqueous samples.

A novel gas production bioassay of thiosulfate utilizing denitrifying bacteria (TUDB) for the toxicity assessment of heavy metals contaminated water.

This study reports for the first-time the possibility of deploying gas production by thiosulfate utilizing denitrifying bacteria (TUDB) as a proxy to evaluate water toxicity. The test relies on gas production by TUDB due to inhibited metabolic activity in the presence of toxicants. Gas production was measured using a bubble-type respirometer. Optimization studies indicated that 300 mg NO3--N/L, 0.5 mL acclimated culture, and 2100 mg S2O32-/L were the ideal conditions facilitating the necessary volume of gas production for sensitive data generation. Determined EC50 values of the selected heavy metals were: Cr6+, 0.51 mg/L; Ag+, 2.90 mg/L; Cu2+, 2.90 mg/L; Ni2+, 3.60 mg/L; As3+, 4.10 mg/L; Cd2+, 5.56 mg/L; Hg2+, 8.06 mg/L; and Pb2+, 19.3 mg/L. The advantages of this method include operational simplicity through the elimination of cumbersome preprocessing procedures which are used to eliminate interferences caused by turbidity when the toxicity of turbid samples is determined via spectrophotometry.

A review on bio-electro-Fenton systems as environmentally friendly methods for degradation of environmental organic pollutants in wastewater.

Bio-electro-Fenton (BEF) systems have been potentially studied as a promising technology to achieve environmental organic pollutants degradation and bioelectricity generation. The BEF systems are interesting and constantly expanding fields of science and technology. These emerging technologies, coupled with anodic microbial metabolisms and electrochemical Fenton's reactions, are considered suitable alternatives. Recently, great attention has been paid to BEFs due to special features such as hydrogen peroxide generation, energy saving, high efficiency and energy production, that these features make BEFs outstanding compared with the existing technologies. Despite the advantages of this technology, there are still problems to consider including low production of current density, chemical requirement for pH adjustment, iron sludge formation due to the addition of iron catalysts and costly materials used. This review has described the general features of BEF system, and introduced some operational parameters affecting the performance of BEF system. In addition, the results of published researches about the degradation of persistent organic pollutants and real wastewaters treatment in BEF system are presented. Some challenges and possible future prospects such as suitable methods for improving current generation, selection of electrode materials, and methods for reducing iron residues and application over a wide pH range are also given. Thus, the present review mainly revealed that BEF system is an environmental friendly technology for integrated wastewater treatment and clean energy production.

Effect of different concentrations of substrate in microbial fuel cells toward bioenergy recovery and simultaneous wastewater treatment.

Microbial fuel cells (MFCS) is a promising and expanding technology able to eliminate various pollutants of wastewater while converting its chemical energy into power energy using biocatalysts. The potential application of double-chamber microbial fuel cell (DC-MFC) for chemical oxygen demand (COD) removal and generated power from wastewater in the different conditions is investigated. DC-MFC is operated with anaerobic sludge as an active biocatalyst in an anode section, an aerobic cathode section and a Nafion117 membrane as a separator. The performance of the bioreactor is determined with different concentrations of chemical oxygen demand (COD) loadings in the MFC process, in terms of COD removal, power generation and columbic efficiencies. The results illustrated that COD removal efficiency increased at the high concentrations of organic matter. So that at COD concentration of 2000.0 mg/L the highest COD removal efficiency (84%) was obtained. But with increasing substrate initial concentration to 10000.0 mg/L the efficiency decreased to 79%. The important outputs of the system like the highest voltage, maximum generated power, current density, and energy efficiency with the 100,000 mg/L COD are 447 mV, 50.7 mW/m2, 570.0 mA/m2, and 18.6%, respectively. The optical density levels increased due to bacterial growth while pH severely decreased in the anode chamber when using high-concentration substrates in the MFC.

Zinc Phosphate Nanoparticles: A Review on Physical, Chemical, and Biological Synthesis and their Applications.

Nanotechnology is considered one of the emerging fields of science that has influenced diverse applications, including food, biomedicine, and cosmetics. The production and usage of materials with nanoscale dimensions like nanoparticles are attractive parts of nanotechnology. Among different nanoparticles, zinc phosphate nanoparticles have attracted attention due to their biocompatibility, biosafety, non-toxicity, and environmental compatibility. These nanoparticles could be employed in various applications like anticorrosion, antibacterial, dental cement, glass ceramics, tissue engineering, and drug delivery. A variety of physical, chemical, and green synthesis methods have been used to synthesize zinc phosphate nanoparticles. All these methods have some limitations along with certain advantages. Chemical approaches may cause health risks and environmental problems due to the toxicity of hazardous chemicals used in these techniques. Moreover, physical methods require high amounts of energy as well as expensive instruments. However, biological methods are free of chemical contaminants and eco-friendly. This review is aimed to explore different methods for the synthesis of zinc phosphate nanoparticles, including physical, chemical, and more recently, biological approaches (using various sources such as plants, algae, and microorganisms). Also, it summarizes the practicable applications of zinc phosphate nanoparticles as anticorrosion pigment, dental cement, and drug delivery agents.

Overview of electroactive microorganisms and electron transfer mechanisms in microbial electrochemistry.

Electroactive microorganisms acting as microbial electrocatalysts have intrinsic metabolisms that mediate a redox potential difference between solid electrodes and microbes, leading to spontaneous electron transfer to the electrode (exo-electron transfer) or electron uptake from the electrode (endo-electron transfer). These microbes biochemically convert various organic and/or inorganic compounds to electricity and/or biochemicals in bioelectrochemical systems (BESs) such as microbial fuel cells (MFCs) and microbial electrosynthesis cells (MECs). For the past two decades, intense studies have converged to clarify electron transfer mechanisms of electroactive microbes in BESs, which thereby have led to improved bioelectrochemical performance. Also, many novel exoelectrogenic eukaryotes as well as prokaryotes with electroactive properties are being continuously discovered. This review presents an overview of electroactive microorganisms (bacteria, microalgae and fungi) and their exo- and endo-electron transfer mechanisms in BESs for optimizing and advancing bioelectrochemical techniques.

A novel bio-electro-Fenton system with dual application for the catalytic degradation of tetracycline antibiotic in wastewater and bioelectricity generation.

In this new insight, the potential application of the eco-friendly Bio-Electro-Fenton (BEF) system was surveyed with the aim of simultaneous degradation of tetracycline and in situ generation of renewable bioenergy without the need for an external electricity source. To shed light on this issue, catalytic degradation of tetracycline was directly accrued via in situ generated hydroxyl free radicals from Fenton's reaction in the cathode chamber. Simultaneously, the in situ electricity generation as renewable bioenergy was carried out through microbial activities. The effects of operating parameters, such as electrical circuit conditions (in the absence and presence of external resistor load), substrate concentration (1000, 2000, 5000, and 10 000 mg L-1), catholyte pH (3, 5, and 7), and FeSO4 concentration (2, 5, and 10 mg L-1) were investigated in detail. The obtained results indicated that the tetracycline degradation was up to 99.04 ± 0.91% after 24 h under the optimal conditions (short-circuit, pH 3, FeSO4 concentration of 5 mg L-1, and substrate concentration of 2000 mg L-1). Also, the maximum removal efficiency of anodic COD (85.71 ± 1.81%) was achieved by increasing the substrate concentration up to 2000 mg L-1. However, the removal efficiencies decreased to 78.29 ± 2.68% with increasing substrate concentration up to 10 000 mg L-1. Meanwhile, the obtained maximum voltage, current density, and power density were 322 mV, 1195 mA m-2, and 141.60 mW m-2, respectively, at the substrate concentration of 10 000 mg L-1. Present results suggested that the BEF system could be employed as an energy-saving and promising technology for antibiotic-containing wastewater treatment and simultaneous sustainable bioelectricity generation.

Recent advances in electroanalytical methods for the therapeutic monitoring of antiepileptic drugs: A comprehensive review.

Frequency of seizures is often managed by a wide group of antiepileptic drugs. Regarding the pharmacokinetic variability, narrow targeted range, and difficulty of detecting signs of toxicity based on laboratory responses, therapeutic monitoring of antiepileptic drugs can play a pivotal role in optimizing the drug dosage. Electrochemical sensors and biosensors can facilitate analysis of these drugs due to their unique advantages such as fast analysis, sensitivity, selectivity, and low cost. This review article, for the first time, describes the recent advances in electrochemical sensors and biosensors developed for the analysis of antiepileptic drugs. General electrochemical measuring techniques and types of applied electrode substrates were described first. To simplify the work, various chemical and biological modifiers applied to improve the sensitivity and selectivity of the sensors were classified and explained briefly. Finally, the future prospective on the development of electrochemical platforms in the quantification of antiepileptic drugs will be presented.

Bio-Mediated Synthesis and Characterization of Zinc Phosphate Nanoparticles Using Enterobacter aerogenes Cells for Antibacterial and Anticorrosion Applications.

BACKGROUND: The promising properties of Zinc Phosphate (ZnP) Nanoparticles (NPs) have made them come into prominence as one of the most favorable catalysts in various industries with ever- increasing applications. Among several proposed synthetic methods, biological methods have mostly been desired for their sheer person-environment compatibility in comparison with those of chemical and physical ones. OBJECTIVE: Therefore, the synthesis of ZnP NPs via biological route was developed in this study. METHOD: Herein proposed a facile, applicable procedure for ZnP NPs via biosynthesis route, which included precipitation of Zinc Nitrate (Zn(NO3)2.6H2O) and diammonium hydrogen phosphate ((NH4)2HPO4) in the presence of Enterobacter aerogenes as the synthetic intermediate. Investigation of the anti-corrosion behavior of the synthesized NPs was explored on carbon steel in the hydrochloric acid corrosive environment to provide deeper insight into their unique anti-corrosion properties. Additionally, their antibacterial activities were also examined against Escherichia coli, Staphylococcus aureus and Streptococcus mutans. RESULTS: The results of X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, Field Emission Scanning Electron Microscope (FE-SEM) and the Energy Dispersive X-Ray Spectroscopy (EDS) analyses confirmed the successful synthesis of ZnP NPs. Moreover, the examinations of both anti-corrosion and antibacterial properties, revealed that the synthesized NPs could be a promising anti-corrosion/antibacterial agent. CONCLUSION: ZnP NPs with an average size of 30-35 nm were successfully synthesized via the simple, suitable biological method. Results implied that these particles could be used as a non-toxic, environmentally friendly, corrosion-resistant and antibacterial agent instead of toxic and uneco-friendly ones.

Simultaneous voltammetric determination of rizatriptan and acetaminophen using a carbon paste electrode modified with NiFe2O4 nanoparticles.

Nickel-ferrite nanoparticles (NiFe2O4) were synthesized by a hydrothermal method. They were used to modify a carbon paste electrode (CPE) and to prepare an electrochemical sensor for simultaneous determination of rizatriptan benzoate (RZB) and acetaminophen (AC). The structure and morphology of the bare CPE and modified CPE were studied using field emission scanning electron microscopy, while the structural characterization of NiFe2O4 was performed via X-ray diffraction. In the potential range 0.2-1.2 V, AC and RZB were detected at potentials of 0.5 V and 0.88 V (vs. Ag/AgCl saturated KCl 3 M), respectively. Both calibration plots are linear in the 1 to 90 µM concentration range. The limits of detection (at 3σ) of AC and RZB are 0.49 and 0.44 µM, respectively. The performance of the modified CPE was evaluated by quantifying the two drugs in spiked urine and in tablets. Graphical abstract The modified electrode consist of Nickel-ferrite and graphite by differential pulse voltammetry methods are schematically presented for simultaneous detection of acetaminophen (a painkiller drug) and rizatriptan benzoate (an antimigraine drug) in human urine and tablet samples.

Advanced sensing platform for electrochemical monitoring of the environmental toxin; bisphenol A.

Environmental xenoestrogen, Bisphenol A (BPA), is a vitally important industrial raw chemical which can bring about a wide variety of adverse impacts on our health and environment. Therefore, it is imperative to develop efficacious systems to measure BPA and improve the life quality. Herein, a mixture of titanium dioxide nanoparticles (TiO2NPs) and glutaraldehyde cross-linked chitosan (GA-CS) loaded into a carbon nanotubes paste matrix to construct a novel electrochemical sensor (TiO2NPs/GA-CS/CNTPE) with a synergetic intensified current signal for the quantitative analysis of BPA. The surface morphology of the modified sensor was assessed by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). The prepared TiO2NPs/GA-CS/CNTPE displayed increased electrocatalytic activity toward BPA. The calibration curve of BPA shows linear response in the BPA concentration range of 0.01-6 µM with the lowest limit of detection of 9.58 nM (S/N = 3). The sensor exhibited high sensitivity and selectivity, good reproducibility, desirable stability and excellent performance in detection of BPA in real samples, which prove that TiO2NPs/GA-CS/CNTPE is quite applicable for food, medical and environmental analyses.

Real-time monitoring of water quality of stream water using sulfur-oxidizing bacteria as bio-indicator.

In aquatic ecosystems, real-time water-quality (WQ) biomonitoring has become the most effective technology for monitoring toxic events by using living organisms as a biosensor. In this study, an online WQ monitoring system using sulfur oxidizing bacteria (SOB) was tested to monitor WQ changes in real-time in natural stream water. The WQ monitoring system consisted of three SOB reactors (one continuous and two semi-continuous mode reactors). The SOB system did not detect any toxicity in relatively-unpolluted, natural stream water when operated for more than six months. When diluted swine wastewater (50:1) was added to the influent of the reactors, the system detected toxic conditions in both the continuous and semi-continuous operational modes, showing 90% inhibition of SOB activity within 1 h of operation. The addition of 30 mg/L NO2--N or 2 mg/L of Cr6+ to the influents of SOB reactors resulted in the complete inhibition of the SOB activity within 1-2 h. The results demonstrated the successful application of an SOB bioassay as an online toxicity monitoring system for detecting pollutants from stream or river waters.

Introduction of 5-aminolevulinic acid as a theranostics agent in dentistry.

OBJECTIVE: The aim of this paper is to study the theranostic potential of 5-Aminolevulinic Acid (5-ALA)in dentistry. METHODS: Photodynamic inactivation (PDI) and fluorescence spectroscopy of Streptococcus sanguis, and laser induced fluorescence (LIF) of several decayed teeth were performed using 5-ALA. RESULTS: In the absence of 5-ALA, 15 min illumination of the bacteria by the means of an LED light source led to only 1.16% viability reduction. On the other hand, 5-ALA revealed remarkable dark toxicity at concentrations above 20 µM. Furthermore, the synergistic effects of 10 µM 5-ALA and illumination by the light source for 5 and 15 min intervals led respectivelyto0.74log10 and 1.69log10 reduction of viability. Also, fluorescence spectroscopy of the bacteria showed a direct relationship between emission line intensity at 620 nm and the concentration of 5-ALA. In dental experiments, following exposing tooth with 40 mM 5-ALA, a significant autofluorescence growth was observed just in the decayed parts. CONCLUSION: Based on the strong dual modality of 5-ALA to annihilate cariogenic bacteria through photodynamic inactivation and enhancing LIF intensity for identification of dental caries, 5-ALA is proposed as a theranostic agent in dentistry.