Green magnetic carbon/alginate biocomposite beads from iron scrap waste for efficient removal of textile dye and heavy metal.

The circular economy can help enhance the value of industrial waste and remediate the environment. This study considers the application of iron scrap from steel production as a free resource to produce magnetic adsorbent beads to remove methylene blue dye and lead (II) ions from wastewater. Composite beads were prepared by incorporating iron scrap and activated carbon into a calcium alginate gel using a simple 'mix and drop' synthesis. The optimized magnetic beads were stable and offered a large specific surface area. The maximum adsorption capacity of the adsorbent, calculated from the Langmuir isotherm model, was 476.19 mg g-1 for methylene blue and 163.93 mg g-1 for lead (II) ions. This study places emphasis upon the zero-waste principle and employs a scalable synthetic approach for the conversion of waste iron scrap into an adsorbent material capable of delivering significant environmental benefits.

Acetylcholinesterase modified inkjet-printed graphene/gold nanoparticle/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) hybrid electrode for ultrasensitive chlorpyrifos detection.

This study successfully created a portable acetylcholinesterase sensor on a printed hybrid electrode capable of detecting chlorpyrifos in the field. While a screen-printed electrode was chosen herein to enable a single-use and portable platform for the in-field application, the hybrid material was incorporated to ensure ultrasensitive detection at lower electrode potentials. The hybrid ink of gold nanoparticles (AuNPs) decorated on graphene (GP) sheets in poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) was synthesized through a simple completely-green one-pot process. The subsequent characterization was carried out via transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR). The synergy resulting from the greater surface area and enhanced transfer of electrons combined with high levels of electrocatalytic activity and superb conductivity offered by GP, AuNP, and PEDOT:PSS allows the sensor to exhibit ultrasensitive chlorpyrifos detection at the relatively low detection limit of 0.07 nM. The sensor demonstrated in this study also exhibits good reproducibility, desirable stability, and a successful application for the real sample with satisfactory recovery results of around 106 %, indicating its potential for use as a tool in the analysis of pesticides.

Allicin and Capsaicin Ameliorated Hypercholesterolemia by Upregulating LDLR and Downregulating PCSK9 Expression in HepG2 Cells.

Hypercholesterolemia is a common cause of cardiovascular diseases (CVDs). Although allicin and capsaicin possess hypolipidemic effects through several molecular mechanisms, their effects on LDLR and PCSK9 expression are still unknown. This study aimed to investigate the effects of allicin and capsaicin on LDLR and PCSK9 expression in HepG2 cells. The effects of allicin and capsaicin on cell viability were evaluated by MTT assay and trypan blue exclusion assay. Low-density lipoprotein receptor (LDLR) levels and LDL uptake were determined by flow cytometry and confocal laser scanning microscopy (CLSM), respectively. RT-qPCR and Western blot analyses were performed to evaluate the expression of PCSK9, LDLR, SREBP-2, and HNF1α. ELISA was used to measure PCSK9 levels in culture media. Allicin and capsaicin increased the protein expression levels of LDLR via activation of the transcription factor SREBP2. However, allicin and capsaicin decreased the expression of PCSK9 protein and the secretion of PCSK9 in culture media via the suppression of HNF1α. Moreover, allicin and capsaicin increased LDL uptake into HepG2 cells. The efficacies of the hypolipidemic effects of allicin (200 µM) and capsaicin (200 µM) were comparable to that of atorvastatin (10 µM) in this study. In conclusion, allicin and capsaicin possessed hypolipidemic effects via the upregulation of LDLR and downregulation of PCSK9 expression, thereby enhancing LDL uptake into HepG2 cells. This indicates that allicin and capsaicin should be used as potent supplements to ameliorate hypercholesterolemia.

One-Pot and Green Preparation of Phyllanthus emblica Extract/Silver Nanoparticles/Polyvinylpyrrolidone Spray-On Dressing.

A spray-on wound dressing has many benefits, including easy and quick administration to broad and uneven wounds, better interface with the wound site, adhesion without additional dressing, and multiple applications in a portable package. By limiting direct contact with the wound site, such a design can prevent wound damage during treatment. This study revealed a simple, one-pot synthesis of spray-on wound dressing relying on polyvinylpyrrolidone solution incorporating silver nanoparticles as a broad-spectrum antibacterial agent and wound-healing antioxidant Phyllanthus emblica extract. Silver nanoparticles were synthesized in situ using Phyllanthus emblica extract as a biogenic reducing agent. Polyvinylpyrrolidone was employed as a film-forming agent to create an adhesive hydrogel-based dressing matrix to provide moisture and establish a shielding barrier for the wound bed as well as to regulate the release of fruit extract. In vitro tests revealed that the produced dressing film had a controlled release of the fruit extract, high antioxidant activity, and a good antibacterial action against S. aureus, P. aeruginosa, E. coli, and MRSA. Additionally, a biocompatibility study has shown that both human fibroblasts and keratinocytes are unaffected by the dressing film. Based on established findings, the current spray-on solution might be a potential option for antibacterial wound dressing.

Zingiber cassumunar Roxb. Essential Oil-Loaded Electrospun Poly(lactic acid)/Poly(ethylene oxide) Fiber Blend Membrane for Antibacterial Wound Dressing Application.

The essential oil from Zingiber cassumunar Roxb. (Plai) has long been used in Thai herbal remedies to treat inflammation, pains, sprains, and wounds. It was therefore loaded into an electrospun fibrous membrane for use as an analgesic and antibacterial dressing for wound care. The polymer blend between poly(lactic acid) and poly(ethylene oxide) was selected as the material of choice because its wettability can be easily tuned by changing the blend ratio. Increasing the hydrophilicity and water uptake ability of the material while retaining its structural integrity and porosity provides moisture balance and removes excess exudates, thereby promoting wound healing. The effect of the blend ratio on the fiber morphology and wettability was investigated using scanning electron microscopy (SEM) and contact angle measurement, respectively. The structural determination of the prepared membranes was conducted using Fourier-transform infrared spectroscopy (FTIR). The release behavior of (E)-1-(3,4-dimethoxyphenyl) butadiene (DMPBD), a marker molecule with potent anti-inflammatory activity from the fiber blend, showed a controlled release characteristic. The essential oil-loaded electrospun membrane also showed antibacterial activity against S. aureus and E. coli. It also exhibited no toxicity to both human fibroblast and keratinocyte cells, suggesting that the prepared material is suitable for wound dressing application.

Magnetic carbon nanofiber composite adsorbent through green in-situ conversion of bacterial cellulose for highly efficient removal of bisphenol A.

A magnetic carbon nanofiber sorbent was facilely synthesized from bio-based bacterial cellulose and FeCl3via impregnation, freeze-drying, followed by pyrolysis at 700 °C, without additional activation or nanofiber fabrication. The obtained material possessed intrinsic 3D naturally fibrous and porous structure with good magnetization. The adsorption results showed that the adsorption capacity of the prepared adsorbent towards bisphenol A (BPA) was as high as 618 mg/g, outperforming other adsorbents. Moreover, recycling the adsorbent for 10 consecutive cycles retained 96% of initial adsorption efficiency. The magnetic sorbent can maintain good magnetic properties even with recycling. Hence, the use of bacterial cellulose as a renewable carbon nanofiber precursor and FeCl3 as a source of magnetic particles, and a green pore generating agent in the present protocol, lead to a superior magnetic carbon nanofiber adsorbent with sustainable characteristics.

Moisture-Resistant Electrospun Polymer Membranes for Efficient and Stable Fully Printable Perovskite Solar Cells Prepared in Humid Air.

Fully printable perovskite solar cells (PPSCs) attract attention in the photovoltaic industry and research owing to their controllable and scalable production with reduced material waste during manufacturing. However, the commercialization of PPSCs has been impeded by their inherent vulnerability to ambient moisture, leading to a rapid loss of device efficiency and lifetime. Here, we propose a novel idea to enhance the photovoltaic performance and stability of PPSCs in humid air (relative humidity exceeding 80%) using electrospun hydrophobic polymer membranes, i.e., polylactic acid (PLA), polycaprolactone (PCL), and PLA/PCL blends, as moisture-resistant layers for PPSCs. After optimizing the morphologies, hydrophobicity, and thermal properties of the electrospun membranes by varying the contents of the polymer components in the membranes, the unencapsulated devices with these membranes demonstrated power conversion efficiencies of up to 8.2%, which was significantly higher than for devices without the membranes (6.8%). Moreover, devices with the optimum electrospun membrane retained more than 85% of their original efficiency after being stored in humid air for over 35 days. In comparison, devices without the electrospun membranes lost about 50% of their initial efficiency over the same time. Our work is very useful for the development of highly efficient and stable commercial PPSCs.

Green and sustainable zero-waste conversion of water hyacinth (Eichhornia crassipes) into superior magnetic carbon composite adsorbents and supercapacitor electrodes.

Troublesome aquatic weed, water hyacinth (Eichhornia crassipes) was converted into solid and liquid fractions via green and energy-saving hydrothermal carbonization (HTC). The solid product, hydrochar, was employed as a precursor to prepare magnetic carbon materials by simple activation and magnetization using KOH and Fe3+ ions, respectively. The obtained magnetic adsorbent possessed good magnetic properties and presented outstanding capacities to adsorb methylene blue (524.20 mg g-1), methyl orange (425.15 mg g-1) and tetracycline (294.24 mg g-1) with rapid adsorption kinetics even at high concentrations (up to 500 mg L-1), attributed to high specific surface area and mesopore porosity. Besides the solid hydrochar, the water-soluble liquid product was used to fabricate carbon-based supercapacitors through facile KOH activation with a considerably lower KOH amount in comparison to conventional activation. The supercapacitor electrode made from activated liquid product possessed an extremely high specific surface area of 2545 cm2 g-1 and showed excellent specific capacitance (100 F g-1 or 50 F cm-3 at 1 A g-1) and good retention of capacitance (92% even after 10 000 cycles). This work demonstrated that both solid and liquid HTC fractions from this bio-waste can serve as effective sources to prepare functional carbon materials, making this approach a sustainable zero-waste biomass conversion process.

A screen-printed carbon electrode modified with gold nanoparticles, poly(3,4-ethylenedioxythiophene), poly(styrene sulfonate) and a molecular imprint for voltammetric determination of nitrofurantoin.

A molecularly imprinted polymer (MIP) and a nanocomposite prepared from gold nanoparticles (AuNP) and poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) (PEDOT:PSS) were deposited on a screen-printed carbon electrode (SPCE). The nanocomposite was prepared by one-pot simultaneous in-situ formation of AuNPs and PEDOT:PSS and was then inkjet-coated onto the SPCE. The MIP film was subsequently placed on the modified SPCE by co-electrodeposition of o-phenylenediamine and resorcinol in the presence of the antibiotic nitrofurantoin (NFT). Using differential pulse voltammetry (DPV), response at the potential of ~ 0.1 V (vs. Ag/AgCl) is linear in 1 nM to 1000 nM NFT concentration range, with a remarkably low detection limit (at S/N = 3) of 0.1 nM. This is two orders of magnitude lower than that of the control MIP sensor without the nanocomposite interlayer, thus showing the beneficial effect of AuNP-PEDOT:PSS. The electrode is highly reproducible (relative standard deviation 3.1% for n = 6) and selective over structurally related molecules. It can be re-used for at least ten times and was found to be stable for at least 45 days. It was successfully applied to the determination of NFT in (spiked) feed matrices and gave good recoveries. Graphical abstract Schematic representation of a voltammetric sensor for the determination of nitrofurantoin. The sensor is based on a screen-printed carbon electrode (SPCE) modified with an inkjet-printed gold nanoparticles-poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) nanocomposite and a molecularly imprinted polymer.

A facile one-pot green synthesis of gold nanoparticle-graphene-PEDOT:PSS nanocomposite for selective electrochemical detection of dopamine.

A facile one-pot and green method was developed to prepare a nanocomposite of gold nanoparticle (AuNP), graphene (GP) and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). Graphene was first electro-exfoliated in a polystyrene sulfonate solution, followed by a one-step simultaneous in situ formation of gold nanoparticle and PEDOT. The as-synthesized aqueous dispersion of AuNP-GP-PEDOT:PSS was thereafter used to modify the glassy carbon electrode (GCE). For the first time, the quaternary composite between AuNP, GP, PEDOT and PSS was used for selective determination of dopamine (DA) and uric acid (UA) in the presence of ascorbic acid (AA). In comparison to a bare GCE, the nanocomposite electrode shows considerably higher electrocatalytic activities toward the oxidation of DA and UA due to a synergistic effect between AuNP, GP, PEDOT and PSS. Using differential pulse voltammetry (DPV), selective determination of DA and UA in the presence of AA could be achieved with a peak potential separation of 110 mV between DA and UA. The sensor exhibits wide linear responses for DA and UA in the ranges of 1 nM to 300 µM and 10 µM to 1 mM with detection limits (S/N = 3) of 100 pM and 10 µM, respectively. Furthermore, the proposed sensor was also successfully used to determine DA in a real pharmaceutical injection sample as well as DA and UA in human serum with satisfactory recovery results.

Electrochemical displacement sensor based on ferrocene boronic acid tracer and immobilized glycan for saccharide binding proteins and E. coli.

Pathogens such as viruses and bacteria use their envelope proteins and their adhesin lectins to recognize the glycan residues presented on the cell surface of the target tissues. This principle of recognition is used in a new electrochemical displacement sensor for the protein concanavalin A (ConA). A gold electrode was first modified with a self-assembled monolayer of a thiolated mannose/OEG conjugate and a ferrocene boroxol derivative was pre-assembled as reporter molecule onto the mannose surface. The novel tracer molecule based on a 2-hydroxymethyl phenyl boronic acid derivative binds even at neutral pH to the saccharides which could expand the application towards biological samples (i.e., urine and feces). Upon the binding of ConA, the tracer was displaced and washed away from the sensor surface leading to a decrease in the electrochemical signal. Using square wave voltammetry (SWV), the concentration of ConA in the sample solution could be determined in the dynamic concentration range established from 38nmolL(-1) to 5.76µmolL(-1) with a reproducible detection limit of 1µgmL(-1) (38nmolL(-1)) based on the signal-to-noise ratio (S/N=3) with fast response of 15min. The new reporter molecule showed a reduced non-specific displacement by BSA and ribonuclease A. The sensor was also successfully transferred to the first proof of principle for the detection of Escherichia coli exhibiting a detection limit of approximately 6×10(2)cells/mL. Specificity of the displacement by target protein ConA and E. coli was demonstrated since the control proteins (i.e., BSA and RNaseA) and the control E. coli strain, which lack of type 1 fimbriae, were ineffective.

Acidic and basic deprotection strategies of borane-protected phosphinothioesters for the traceless Staudinger ligation.

The traceless Staudinger ligation has recently found various applications in the field of peptide synthesis and modification, including immobilization and cyclization strategies. In this report, we utilize the traceless Staudinger ligation in the formation of amide bonds, which allows the acquisition of acylated aminosugars and peptides as well as the cyclization of peptides. A key element in these synthetic procedures is the use of a borane-protected phosphinomethanethiol, which is demonstrated to be prone towards oxidation in its unprotected form, during the synthesis of phosphinothioesters. In combination with acidic and basic deprotection strategies for the borane-protected phosphinothioesters, amide bonds can be formed in the presence of azides in moderate to good overall yields.