Quantitative assessment of cardiomyocyte mechanobiology through high-throughput cantilever-based functional well plate systems.

Proper regulation of the in vitro cell culture environment is essential for disease modelling and drug toxicity screening. The main limitation of well plates used for cell culture is that they cannot accurately maintain energy sources and compounds needed during cell growth. Herein, to understand the importance of perfusion in cardiomyocyte culture, changes in contractile force and heart rate during cardiomyocyte growth are systematically investigated, and the results are compared with those of a perfusion-free system. The proposed perfusion system consists of a Peltier refrigerator, a peristaltic pump, and a functional well plate. A functional well plate with 12 wells is made through injection moulding, with two tubes integrated in the cover for each well to continuously circulate the culture medium. The contractile force of cardiomyocytes growing on the cantilever surface is analysed through changes in cantilever displacement. The maturation of cardiomyocytes is evaluated through fluorescence staining and western blot; cardiomyocytes cultured in the perfusion system show greater maturity than those cultured in a manually replaced culture medium. The pH of the culture medium manually replaced at intervals of 3 days decreases to 6.8, resulting in an abnormal heartbeat, while cardiomyocytes cultured in the perfusion system maintained at pH 7.4 show improved contractility and a uniform heart rate. Two well-known ion channel blockers, verapamil and quinidine, are used to measure changes in the contractile force of cardiomyocytes from the two systems. Cardiomyocytes in the perfusion system show greater stability during drug toxicity screening, proving that the perfusion system provides a better environment for cell growth.

Highly durable crack sensor integrated with silicone rubber cantilever for measuring cardiac contractility.

To date, numerous biosensing platforms have been developed for assessing drug-induced cardiac toxicity by measuring the change in contractile force of cardiomyocytes. However, these low sensitivity, low-throughput, and time-consuming processes are severely limited in their real-time applications. Here, we propose a cantilever device integrated with a polydimethylsiloxane (PDMS)-encapsulated crack sensor to measure cardiac contractility. The crack sensor is chemically bonded to a PDMS thin layer that allows it to be operated very stably in culture media. The reliability of the proposed crack sensor has been improved dramatically compared to no encapsulation layer. The highly sensitive crack sensor continuously measures the cardiac contractility without changing its gauge factor for up to 26 days (>5 million heartbeats), while changes in contractile force induced by drugs are monitored using the crack sensor-integrated cantilever. Finally, experimental results are compared with those obtained via conventional optical methods to verify the feasibility of building a contraction-based drug-toxicity testing system.

Exploiting fruit byproducts for eco-friendly nanosynthesis: Citrus × clementina peel extract mediated fabrication of silver nanoparticles with high efficacy against microbial pathogens and rat glial tumor C6 cells.

Process byproducts from the fruit industry may represent a cheap and reliable source of green reducing agents to be used in current bio-nanosynthesis. This study reports the use of orange (Citrus × clementina) peel aqueous extract (OPE) for one-pot green synthesis of silver nanoparticles (AgNPs) with high effectiveness against various microbial pathogens as well as rat glial tumor C6 cells. The effects of various operational parameters on the synthesis of AgNPs were systematically investigated. The morphology, particle size, and properties of synthesized AgNPs were characterized using UV-visible spectroscopy, x-ray diffraction, x-ray photoelectron spectroscopy, field emission scanning electron microscopy, energy-dispersive x-ray spectroscopy, and Fourier transform infrared spectroscopy. High-resolution transmission electron microscopy shows that the nanoparticles are mostly spherical in shape and monodispersed, with an average particle size of 15-20 nm. Notably, the OPE-synthesized AgNPs were stable up to 6 months without change in their properties. Low doses of OPE-AgNPs inhibited the growth of human pathogens Escherichia coli, Bacillus cereus, and Staphylococcus aureus. The minimum inhibitory concentration and minimum bactericidal concentration of AgNPs against selected pathogenic bacteria were determined. OPE-AgNPs exhibited strong antioxidant activity in terms of ABTS (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)) radical scavenging (IC50 49.6 µg/mL) and DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging (IC50 63.4 µg/mL). OPE-AgNPs showed dose-dependent response against rat glial tumor C6 cells (LD50 60 µg/mL) showing a promising potential as anticancer agents. Overall, the current investigation highlighted a cheap green technology route to synthesize AgNPs using OPE byproducts and could potentially be utilized in biomedical, cosmetic, and pharmaceutical industry.

Exploiting antidiabetic activity of silver nanoparticles synthesized using Punica granatum leaves and anticancer potential against human liver cancer cells (HepG2).

This study first time reports the novel synthesis of silver nanoparticles (AgNPs) using a Punica granatum leaf extract (PGE). The synthesized AgNPs were characterized by various analytical techniques including UV-Vis, Fourier transform infrared (FTIR), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy and energy-dispersive spectra (FESEM-EDS) and high-resolution transmission electron microscopy (HRTEM). FTIR analysis revealed that the involvement of biological macromolecules of P. granatum leaf extract were distributed and involved in the synthesis and stabilization of AgNPs. A surface-sensitive technique of XPS was used to analyse the composition and oxidation state of synthesized AgNPs. The analytical results confirmed that the AgNPs were crystalline in nature with spherical shape. The zeta potential study revealed that the surface charge of synthesized AgNPs was highly negative (-26.6 mV) and particle size distribution was ranging from ∼35 to 60 nm and the average particle size was about 48 nm determined by dynamic light scattering (DLS). The PGE-AgNPs antidiabetic potential exhibited effective inhibition against α-amylase and α-glucosidase (IC50; 65.2 and 53.8 µg/mL, respectively). The PGE-AgNPs showed a dose-dependent response against human liver cancer cells (HepG2) (IC50; 70 µg/mL) indicating its greater efficacy in killing cancer cells. They also possessed in vitro free radical-scavenging activity in terms of ABTS (IC50; 52.2 µg/mL) and DPPH (IC50; 67.1 µg/mL) antioxidant activity. PGE-AgNPs displayed strong antibacterial activity and potent synergy with standard antibiotics against pathogenic bacteria. Thus, synthesized PGE-AgNPs show potential biomedical and industrial applications.

Bio-fabrication of silver nanoparticles using the leaf extract of an ancient herbal medicine, dandelion (Taraxacum officinale), evaluation of their antioxidant, anticancer potential, and antimicrobial activity against phytopathogens.

In recent years, the use of nanoparticle-based antimicrobials has been increased due to many advantages over conventional agrochemicals. This study investigates the utilization of common medicinal plant dandelion, Taraxacum officinale, for the synthesis of silver nanoparticles (TOL-AgNPs). AgNPs were evaluated for antimicrobial activity against two important phytopathogens, Xanthomonas axonopodis and Pseudomonas syringae. The morphology, size, and structure of TOL-AgNPs were characterized using UV-visible spectroscopy and X-ray diffraction (XRD). Fourier transform infrared spectroscopy (FT-IR) showed the presence of phytochemicals involved during synthesis of NPs. High-resolution transmission electron microscopy (HR-TEM) analysis shed light on the size of monodispersed spherical AgNPs ranging between 5 and 30 nm, with an average particle size of about 15 nm. The TOL-AgNPs (at 20 µg/mL concentration) showed significant antibacterial activity with significant growth inhibition of phytopathogens X. axonopodis (22.0 ± 0.84 mm) and P. syringae (19.5 ± 0.66 mm). The synthesized AgNPs had higher antibacterial activity in comparison with commercial AgNPs. Synergistic assays with standard antibiotics revealed that nanoformulations with tetracycline showed better broad-spectrum efficiency to control phytopathogens. They also possessed significant antioxidant potential in terms of ABTS (IC50 = 45.6 µg/mL), DPPH (IC50 = 56.1 µg/mL), and NO (IC50 = 55.2 µg/mL) free radical scavenging activity. The TOL-AgNPs showed high cytotoxic effect against human liver cancer cells (HepG2). Overall, dandelion-mediated AgNPs synthesis can represent a novel approach to develop effective antimicrobial and anticancer drugs with a cheap and eco-friendly nature.

A facile one-pot preparation of organoselanyltrifluoroborates from dihalobenzenes and their cross-coupling reaction.

Potassium organoselanyltrifluoroborates have been prepared from the corresponding dihalobenzene compounds in 56-92% yields through a facile one-pot, multicomponent reaction. The microwave-promoted Suzuki-Miyaura cross-coupling reaction of these substrates with various aryl and alkenyl bromides in the presence of 3.0 mol % of Pd(PPh(3))(4) and 3.0 equiv of K(2)CO(3) in aqueous 1,4-dioxane at 130 degrees C provided the desired compounds in 54-91% yields.

Microbial recovery of copper from printed circuit boards of waste computer by Acidithiobacillus ferrooxidans.

The bioleaching of copper contained in the printed circuit boards (PCB) of waste computers by A. ferrooxidans was studied. The Fe oxidation rates by A. ferrooxidans in the 9K medium supplemented with the leachate of PCB (0.15-0.13 g L(-1) d(-1)) were similar to that in the 9K medium without the leachate (0.15 g L(-1) d(-1)). This finding suggests that the leachate of PCB did not seriously affect the bioleaching process by this bacterium. The amount of copper leached from PCB shreds increased with the addition of ferrous ion and reached up to 5190 mg L(-1) when the initial concentration of Fe2+ ion was 7 g L(-1). As the microbial leaching progressed, pale brown precipitate was observed to form in the solution. Based on the total amount of copper, both in solution and precipitate, the optimal addition of ferrous ion for the leaching of copper was around 7 g L(-1). When citric acid was not added, only about 37 wt% of the total leached copper remained dissolved; however, the amount of dissolved copper increased to greater than 80 wt% in the presence of citric acid. This fact indicates that the addition of a complexing agent (citric acid) to the bioleaching solution can raise the solubility of the leached metal ions.

Heavy metal pollution in the soils of various land use types based on physicochemical characteristics.

In this study, soil samples were collected at eight different regional types of Seoul City and analyzed for their physicochemical properties. In addition, the distribution of heavy metal concentrations was analyzed using samples representing both the surface and deep soil layer. The physicochemical properties analyzed for those samples included parameters such as pH, moisture content, apparent (and true) density, pore ratio, solid content, conductivity, ionic strength, total dissolved solid (TDS), total organic carbon (TOC), and total phosphorus (TP). The contents of heavy metal components contained in plant leaves were also analyzed and compared with those measured from different soil layers. Contents of Cu and Cd were highest in the DH area among eight locations investigated and Pb was higher in the surface soil samples of the GS region than any other locations. According to physicochemical properties of the surface and deep soils, acidity was higher in the surface than deep soils. Depending on the selection of treatment method between strong and weak acids, the metal concentrations were larger by 3-5 times in the strong acid than the weak acid treatments. In addition, metals were higher in the deep than in the surface soil and relative metal contents of leaf samples closely resembled those of soil samples. Results of this study suggest that the physicochemical properties of soils determined from different regional types of Seoul area exhibited a close relationship with the land use types and environmental conditions surrounding each region.