A High-Performance Broadband Photodetector with p-SnS/n-ZnS Heterojunction Nanowires as Active Layer and Novel Nanoparticle-Anchored Silver Nanowires as Efficient Plasmonic Electrodes

Objective: To isolate and elucidate a cytotoxic principle against breast tumor MCF-7 cells of the Indonesian terrestrial plant Ficus deltoidea Jack leaves.Methods: F. deltoidea leaves collected at National Park of mount Gede-Pangrango, Indonesia have been subjected to chemical and biological work. F. deltoidea leaves were extracted with 96% aqueous ethanol (EtOH) and was then partitioned into three layers n-hexane, dichloromethane (CH2Cl2), and n-butanol (n-BuOH). All layers were checked for their activity against breast tumor MCF-7 cells using MTT assay method. A portion of the most active layer was purified using open column chromatography to give fraction that has toxicity against zebra fish embryos. Based on the assay-guided isolation, compound 1 was isolated. The chemical structure of 1 was elucidated using nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS) data as well as comparing data with literature.Results: The CH2Cl2 layer of F. deltoidea leaves was found to inhibit breast tumor MCF-7 cells with IC50 10 µg/ml which was the most toxic among the layers. A portion of the most active layer was purified using open column chromatography to give 7 fractions. The fraction 5 showed toxicity against zebrafish embryos (LC50 35 µg/ml, 48 hpf). This fraction was purified using high performance liquid chromatography (HPLC) octadecylsilyl (ODS) column with gradient elution 70% aqueous acetonitrile (MeCN) to 100% MeCN (linear gradient) for 40 min with UV detection at 254 nm (tR = 30.99 min) to give compound 1. The chemical structure of 1 was revealed as a chlorin-type compound named methyl 10-epi-pheophorbide A.Conclusion: Methyl 10-epi-pheophorbide A was isolated for the first time from the active fraction of the Indonesian F. deltoidea leaves or tabat barito. The chemical structure including absolute stereo chemistry was elucidated using NMR and HRMS data as well as by comparison with the literature values. The 13C NMR data has been added to complete the previous report.

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High-Performance Resistive Pressure Sensor Based on Elastic Composite Hydrogel of Silver Nanowires and Poly(ethylene glycol)

Micromachines ◽

10.3390/mi9090438 ◽

2018 ◽

Vol 9 (9) ◽

pp. 438 ◽

Cited By ~ 3

Author(s):

Youngsang Ko ◽

Dabum Kim ◽

Goomin Kwon ◽

Jungmok You

Keyword(s):

Composite Material ◽

Ethylene Glycol ◽

Pressure Sensor ◽

High Performance ◽

Silver Nanowires ◽

High Sensitivity ◽

Composite Hydrogel ◽

Poly Ethylene Glycol ◽

Pressure Sensing ◽

Poly Ethylene

Improved pressure sensing is of great interest to enable the next-generation of bioelectronics systems. This paper describes the development of a transparent, flexible, highly sensitive pressure sensor, having a composite sandwich structure of elastic silver nanowires (AgNWs) and poly(ethylene glycol) (PEG). A simple PEG photolithography was employed to construct elastic AgNW-PEG composite patterns on flexible polyethylene terephthalate (PET) film. A porous PEG hydrogel structure enabled the use of conductive AgNW patterns while maintaining the elasticity of the composite material, features that are both essential for high-performance pressure sensing. The transparency and electrical properties of AgNW-PEG composite could be precisely controlled by varying the AgNW concentration. An elastic AgNW-PEG composite hydrogel with 0.6 wt % AgNW concentration exhibited high transmittance including T550nm of around 86%, low sheet resistance of 22.69 Ω·sq−1, and excellent bending durability (only 5.8% resistance increase under bending to 10 mm radius). A flexible resistive pressure sensor based on our highly transparent AgNW-PEG composite showed stable and reproducible response, high sensitivity (69.7 kPa−1), low sensing threshold (~2 kPa), and fast response time (20–40 ms), demonstrating the effectiveness of the AgNW-PEG composite material as an elastic conductor.

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