Use of Ag-Au-ICG to increase fluorescence image of human hepatocellular carcinoma cell lines.

Indocyanine green (ICG) is effective for a variety of applications including liver tumour imaging and operates in the near-infrared window. Agents for near-infrared imaging are, however, still in clinical development. The present study aimed to prepare and investigate fluorescence emission properties of ICG in combination with Ag-Au in order to enhance their specific interactions with human hepatocellular carcinoma cell lines (HepG-2). The Ag-Au-ICG complex was prepared via physical adsorption, and hence evaluated for fluorescence spectra using a spectrophotometer. Ag-Au-ICG at an optimised dosage (Ag-Au:ICG = 0.0147:1 molar ratio) in Intralipid medium was added to HepG-2 to observe the maximum fluorescence signal intensity, which further enhanced HepG-2 contrast fluorescence. Ag-Au-ICG served as a fluorescence enhancer bound onto the liposome membrane, whilst free Ag, Au, and pure ICG induced low levels of cytotoxicity in HepG-2 and a normal human cell line. Thus, our findings provided new insights for the liver cancer imaging.HighlightsConcentration-dependent fluorescence peaking in the near-infrared window revealed ICG aggregation in Ag-Au molecules.Ag-Au-ICG fluorescence intensity depended strongly on the environmental media.Human hepatocellular carcinoma cell lines treated with Ag-Au-ICG in Intralipid enhanced the contrast of fluorescence microscopy images by decreasing the level of scattering in the cell lines with the contrast values being approximately five times those observed in pure ICG in Intralipid.

Wettability, Surface Morphology and Structural Properties of ß-FeSi2 Films Manufactured Through Usage of Radio-Frequency Magnetron Sputtering.

In this research, ß-FeSi2 thin films were manufactured onto Si(111) wafer substrates through the usage of radio-frequency magnetron sputtering (RFMS) method at 2.66 × 10-1 Pa of sputtering pressure. The substrate temperatures were varied at 500 °C, 560 °C, and 600 °C. The Raman lines of the ß-FeSi2 fabricated at 500 °C revealed the peaks at the positions of ~174 cm-1, ~189 cm-1, ~199 cm-1, ~243 cm-1, ~278 cm-1, and ~334 cm-1. For the higher substrate temperatures of 560 °C and 600 °C, the Raman peaks of ~189 cm-1, ~243 cm-1, and ~278 cm-1 were shifted toward higher Raman positions. The surface view of the films was observed with several grains over the ß-FeSi2 film surface at all substrate temperatures. The average grain size of the films for the samples deposited at 500 °C and 560 °C was in the range of 28 to 30 nm, where the size was enlarged to 36 nm at 600 °C of substrate temperature. The root mean square roughness were 10.19 nm, 10.84 nm, and 13.67 nm for the ß-FeSi2 film surface prepared at the substrate temperatures of 500 °C, 560 °C, and 600 °C, respectively. The contact angle (CA) values were 99.25°, 99.80°, and 102.00° for the created samples at 500 °C, 560 °C, and 600 °C, respectively. As the acquired CA values, all ß-FeSi2 samples exhibited a hydrophobic property with CA in the range of 90° to 150°. Consequently, the produced ß-FeSi2 film surface employing the RFMS method indicated a potential to be employed in a hydrophobic coating application.

Light Detection and Carrier Transportation Mechanism in p-Type Si/n-Type Nanocrystalline FeSi2 Heterojunctions Produced via Radio-Frequency Magnetron Sputtering.

In the current research, p-type Si/n-type nanocrystalline FeSi2 heterojunctions were fabricated at room temperature with an argon pressure of 2.66×10-1 Pa by means of the utilization of a radiofrequency magnetron sputtering technique. These heterojunctions were studied for the carrier transportation mechanism and near-infrared (NIR) light detection at various temperatures ranging from 300 K down to 150 K. At 300 K, the fabricated heterojunctions displayed a typical rectifying action together with substantial leakage current. At 150 K, the leakage current was clearly reduced by greater than four orders of magnitude. The value of the ideality factor (n) at 300 K was computed to be 1.87 and this was nearly constant under temperatures ranging from 300 down to 260 K. This implies that a recombination process was predominant. At temperatures lower than 250 K, the value of n was found to be more than 2. These results demonstrated that the carrier transportation mechanism was governed by a tunnelling process. A weak response for the irradiation of NIR light was observed at 300 K. At 150 K, the ratio of the photocurrent to the dark current evidently increased by more than two orders of magnitude. The detectivity at 150 K was 4.84×1010 cm Hz1/2 W-1 at zero bias voltage, which was clearly improved as compared to that at 300 K.