Abstract:We show that Au nanopowders with arbitrary shapes can be converted into nanoparticles with a narrow size distribution by using a nanosecond Nd:YAG laser. Commercial Au powders were first dissolved in deionized water and irradiated with laser pulses at 532 nm. This converted the powder clusters into spherical particles with sizes ranging from 100 nm to a few micrometer. Subsequent irradiation of these Au spheres with 1064-nm pulses produced a larger quantity of nanoparticles with fairly uniform sizes. The overa… Show more
“…This confirms the self-assembly of HDM2 peptide on GNP. 37 , 38 , 39 Taken together, the XPS analysis confirmed the conjugation of the HDM2 peptide with the GNPs in the GNP-HDM2 conjugate as revealed by oxidation of Au4f 7/2 and S2p. 40 Figure 3 X-Ray Photoelectron Spectroscopy and Transmission Electron Microscopy of GNP-HDM2 (A–F) A wide XPS scan showed the spectra of the major peak C1s, O1s, and N1s (A) and higher-resolution spectra for Au4f and S2p (B) and the original and fitted spectra in the GNPs.…”
Inhibition of the interaction between p53 and HDM2 is an effective therapeutic strategy in cancers that harbor a wild-type p53 protein such as retinoblastoma (RB). Nanoparticle-based delivery of therapeutic molecules has been shown to be advantageous in localized delivery, including to the eye, by overcoming ocular barriers. In this study, we utilized biocompatible gold nanoparticles (GNPs) to deliver anti-HDM2 peptide to RB cells. Characterization studies suggested that GNP-HDM2 was stable in biologically relevant solvents and had optimal cellular internalization capability, the primary requirement of any therapeutic molecule. GNP-HDM2 treatment in RB cells in vitro suggested that they function by arresting RB cells at the G2M phase of the cell cycle and initiating apoptosis. Analysis of molecular changes in GNP-HDM2-treated cells by qRT-PCR and western blotting revealed that the p53 protein was upregulated; however, transactivation of its downstream targets was minimal, except for the PUMA-BCl2 and Bax axis. Global gene expression and in silico bioinformatic analysis of GNP-HDM2-treated cells suggested that upregulation of p53 might presumptively mediate apoptosis through the induction of p53-inducible miRNAs.
“…This confirms the self-assembly of HDM2 peptide on GNP. 37 , 38 , 39 Taken together, the XPS analysis confirmed the conjugation of the HDM2 peptide with the GNPs in the GNP-HDM2 conjugate as revealed by oxidation of Au4f 7/2 and S2p. 40 Figure 3 X-Ray Photoelectron Spectroscopy and Transmission Electron Microscopy of GNP-HDM2 (A–F) A wide XPS scan showed the spectra of the major peak C1s, O1s, and N1s (A) and higher-resolution spectra for Au4f and S2p (B) and the original and fitted spectra in the GNPs.…”
Inhibition of the interaction between p53 and HDM2 is an effective therapeutic strategy in cancers that harbor a wild-type p53 protein such as retinoblastoma (RB). Nanoparticle-based delivery of therapeutic molecules has been shown to be advantageous in localized delivery, including to the eye, by overcoming ocular barriers. In this study, we utilized biocompatible gold nanoparticles (GNPs) to deliver anti-HDM2 peptide to RB cells. Characterization studies suggested that GNP-HDM2 was stable in biologically relevant solvents and had optimal cellular internalization capability, the primary requirement of any therapeutic molecule. GNP-HDM2 treatment in RB cells in vitro suggested that they function by arresting RB cells at the G2M phase of the cell cycle and initiating apoptosis. Analysis of molecular changes in GNP-HDM2-treated cells by qRT-PCR and western blotting revealed that the p53 protein was upregulated; however, transactivation of its downstream targets was minimal, except for the PUMA-BCl2 and Bax axis. Global gene expression and in silico bioinformatic analysis of GNP-HDM2-treated cells suggested that upregulation of p53 might presumptively mediate apoptosis through the induction of p53-inducible miRNAs.
“…It can be noticed that after 4 h irradiation, peaks appeared around 520 nm, confirming the production of AuNPs. [20][21][22] It can be seen that the higher concentration solutions resulted in larger peaks. This could indicate the production of more AuNPs or the production of AuNPs with larger sizes.…”
Section: Uv-vis Spectramentioning
confidence: 95%
“…Also, pulsed laser irradiation on gold powder has been used to produce AuNPs. 20 In this work we are presenting results for the synthesis of gold nanoparticles by the direct irradiation of a gold(III) chloride solution with the 532 nm wavelength emission of a Nd:YAG laser. This method allows the adjustment of a large number of parameters, so that an accurate control of the AuNPs characteristics can be obtained.…”
A synthesis method was developed capable of obtaining pristine gold nanoparticles (AuNPs) using the lowest possible amount of auxiliary compounds. An aqueous solution of HAuCl 4 .3H 2 O was irradiated, in the absence of any stabilizing species, with the 532-nm radiation of a Nd:YAG laser. Spherical shaped AuNPs were produced by this method with sizes below 10 nm. The crystalline structures were stable for up to 28 days. A mechanism for this process is also proposed based on the initial cleavage of water molecules by the laser irradiation followed by the formation of hydrogen peroxide that reduces the gold species Au III. The resulting species of these reactions (H 2 and O 2) were identified by mass spectrometry. This new method suggests that laser irradiation is a feasible alternative to produce ready-to-use AuNPs, for drug delivery, diagnostics or bio-imaging.
“…Several methods have been reported for the preparation of silver (AgNPs) and gold (AuNPs) nanoparticles, including chemical reduction, 9,10 UV irradiation 11 and pulsed laser ablation. [12][13][14] The photochemical synthesis of nanoparticles presents advantages over other methods due to the absence of other reductive chemicals in the system that might contaminate the nanoparticles and affect its properties when used in practical applications. Photochemical syntheses of metal nanoparticles can be performed by direct photoreduction of the corresponding metal complex, or by photosensitization using an appropriate photosensitizer.…”
Silver (AgNPs) and gold (AuNPs) nanoparticles in aqueous solution were generated and stabilized using the 10-oxo-10H-dibenzene thiopyran-3-4-dicarboximide chitosan (TXICh) macrophotoinitiator. The photoinitiator and the nanoparticles in aqueous solution were characterized by UV-Vis spectroscopy and transmission electron microscopy (TEM). Pure TXICh in aqueous solution forms self-assembled particles with diameter around 30 nm. AgNPs were prepared using TXICh in the presence and absence of triethanolamine (TEOH). During irradiation, a broad band in the range of 410-415 nm was observed, corresponding to the plasmon absorption, indicating the AgNPs formation. TEM images revealed that the AgNPs had spherical shape in the absence and presence of TEOH. The synthesis of AgNPs in the presence of TEOH occurred rapidly (maximum conversion reached after 15 min), whereas in its absence 4 hours were required. The AgNPs prepared with TXICh/TEOH presented smaller and more uniform nanoparticles size. AuNPs were also prepared using TXICh as photoinitiator/stabilizer system. These nanoparticles showed an intense surface plasmon band at 530 nm and the TEM images revealed spherical particles of around 4 nm. These studies indicate that TXICh can act not only as a photoinitiator, but also as a stabilizer in the AgNPs and AuNPs formation.
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