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The Advantages and Versatility of Carrier-Free Nanodrug and Nanoparticle Systems for Cancer Therapy
Published in Loutfy H. Madkour, Nanoparticle-Based Drug Delivery in Cancer Treatment, 2022
Lengke et al. showed that after reaction between Plectonema boryanum UTEX 485 system and silver nitrate, spherical, octahedral, and anhedral Ag-NPs were precipitated inside cells and in the culture solution [25]. They suggested that the silver ions were reduced by an intracellular electron donor or exported by a membrane transporter system. This indicates that the metabolic status (e.g., respiration or photosynthesis) and the growth phase of an organism determine its ability to synthesize NPs. Remarkably, P. boryanum was shown to reduce gold(III) chloride solutions to Au-NPs intracellularly [67]. The authors attributed the biorecovery mechanism of P. boryanum strains to either the gold(III) chloride solution or the acidic medium, which killed cyanobacteria and liberated more organic sulfur, leading to further precipitation of gold particles. The interactions of cyanobacteria or organic material released through the cyanobacterial membrane with gold(III) chloride enhanced the growth of metallic Au-NPs.
Nanosensors for Homeland Security
Published in Vinod Kumar Khanna, Nanosensors, 2021
The designed DNA probe is specific to the BCSP31 gene of Brucella (Pal et al. 2017). The colloidal AuNPs solution is prepared by citrate reduction of gold(III) chloride hydrate. The AuNPs are functionalized by conjugating with a thiol-modified oligonucleotide probe to give oligo-AuNP. The assay is validated by observing the difference in behavior on interaction of the oligo-AuNP probe with specific and non-specific target DNA (Figure 12.23). Specific target DNA is the complementary DNA, e.g., the genomic DNA from Brucella abortus. Non-specific target DNA is the non-complementary DNA, e.g., E. coli DNA.AuNP non-aggregation/aggregation-based probe for specific/non-specific target DNA of Brucella. (Pal et al. 2017.)
Hybrid Gold Nanoparticles
Published in Vladimir Torchilin, Handbook of Materials for Nanomedicine, 2020
Alireza Gharatape, Roya Salehi
Tyagi et al. studied a citrate-based reduction method optimized at room temperature. They introduced a novel and easy method that did not require heat treatment. GNP synthesis with the Turkevich method involves several steps. In this method, Au3+ species were reduced to Au0. Eventually, with the accumulation of these atoms, the nanoparticles were formed. The size of nanoparticles depended on the number of accumulated atoms, even though the temperature has an important role in the mentioned method. They could prove the possibility of GNP synthesis at room temperature. In this method, particle size distribution was (11.7 ± 2.2 nm). A certain concentration of trisodium citrate dihydrate was mixed with gold (III) chloride and stirred at room temperature for up to 48 h. Eventually, pH was controlled by addition of the diluted solution of HCl or NaOH. The results demonstrated non-uniform shape and size of GNPs obtained in lower and higher than the optimal pH. Also, an optimal condition was obtained in a citrate to AuCl3 ratio of 2:1 [29].
Synthesis, characterization, antimalarial, antitrypanocidal and antimicrobial properties of gold nanoparticle
Published in Green Chemistry Letters and Reviews, 2019
Larayetan Rotimi, Mike O. Ojemaye, Omobola O. Okoh, Alexander Sadimenko, Anthony I. Okoh
The successful synthesis of gold nanoparticles was confirmed by the change in color of the reacting solution brought about by the reduction of Au (III) to Au (I) in Gold (III) Chloride solution followed by scanning with UV–visible spectrophotometer. The UV–visible spectrophotometer measurement (Figure 2) showed an absorption band at 225 nm for gold nanoparticles formed by plant extract reduction. This band has been demonstrated to be the absorption band for gold nanoparticles with sizes ranging from 1 to 50 nm in previously reported study (35).