Non-toxic Gold Nanoparticles Research Articles

Inhaled Gold Nano-star Carriers for Targeted Delivery of Triple Suicide Gene Therapy and Therapeutic MicroRNAs to Lung Metastases: Development and Validation in a Small Animal Model.

Pulmonary metastases pose significant treatment challenges for many cancers, including triple-negative breast cancer (TNBC). We developed and tested a novel suicide gene and therapeutic microRNAs (miRs) combination therapy against lung metastases in vivo in mouse models after intranasal delivery using nontoxic gold nanoparticles (AuNPs) formulated to carry these molecular therapeutics. We used AuNPs coated with chitosan-β-cyclodextrin (CS-CD) and functionalized with a urokinase plasminogen activator (uPA) peptide to carry triple cancer suicide genes (thymidine kinase-p53-nitroreductase: TK-p53-NTR) plus therapeutic miRNAs (antimiR-21, antimiR-10b and miR-100). We synthesized three AuNPs: 20nm nanodots (AuND), and 20nm or 50nm nanostars (AuNS), then surface coated these with CS-CD using a microfluidic-optimized method. We sequentially coated the resulting positively charged AuNP-CS-CD core with synthetic miRNAs followed by TK-p53-NTR via electrostatic interactions, and added uPA peptide through CD-adamantane host-guest chemistry. A comparison of transfection efficiencies for different AuNPs showed that the 50nm AuNS allowed ∼4.16-fold higher gene transfection than other NPs. The intranasal delivery of uPA-AuNS-TK-p53-NTR-microRNAs NPs (pAuNS@TK-p53-NTR-miRs) in mice predominantly accumulated in lungs and facilitated ganciclovir and CB1954 prodrug-mediated gene therapy against TNBC lung metastases. This new nanosystem may serve as an adaptable-across-cancer-type, facile, and clinically scalable platform to allow future inhalational suicide gene-miR combination therapy for patients harboring pulmonary metastases.

Green synthesis, characterization and antibacterial activity of gold nanoparticles using hydroxyethyl starch-g-poly (methylacrylate-co-sodium acrylate): A novel biodegradable graft copolymer

In this study, eco-friendly, non-toxic gold nanoparticles (AuNPs) were synthesized by green technique using a novel biodegradable graft copolymer based on hydroxy ethyl starch (HES) and methylacrylate (MA). The graft copolymer was prepared by first grafting of MA onto HES backbone by solution polymerization technique using potassium persulfate (K2S2O8) as the initiator followed by alkaline hydrolysis. The graft copolymer was characterized by FTIR and 1H NMR spectroscopy and XRD and SEM studies and by measuring saponification equivalent (S.E.). Biodegradation of the graft copolymer was studied by enzyme hydrolysis. AuNPs prepared by this method were characterized by UV–VIS spectroscopy and XRD, HR-TEM and EDAX analyses. The formation of AuNPs was confirmed by a visual color change (colorless to purple) and appearance of SPR band at 529nm. The prepared AuNPs are globular in shape with an average particle size of 16–20nm. Antibacterial activity of the green synthesized AuNPs was studied against two gram negative bacteria namely Shigella flexneri and Proteus mirabilis and two gram positive bacteria namely Bacillus cereus and Bacillus subtilis by agar well diffusion method. AuNPs synthesized by using the graft copolymer had a significant antibacterial effect against gram positive bacteria at very low concentration of nanoparticles.

Green synthesis, characterization and antimicrobial activity of Au NPs using Euphorbia hirta L. leaf extract

The activity of a nano sized particle is said to be greater when compared to that of its parent materials combined. Thus, an attempt was made to produce gold nanostructures having unusual physicochemical properties. In this study, eco-friendly, non-toxic gold nanoparticles (Au NPs) were biologically synthesized using the leaf extract of Euphorbia hirta L. The synthesis of Au NPs was confirmed by a change in extract color from pale yellow to purple and surface plasmon resonance spectra obtained in a range of approximately 530nm. Nanoparticles whose sizes ranged from 6nm to 71nm, were synthesized. Different instrumental techniques were used to characterize the synthesized AuNPs, such TEM, XRD, EDAX, AFM, particle size analyzer, FTIR and Raman spectra. Also the antibacterial activity of the green synthesized Au NPs against bacterial strains of Escherchia coli, Pseudomonas aeroginosa and Klebsiella pneumonia was studied using MIC method, and found to be highly effective.