Synthesis of a novel glucose capped gold nanoparticle as a better theranostic candidate.

Gold nanoparticles are predominantly used in diagnostics, therapeutics and biomedical applications. The present study has been designed to synthesize differently capped gold nanoparticles (AuNps) by a simple, one-step, room temperature procedure and to evaluate the potential of these AuNps for biomedical applications. The AuNps are capped with glucose, 2-deoxy-D-glucose (2DG) and citrate using different reducing agents. This is the first report of synthesis of 2DG-AuNp by the simple room temperature method. The synthesized gold nanoparticles are characterized with UV-Visible Spectroscopy, Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM) and selected area electron diffraction (SAED), Dynamic light scattering (DLS), and Energy-dispersive X-ray spectroscopy (SEM-EDS). Surface-enhanced Raman scattering (SERS) study of the synthesized AuNps shows increase in Raman signals up to 50 times using 2DG. 3-(4, 5-dimethylthiozol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay has been performed using all the three differently capped AuNps in different cell lines to assess cytotoxcity if any, of the nanoparticles. The study shows that 2DG-AuNps is a better candidate for theranostic application

FTIR and SERS spectrum analysis.

<p>FTIR spectrum of (<b>A)</b> glucose and glucose-gold nanoparticles; (<b>B)</b> 2DG and 2DG-gold nanoparticles; <b>C</b>: SERS Raman spectra of 2DG-Au and Raman spectra of 2DG.</p

Size distribution measurement plot of AuNPs.

<p>Size distribution measurement curve of (<b>A)</b> glucose-gold nanoparticles; (<b>B)</b> citrate-gold nanoparticles; <b>C</b> Dynamic light scattering measurement of 2DG coated gold of size 21.51nm.</p

Flow chart of 2DG AuNP.

<p>Flow chart of synthesis of 2DG gold nanoparticle at room temperature method.</p

Cell viability plot and dendrogram plot.

<p><b>A</b> Viability of HeLa cells, HepG2 cells and HCT 116 cells treated with 2-Deoxy-D-Glucose-gold nanoparticles; <b>B</b> Viability of HeLa cell line; HepG2 cell line and HCT116 cells treated with glucose capped gold nanoparticles; <b>C</b> Viability of HeLa cells, HepG2 cells and HCT 116 cells treated with citrate-gold nanoparticles. Standard deviation shown as error bar, p<0.05. <b>D</b>: Dendrogram shows cell lines are aligned separately and grouped based on similarities in their cytotoxicity expression using a hierarchical clustering analysis technique. 1 represents 2DG-AuNp-Hela,2: 2DG-AuNp-HepG2, 3:2DG-AuNp-HCT116, 4:Glu-AuNp-Hela,5:Glu-AuNp-HepG2,6: Glu-AuNp-HCT116,7: Citr-AuNp-Hela,8: Citr-AuNp-HepG2, 9: Citr-AuNp-HCT116.</p

TEM analysis of AuNPs.

<p><b>5A, 5C</b> High magnification TEM image of glucose capped gold nanoparticles showing FFT measurement using Image-J software; <b>5B</b> SAED pattern of glucose capped gold nanoparticles; <b>5D, 5F</b> High magnification TEM image of citrate -gold nanoparticles showing FFT measurement using Image J-software; <b>5E</b> SAED pattern of citrate—gold nanoparticles; <b>5 G, 5I</b> Shows the high magnification TEM image of 2-Deoxy-D-Glucose capped gold nanoparticles;5 <b>H</b> SAED pattern of 2DG-Capped gold nanoparticles.</p

UV-visible absorption spectrum of AuNPs.

<p><b>A</b> UV-visible absorption spectrum of glucose-AuNps showing SPR peak at 540 nm; <b>B</b> Citrate-AuNps showing SPR peak at 520 nm; <b>C</b> 2DG-AuNps showing SPR peak at 525 nm.</p

SEM-EDS spectrum of glucose-capped gold nanoparticles and 2DG-capped gold nanoparticles.

<p>SEM-EDS analysis of (<b>A)</b> glucose-capped gold nanoparticles; (<b>B)</b> 2DG-capped gold nanoparticles;</p

Chemical equation.

<p>The reduction reaction equation for the formation of Au nanoparticles.</p