Research Article: Synthesis of a novel glucose capped gold nanoparticle as a better theranostic candidate

Date Published: June 5, 2017

Publisher: Public Library of Science

Author(s): Saritha Suvarna, Ujjal Das, Sunil KC, Snehasis Mishra, Mathummal Sudarshan, Krishna Das Saha, Sanjit Dey, Anindita Chakraborty, Y. Narayana, Yogendra Kumar Mishra.


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.

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Application of nanotechnology has gained a major thrust in research especially in the area of medicine and biology. With several gold nanoparticle based therapies currently undergoing clinical trials, gold nanoparticles have become the subject of a wide ranging international research effort with preclinical studies underway [1]. Synthesis of nanoscale structures of inert metals like gold are of great interest for the present day researchers as gold possess certain physical properties which are suitable for several biomedical applications. Thus gold nanoparticles show significant future promise in the fields of diagnostic imaging and therapy, including multifunctional drug-delivery vehicles [2–8], The Au-ZnO nanocomposite exhibits significant enhancement in the Raman signals for C70 C70 molecules [9]. Various standard protocols and recent advances for shape-controlled synthesis of nanocrystals are reported, it is clear that significant progress has been made towards design synthesis of nanocrystals, with desired shape, crystallity and composition by controlling the nucleation and growth process using specific synthetic protocols[10]. Studies also reported doses (concentration) of Au-Nps required for controlling the growth or decay of C2C12 myoblast cells. The obtained results clearly demonstrate that the treatments with nanoparticles diminished the growth of cells. Apoptosis was determined to be enhanced with an increase in nanoparticle concentration, and a significant concentration of nanoparticles resulted in cellular death [11]. Additionally, the galvanic replacement reaction with HAuCl4 in an organic medium was implemented to prepare hydrophobic hollow Au-Ag nanocages with tunable localized surface Plasmon resonances [12]. The superiority of atom beam sputtering over in beam mixing and ion implantation in the synthesis of Au nanoparticles has also been demonstrated. The possibility of using Au-SiO2 nanocomposites as a biosensor for the detection of ovarian cancer cells has been explored [13]. Studies also lay special emphasis on the uniqueness of the gold nanoparticles for treatment of life threatening diseases like cancer [14]. Available reports show potential of gold nanoparticles in the field of photodynamic therapy due to their ability of producing heat to kill the tumors [15]. AuNPs are reported as good photo-thermal agents for cancer therapy because they show efficient local heating upon excitation of surface plasmon oscillations. The strong absorption, efficient heat conversion, high stability, inherent low toxicity and well-defined surface chemistry of AuNps, contribute to the growing interest in their photothermal therapy (PTT) applications [16]. In the recent past, researchers also discussed the near-infrared-active AuNps, which include different shape of nanoparticle systems, especially regarding the clinical translation of AuNp[17]. Varity of shapes have driven a new wave of interest in their optical properties and thus offers applications like imaging and spectroscopic detection of cancer [18,19] Urchin-shaped gold nanoparticles deserves special mention as this type of the AuNps may find applications as materials for Surface Enhanced Raman Scattering (SERS)[20]. The gold supraparticles have nanoparticle building blocks in close contact that generate highly intense SERS signals. They also generate plasmonic heat more efficiently and kill more cancer cells than the constituent nanoparticle building blocks. These traits make the proposed crystallographically aligned supraparticles promising candidates for nanomedicine applications such as SERS -based diagnostics and plasmonics-based theranostics [21]. Studies also reported generalized application of gold nanostars for ultrasensitive identification of molecules based on both localized surface Plasmon resonance (LSPR) and surface enhanced Raman scattering (SERS) are the requirements of plasmonic sensors, related to sufficiently large areas where nanoparticles are uniformly immobilized with high density, as well as mechanical flexibility, which offers additional advantages for real world applications [22]. However, although gold is biologically inert and thus shows much less toxicity as compared to other metal nanoparticles, gold has a relatively lower rate of clearance from circulation and hence can pose serious deleterious effects on health [23]. Recent studies showed that AuNPs can cross the blood-brain barrier, interact with the DNA and even produce genotoxic effects [24]. As such, surface modifications of AuNps are gaining attention in current day research programs where attaching a ligand and/or capping of the AuNps could help making the particles more biocompatible so as to achieve specific targeting of diseased cells and tissues [25,26]. Synthesizing AuNps with lesser toxicity is now one of the primary interests in the field of nanotechnology for its applicability in biomedical sciences. Based on this perspective, the present work has been designed to formulate a synthesis of a novel glucose capped gold nanoparticle which can be considered as a better theranostic candidate.