Synthesis and Ultraviolet Visible Spectroscopy Studies of Chitosan Capped Gold Nanoparticles and Their Reactions with Analytes

Abstract

Gold nanoparticles (AuNPs) had been synthesized with various molarities and weights of reducing agent, monosodium glutamate (MSG), and stabilizer chitosan, respectively. The significance of chitosan as stabilizer was distinguished through transmission electron microscopy (TEM) images and UV-Vis absorption spectra in which the interparticles distance increases whilst retaining the surface plasmon resonance (SPR) characteristics peak. The most stable AuNPs occurred for composition with the lowest (1 g) weight of chitosan. AuNPs capped with chitosan size stayed small after 1 month aging compared to bare AuNPs. The ability of chitosan capped AuNPs to uptake analyte was studied by employing amorphous carbon nanotubes (α-CNT), copper oxide (Cu2O), and zinc sulphate (ZnSO4) as the target material. The absorption spectra showed dramatic intensity increased and red shifted once the analyte was added to the chitosan capped AuNPs.

Zinc Oxide Nanoparticle–Poly I:C RNA Complexes: Implication as Therapeutics against Experimental Melanoma

“…Previous work on silica or iron oxide NPs has either used liposome, dendrimers, polymers, or linker amine molecules to attach pIC or design biopolymer NPs like chitosan as delivery vehicles. − Here, for the first time, we report direct binding of pIC to ZnO-NP, and convincing evidence for the adsorption of pIC on ZnO-NP surface is observed from the RNA corona in TEM (Figure d). If ZnO-NPs can complex with RNA, the molar extinction coefficient of the species produced would be significantly different from that of the pristine NPs, which is indicated by an increase in absorbance intensity of the NP (Figure a). This change in absorbance signifies π–π* stacking interactions between the NPs and the RNA base pairs, consistent with our observation and theoretical studies .…”

Kinetic study of gold nanoparticles synthesized in the presence of chitosan and citric acid

“…In the literature various schemes for the synthesis of GNPs in presence of chitosan can be found [31][32][33][34][35]. Most frequently, chitosan is dissolved in acetic acid.…”

In situSynthesis of Fluorescent Gold Nanoclusters by Nontumorigenic Microglial Cells

“…These authors describe a preliminary mechanism in which the reduction of Au(III), Ag (II), Pt(IV), or Zn(II) leading to the formation of AuNCs, AgNCs, ZnNCs, and PtNCs in situ could be attributed to the high levels of either the reactive oxygen and nitrogen species (ROS and RNS) present in tumorigenic cells, or the elevated levels of intracellular reductants such as GSH-GSSG and NAD(P)H that work to mitigate ROS and RNS in tumorigenic cells (2,7,8,19,20). In fact, H 2 O 2 has been demonstrated as a reducing agent for gold nanoparticle synthesis (21)(22)(23)(24)(25), as has glutamate, a building block of GSH (26)(27)(28). This implied that only cells which are tumorigenic in nature should be capable of synthesizing P:NCs in situ.…”

“…Very recently, the in situ synthesis of protein stabilized silver, zinc, and platinum nanoclusters in tumorigenic cells have also been published. ,, Interestingly, the synthesis of near-IR-emitting AgNCs was nonspontaneous and necessitated the development of new protocols requiring additional steps for stable cluster formation . These authors describe a preliminary mechanism in which the reduction of Au­(III), Ag­(II), Pt­(IV), or Zn­(II) ions leading to the formation of AuNCs, AgNCs, ZnNCs, and PtNCs in situ could be attributed to the high levels of either the reactive oxygen and nitrogen species (ROS and RNS) present in tumorigenic cells or the elevated levels of intracellular reductants such as GSH-GSSG and NAD­(P)H that work to mitigate ROS and RNS in tumorigenic cells. ,,,, In fact, H 2 O 2 has been demonstrated as a reducing agent for gold-nanoparticle synthesis, − as has glutamate, a building-block of GSH. − This implied that only cells that are tumorigenic in nature should be capable of synthesizing P:NCs in situ . In fact, this very concept was the foundation for the specific tumor-imaging application proposed in the above studies. ,,, …”