In situ formation of curcumin stabilized shape-selective Ag nanostructures in aqueous solution and their pronounced SERS activity

Abstract

In-situ formation of shape-selective silver nanoparticles (Ag NPs) inaqueous solution has been demonstrated just within an hour time. Ag NPs were synthesized by the reduction of Ag(I) ions in presence of a new reducing and stabilizing reagent, curcumin under continuous stirring and heating at 80 °C. Different size and shaped Ag NPs like small and large spheres, nanowires and anisotropic nano-flakes are formed just by tuning the molar ratio of curcumin to Ag(I) ions and controlling the other reaction parameters. The mechanism of formation, the role of curcumin and other reaction parameters for the formation of shape-selective Ag NPs has been examined in details. The different shaped Ag NPs has been successfully employed for the application in surface enhanced Raman spectroscopy (SERS) study using methylene blue (MB) as Raman probe. The shape effect of the NPs has been examined in-detail and the corresponding SERS enhancement factor (EF) values have been calculated. The observed EF values are in the range ~ 10 6 to 10 7 . It was found that the anisotropic nano-flake structure have the highest EF compared to other shapes. The synthesis process is straightforward, simple, reproducible, cost effective and robust. The synthesized Ag NPs are stable for more than two months while kept in a sealed bottle in refrigerator. In futuristic, the present process might be helpful for the synthesis of other types of nanomaterials in a small time scale with larger yield. Moreover, the high EF Recently, Au NPs with nanorods, nanowires, and nano triangles have been applied as SERS substrate to improve the sensitivity and reliability of conventional chemical and biological sensing. 57 Although, most of the nanomaterials used are not either uniform in shape or used a mixture of different size or shaped particles. Moreover, most of the cases, due to presence of surfactant or other capping agents on the NPs surface reduce their efficiency.In our present SERS study, we have synthesized four different sizes and shaped Ag NPs without addition of any seed particles or surfactant. We used small and larger size Ag spheres, Ag nanowires and Ag nano-flakes for study their shape effect on SERS. For comparison

Single step synthesis, characterization and applications of curcumin functionalized iron oxide magnetic nanoparticles

“…28,29,30 Although curcumin has low bioavailability, it has been reported that conjugation of curcumin with metal nanoparticles could increase its bioavailability. 31 Also, based on previously reported spectroscopic measurements at various temperatures, the breaking of intra-molecular H-bonding could increase the solubility of curcumin in water at higher temperatures. 32 The molecular structure of curcumin possesses multiple aromatic groups with hydroxyl functionalities that could be utilized for interaction with other aromatic molecules such as polychlorinated biphenyls (PCBs) via pi-pi stacking interactions.…”

“…33 In a similar study, Kundu and co-workers have shown the synthesis of curcumin stabilized Ag nanoparticles and their application in surface enhance Raman spectroscopy (SERS) using methylene blue as Raman probe. 31 Kale and coworkers have also designed a Fe 3 O 4 -citric acid-curcumin conjugated nanoplatform with application in superoxide scavenging, tumor suppression and cancer hyperthermia. 25 Many reports of curcumin conjugation with Fe 3 O 4 nanoparticles have been reported in literature with an additional linker to modify the nanoparticle surface with curcumin; however, a direct functionalization in single step without any linkers and additional reaction steps has not been reported to date.…”

Enhanced catalytic and SERS activities of CTAB stabilized interconnected osmium nanoclusters

“…26 Apart from the catalysis reaction, metal NPs were also tested for surface enhanced Raman scattering (SERS) studies. [27][28][29][30] In SERS, the plasmonic coupling effect at the nanometric gap junctions between the particles induces an enormous electromagnetic enhancement that allows the SERS signal to be detected with single molecular sensitivity. Moreover, SERS enables molecules to be identified by their vibrational 'fingerprint' and the other applications range from detection of bio-molecules, sensors or even in medical therapeutics.…”

Visible light sensitization of TiO2 nanoparticles by a dietary pigment, curcumin, for environmental photochemical transformations

“…S1a, † the curcumin/TiO 2 sample exhibits two distinct peaks at 1691 cm À1 and 1507 cm À1 , which correspond to the C]O and C]C functional groups of curcumin, respectively. 38 This also conrms that curcumin is adsorbed on the TiO 2 surface. The C]O peak was slightly shied to a higher wavenumber, which indicates that the b-diketone group in curcumin forms a chelate complex on the TiO 2 surface.…”