Twinning as a Guiding Factor in Morphological Anisotropy of Silver Nanoparticles Stabilized Over L–DOPA: A Colorimetric Probe for Sulfide in Aqueous Medium

Abstract

Herein an interesting case study of morphological anisotropy of silver nanoparticles (AgNPs) stabilized over 3,4-dihydroxy-Lphenylalanine (L-DOPA) is presented. The deeper investigation of a variety of shapes of these silver nanoparticles through TEM and HRTEM clearly revealed the definite role of twinning besides the role of multiple structures of L-DOPA prevailing in alkaline medium. These AgNPs were further also exploited as a colorimetric sensor for sulfide (S 2À ). The same underwent bleaching of their deep yellowish brown color upon their interaction with sulfide in the aqueous medium with an appealing LOD of 65 nM. The probe worked well within the broad pH range 5 to 11. The chemosensing studies were well accomplished by UV-visible, TEM, EDX and elemental mapping studies.

Review on Anti-Aggregation-Enabled Colorimetric Sensing Applications of Gold and Silver Nanoparticles

“…In the presence of a specific analyte, the Au NPs and Ag NPs displayed a color change from wine-red to blue/purple and yellow to orange/brown, respectively [26][27][28][29][30]. In these sensory investigations, the color change was attributed to the analyte-induced aggregation of dispersed Au NPs and Ag NPs [31].…”

Synthesis of Silver Nanostructures on Different Supports: From Nanoparticle Decoration to a Complete Shell Growth

“…Although the attachment of the AgNPs to substrates is a fundamental process, in order to meet application standards, in most cases it is necessary to modify the morphology of the AgNPs to tune optical properties, [19][20][21][22][23] antimicrobial activity, [24,25] or catalytic activity, [26] among other properties. Growing anisotropic nanoparticles to obtain non-spherical AgNPs can generate fascinating optical phenomena which can be exploited in, for example, surface-enhanced Raman scattering (SERS), [27] colorimetric sensing, [28,29] and various biomedical systems. [30][31][32][33] Seedmediated growth methods are the preferred strategy to modify the morphology of AgNPs, since they allow regulating the amount of deposited silver, growth to specific sizes, controlling the anisotropic shape, or completing a shell.…”

Mussel-inspired antimicrobial coating on PTFE barrier membranes for guided tissue regeneration

“…Through this green approach, implying the reduction of Ag + ions in the presence of a DOPA solution, monodisperse AgNPs were previously produced for applications as colorimetric sensors for heavy metal [25], melamine [26] and sulfide [27] detection. For instance, Das et al [28] prepared polyDOPA-coated halloysite nanotubes, further functionalized with AgNPs through the reduction of Ag + ions in contact with polyDOPA coating. Functionalized halloysite nanotubes were used as nanocatalysts for the decomposition of wastewater pollutants.…”