Experimental and Computational Study on the Selective Interaction of Functionalized Gold Nanoparticles with Metal Ions: Sensing Prospects

Abstract

Herein, we have developed citrate-, glutathione-, and ascorbate-functionalized gold nanoparticles (AuNPs) to examine their interactions with diverse heavy metal ions, such as Cd, Mn, Cr, Fe, Co, Pb, Hg, Zn, and Ti. These interactions are crucial in defining the final outcome of AuNP-based sensing/removal of heavy metals. We have evaluated these interactions by analyzing the variations in the color and spectroscopic signals of functionalized AuNPs. Additionally, the obtained results were also compared and validated with the computational studies. It has been observed that citrate-AuNPs and GSH-AuNPs displayed high selectivity toward Cr and Mn with E force values of −23.4 and −14.0 kJ/mol, respectively. Likewise, the ascorbate-AuNPs displayed sensitivity for multiple ions, for example, Cd, Fe, and Mn, with an E force value of −19.6 kJ/mol. A detailed analysis focusing on the electrostatic charges, ionic sizes, and interaction energy values has been provided to show specific interactions between functionalized AuNPs and heavy metal ions. The respective mechanisms of interaction between heavy metal ions and functionalized AuNPs have been explored with the help of experimental and computational outcomes.

Controlled Citrate Oxidation on Gold Nanoparticle Surfaces for Improved Surface-Enhanced Raman Spectroscopic Analysis of Low-Affinity Organic Micropollutants

“…Raman spectra provide the kinetics of citrate transformation on AuNP surfaces in the presence of SO 4 −• , while the UV−vis spectra provide the kinetics of AuNP aggregation − an indirect evidence of citrate oxidation on AuNP surfaces. 35 Before each spectroscopic measurement, the cuvette was gently shaken three times to make sure the thorough mixing of all the components inside. was kept at 3 mL, to which 0.5 mL of PDS stock solution and 0.5 mL of analyte stock solution were added successively.…”

A Novel Approach for Effective Alteration of Morphological Features of Polyaniline through Interfacial Polymerization for Versatile Applications

“…The centers of the nodules are expected to serve as nucleation centers for PANI growth while the over-growth of PANI led to the formation of nodule-like structures near nucleation centers. The nodule-like morphology in citrate-AuNP/PANI composites might be due to the interaction of anilinium ions with the three free negatively charged carboxyl-groups of the citrate on the AuNPs (Figure 6A) [28]. These groups are available simultaneously for the attachment of anilinium ions.…”

“…Additionally, the formation of hollow hemispherical vesicles can be expected due to the presence of ascorbate functionalization on AuNPs-surface. During the ascorbate-AuNPs synthesis, the -OH group on furan ring interacts with AuNP whereas the negatively charged aliphatic chain is free to contribute to negative charge of ascorbate-AuNPs [28]. Thus, ascorbate-AuNPs can directly interact with positively charged anilinium ions (see Figure 6B).…”

Porphyrin-Based Conjugated Microporous Polymers for Highly Efficient Adsorption of Metal Ions

“…For example, Xu et al applied porphyrin as the monomer and prepared two new CMP materials (Por-TPE-CMP and Por-Py-CMP), which possessed high selective adsorption ability with respect to CO 2 and good adsorption performance with respect to benzene, toluene, cyclohexane, and water vapor. To the best of our knowledge, porphyrin-based CMPs as ideal absorbents for the elimination of metallic ions , are still lacking. This has inspired great interest in synthesizing porphyrin-based CMPs and studying their high efficiency and specific selectivity properties and the potential for removal of heavy metal ion contaminants via adsorption applications.…”