A theoretical approach on the ability of functionalized gold nanoparticles for detection of Cd2+

Abstract

Cadmium (Cd) as a toxic element that is widely present in water, soil, and air has important effects on human health, therefore proposing an accurate and selective method for detection of this element is of importance. In this article, by employing full atomistic molecular dynamics (MD) simulations and density functional theory dispersion corrected (DFT-D3) calculations, the effects of 6-mercaptonicotinic acid (MNA) and l-cysteine (CYS) on the stability of gold nanoparticles (AuNPs) and their sensitivity against Cd2+ were investigated. The obtained results indicate that pure AuNPs are not stable in water, while functionalized AuNPs with CYS and MNA groups have considerable stability without aggregation. In other words, the functional groups on the surface of AuNPs elevate their resistance against aggregation by an increase in the repulsive interactions between the gold nanoparticles. Moreover, functionalized AuNPs have considerable ability for selective detection of Cd2+ in the presence of different metal ions. Based on the MD simulation results, MNA-CYS-AuNPs (functionalized AuNPs with both functional groups) have the maximum sensitivity against Cd2+ in comparison with MNA-AuNPs and CYS-AuNPs due to the strong electrostatic interactions. DFT-D3 calculations reveal that the most probable interactions between the metal ions and functional groups are electrostatic, and Cd2+ can aggregate functionalized AuNPs due to strong electrostatic interactions with MNA and CYS groups. Moreover, charge transfer and donor–acceptor analyses show that molecular orbital interactions between the functional groups and Cd2+ can be considered as the driving force for AuNPs aggregation. A good agreement between the theoretical results and experimental data confirms the importance of the molecular modeling methods as a fast scientific protocol for designing new functionalized nanoparticles for application in different fields.

Comprehensive metabolic modulations of sphingolipids are promising severity indicators in COVID‐19

“…Regarding Cer, recognized as a significant factor in inflammation, 22 prior COVID-19 studies have indicated elevated Cer levels, contingent on the molecular species. 17,23,24 However, in our investigation, both the COVID and non-COVID groups exhibited decreased Cer levels, which remained consistently reduced regardless of disease severity or time-course, mirroring the pattern observed with S1P. This reduced Cer level may be attributed to elevated levels of its downstream sphingolipid metabolites, including Sph, Cer1P, HexCer, and LacCer (Figure 6).…”

“…Furthermore, a notable decrease was evident in the severe group at multiple time points (Figure 3B). Regarding Cer, recognized as a significant factor in inflammation, 22 prior COVID‐19 studies have indicated elevated Cer levels, contingent on the molecular species 17,23,24 . However, in our investigation, both the COVID and non‐COVID groups exhibited decreased Cer levels, which remained consistently reduced regardless of disease severity or time‐course, mirroring the pattern observed with S1P.…”

Facile synthesis of neodymium vanadate nanoribbons and its application to highly efficient determination of cadmium ions

“…Heavy metal ions as the main environmental contaminants in water systems cause great harm to human beings and different species of organisms throughout the world 1‐3 . Among these heavy metal ions, cadmium ions are highly toxic to human beings and lead to serious damage to the nervous system, kidney and liver, causing metabolic disorders and other related diseases 4‐6 . Cd 2+ is a priority pollutant and tolerable Cd 2+ concentrations in water are limited as 27 nmol L −1 due to the strong toxic role of cadmium ions 7,8 .…”

“…[1][2][3] Among these heavy metal ions, cadmium ions are highly toxic to human beings and lead to serious damage to the nervous system, kidney and liver, causing metabolic disorders and other related diseases. [4][5][6] Cd 2+ is a priority pollutant and tolerable Cd 2+ concentrations in water are limited as 27 nmol L −1 due to the strong toxic role of cadmium ions. 7,8 However, cadmium ions may be discarded to environments with living organisms from fossil fuel combustion, phosphate fertilizer and battery industries.…”

Nucleation and growth of gold nanoparticles in the presence of different surfactants. A dissipative particle dynamics study

“…NPs are very reactive due to the high surface-volume ratio, and tend to precipitate to minimize the surface tension in the colloidal suspension. Therefore, to ensure their colloidal stability, NPs are coated with organic molecules -surfactants- which provide electrostatic, steric or a mixture of both stabilization to NP’s surface 6 – 8 . They are present in the synthetic mixture from which NPs are produced and play a key role in regulating nucleation and growth processes.…”