Spectral Response of Interfacial Water at Different Lipid Monolayer Interfaces upon Interaction with Charged Gold Nanoparticles

Abstract

Understanding the interactions of nanoparticles with cell membranes is crucial for designing materials for biomedical applications. In this paper, through the combination of vibrational sum frequency generation (VSFG) and molecular dynamics simulation techniques, the spectral responses of the interfacial water molecules due to interaction of anionic gold nanoparticles (AGNPs) and cationic gold nanoparticles (CGNPs) with three differently charged model cell membranes, namely, 1,2-dipalmitoyl-sn-glycero-3-phosphoglycerol (DPPG, negatively charged), 1,2-dipalmitoyl-3-trimethylammonium-propane (DPTAP, positively charged), and zwitterionic 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC, neutral), have been investigated. The interfacial water intensity at the DPPG–water interface decreases abruptly in the presence of CGNPs because of the significant change in Stern layer configuration, whereas it does not show any noticeable change in the presence of AGNPs, resulting in an unperturbed stern layer configuration. However, in the case of DPTAP and DPPC interfaces, the Stern layer is significantly perturbed in the presence of both the charged GNPs, resulting in a substantial change in the interfacial water intensity. This is attributed to the change in orientation and structure of interfacial water molecules in the presence of both charged GNPs. These results provide valuable insights into the solvation structure and dynamics of water molecules to exploit for designing and optimizing the delivery system for biomedical applications.

Unravelling the Mechanism behind Charge Reversal at Silica Nanoparticle–Model Cell Membrane Interfaces

“…This reduction in intensity is attributed to changes in the Stern layer configuration. 19 In this paper, we control the potential at the positive DPTAP interface by varying the concentration of negative SNPs to explore their effect on the organization of water at the interface. We have probed the interaction of a model cationic lipid, DPTAP (Figure 1a) with 28.0 ± 2.10 nm SNPs at two different pH values, i.e., pH ∼ 2 and pH ∼ 11.…”

“…Therefore, the investigation of the underlining mechanism of interaction of NPs with biological membranes plays a pivotal role in proposing strategies for the efficient and safe transfer of NPs into the cell membranes. Various techniques, such as surface plasmon resonance, atomic force microscopy, surface-enhanced Raman scattering, and second harmonic and sum frequency generation (SFG) − spectroscopy, have been used to probe the NP–membrane interactions. Although NP–membrane interactions have received significant attention, the biochemical role of interfacial water molecules in mediating these interactions is particularly significant.…”

“…Specifically, for the 1,2-dipalmitoyl-3-(trimethylammonium)­propane (DPTAP) monolayer, the vibrational intensity of interfacial water molecules is significantly reduced with the addition of cationic and anionic GNPs. This reduction in intensity is attributed to changes in the Stern layer configuration …”

Sixty Years of Surface-Specific Spectroscopy

“…VSFG was used by Strazdaite and Roeters et al to investigate the interaction between lipid monolayers and amyloid-β protein, showing that the identity of the lipids affects the degree and type of aggregation of the protein . VSFG in conjunction with molecular dynamics simulations was used by Pandey and co-workers to study how differently charged gold nanoparticles interact with model cell membranes . They showed that the presence of the nanoparticles disrupts the structure of the water molecules in the membranes.…”

“…37 VSFG in conjunction with molecular dynamics simulations was used by Pandey and co-workers to study how differently charged gold nanoparticles interact with model cell membranes. 38 They showed that the presence of the nanoparticles disrupts the structure of the water molecules in the membranes. VSFG was used to study the structure of self-assembled monolayers, and the interaction of the monolayers with prostate cancer antigen biomarker by Raymundo-Pereira et al 39 Guo et al used VSFG to measure differences in ion binding for free and surface bound proteins.…”