Influence of Gold Nanoparticles with Different Surface Charges on Localization and Monocyte Behavior

Abstract

The use of gold nanoparticles (AuNP) has been established in nanocarriers, diagnostics, and biosensors. Access to the targeted sites of these nanomaterials could directly involve the first line of defense, the innate immune system. Charges of nanomaterials play a critical role in a number of aspects such as stabilization, cellular uptake, modulation, and function of cells. Interactions and modulations of the charged nanomaterials against the innate immune system may occur even at very low concentration. To understand the effects of charges on monocyte behavior, in this study, the positively and negatively charged AuNP (AuNP+ve and AuNP-ve) of the similar size and shape on cytotoxicity, recognition, cellular behavior, and function were evaluated in vitro using U937 human monocyte cells as an innate immunity model. Both types of AuNP at various concentrations (0−5 nM) exhibited low toxicity. In addition, the cellular internalization of the AuNP+ve and AuNP-ve, as determined by TEM, occurred by different mechanisms, and the internalization had no effect on cellular destruction, as implied by the low levels of %LDH. Interestingly, the AuNP+ve recognition and internalization seemingly entered cells through receptor dependence and strongly affected cellular response to express both pro-inflammatory (IL-1β) and anti-inflammatory (TGF-β) cytokines, while the AuNP-ve stimulated TNF-α expression. Nevertheless, the AuNP-treated cells maintained normal function when exposed to planktonic bacteria. Thus, these results indicated that one part of the immune system interacted with different surface-charged AuNP, suggesting appropiate immunomodulation in biomedicine.

Role of Ionic Strength in the Formation of Stable Supramolecular Nanoparticle–Protein Conjugates for Biosensing

“…Inorganic nanoparticles can be engineered to possess physiochemical properties for specific applications, e.g., their shape [17] and size [18] can be tuned to define nanoparticle properties. The molecular recognition properties of these particles are dictated by the chemical structure of the coating ligands, which form self-organized and multivalent binding sites for the guest species [19], a feature crucial for nanoparticle colloidal stability [20,21]. The surface of the nanoparticles interfaces with the external environment, and appropriately engineered surfaces can be used to regulate interactions between nanoparticles and biomolecules [22][23][24] driven by non-covalent interactions [9,25].…”

Nanoparticles as Smart Carriers for Enhanced Cancer Immunotherapy

“…Furthermore, Yan et al (2008) reported that in contrast to neutral liposomes, cationic liposomes produce ROS inside DCs and this ROS is further required for ERK and p38 activation as well as induction of downstream cytokines, chemokines, and co-stimulatory molecules. Recently, Srijampa et al (2020) demonstrated that positively charged GNPs exhibited a high potential to induce immune responses (induce both proinflammatory, IL-1β and anti-inflammatory, TGF-β cytokine expression) as compared to negatively charged GNPs (induce only pro-inflammatory, TNF-α cytokine expression) in human monocyte cells. Although cationic NPs are suitable for cellular internalization through electrostatic interaction but sometime cationic NPs can cause platelet aggregation and hemolysis or can disturb membrane integrity.…”

Nanotechnology Solutions for Controlled Cytokine Delivery: An Applied Perspective

“…Although generally described as biocompatible, gold nanoparticles can, in some cases, elicit an immune reaction and it is thus essential to evaluate cellular responses such as cytokine or reactive oxygen species (ROS) production, an overlooked aspect in many reports. For instance, Srijampa and co-workers showed that the surface charge of gold nanoparticles determined whether pro-inflammatory cytokine production is increased or decreased [59,60]. However, other physical and chemical properties of the nanoformulations, such as size and hydrophobicity of the particle coating, may also be responsible for causing cytotoxicity, influencing compatibility with cellular immune responses such as transport processes or cellular damage [60].…”

“…For instance, Srijampa and co-workers showed that the surface charge of gold nanoparticles determined whether pro-inflammatory cytokine production is increased or decreased [59,60]. However, other physical and chemical properties of the nanoformulations, such as size and hydrophobicity of the particle coating, may also be responsible for causing cytotoxicity, influencing compatibility with cellular immune responses such as transport processes or cellular damage [60]. In this way, the design of nanoparticles for biomedical applications should respect these key aspects as well as the final objective and type of application.…”