Inorganic nanoparticles and the immune system: detection, selective activation and tolerance

Abstract

The immune system is the responsible for body integrity and prevention of external invasion. On one side, nanoparticles are no triggers that the immune system is prepared to detect, on the other side it is known that foreign bodies, not only bacteria, viruses and parasites, but also inorganic matter, can cause various pathologies such as silicosis, asbestosis or inflammatory reactions. Therefore, nanoparticles entering the body, after interaction with proteins, will be either recognized as self-agents or detected by the immune system, encompassing immunostimulation or immunosuppression responses. The nature of these interactions seems to be dictated not specially by the composition of the material but by modifications of NP coating (composition, surface charge and structure). Herein, we explore the use of gold nanoparticles as substrates to carry multifunctional ligands to manipulate the immune system in a controlled manner, from undetection to immunostimulation. Murine bone marrow macrophages can be activated with artificial nanometric objects consisting of a gold nanoparticle functionalized with peptides. In the presence of some conjugates, macrophage proliferation was stopped and pro-inflammatory cytokines were induced. The biochemical type of response depended on the type of conjugated peptide and was correlated with the degree of ordering in the peptide coating. These findings help to illustrate the basic requirements involved in medical NP conjugate design to either activate the immune system or hide from it, in order to reach their targets before being removed by phagocytes. Additionally, it opens up the possibility to modulate the immune response in order to suppress unwanted responses resulting from autoimmunity, or allergy or to stimulate protective responses against pathogens.

Self‐Assembly of Mechanoplasmonic Bacterial Cellulose–Metal Nanoparticle Composites

“…In contrast, a large number of strategies for solution‐based synthesis of high‐quality colloidal metal NPs have been developed and optimized to yield NPs of defined sizes, [ 29 ] shapes, [ 30,31 ] and compositions [ 32 ] and with narrow size distributions. [ 33 ] The possibility to use presynthesized colloidal NPs in the fabrication of BC‐based nanocomposites can potentially enable fabrication of more well‐defined and complex materials with a wider range of optical and biophysical properties.…”

A red light‐activable MnI(CO)3‐functionalized gold nanocomposite as the anticancer prodrug with theranostic potential

“…AuNPs 15 ± 2 nm in diameter were synthesized via the citrate reduction method. [ 67 ] The structural uniformity of the synthesized AuNPs was confirmed by UV–Vis spectroscopy, DLS measurements, and powder X‐ray diffraction analysis (λ max /H 2 O: 520 nm [SPR band]; diameter = 52 ± 5 nm [hydrated] and 15 ± 2 nm [determined from TEM image]; and zeta potential = −17.8 ± 5 mV). The diffraction (2θ) peaks observed at 38.22°, 44.22°, 64.72°, and 77.69° in the XRD patterns of the AuNPs were indexed to the (111), (200), (220), and (311) planes, respectively, typical of the simple cubic crystal structure of AuNPs (Figures S13–S15).…”

Highly Sensitive Strain Sensors Based on Molecules–Gold Nanoparticles Networks for High‐Resolution Human Pulse Analysis

“…The strain sensors were fabricated by growing the AuNPs–TEG network onto interdigitated gold electrodes supported on flexible polyimide substrate ( Figure ). Citrate‐stabilized AuNPs with a diameter of 25 ± 3 nm were synthesized by a seeded‐growth method, [ 13 ] whereas interdigitated Au electrodes with a narrow channel length (6.5 µm) were photolithographed (see details in the Supporting Information). To promote the adhesion of the particles on the surface, a solution of (3‐aminopropyl) triethoxysilane was deposited onto the prepatterned surface.…”