Size- and Shape-Dependent Interactions of Lipid-Coated Silver Nanoparticles: An Improved Mechanistic Understanding through Model Cell Membranes and Toxicity.

The widespread use of silver nanoparticles (AgNPs) in various applications and industries has brought to light the need for understanding the complex relationship between the physicochemical properties (shape, size, charge, and surface chemistry) of AgNPs that affect their ability to enter cells and cause toxicity. To evaluate their toxicological outcomes, this study systematically analyzed a series of homogeneous hybrid lipid-coated AgNPs spanning sizes from 5 to 100 nm with diverse shapes (spheres, triangles, and cubes). The hybrid lipid membrane comprises hydrogenated phosphatidylcholine (HPC), sodium oleate (SOA), and hexanethiol (HT), which shield the AgNP surface from surface oxidation and toxic Ag ion release to minimize its contribution to toxicity.

Impacts of Differentially Shaped Silver Nanoparticles with Increasingly Complex Hydrophobic Thiol Surface Coatings in Small-Scale Laboratory Microcosms.

We investigated the impacts of spherical and triangular-plate-shaped lipid-coated silver nanoparticles (AgNPs) designed to prevent surface oxidation and silver ion (Ag) dissolution in a small-scale microcosm to examine the role of shape and surface functionalization on biological interactions. Exposures were conducted in microcosms consisting of algae, bacteria, crustaceans, and fish embryos. Each microcosm was exposed to one of five surface chemistries within each shape profile (at 0, 0.

Integrating Scientific Growth and Professional Development Skills in Research Environments to Aid in the Persistence of Marginalized Students.

Here, we describe strategies for integrating transferrable professional development (PD) skills into research learning environments for marginalized undergraduate students. The undergraduate research experience evolved to include the competencies students need to be successful and to gain a sense of belonging in the chemistry community they are seeking. These asset-based transferrable PD skills are part of the "hidden curriculum" not taught in traditional classrooms and yet are an integral part of student learning and success.

Phosphorylation of the aggregate-forming protein alpha-synuclein on serine-129 inhibits its DNA-bending properties.

Alpha-synuclein (aSyn) is a vertebrate protein, normally found within the presynaptic nerve terminal and nucleus, which is known to form somatic and neuritic aggregates in certain neurodegenerative diseases. Disease-associated aggregates of aSyn are heavily phosphorylated at serine-129 (pSyn), while normal aSyn protein is not. Within the nucleus, aSyn can directly bind DNA, but the mechanism of binding and the potential modulatory roles of phosphorylation are poorly understood.

Silver Nanoparticles Stable to Oxidation and Silver Ion Release Show Size-Dependent Toxicity In Vivo.

Silver nanoparticles (AgNPs) are widely used in commerce, however, the effect of their physicochemical properties on toxicity remains debatable because of the confounding presence of Ag ions. Thus, we designed a series of AgNPs that are stable to surface oxidation and Ag ion release. AgNPs were coated with a hybrid lipid membrane comprised of L-phosphatidylcholine (PC), sodium oleate (SOA), and a stoichiometric amount of hexanethiol (HT) to produce oxidant-resistant AgNPs, Ag-SOA-PC-HT.

Supporting Biomedical Research Training for Historically Underrepresented Undergraduates Using Interprofessional, Nonformal Education Structures.

Research experience provides critical training for new biomedical research scientists. Students from underrepresented populations studying science, technology, engineering, and mathematics (STEM) are increasingly recruited into research pathways to diversify STEM fields. However, support structures outside of research settings designed to help these students navigate biomedical research pathways are not always available; nor are program support components outside the context of laboratory technical skills training and formal mentorship well understood.

Size-Dependent Interactions of Lipid-Coated Gold Nanoparticles: Developing a Better Mechanistic Understanding Through Model Cell Membranes and in vivo Toxicity.

Introduction: Humans are intentionally exposed to gold nanoparticles (AuNPs) where they are used in variety of biomedical applications as imaging and drug delivery agents as well as diagnostic and therapeutic agents currently in clinic and in a variety of upcoming clinical trials. Consequently, it is critical that we gain a better understanding of how physiochemical properties such as size, shape, and surface chemistry drive cellular uptake and AuNP toxicity in vivo. Understanding and being able to manipulate these physiochemical properties will allow for the production of safer and more efficacious use of AuNPs in biomedical applications.

A hybrid lipid membrane coating "shape-locks" silver nanoparticles to prevent surface oxidation and silver ion dissolution.

The controlled synthesis of stable silver nanoparticles (AgNPs), that do not undergo surface oxidation and Ag ion dissolution, continues to be a major challenge. Here the synthesis of robust hybrid lipid-coated AgNPs, comprised of l-α-phosphatidylcholine (PC) membranes anchored by a stoichiometric amount of long-chained hydrophobic thiols and sodium oleate (SOA) as hydrophobic binding partners, that do not undergo surface oxidation and Ag ion dissolution, is described. UV-Visible (UV-Vis) spectroscopy, transmission electron microscopy (TEM), and inductively coupled plasma mass spectrometry (ICP-MS) demonstrate that in the presence of strong oxidants, such as potassium cyanide (KCN), the hybrid lipid-coated AgNPs are stable and do not undergo surface oxidation even in the presence of membrane destabilizing surfactants.

The Impact of Surface Ligands and Synthesis Method on the Toxicity of Glutathione-Coated Gold Nanoparticles.

Gold nanoparticles (AuNPs) are increasingly used in biomedical applications, hence understanding the processes that affect their biocompatibility and stability are of significant interest. In this study, we assessed the stability of peptide-capped AuNPs and used the embryonic zebrafish () as a vertebrate system to investigate the impact of synthesis method and purity on their biocompatibility. Using glutathione (GSH) as a stabilizer, Au-GSH nanoparticles with identical core sizes were terminally modified with Tryptophan (Trp), Histidine (His) or Methionine (Met) amino acids and purified by either dialysis or ultracentrifugation.

A facile route to tailoring peptide-stabilized gold nanoparticles using glutathione as a synthon.

The preparation of gold nanoparticles (AuNPs) of high purity and stability remains a major challenge for biological applications. This paper reports a simple synthetic strategy to prepare water-soluble peptide-stabilized AuNPs. Reduced glutathione, a natural tripeptide, was used as a synthon for the growth of two peptide chains directly on the AuNP surface.

C-reactive protein induced rearrangement of phosphatidylcholine on nanoparticle mimics of lipoprotein particles.

Lipid-coated metal nanoparticles are developed here as a mimic of low-density lipoprotein (LDL) particles and used to study C-reactive protein (CRP) binding to highly curved lipid membranes. A 12 nm shift in the localized surface plasmon resonance (LSPR) was observed when CRP was added to the lipid-coated gold nanoparticles. Transmission electron microscopy (TEM) revealed that CRP induced a structural change to the lipids, resulting in clusters of nanoparticles.

Gold nanoparticles become stable to cyanide etch when coated with hybrid lipid bilayers.

Hybrid bilayers composed of the lipid phosphatidylcholine (PC) and a submonolayer of 1-decanethiol bound to gold nanoparticles are very stable to potassium cyanide.

Reversible, reagentless solubility changes in phosphatidylcholine-stabilized gold nanoparticles.

Phosphatidylcholine (PC) is a versatile ligand for synthesizing gold nanoparticles that are soluble in either organic or aqueous media. Here we report a novel route to organic-soluble, PC-stabilized gold nanoparticles that can be re-suspended in water after removal of the organic solvent. Similarly, we show that PC-stabilized gold nanoparticles synthesized in water can be re-suspended in organic solvents after complete removal of water.