Study provides insight into how nanoparticles interact with biological systems

Northwestern Now: Summaries

Personal electronic devices — smartphones, computers, TVs, tablets, screens of all kinds — are a significant and growing source of the world’s electronic waste. Many of these products use nanomaterials, but little is known about how these modern materials and their tiny particles interact with the environment and living things. Now a research team of Northwestern University chemists and colleagues from the national Center for Sustainable Nanotechnologyhas discovered that when certain coated nanoparticles interact with living organisms it results in new properties that cause the nanoparticles to become sticky. Fragmented lipid coronasform on the particles, causing them to stick together and grow into long kelp-like strands. Nanoparticles with 5-nanometer diameters form long structures that are microns in size in solution. The impact on cells is not known. “Why not make a particle that is benign from the beginning?” said Franz M. Geiger, professor of chemistry in Northwestern’s Weinberg College of Arts and Sciences. He led the Northwestern portion of the research.“This study provides insight into the molecular mechanisms by which nanoparticles interact with biological systems,” Geiger said. “This may help us understand and predict why some nanomaterial/ligand coating combinations are detrimental to cellular organisms while others are not. We can use this to engineer nanoparticles that are benign by design.”Why not make a particle that is benign from the beginning?”Franz GeigerchemistUsing experiments and computer simulations, the research team studied polycation-wrapped gold nanoparticles and their interactions with a variety of bilayer membrane models, including bacteria. The researchers found that a nearly circular layer of lipids forms spontaneously around the particles. These “fragmented lipid coronas” have never been seen before. The study points to solving problems with chemistry. Scientists can use the findings to design a better ligand coating for nanoparticles that avoids the ammonium-phosphate interaction, which causes the aggregation. (Ligands are used in nanomaterials for …

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