title: Molecularly stabilised ultrasmall gold nanoparticles: synthesis, characterization and bioactivity.
abstract: Gold nanoparticles (AuNPs) are widely used as contrast agents in electron microscopy as well as for diagnostic tests. Due to their unique optical and electrical properties and their small size, there is also a growing field of potential applications in medical fields of imaging and therapy, for example as drug carriers or as active compounds in thermotherapy. Besides their intrinsic optical properties, facile surface decoration with (bio)functional ligands renders AuNPs ideally suited for many industrial and medical applications. However, novel AuNPs may have toxicological profiles differing from bulk and therefore a thorough analysis of the quantitative structure-activity relationship (QSAR) is required. Several mechanisms are proposed that cause adverse effects of nanoparticles in biological systems. Catalytic generation of reactive species due to the large and chemically active surface area of nanomaterials is well established. Because nanoparticles approach the size of biological molecules and subcellular structures, they may overcome natural barriers by active or passive uptake. Ultrasmall AuNPs with sizes of 2 nm or less may even behave as molecular ligands. These types of potential interactions would imply a size and ligand-dependent behaviour of any nanomaterial towards biological systems. Thus, to fully understand their QSAR, AuNPs bioactivity should be analysed in biological systems of increasing complexity ranging from cell culture to whole animal studies.
authors.affiliation: RWTH Aachen University, Helmholtz Institute for Biomedical Engineering, Biointerface Laboratory, Pauwelsstrasse 30, 52074 Aachen, Germany.
authors.forename: Annika
authors.initials: A
authors.lastname: Leifert
authors.forename: Yu
authors.initials: Y
authors.lastname: Pan-Bartnek
authors.forename: Ulrich
authors.initials: U
authors.lastname: Simon
authors.forename: Willi
authors.initials: W
authors.lastname: Jahnen-Dechent
mesh_terms: D000818:Animals; D001812:Blood-Brain Barrier / Q000378:metabolism; D003287:Contrast Media / Q000138:chemical synthesis* / Q000493:pharmacokinetics / Q000627:therapeutic use; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004337:Drug Carriers / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007473:Ion Channels / Q000737:chemistry / Q000378:metabolism; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000627:therapeutic use; D009369:Neoplasms / Q000188:drug therapy; D021281:Quantitative Structure-Activity Relationship; D014018:Tissue Distribution
chemical_list: D003287:Contrast Media; D004337:Drug Carriers; D007473:Ion Channels; D006046:Gold; D004247:DNA