title: Gold nanoparticle surface  functionalization: mixed monolayer versus  hetero bifunctional peg linker.
abstract: To create a clinically relevant gold nanoparticle (AuNP) treatment, the surface must be functionalized with multiple ligands such as drugs, antifouling agents and targeting moieties. However, attaching several ligands of differing chemistries and lengths, while ensuring they all retain their biological functionality remains a challenge. This review compares the two most widely employed methods of surface cofunctionalization, namely mixed monolayers and hetero-bifunctional linkers. While there are numerous in vitro studies successfully utilizing both surface arrangements, there is little consensus regarding their relative merits. Animal and preclinical studies have demonstrated the effectiveness of mixed monolayer functionalization and while some promising in vitro results have been reported for PEG linker capped AuNPs, any potential benefits of the approach are not yet fully understood.
authors.forename: Emma
authors.initials: E
authors.lastname: Harrison
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Coulter
authors.forename: Dorian
authors.initials: D
authors.lastname: Dixon
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D006046:Gold / Q000737:chemistry* / Q000378:metabolism / Q000633:toxicity; D006801:Humans; D008024:Ligands; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000633:toxicity; D050997:Nanomedicine / Q000379:methods; D036103:Nanotechnology / Q000379:methods*; D011092:Polyethylene Glycols / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D008024:Ligands; D011092:Polyethylene Glycols; D006046:Gold