Synthesis and surface modifications for functionalization of gold nanoparticles

Abstract

With multiple synthesis methods and varying characteristics, gold nanoparticles (AuNPs) are desired for a wide range of applications. There are a variety of chemical processes through which AuNPs can be synthesized, such as the Turkevich-Frens method, Brust–Schiffrin method and ionic liquids. The Turkevich-Frens approach is the most frequently employed; however, it is constrained by capacity limitations, permitting the production of only a modest quantity of AuNPs per batch. The Brust-Schiffrin method, while producing smaller AuNPs with a more uniform size distribution, has been critiqued for its complexity. Meanwhile, the ionic liquid method facilitates the synthesis of diverse shapes and sizes, yet it is susceptible to aggregation, which may adversely affect the synthesis process in unpredictable ways. AuNPs functionalization can be tailored to specific needs through modifying them with varying coating options. Surface coating of AuNPs can be achieved either during the synthesis process or later through secondary modifications. Both the chosen synthesis method and modifications influence application possibilities of AuNPs. AuNPs have been applied as drug carriers and biosensors. In the context of drug carriers, light and pH have been employed as mechanisms to initiate the discharge of drugs at the target site from the AuNPs surface. For biosensors, AuNPs have been used to detect the presence of varying molecules. The discussed synthesis and functionalization methods facilitate customization of AuNPs for specific applications, with focus on selecting appropriate methods based on desired properties.