Overview on the Use of This Module
This module is designed to guide students to investigate gold nanoparticles, their synthesis and optical properties, with the goal of identifying experimental conditions that lead to the synthesis of nearly monodisperse gold nanoparticles for sensor development applications.
The module is designed as a sequence of class activities and provides a set of experimental data (TEM images, size and size distribution analyses, and absorbance vs. concentration data) that can be downloaded from this site. Additional TEM images are available upon request from the instructor. Alternatively, if the instructor has access to a transmission electron microscope and a UV-VIS spectrophotometer, the module could be used in the context of a lab experiment where students, divided in groups of 2 or 3, can conduct gold nanoparticle syntheses exploring different experimental parameters. The lab outcome would be a comparison of optical properties for gold nanoparticles synthesized under different conditions of reagents ratio and pH.
Whether conducted as class activity or actual experimental lab, the instructor should ensure that students receive instructions for chemical safety and hazardous material handling (refer to SDS for each chemical). Safety goggles, lab coats and gloves should be worn when performing the activity in a lab setting.
The materials are designed to be modular in their format and used relatively independently. They can also be implemented at different levels of guidance to students. For example, instructors in a general chemistry course could provide students with more detailed instructions on the synthesis and characterization of gold nanoparticles while students in an upper division course may be asked to explore the literature, develop the experimental procedure for the synthesis and fine tune experimental conditions and instrumental parameters if a TEM and/or a UV-VIS spectrophotometer are used.
Students are first introduced to the nano dimension and relevance of nanoparticles in the area of optical sensors development. They are then guided to explore fundamental relationships in spectrophotometry which will be used later in the module to determine the molar extinction coefficient of different sizes of nanoparticles. Depending on the level of preparation, the instructor may choose to provide additional information on gold nanoparticle structure and properties and familiarize students with UV-VIS spectroscopy and use of instrumentation, if available.
Answers to Questions
The following section provides answers to the questions interdispersed in subsections of the module. A brief introduction to the nano dimension and relevance of nanoparticles in the area of optical sensors development is provided. Depending on the level of preparation, the instructor may choose to provide additional information on gold nanoparticle structure and properties.