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Updated: Jun 9, 2026
Synthesis of Near-Infrared Emitting Gold Nanoclusters for Biological Applications
Published on: March 22, 2020
Preparation of near-infrared light absorbing gold nanoparticles using polyethylene glycol-attached dendrimers
Chie Kojima1, Yasuhito Umeda, Atsushi Harada
1Nanoscience and Nanotechnology Research Center, Research Organization for the 21st Century, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8570, Japan. c-kojima@21c.osakafu-u.ac.jp
Abstract:
The photochemical properties of gold nanoparticles (Au NPs) are largely influenced by their size and morphology. Stably dispersed Au NPs that absorb near-infrared (NIR) light are useful for biomedical applications. We prepared well-dispersed NIR-absorbing Au NPs using seeding growth from Au NPs encapsulated in polyethylene glycol (PEG)-attached dendrimers. Formaldehyde was used as a reductant to prepare gold nanoparticles with convex-concave surfaces. Low pH and an appropriate amount of gold ion were required to prepare Au NPs that absorbed NIR-light. Interestingly, the encapsulation of Au NPs within the PEGylated dendrimers was important for preparation of NIR-absorbing Au NPs. Transmission electron microscope (TEM) analysis showed that these Au NPs had convex-concave surfaces and large diameters. This paper presents a novel preparation method for NIR-responsive Au NPs by reduction with formaldehyde.
