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Updated: Mar 27, 2026
Preparation and Photoacoustic Analysis of Cellular Vehicles Containing Gold Nanorods
Published on: May 2, 2016
Macrophage with gold nanorod visualized by optical-resolution and acoustic-resolution photoacoustic microscopes
Abstract:
Macrophages play a key role in inflammation and they are frequently observed in vulnerable atherosclerotic plaque. In the present study, macrophages phagocytosing gold nanorod (AuNR) were observed by optical-resolution (OR) and acoustic-resolution (AR) photoacoustic microscope (PAM). The OR-PAM consisted of diode laser optically focused to 60 micron and planar ultrasonic transducer with the central frequency of 8 MHz placed under the object. AR-PAM consisted of concave ultrasonic transducer with the central frequency of 20 MHz and optical fiber through the center hole of the transducer for laser irradiation. First, PA signal from gold, silver and copper wire were measured in order to determine the best metal substrate for enhancing PA contrast. Gold generated largest PA signal. AuNR with the resonance wavelength of 1064 nm was co-cultured with the macrophages for phagocytosis. PA signal was successfully detected from macrophages with AuNR by both OR-PAM and AR-PAM. PA imaging of the macrophages with AuNR indicates inflammation in the vulnerable plaque and AR-PAM method would be applicable for clinical settings.
Insights
Macrophages engulfing gold nanorods (AuNR) were imaged using photoacoustic microscopy (PAM). This technique shows potential for detecting inflammation in vulnerable atherosclerotic plaque, aiding in clinical diagnostics.
Area of Science:
- Biomedical Imaging
- Nanotechnology
- Cardiovascular Research
Background:
- Macrophages are crucial in inflammation and prevalent in vulnerable atherosclerotic plaques.
- Photoacoustic microscopy (PAM) offers a non-invasive imaging modality.
Purpose of the Study:
- To investigate the use of gold nanorods (AuNR) as contrast agents for PAM.
- To evaluate optical-resolution (OR) and acoustic-resolution (AR) PAM for imaging macrophages with AuNR.
- To assess the potential for detecting inflammation in atherosclerotic plaques.
Main Methods:
- Compared PA signal from gold, silver, and copper substrates, with gold yielding the highest signal.
- Co-cultured macrophages with AuNR (1064 nm resonance wavelength) for phagocytosis.
- Utilized OR-PAM (60 micron optical focus, 8 MHz transducer) and AR-PAM (20 MHz transducer, integrated fiber optics).
Main Results:
- Successfully detected PA signals from macrophages containing AuNR using both OR-PAM and AR-PAM.
- Gold nanorods demonstrated superior PA contrast enhancement.
- PA imaging visualized AuNR-laden macrophages, indicative of inflammation.
Conclusions:
- Gold nanorods are effective contrast agents for PAM imaging of macrophages.
- AR-PAM shows promise for clinical applications in detecting inflammation associated with vulnerable atherosclerotic plaque.
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