Photothermal detection of gold nanoparticles using phase-sensitive optical coherence tomography

• Published in: Optics express Vol. 16; no. 7; pp. 4376 - 4393
• Main Authors: Adler, Desmond C, Huang, Shu-Wei, Huber, Robert, Fujimoto, James G
• Format: Journal Article
• Language: English
• Published: United States 31.03.2008
• Subjects: Gold - analysis; Image Enhancement - methods; Lasers; Nanoparticles - ultrastructure; Phantoms, Imaging; Reproducibility of Results; Sensitivity and Specificity; Temperature; Tomography, Optical Coherence - instrumentation; Tomography, Optical Coherence - methods
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/oe.16.004376

The detection of a gold nanoparticle contrast agent is demonstrated using a photothermal modulation technique and phase sensitive optical coherence tomography (OCT). A focused beam from a laser diode at 808 nm is modulated at frequencies of 500 Hz-60 kHz while irradiating a solution containing nanoshells. Because the nanoshells are designed to have a high absorption coefficient at 808 nm, the laser beam induces small-scale localized temperature oscillations at the modulation frequency. These temperature oscillations result in optical path length changes that are detected by a phase-sensitive, swept source OCT system. The OCT system uses a double-buffered Fourier domain mode locked (FDML) laser operating at a center wavelength of 1315 nm and a sweep rate of 240 kHz. High contrast is observed between phantoms containing nanoshells and phantoms without nanoshells. This technique represents a new method for detecting gold nanoparticle contrast agents with excellent signal-to-noise performance at high speeds using OCT.