Background and objectives: We tagged melanoma cells with gold nanoparticles to show their viability for increasing sensitivity in a photoacoustic detection system. Ultimately, this study models the detection of circulating tumor cells, which are an important prognostic factor in the progress of melanoma.
Study design/materials and methods: A Q-switched, tunable Nd:YAG laser was used to irradiate cells in both a stationary and flow set-up. Photoacoustic signals were measured using a polyvinylidene fluoride (PVDF) film in the stationary test, and a commercially available ultrasonic probe for flow tests. Both unmodified melanoma cells and gold nanoparticle (AuNP) tagged melanoma were tested.
Results: AuNP tagged melanoma in a stationary set-up showed an average of 0.227 mV/mJ larger signal than the untagged, indicating a signal increase of 34%. At 500 nm there is a maximum difference of 0.295 mV/mJ, or a 41% increase. In flow tests, the ultrasound probe was able to detect single cells, but the increased signal from AuNP tagging was minimal.
Conclusion: AuNP tagging proved to give an increased photoacoustic signal allowing greater sensitivity in stationary metastasized melanoma detection systems using photoacoustics.
Copyright © 2011 Wiley-Liss, Inc.