Detection of pH-induced aggregation of "smart" gold nanoparticles with photothermal optical coherence tomography

Peng Xiao, Qingyun Li, Yongjoon Joo, Jutaek Nam, Sekyu Hwang, Jaejung Song, Sungjee Kim, Chulmin Joo, Ki Hean Kim

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

We report the feasibility of a novel contrast agent, namely "smart" gold nanoparticles (AuNPs), in the detection of cancer cells with photothermal optical coherence tomography (PT-OCT). "Smart" AuNPs form aggregation in low pH condition, which is typical for cancer cells, and this aggregation results in a shift of their absorption spectrum. A PT-OCT system was developed to detect this pH-induced aggregation by combining an OCT light source and a laser with 660 nm in wavelength for photothermal excitation. Optical detection of pH-induced aggregation was tested with solution samples at two different pH conditions. An increase in optical path length (OPL) variation was measured at mild acidic condition, while there was not much change at neutral condition. Detection of cancer cells was tested with cultured cell samples. HeLa and fibroblast cells, as cancer and normal cells respectively, were incubated with "smart" gold nanoparticles and measured with PT-OCT. An elevated OPL variation signal was detected with the HeLa cells while not much of a signal was detected with the fibroblast cells. With the novel optical property of "smart" AuNPs and high sensitivity of PT-OCT, this technique is promising for cancer cell detection.

Original languageEnglish
Pages (from-to)4429-4432
Number of pages4
JournalOptics Letters
Volume38
Issue number21
DOIs
Publication statusPublished - 2013 Nov 1

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics

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