title: Plasmonic Nanoparticles with Quantitatively Controlled Bioconjugation for Photoacoustic Imaging of Live Cancer Cells.
abstract: Detection and imaging of single cancer cells is critical for cancer diagnosis and understanding of cellular dynamics. Photoacoustic imaging (PAI) provides a potential tool for the study of cancer cell dynamics, but faces the challenge that most cancer cells lack sufficient endogenous contrast. Here, a type of colloidal gold nanoparticles (AuNPs) are physically fabricated and are precisely functionalized with quantitative amounts of functional ligands (i.e., polyethyleneglycol (PEG) and (Arginine(R)-Glycine(G)-Aspartic(D))4(RGD) peptides) to serve as an exogenous contrast agent for PAI of single cells. The functionalized AuNPs, with a fixed number of PEG but different RGD densities, are delivered into human prostate cancer cells. Radioactivity and photoacoustic analyses show that, although cellular uptake efficiency of the AuNPs linearly increases along with RGD density, photoacoustic signal generation efficiency does not and only maximize at a moderate RGD density. The functionalization of the AuNPs is in turn optimized based on the experimental finding, and single cancer cells are imaged using a custom photoacoustic microscopy with high-resolution. The quantitatively functionalized AuNPs together with the high-resolution PAI system provide a unique platform for the detection and imaging of single cancer cells, and may impact not only basic science but also clinical diagnostics on a range of cancers.
authors.affiliation: Department of Biomedical Engineering University of Michigan Ann Arbor MI 48109 USA.
authors.forename: Chao
authors.initials: C
authors.lastname: Tian
authors.affiliation: IMRA America, Inc Ann Arbor MI 48105 USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Qian
authors.affiliation: Department of Radiology University of Michigan Ann Arbor MI 48109 USA.
authors.forename: Xia
authors.initials: X
authors.lastname: Shao
authors.affiliation: Department of Radiology University of Michigan Ann Arbor MI 48109 USA.
authors.forename: Zhixing
authors.initials: Z
authors.lastname: Xie
authors.affiliation: Department of Urology University of Michigan Ann Arbor MI 48109 USA.
authors.forename: Xu
authors.initials: X
authors.lastname: Cheng
authors.affiliation: College of Physical Science and Technology Heilongjiang University Harbin 150080 China.
authors.forename: Shengchun
authors.initials: S
authors.lastname: Liu
authors.affiliation: Institute of Acoustics Tongji University Shanghai 200092 China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Cheng
authors.affiliation: IMRA America, Inc Ann Arbor MI 48105 USA.
authors.forename: Bing
authors.initials: B
authors.lastname: Liu
authors.affiliation: Department of Biomedical Engineering University of Michigan Ann Arbor MI 48109 USA; Department of Radiology University of Michigan Ann Arbor MI 48109 USA; Institute of Acoustics Tongji University Shanghai 200092 China.
authors.forename: Xueding
authors.initials: X
authors.lastname: Wang
keywords: cancer cells; photoacoustic imaging; plasmonic nanoparticles; quantitative bioconjugation