title: Visualization of molecular composition and functionality of cancer cells using nanoparticle-augmented ultrasound-guided photoacoustics.
abstract: Assessment of molecular signatures of tumors in addition to their anatomy and morphology is desired for effective diagnostic and therapeutic procedures. Development of in vivo imaging techniques that can identify and monitor molecular composition of tumors remains an important challenge in pre-clinical research and medical practice. Here we present a molecular photoacoustic imaging technique that can visualize the presence and activity of an important cancer biomarker - epidermal growth factor receptor (EGFR), utilizing the effect of plasmon resonance coupling between molecular targeted gold nanoparticles. Specifically, spectral analysis of photoacoustic images revealed profound changes in the optical absorption of systemically delivered EGFR-targeted gold nanospheres due to their molecular interactions with tumor cells overexpressing EGFR. In contrast, no changes in optical properties and, therefore, photoacoustic signal, were observed after systemic delivery of non-targeted gold nanoparticles to the tumors. The results indicate that multi-wavelength photoacoustic imaging augmented with molecularly targeted gold nanoparticles has the ability to monitor molecular specific interactions between nanoparticles and cell-surface receptors, allowing visualization of the presence and functional activity of tumor cells. Furthermore, the approach can be used for other cancer cell-surface receptors such as human epidermal growth factor receptor 2 (HER2). Therefore, ultrasound-guided molecular photoacoustic imaging can potentially aid in tumor diagnosis, selection of customized patient-specific treatment, and monitor the therapeutic progression and outcome in vivo.
authors.affiliation: Department of Biomedical Engineering, University of Texas at Austin, Austin, TX 78712, United States.
authors.forename: Srivalleesha
authors.initials: S
authors.lastname: Mallidi
authors.affiliation: Department of Biomedical Engineering, University of Texas at Austin, Austin, TX 78712, United States.
authors.forename: Seungsoo
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Biomedical Engineering, University of Texas at Austin, Austin, TX 78712, United States.
authors.forename: Andrei
authors.initials: A
authors.lastname: Karpiouk
authors.affiliation: Department of Biomedical Engineering, University of Texas at Austin, Austin, TX 78712, United States.
authors.forename: Pratixa P
authors.initials: PP
authors.lastname: Joshi
authors.affiliation: Department of Biomedical Engineering, University of Texas at Austin, Austin, TX 78712, United States ; Department of Imaging Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, United States.
authors.forename: Konstantin
authors.initials: K
authors.lastname: Sokolov
authors.affiliation: Department of Biomedical Engineering, University of Texas at Austin, Austin, TX 78712, United States ; Department of Electrical and Computer Engineering, University of Texas at Austin, Austin, TX 78712, United States ; Department of Imaging Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, United States.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Emelianov
keywords: AuNPs, gold nanoparticles; EGFR, epidermal growth factor receptor; Epidermal growth factor receptor; Gold nanoparticles; Molecular imaging; Multi-wavelength imaging; PA, photoacoustic; Photoacoustic imaging; Three-dimensional imaging