Multimodality Raman and photoacoustic imaging of surface-enhanced-Raman-scattering-targeted tumor cells.

A multimodality Raman and photoacoustic imaging system is presented. This system has ultralow background and can detect tumor cells labeled with modified surface-enhanced-Raman-scattering (SERS) nanoparticles in vivo. Photoacoustic imaging provides microvascular context and can potentially be used to guide magnetic trapping of circulating tumor cells for SERS detection in animal models.

Porphyrin Nanodroplets: Sub-micrometer Ultrasound and Photoacoustic Contrast Imaging Agents.

A novel class of all-organic nanoscale porphyrin nanodroplet agents is presented which is suitable for multimodality ultrasound and photoacoustic molecular imaging. Previous multimodality photoacoustic-ultrasound agents are either not organic, or not yet demonstrated to exhibit enhanced accumulation in leaky tumor vasculature, perhaps because of large diameters. In the current study, porphyrin nanodroplets are created with a mean diameter of 185 nm which is small enough to exhibit the enhanced permeability and retention effect.

RNA biomarker release with ultrasound and phase-change nanodroplets.

Microbubbles driven by ultrasound are capable of permeabilizing cell membranes and allowing biomarkers or therapeutics to exit from or enter cancer cells, respectively. Unfortunately, the relatively large size of microbubbles prevents extravasation. Lipid-based perfluorobutane microbubbles can be made seven-fold smaller by pressurization, creating 430-nm nanodroplets.

In-Vivo functional optical-resolution photoacoustic microscopy with stimulated Raman scattering fiber-laser source.

In this paper a multi-wavelength optical-resolution photoacoustic microscopy (OR-PAM) system using stimulated Raman scattering is demonstrated for both phantom and in vivo imaging. A 1-ns pulse width ytterbium-doped fiber laser is coupled into a single-mode polarization maintaining fiber. Discrete Raman-shifted wavelength peaks extending to nearly 800 nm are generated with pulse energies sufficient for OR-PAM imaging.

Multifocus optical-resolution photoacoustic microscopy using stimulated Raman scattering and chromatic aberration.

In this Letter, multifocus optical-resolution photoacoustic microscopy is demonstrated using wavelength tuning and chromatic aberration for depth scanning. Discrete focal zones at several depth locations were created by refocusing light from a polarization-maintaining single-mode fiber pumped by a nanosecond fiber laser. The fiber and laser parameters were chosen to take advantage of stimulated Raman scattering (SRS) in the fiber to create a multiwavelength output that could then be bandpass filtered.

In vivo dynamic process imaging using real-time optical-resolution photoacoustic microscopy.

The authors demonstrate in vivo dynamic process imaging using a label-free real-time optical-resolution photoacoustic microscope (OR-PAM). This reflection-mode system takes advantage of a 532-nm fiber laser source with a high pulse repetition rate of up to 600 kHz combined with a fast-scanning mirror system. Microvasculature in SCID mouse ears is imaged at near real-time (0.

In vivo near-realtime volumetric optical-resolution photoacoustic microscopy using a high-repetition-rate nanosecond fiber-laser.

Optical-resolution photoacoustic microscopy (OR-PAM) is capable of achieving optical-absorption-contrast images with micron-scale spatial resolution. Previous OR-PAM systems have been frame-rate limited by mechanical scanning speeds and laser pulse repetition rate (PRR). We demonstrate OR-PAM imaging using a diode-pumped nanosecond-pulsed Ytterbium-doped 532-nm fiber laser with PRR up to 600 kHz.

Tyrosinase as a dual reporter gene for both photoacoustic and magnetic resonance imaging.

Reporter genes are useful scientific tools for analyzing promoter activity, transfection efficiency, and cell migration. The current study has validated the use of tyrosinase (involved in melanin production) as a dual reporter gene for magnetic resonance and photoacoustic imaging. MCF-7 cells expressing tyrosinase appear brown due to melanin.