Showing papers by "Xingde Li published in 2008"
TL;DR: It was found that cells targeted with the immuno Au nanocages responded immediately to laser irradiation and that the cellular damage was irreversible at power densities greater than 1.6 W/cm(2), and the percentage of dead cells increased with increasing exposure time up to 5 min and then became steady.
Abstract: Gold nanocages with an average edge length of 65 +/- 7 nm and a strong absorption peak at 800 nm were conjugated with monoclonal antibodies (anti-HER2) to target breast cancer cells (SK-BR-3) through the epidermal growth factor receptor (in this case, HER2), which is overexpressed on the surfaces of the cells. Both the number of immuno Au nanocages immobilized per cell and the photothermal therapeutic effect were quantified using flow cytometry. The targeted cells were irradiated with a pulsed near-infrared laser, and by varying the power density, the duration of laser exposure, and the time of response after irradiation, we were able to optimize the treatment conditions to achieve effective destruction of the cancer cells. We found that cells targeted with the immuno Au nanocages responded immediately to laser irradiation and that the cellular damage was irreversible at power densities greater than 1.6 W/cm(2). The percentage of dead cells increased with increasing exposure time up to 5 min and then became steady. By quantifying the photothermal effect of immuno Au nanocages, critical information with regards to both the optimal dosage of nanocages and parameters of the laser irradiation has been garnered and will be applied to future in vivo studies.
310 citations
TL;DR: This system has the potential to greatly improve near-infrared imaging in breast cancer detection by increasing the stability of ICG for formulation/administration, and by providing a means to target ICG to tumor tissue.
Abstract: Indocyanine green (ICG) is a Federal Drug Administration-approved near-infrared imaging agent susceptible to chemical degradation, nonspecific binding to blood proteins, and rapid clearance from the body. In this study, we describe the encapsulation of ICG within polymeric micelles formed from poly(styrene-alt-maleic anhydride)-block-poly(styrene) (PSMA-b-PSTY) diblock copolymers to stabilize ICG for applications in near-infrared diagnostic imaging. In aqueous solution, the diblock copolymers self-assemble to form highly stable micelles approximately 55 nm in diameter with a critical micelle concentration (CMC) of approximately 1 mg/L. Hydrophobic ICG salts readily partition into the PSTY core of these micelles with high efficiency, and produce no change in micelle morphology or CMC. Once loaded in the micelle core, ICG is protected from aqueous and thermal degradation, with no significant decrease in fluorescence emission over 14 days at room temperature and retaining 63% of its original emission at 37 degrees C. Free ICG does not release rapidly from the micelle core, with only 11% release over 24 h. The ICG-loaded micelles do not exhibit significant cell toxicity. This system has the potential to greatly improve near-infrared imaging in breast cancer detection by increasing the stability of ICG for formulation/administration, and by providing a means to target ICG to tumor tissue.
131 citations
Patent•
02 May 2008TL;DR: In this paper, the optical assembly is encapsulated in a glass housing or metal-like housing with a glass window, which is then selectively passed through a hollow needle for needle biopsy.
Abstract: Mechanically robust minimal form factor OCT probes suitable for medical applications such as needle biopsy, intraluminal and intravascular imaging are achieved in part by employing compound lenses with some or all of the optical elements, including an optical fiber, to be thermally fused in tandem. To achieve a desired working distance without increasing a diameter of the optics assembly, a spacer can be disposed between the optical fiber and focusing optics. The compound lens configuration can achieve higher transverse resolution compared to a single lens at a desired working distance without increasing the probe diameter. In exemplary needle biopsy embodiments, the optical assembly is encapsulated in a glass housing or metal-like housing with a glass window, which is then selectively passed through a hollow needle. Esophageal imaging embodiments are combined with a balloon catheter. Circumferential and three-dimensional spiral scanning can be achieved in each embodiment.
93 citations
TL;DR: The compound lens design significantly simplifies the engineering process for an OCT catheter and enables 3-D full circumferential cross sectional imaging of large luminal organs such as human esophagus.
Abstract: We report on a new optics design for an optical coherence tomography (OCT) balloon imaging catheter. The design involves a miniature compound gradient-index (GRIN) rod lens, which consists of a fiber optic mode-field reducer and relay rod lenses to achieve predictable high lateral resolution at a desired large working distance. The compound lens design significantly simplifies the engineering process for an OCT catheter and enables 3-D full circumferential cross sectional imaging of large luminal organs such as human esophagus. An as-designed OCT catheter is developed and demonstrated for real-time in vivo swine esophagus imaging in a 3-D spiral fashion.
59 citations
TL;DR: The results of the feasibility study show that UHR-OCT can provide superb, in situ microstructural characterization of eye bank corneal tissue noninvasively and has the potential to become a routine part of tissue analysis for any eye bank or centers creating customized lamellar corneale tissue for transplantation.
Abstract: Purpose:To use optical coherence tomography (OCT) as a noninvasive tool to perform in situ characterization of eye bank corneal tissue processed for lamellar keratoplasty.Methods:A custom-built ultrahigh-resolution OCT (UHR-OCT) was used to characterize donor corneal tissue that had been processed f
22 citations
TL;DR: The micellar formation indocyanine green (ICG) nano complex has a small size, low cytotoxicity and low critical micelle concentration, and significantly improves ICG thermal and photostability.
Abstract: We report micellar formation indocyanine green (ICG) nano complex. The nano-complex has a small size (30-40nm), low cytotoxicity and low critical micelle concentration (1 mg/L), and significantly improves ICG thermal and photostability.
8 citations
TL;DR: OCT enables optical biopsy, imaging tissue pathology in situ and in real time, and is finding increasing clinical applications ranging from ophthalmology to intravascular imaging.
Abstract: Optical coherence tomography (OCT) enables imaging of tissue pathology in situ and in real time. Using ultrashort pulse lasers, ultrahigh resolutions of -1 μm as well as spectroscopic imaging are possible. OCT can function as a type of optical biopsy because it enables imaging tissue microstructure in situ without the need to excise and process a specimen as in conventional histopathology. OCT can be used to image pathology in tissues where biopsy is impossible.
2 citations
TL;DR: In this paper, spectral-domain optical coherence tomography was used to monitor blood flow in and around the wound bed during the cutaneous wound healing process in a mouse model.
Abstract: We show that spectral-domain optical coherence tomography can monitor blood flow in and around the wound bed during the cutaneous wound healing process in a mouse model.
1 citations
TL;DR: In this paper, a scanning fiber-optic miniature endomicroscope system was developed for tissue nonlinear optical imaging of rat tail tendon and skin/hair for real-time two-photon fluorescence and SHG imaging.
Abstract: A scanning fiber-optic miniature endomicroscope system was developed for tissue nonlinear optical imaging. Real-time two-photon fluorescence and SHG imaging of rat tail tendon and skin/hair was demonstrated for the first time with the fiber-optic endomicroscope.
1 citations
14 Oct 2008
TL;DR: The depth-resolved imaging results strongly suggest the potential of this flexible fiber-optic microscope system for real-time assessment of both epithelial and stromal structures in luminal organs.
Abstract: A flexible fiber-optic endomicroscopy system was developed for nonlinear optical imaging of biological samples. Double-clad fiber and photonic bandgap fiber were employed in the endomicroscope for femtosecond pulse delivery, dispersion compensation, nonlinear optical signals collection and fast beam scanning. Three-dimensional imaging of biological tissues based on second harmonic generation and two-photon excited fluorescence was performed with the endomicroscope. The depth-resolved imaging results strongly suggest the potential of this flexible fiber-optic microscope system for real-time assessment of both epithelial and stromal structures in luminal organs.
1 citations