A ggregation-induced emission nanoparticles for in vivo three-photon fuorescence microscopic rat brain angiography

Rodents are popular biological models for physiological and behavioral research in neuroscience and rats are better models than mice due to their higher genome similarity to human and more accessible surgical procedures.However,rat brain is larger than mice brain and it needs powerful imaging tools to implement better penetration against the scattering of the thicker brain tissue.Three-photon fluorescence microscopy(3PFM)combined with near-infrared(NIR)excitation has great potentials for brain circuits imaging beause of its abilities of anti scattering,deep-tissue imaging,and high signal-to-noise ratio(SNR).In this work,a type of AIE lumninogen with red fuorescence was synthesized and encapsulated with Pluronic F-127 to make up form nano-particles(NPs).Bright DCDPP-2TPA NPs were employed for in trino three-photon fuorescent laser scanning microscopy of blood vessels in rats brain under 1550 nm femtosecond laser exci-tation.A fine three-dimensional(3D)reconstruction up to the deepness of 600 pm was achieved and the blood flow velocity of a selected vessel was measured in vrito as well.Our 3PFM deep brain imaging method simultaneously recorded the morphology and function of the brain blood vessels in vivo in the rat model.Using this angiography combined with the arsenal of rodent's brain disease,models can accelerate the neuroscience research and clinical diagnosis of brain disease in the future.

GASTROINTESTINAL ABNORMALITIES IDENTIFIED BY FLUORESCENCE ENDOMICROSCOPY

Real-tine in vivo microscopic imaging has becomne a reality with the advent of confocal and nonlinear endomicroscopy.These devices are best utilized in conjunction with standard white light endoscopy.We evaluated the use of fuorescence endomicroscopy in detecting microscopic abnormalities in colonic tisues.Mice of C57bl/6 strain had intraperitoneal injection with azoxymethane once every week for five weeks and littermates,not exposed to azoxymethane served as controls.After 14 weeks,intestines were imaged by fuorescence endomicroscopy.The images show obvious cellular structural diferences between those two groups of mice.The difference in endomicroscopy imaging can be used for identifying tissues suspicious for neoplasia or other changes,leading to early diagnosis of gastrointestinal track of cancer.

Synthesis and Nonlinear Optical Characterization of a New Two-photon Absorbing Organic Dye: DMAHAS

Trans 4 ( N,N ′ dimethyl amino) 4′ ( N 2 hydroxyethyl N ′ ethyl amino)stilbene (DMAHAS) has been synthesized and characterized by 1H NMR spectra, IR spectra and elemental analysis. Linear absorption, single photon induced fluorescence and two photon induced fluorescence were experimentally studied. This new dye has a moderate two photon absorption cross section of σ 2=0.91×10 -46 cm 4·s/photon at 532 nm by using an open aperture Z scan technique. The result indicates that DMAHAS shows a strong two photon induced blue fluorescence of 432 nm when pumped with 800 nm laser irradiation.

Synthesis and Properties of a New Two-photon-absorbed Material DMAEAS

Trans 4 (N,N ′ dimethyl amino) 4′ ( N,N′ diethyl amino) stilbene (DMAEAS) has been synthesized and characterized by 1H NMR spectra, IR spectra, and elemental analyses. Its linear absorption, single photon induced fluorescence and two photon induced fluorescence are experimentally studied. This new dye has a great two photon absorption (TPA) cross section of σ 2=1 16×10 -46 cm 4·s/photon at 532 nm by using an open aperture Z scan system. When pumped with 800 nm laser irradiation, DMAEAS shows a strong two photon induced blue fluorescence of 440 nm.